The Influence of Secondary Electron Emission and Electron Reflection on a Capacitively Coupled Oxygen Discharge

The one-dimensional object-oriented particle-in-cell Monte Carlo collision code oopd1 is applied to explore the role of secondary electron emission and electron reflection on the properties of the capacitively-coupled oxygen discharge. At low pressure (10 mTorr), drift-ambipolar heating of the electrons dominates within the plasma bulk, while at higher pressure (50 mTorr), stochastic electron heating in the sheath region dominates. Electron reflection has negligible influence on the electron energy probability function and only a slight influence on the electron heating profile and electron density. Including ion-induced secondary electron emission in the discharge model introduces a high energy tail to the electron energy probability function, enhances the electron density, lowers the electronegativity, and increases the effective electron temperature in the plasma bulk.

The Fractal Dimensions of Carbon-Black-Filled Polymers and Elastomers. Part 1. Materials and Methods of Investigation, and Morphology

Methods for preparing specimens and for processing the results obtained are described. Carbon black of grades T1 and KhS-72, monodispersed polystyrene (molecular weight 200 kDa), polyethylene, polybutadiene rubber, polyisoprene rubber, styrene butadiene elastomer, and butyl rubber were investigated. Two methods were used to prepare filled specimens. In the first case (model systems), the filler and polymer were mixed via a 1–5% solution of polystyrene in toluene. The carbon black content in the suspensions was varied in the range 1–60 wt%. After mixing, the specimens were subjected to ultrasound treatment on a UZDM-2T disperser (44 kHz) for ~10 min. In the second case, sulphur vulcanisates were obtained by the standard procedure. The morphology was studied by transmission electron microscopy (EM-301 electron microscope, Japan) using thin films or etching in high-frequency oxygen discharge plasma on a vacuum reactor (Edwards, UK). A procedure for processing electron micrographs with the aim of obtaining information about local and global fractal dimensions of particle aggregates is described.