UHV

The paper contains an evaluation of possible application of laboratory studies of corona effect acoustic signal, generated by simulated damages and contaminations on the conductor surface, for assessment of technical condition of UHV transmission lines in real ambient conditions. The completed studies have shown, that there is a possibility of extracting such a vector of distinctive features, which allows a construction of a neural network model for the corona effect in laboratory conditions and its further application for recognition of possible sources of the intensified corona effect. Even if the number of correct recognitions in laboratory conditions close to 90% should be treated as satisfactory, it should be also taken into account that in real world conditions, where the line damages are not so frequent and their sources much less obvious, there may be some problems with collecting a properly representative learning set. Therefore the possibility of application of the results collected in laboratory conditions to the construction and verification of a neural model applicable in real conditions seems very attractive. The work presents the results of the laboratory studies and preliminary verification of the " laboratory " model for the set of data collected in selected conditions of 400 and 220 kV UHV transmission line damages in Poland. .

Structural transitions on silicon surfaces during growth and oxygen exposure were investigated by in situ ultra-high vacuum reflection electron microscopy and atomic force microscopy. Consequent stages of gold three dimensional island ordering on silicon (111) surfaces were visualized over a wide temperature range of the substrate. Initial stages of surface oxidation and thermal etching were analysed in details.