The present invention relates generally to a non-return valve comprising a valve body and a valve membrane. Also, a data storage apparatus can record contents data encrypted by a content key and the content key so that the contents data can be reproduced on other apparatuses to improve versatility. The AE sensor detects an elastic wave in the jig device. The plurality of glass fragments are then tumbled or vibrated for a predetermined period of time such that surfaces of the heat-treated glass fragments are smoother than prior to tumbling. The polymeric nanoparticles may further be functionalized to impart additional characteristics to modify the surface of the dried coating to minimize the chances for particles to become embedded or attached to the coating. The method of fabricating a metal interconnection including forming a interlayer dielectric layer on a substrate, forming an interconnection formation region in the interlayer dielectric layer, performing an ultraviolet treatment on the substrate after the interconnection formation region is formed and forming a metal interconnection in the interconnection formation region.