RESUMEN
In this work, GaN/InGaN/GaN nanocolumns (NCs) have been grown by molecular beam epitaxy. Selective area growth (SAG) and self-organized growth (SOG) were performed simultaneously in patterned and unpatterned regions of the same substrate, respectively. The resulting structures show different tip morphologies and structural properties due to the different polarity along the growth direction, namely Ga-polar with r-plane faceted tips for the SAG NCs and N-polar with c-plane top facet for the SOG ones. When growing Ga-polar GaN/InGaN NCs, no indium is incorporated at a substrate temperature of [Formula: see text]°C. Rather, indium incorporation takes place under the same growth conditions on the N-polar NCs. The In-incorporation is investigated by means of nano x-ray fluorescence and diffraction, high-angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electron microscopy.
RESUMEN
Aerosolization of natural salt and brackish waters under laboratory conditions is responsible for the transfer of synthetic surfactants such as linear alkylbenzene sulphonate (LAS) from water to the atmosphere. Excluded the lagoon sample which stands apart, on the average ca. 45% of the LAS present at concentrations between 0.1 and 4.1 microg l(-1) in the tested coastal and offshore marine and lagoon waters was transferred to the aerosol extract. The distribution of the individual LAS homologs in the aerosol is very similar to that in water, which indicates no preferential removal from the bulk water of any LAS homolog. The fraction of dissolved organic carbon (DOC) undergoing aerosolization under the same conditions for each tested sample was on an average ca. 3.3%, corresponding to ca. 5.6 mg l(-1). On the average, the enrichment factor of the sea samples, resulting from the changing of the LAS/DOC ratio before and after aerosolization, was ca. 20.