Abstract: A contaminant detector includes a detection object that is inclined relative to a horizontal direction in a drainage unit for accumulation of discharged water and on which a contaminant is to be deposited and a detection unit configured to emit energy toward the detection object to detect a contamination state of the detection object. The detection unit includes a transmission and reception module configured to emit and receive energy, a calculation module configured to calculate an amount of energy received from the detection object by the transmission and reception module, and a determination module configured to determine, based on the amount of energy calculated by the calculation module, the contamination state of the detection object.

Abstract: An asymmetric membrane including a crosslinked polyimide resin, the crosslinked polyimide resin being formed by crosslinking a polyimide resin by a crosslinking agent; the polyimide resin including a structural unit (A) derived from tetracarboxylic dianhydride and a structural unit (B) derived from diamine; the structural unit (A) including a structural unit (A-1) derived from a compound represented by Formula (a-1); the structural unit (B) including a structural unit (B-1) derived from Formula (b-1), and a proportion of the structural unit (B-1) per 100 mol % of the structural unit (B) being from 0.1 to 50 mol %; and the crosslinking agent being a compound having not less than two functional groups that bond with carboxy groups. In Formula (b-1), Q1 and Q2 are each independently a group including an aromatic group, an aliphatic hydrocarbon group, and/or an alicyclic hydrocarbon group; X is a single bond or a particular group.

Abstract: An asymmetric membrane including a crosslinked polyimide resin, the crosslinked polyimide resin being formed by crosslinking a polyimide resin by a crosslinking agent; the polyimide resin including a structural unit (A) derived from tetracarboxylic dianhydride and a structural unit (B) derived from diamine; the structural unit (A) including a structural unit (A-1) derived from a compound represented by Formula (a-1); the structural unit (B) including a structural unit (B-1) derived from Formula (b-1), and a proportion of the structural unit (B-1) per 100 mol % of the structural unit (B) being from 0.1 to 50 mol %; and the crosslinking agent being a compound having not less than two functional groups that bond with carboxy groups. In Formula (b-1), Q1 and Q2 are each independently a group including an aromatic group, an aliphatic hydrocarbon group, and/or an alicyclic hydrocarbon group; X is a single bond or a particular group.