Abstract: The present invention relates to a coating method for the preparation of a coated nuclear fuel. Particularly, the present invention relates to the coating method of nuclear fuel surface with more than two coated layers of carbides, borides or nitrides and their compounds comprising deposition or permeation steps of i) elements or mixture that can form carbides, borides or nitrides and ii) a layer of pyrolytic carbon or boron prepared by chemical vapor deposition(CVD) or sputtering in sequence or in reverse sequence, or nitrogen prepared by gas permeation in sequence, on the nuclear fuel surface. The coated layers are formed with carbides, borides, nitrides or their mixture at high temperature and pressure by a combustion synthesis.

Abstract: A video signal clamping circuit for maintaining a constant clamping output level is disclosed including a clamper for generating a clamping output level in response to a reference voltage by use of an external condenser receiving a video signal and a plurality of transistors, a level variation detector for sensing a variation the clamping output level of the clamper and generating a level variation signal corresponding to the variation in the clamping output level, and a reference voltage compensator connected to the level variation detector, for receiving the level variation signal and compensating for the reference voltage of the clamper.