Abstract: The invention discloses a method for imparting molecular-level smoothness to the surface of an organic crystal used as a non-linear optical material having a defective depression by levelling the surface depression so as to be free from a decrease in the incidence of a laser beam and energy transducing efficiency. The method comprises: bringing into contact a microprobe having a specified radius of curvature at the probe tip onto the crystal surface with a defective depression under a specified contacting load; scanning the surface with the probe to shave off the surface around the depression forming shavings; and transferring the shavings into the depression to fill the depression up to a flatness level flush with the level around the filled depression.

Abstract: A method of manufacturing shaped articles of cross-linked poly-.alpha.-olefin composition by irradiation of electron beam which comprises the steps of blending a poly-.alpha.-olefin with a compound miscible therewith which is expressed by the general formula:X--Ym(where X is a group free from acetylenic linkage, Y is a group containing acetylenic linkage and m is an integer of 1 or over) and tetrakis-[methylene-(3,5-di-t-butyl-4-hydroxy-hydrocinnamate)]-methane; molding the blended mass into a desired shape; and cross-linking said shaped articles by irradiation of electron beam.