Surfactant mediated synthesis and characterization of Zinc Oxide nanoparticles

ZnO nanoparticles were prepared synthesized by using wet chemical route directly from an aqueous solution of zinc acetate dehydrate and in the presence of sodium dodecyl sulfate (SDS) and sodium hydroxide. ZnO is an interesting semiconductor material due to its application on solar cells, gas sensors, ceramics, catalysts, cosmetics. The as-synthesized Zn(OH)2powders were calcined at various temperatures of 500„aC, 650„aC, 800oC and 1000„aC. The materials prepared were characterized by DSC-TGA, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy. From the thermal studies the mass loss was found to be only 19%. Results show that the calcinations temperature significantly affected the crystalline nature, and optical properties of the processed ZnO nanoparticles. The XRD spectra indicate that the ZnO crystal has a hexagonal wurtzite structure. Zinc oxide showed excellent UV absorption and transparency in the visible region

Nuclear symmetry energy in a modified quark meson coupling model

We study nuclear symmetry energy and the thermodynamic instabilities of asymmetric nuclear matter in a self-consistent manner by using a modified quark-meson coupling model where the confining interaction for quarks inside a nucleon is represented by a phenomenologically averaged potential in an equally mixed scalar-vector harmonic form. The nucleon-nucleon interaction in nuclear matter is then realized by introducing additional quark couplings to $\sigma$, $\omega$, and $\rho$ mesons through mean-field approximations. We find an analytic expression for the symmetry energy ${\cal E}_{sym}$ as a function of its slope $L$. Our result establishes a linear correlation between $L$ and ${\cal E}_{sym}$. We also analyze the constraint on neutron star radii in $(pn)$ matter with $\beta$ equilibrium