Plasma Jet-Substrate Interaction in Low Pressure Plasma Spray-CVD Processes

Conventional equipment for plasma spraying can be adapted for operation at low pressure so that PECVD-like processing can be performed. The plasma jet generated by the torch is characterized by a high convective velocity and a high gas temperature. The influence of these properties on a deposition process are investigated in the framework of simple theoretical considerations and illustrated by various experimental results obtained with SiO x deposition. A conclusion of this study is that the deposition process is dominated by diffusion effects on the substrate surface: the deposition profiles and the deposition rates are determined by the precursor density and by the gas temperature on the substrate surface. The high velocity of the jet does not play a direct role in the deposition mechanism. On the other hand it strongly increases the precursor density available for the deposition since it efficiently transports the precursor up to the substrat

CGPS time-series and trajectories of crustal motion along the West Hellenic Arc

Western Greece is one of the seismotectonically most active regions in Europe. The main tectonic structures are the West Hellenic Arc (WHA) and the Kephalonia Fault Zone. In order to monitor and understand the crustal movements in space and time, a continuous GPS network was installed. In this paper we present results of 6 yr (1995-2001) of measurements. To ensure a consistent reference frame, 54 mainly European IGS and EUREF sites were included in the processing. A selected subset was used to estimate an Euler pole for the rotation of Eurasia. In order to obtain coordinate time-series of high precision that are representative for crustal deformation, special emphasis was given to the elimination of non-tectonic effects. Four steps of improvement were pursued, including a reprocessing after exclusion of poor data, the removal of remaining outliers, the correction of unknown phase centre offsets after antenna changes and weighted common-mode filtering. With this procedure, non-tectonic irregularities were reduced significantly, and the precision was improved by an average of 40 per cent. The final time-series are used as a base for depicting trajectories of crustal motion, interpreting the temporal behaviour of the sites and for estimating velocities. For the first time, height changes in the WHA area were detected and quantified by GPS. Sites that are located near the epicentres of the 1997 Strofades (Mw = 6.6) and the 1999 Athens (Mw = 6.0) earthquakes are particularly considere