Abstract: A sensor coil characterized by an elongated insulating substrate, which substrate is folded and formed into a cylindrical toroidal core having adjacent substrate sections disposed at acute angles to each other forming a star-like cross-section, a winding on at least one side of the substrate which winding includes transverse and longitudinal portions on each substrate section which transverse portions are parallel to the axis of a current conductor on which the coil is mounted.

Abstract: Amide-imide polymers formable in deep section and prepared by the condensation reaction of at least one of a diacid halide or a polyanhydride or equivalent, and a diamine containing at least one imide linkage. Soluble amide-imide polymers having the general formula: ##STR1## where n is an integer greater than 10 and preferably greater than 20.

Abstract: Deep curable polymers having heterocyclic ring systems such as isoindoloquinazolinedione ring systems prepared from novel cyanoimide polymers, most desirably 2'-cyanoimide polymers. Preferably the cyanoimide polymers are prepared from a diamine having at least one nitrile group in the two position to an amine group and a dianhydride having at least two cyclic anhydride groups. Copolymers may be prepared having other linkages, notably imide linkages, in addition to isoindoloquinazolinedione ring systems and/or other similar heterocyclic ring systems. The copolymers can be prepared by use of diamines containing one or more cyanoimide groupings and/or imide groups in their structure.

Abstract: 1. A polyamide-imide resin consisting essentially of the repeating amide-imide polymeric unit ##SPC1##Wherein R is a member selected from the group consisting of ##SPC2##And copolymers thereof, in which X is an integer of from 1 to about 500.

Abstract: A hydrophilic permselective polymeric material for use in a liquid purification system comprises nitrogen linked cyclic polyether divalent radical constituents.

Abstract: Polymers containing both oxadiazole and imide recurring units are made from soluble polymeric precursors that contain hydrazide and/or amic acid recurring units. Dehydration of the hydrazide produces the oxadiazole unit and dehydration of the amic acid produces the imide unit. The oxadiazole unit may also be advantageously formed in various monomeric hydrazine compounds. The monomeric hydrazine compounds are made reactive by converting the dinitroso form of the compound into a reactive diamino form. The polymers may be used as molding and laminating resins, wire coatings, films, filaments and adhesives.