We report the existence of a reversible first-order phase transition of BeS from the zinc-blende structure, B3, to the nickel-arsenide structure, B8, at 51 GPa with a volume change of 11%. The NiAs phase remains stable up to at least 96 GPa. A second-order Birch equation describes the equation of state of the B3 phase with B o ϭ105 GPa and B o Јϭ3.5. Preliminary studies of BeO to 66 GPa are described.

The present study explores the features of tetragonally stabilized polycrystalline zirconia nanophosphors prepared by a sonochemistry based synthesis from zirconium oxalate precursor complex. The sonochemically prepared pristine zirconia, 3 mol%, 5 mol% and 8 mol% yttrium doped zirconia nanophosphors were characterized using thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). The reaction mechanism of formation of zirconia nanophosphors is discussed in detail. The probable sonochemical formation mechanism is being proposed. Stabilization of tetragonal phase of pristine zirconia even at room temperature was effectively established by controlling the particle size using ultrasonic waves. Improved phase purity and good surface morphology of the nanophosphors is being achieved via sonochemical route. FE-SEM micrographs reveal that the nanoparticles have uniform spherical shape and size. The narrow particle size distribution (∼15-25 nm) of the zirconia nanoparticles was found from FE-SEM statistical analysis and further confirmed by TEM. Zirconia nanophosphors exhibit a wide energy band gap and which was found to vary with yttrium dopant concentration. The highlight of the present study is the synthesis of novel nanocrystalline ZrO₂ and Y-ZrO₂ phosphor which simultaneously emits extremely sharp as well as intense UV, violet and cyan light on exciting the host atom. The yttrium ion dopant further enhances the photoluminescence property of zirconia. These nanocrystalline phosphors are likely to have remarkable optical applications as light emitting UV-LEDs, UV lasers and multi color displays.

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The nanostructured material properties are different from the bulk materials. Nanofibers are widely studied for many applications like tissue engineering, wound dressings, electronics, storage, catalysts, protective clothing, sensors, and cosmetics. In this study, pure form of one-dimensional TiO2 nanofibers have been successfully obtained by electrospinning technique and TiO2 nanopowders are synthesized by a conventional Sol-Gel method followed by high temperature calcinations. The as-obtained products are characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-Ray (EDX) spectroscopy. The XRD results reveal the crystallite size of the synthesized material. SEM images depict the formation of nanopowders and nanofibers. EDX studies confirmed the presence of Ti and O in the prepared samples.