Browsing by Author "Vassilev G."

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    Dry etching of thin chalcogenide films
    (2010-01-01) Petkov K.; Vassilev G.; Vassilev V.
    Fluorocarbon plasmas (pure and mixtures with Ar) were used to investigate the changes in the etching rate depending on the chalcogenide glasses composition and light exposure. The experiments were performed on modified commercial HZM-4 vacuum equipment in a diode electrode configuration. The surface microstructure of thin chalcogenide layers and its change after etching in CCl2F2 and CF4 plasmas were studied by SEM. The dependence of the composition of As-S-Ge, As-Se and multicomponent Ge-Se-Sb-Ag-I layers on the etching rate was discussed. The selective etching of some glasses observed after light exposure opens opportunities for deep structure processing applications. © 2010 IOP Publishing Ltd.
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    Polymer composites containing waste dust from power production: II Strength characteristics of composites based on UPR/HIPS polymer system
    (2008-01-01) Koleva M.; Vassilev V.; Vassilev G.
    Polymer composite material based on ``unsaturated polyester resin/ high impact polystyrene`` polymer system as matrix and waste dust from power production as filler was studied. The waste was mechanically activated at dry conditions at room temperature for 30 minutes. Strength characteristics - impact, bending and compressive strength - dependance on the waste concentration was determined. The optimal results were achieved at waste concentration of 10 w.%. Morphology observations of filled systems were performed to clarify the influence of the structure on composite's properties.