The modification of the characteristics of nanocrystalline ZnO thin films by variation of Ta doping content

Thin films of Ta-doped ZnO were synthesised via sol–gel spin coating route. The structural and optical properties of the films were evaluated to find out the effect of Ta dopant content. X-ray diffraction results indicated that all samples have hexagonal wurtzite crystal structure with polycrystalline nature. (0 0 2) peak is the most intense peak observed in all samples as well as the highest textured coefficient. Standard deviation results have shown that the kind of nucleation varies from heterogeneous to homogenous with Ta doping content. Additionally, Ta-incorporated ZnO films revealed not only a decreased surface roughness, but also an increased optical transmittance. Direct optical band gap values increased from 3.14 to 3.28 eV, and Urbach energy values decreased from 217 to 147 meV with increasing Ta doping. Refractive index and dielectric constant values were determined by means of two different functions and a significant consistency was found among them. Moreover, the correlation between the optical and structural properties showed that there is a relationship between refractive index and lattice constants of Ta-doped ZnO films.     

Supergravity-induced interactions on thick branes

The gravity coupling of the symmetric space sigma model is studied in the solvable Lie algebra parametrization. The corresponding Einstein equations are derived and the energy-momentum tensor is calculated. The results are used to derive the dynamical equations of the warped five-dimensional （5D） geometry for localized bulk scalar interactions in the framework of thick brane world models. The Einstein and scalar field equations are derived for flat brane geometry in the context of minimal and non-minimal gravity-bulk scalar couplings.     

Light scattering by DNA structure due to phase transition

Modelling and numerical calculations of light scattering by the deoxyribonucleic acid (DNA) molecule were investigated using the transition matrix method at the phase transition region. In this model for a DNA molecule with helix structure, the electrical field was established and the transition matrix calculated for this field. Numerical computation of a simple cylindrical model, represented by adenine–thymine (A–T) and guanine–cytosine (G–C) formed with a lamellar-like helix, enabled important results to be obtained. These results were generalized for different molecular orientations with dielectric properties at the phase transition, which occurred due to the electric field changing. Finally, these results are associated with improved models for previous geometries.     

Highly Chemoselective Thiocarbonyl Oxidation upon Reaction of 4-Methyl-3-phenyl-2-thiazolidinethione with Singlet Oxygen

4-Methyl-3-phenyl-2-thiazolidinethione was reacted with both photochemically and chemically generated singlet oxygen. Despite reaction conditions which were selected to favor oxidation of the sulfide group, both reactions afforded a single product arising solely from thiocarbonyl oxidation.