Barrier-layer discharge

Glow discharges have also now been miniaturized. In the discharge in a micro-structured system, described by Eijkel et al. [607], molecular emission is obtained and the system can be used successfully to detect down to 10 14 g/s methane with a linear response over two decades. A barrier-layer discharge for use in diode laser atomic spectrometry has also been described recently (Fig. 122) [608],... 

C. Gas-phase deposition of the barrier layer from a glow discharge plasma. 

For most positives, the formation of PhS04 hy self-discharge is slow, typically much less than 0.5%/day at 25°C. (Some positives which have been made with nonantimonial grids can fail by a different mechanism on open circuit, namely, the development of a grid-active material barrier layer.) The self-discharge of the negative is generally more rapid, especially if the cell is contaminated with various catalytic metaUic ions. For example, antimony lost... 

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