Abstract: A semiconductor device includes a main groove formed in a main surface of a substrate, a semiconductor region formed in contact with a surface of the main groove, an electron supply region formed in contact with a surface of the semiconductor region on opposite sides of at least side surfaces of the main groove to generate a two-dimensional electron gas layer in the semiconductor region, and a first electrode and a second electrode formed in contact with the two-dimensional electron gas layer and apart from each other.

Abstract: The solvent recovery apparatus includes an adsorption tower having a gas adsorption element; a gas supply pipe for supplying a solvent-containing gas to the adsorption tower; a steam supply pipe for supplying steam to the adsorption tower; and a solvent recovery pipe for recovering a removed solvent. Disposed at the solvent recovery pipe are a condenser and a specific-gravity separating unit for recovering a liquefield solvent. An intermediate liquid storing unit is disposed between the condenser and the specific-gravity separating unit, and has a valve adapted to be automatically opened when the intermediate liquid storing unit stores a liquid of which amount exceeds a preset value, so that the liquid flows into the specific-gravity separating unit. With this solvent recovery apparatus, organic solvent gas or flon gas may be recovered.