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An inert gas stripping gas chromatography method was described for the determination of infinite dilution activity coefficients ( ^) of organic compounds in water. The infinite dilution activity coefficients for 31 compounds including many halogenated and aromatic compounds were measured. In general, the y% values measured by gas stripping are in very good agreement with y% values estimated from the inverse solubilities and other experimental measurements. This suggests that when there is no directly measured data available, y^v alues estimated from the inverse of solubility can be used for the development and test of the models predicting limiting activity coefficients. A major advantage of this method relative to headspace gas chromatography that improves its precision and accuracy is the fact that the absolute detector response is unimportant. The detector only needs to be linear.

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Voids have been observed in sputtered SiO2 films when deposited over substrate topographies with high aspect ratios (depth/width). This report describes experimental results which show the conditions under which voids are found, and the response of void formation to available deposition parameter variations, such as resputtering bias, power, and frequency. A simple model for void formation is used to predict quantitatively the limits of the process with respect to void formation. The results show that it is possible to obtain void-free coatings up to an aspect ratio of ∼2.0, and that the controlling factor is the sputtering yield versus angle of incidence curve. Data suggest that 40-MHz conditions are slightly more favorable than 13 MHz.