Chemical vapour-phase mechanism

Fabrication of polymers for these small and integrated sensors should be by the new processing technologies, which can produce accurate, mass reproducible and thin polymers. The polymers fabricated by conventional methods may have potential problems such as the difficulty of preparing thin (<1 pm) and homogeneous films. A plasma-polymerised film offers a new alternative [19]. The plasma-polymerised film is achieved in a glow discharge or plasma in the vapour phase. Such films are thin (< 1 pm), pinhole-free, flat-surface structures and are chemically and mechanically stable. 

The general anaesthetics appear to be the only pharmacological group (applied in the vapour phase) in which molecules of widely different structure have been correlated by Ferguson s principle. As they function by accumulating in essential parts of the nerve cells and disorganising their metabolism, such a mechanism depends on physical nature rather than on chemical structure. 

The rearrangements of 1- and 2-methylbicyclo[2,l,0]pent-2-ene to methylcyclo-pentadienes has been examined in solution and in the vapour phase and a mechanism in which cleavage of the C-1—C-4 bond produces a chemically activated cyclopenta-diene, which then suffers competitive hydrogen shifts and collisional deactivation, has been advanced RRKM calculations support this conclusion. The principle of least motion technique has been applied to this and bicyclobutane rearrangements. ... 

Heterogeneous reaction systems are modelled by detailed chemical kinetics and transport models and numerically simulated for two simple configurations, an cataJytically active wire and disk. As special case for the latter configuration, chemical vapour deposition of diamond is simulated. Elementary reaction mechanisms are applied in the gas phase and on the surface, and the coupling of the catalytic surface with the surrounding reactive fiow is accounted for by a detailed transport model. 

Although much work has been carried out on the mode of action of flame retardants generally, the mechanisms associated with tin additives are only partially understood. It is clear that tin-based fire retardants can exert their action in both the condensed and vapour phases, and that the precise action in any particular system depends on a number of factors, including incorporation level, the amount and chemical nature of other additives present and, indeed, the nature of the polymer itself. 

Level swell is the mechanism by which runaway chemical reactions vent a two-phase mixture. When a runaway chemical reaction generates gas or vapour, bubbles are formed throughout the bulk of the liquid. Because the bubbles are buoyant, they wijl tend to rise through the liquid in order to disengage at the surface. However, whilst they remain in the liquid, they occupy volume and so cause the... 

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