Abstract: Highly selective membranes for the separation of mixtures He/N.sub.2 and O.sub.2 /N.sub.2, which have suitable mechanical properties and high permeability are dislcosed. They consist of a polymeric porous base from poly-2,6-dimethyl-1,4-phenyleneoxide and a polymeric selective layer formed from polyamidoimide of the general formula I, where R= ##STR1## and n=140-220 ##STR2## or from an interpolymeric equimolar complex of PAI-1 with polyvinylpyrrolidone, or from an aromatic polyimide of the general formula II, where X is --O-- or ##STR3## and n=150-230 ##STR4## or of the general formula III, where n=150-240 ##STR5## or from polymeric imides of the general formula IV, where R=H or CH.sub.3 ##STR6## or also from their copolymers with styrene, methyl methacrylate, methyl acrylate, and dimethylaminoethyl methacrylate. A method for the preparation of composite polymeric membranes consists of saturation of the porous base from poly-2,6-dimethyl-1,4-phenyleneoxide with an organic solvent inert to it, e.g. with C.sub.
Type:
Grant
Filed:
November 15, 1989
Date of Patent:
October 22, 1991
Assignees:
Ceskoslovenska Akademie ved, Akademija Nauk SSSR
Inventors:
Miroslav Bleha, Jan Schauer, Jan Lokaj, Galina A. Polockaja, Jurij P. Kuznecov, Kira A. Romaskova
Abstract: A single crystal of pure or mixed univalent mercury halide, which is formed having a pair of opposed polished faces at least one of which is perpendicular to a direction which is inclined from the optical axis of the crystal about the crystallographic direction by an angle between 0.2.degree. to 20.0.degree.. Another face of the crystal is provided with a source of transverse acoustic waves.
Type:
Grant
Filed:
January 25, 1979
Date of Patent:
March 24, 1981
Assignees:
Ceskoslovenska Akadamie ved, Akademija Nauk SSSR
Inventors:
Cestmir Barta, Jiri Ctyroky, Iraida M. Silvestrova, Jurij V. Pisarevskij