Narrow Results

We have analyzed the light curves of 527 short gamma-ray bursts (GRBs) registered by the SPI-ACS, SPI and IBIS/ISGRI experiments of INTEGRAL observatory totally to search for precursors. Both the light curves of each 527 individual burst and the averaged light curve of 372 brightest SPI-ACS bursts have been analyzed. In a few cases, we have found and investigated precursor candidates using SPI-ACS, SPI and IBIS/ISGRI of INTEGRAL, GBM and LAT of Fermi data. No convincing evidence for the existence of precursors of short GRBs has been found. A statistical analysis of the averaged light curve for the sample of brightest short bursts has revealed no regular precursor. Upper limits for the relative intensity of precursors have been estimated. We show that the fraction of short GRBs with precursors is less than 0.4% of all short bursts, detected by INTEGRAL.

New materials nanocomposites were synthesized for the degradation of organic and inorganic pollutants. This study reviews CuO/SnO₂ nanocomposite thin films for their photocatalytic effect. The latter were deposited using the spray pyrolysis method, which is a simple, cheapest and rapid technique. Different concentration ratios of precursors and solvent are used. The thin films were deposited on ordinary glass substrates heated to 550^∘C from solutions of copper chloride and tin chloride as precursors. The optical and structural properties of nanocomposite thin films have been demonstrated, and the equi-percentage of the precursor combination shows the good bandgap energy according to the literature. Investigations of structural properties using (SEM, EDS, XRD and RAMAN) techniques depict the good agreement photocatalytic degradation according to the surface roughness, quantities of elements and the existence of phases which will be of interest to the photocatalytic of organic and inorganic pollutants in aqueous and gas media according to the huge specific area due to the roughness and heterogeneity.

This article gives an introduction to the principles and practices of high-resolution electron-beam-induced deposition (EBID). In EBID, a small focused electron beam is used to locally dissociate a precursor onto the surface of a substrate giving rise to a small deposit. Recently it has been discovered that the size of the deposited structure can be as small as one nanometer allowing EBID to be used to fabricate very small nanostructures of arbitrary shape. EBID provides an alternative to more traditional fabrication methods such as electron beam lithography (EBL) and ion beam induced deposition (IBID). EBID is a direct write technique requiring no pre-deposited resist or development and it can be applied to planar and nonplanar surfaces. This article reviews all aspects of the technique including instrumentation, gas-solid reactions, electron-beam specimen interaction, deposition parameters and deposit composition. Special attention is devoted to factors that must be understood and controlled in order to achieve a resolution of 1 nm. Examples of very small nanostructures fabricated by performing EBID with high-energy subnanometer focused electron beams (200 kV) are demonstrated. The chapter compares and contrasts EBID with other fabrication techniques and discusses current and future applications for the technique.