Abstract: Disclosed are a group III-nitride semiconductor substrate and a production method therefor. A group III-nitride semiconductor substrate having an element-forming surface with a dislocation density of 107 cm?2 or less in its entirely is formed only two steps. In a first step, a AlGaN-based low-temperature buffer layer is formed on a ZrB2 single crystal base having a defect density of 107 cm?2 or less, at a base temperature allowing the low-temperature buffer layer to be grown or deposited on the ZrB2 single crystal base substantially without creation of any Zr—B—N amorphous nitrided layer. Subsequently, in a second step, an AlGaN-based single crystal film is grown directly on the low-temperature buffer layer.

Abstract: A single tow prepreg which is impregnated with a composition comprising 100 parts by weight of a thermosetting resin having a softening point below 20.degree. C. and 3 to 30 parts by weight of a high molecular weight compound having a glass transition temperature below -10.degree. C. This prepreg is characterized in particular by high flexibility and non-tackiness.

Abstract: A process for producing a regenerated cellulose fiber having a good hand and a good shrink resistance characterized by attaching a liquid not readily soluble in liquid ammonia and adsorbable on regenerated cellulose fiber to the surface of regenerated cellulose fiber or attaching a polymer to the surface of regenerated cellulose fiber in the form of a film or not carrying out the surface treatment mentioned above, and adjusting the moisture content of said regenerated cellulose fiber to 5% or more based on the absolute dry weight of said fiber, and thereafter impregnating said regenerated cellulose fiber with liquid ammonia, and subsequently removing the ammonia from the regenerated cellulose fiber.