Abstract: This invention relates to a process for enriching carbon 13 by mixing a halogenomethane containing one or more fluorine atoms and carbon 13 of natural isotopic abundance with one or two or more additive gases selected from a group of oxygen-containing oxidizing agents, halogens, and hydrogen halides, irradiating the resulting raw material gas mixture by a carbon dioxide laser to cause selective dissociation and reaction of the halogenomethane of carbon 13, separating the unchanged substances from the reaction mixture to obtain a product enriched with carbon 13, further converting the enriched product to carbon monoxide, and enriching carbon 13 by low-temperature distillation of the carbon monoxide. The process has advantages of low overall energy consumption, high yields of carbon 13, easy separability of the unchanged substances and high degrees of carbon 13 enrichment.

Abstract: Hydrogen in a metal, particularly in a welded metal, can be quantitatively measured by a simple apparatus using sequence control or computer control.The lower limit of hydrogen to be measured according to this invention is much lower yet is more accurate as compared with the prior mechanism of this field.