| 摘要 |
The deuterium content, or the ortho-para ratio, in hydrogen containing deuterium which has been freed at a low temperature from nitrogen and other low boiling gases is measured by means of a katharometer: where deuterium is to be determined, the o/p ratio of both the hydrogen to be tested and a standard sample of the hydrogen is adjusted to the equilibrium value at the temperature of the wire before introduction into the katharometer; where the o/p ratio is to be determined, a portion of the hydrogen is thus adjusted and passed into the reference cell and a second, unadjusted portion is introduced into the measuring cell. The adjustment of the o/p ratio may be achieved by passing the hydrogen at the required temperature over a catalytic material such as palladium, cobalt, titanium or other paramagnetic substance which may, if desired, be supported on asbestos, silica gel or ferric oxide gel: room temperature is frequently sufficient since the o/p ratio changes little above this temperature. After freezing out or adsorbing nitrogen, carbon monoxide and oxygen, e.g. with silica gel at low temperatures, any neon and helium still remain in the hydrogen: such a mixture may be passed through a gas chromatography column packed with a molecular seive zeolite before adjustment of the o/p ratio, whereby the gases helium neon and hydrogen are separated and successively passed through a conductivity cell. Pure hydrogen may be produced by this means and employed as comparison gas in the determination of a deuterium-containing hydrogen to be subsequently employed as a reference gas. Several procedures are described in relation to Figs. I-IV (not illustrated). |
