(US4714639-A)      Material which converts light energy into heat energy consists of a hollow light transmissive member with a thin C layer on the inner surface.    In the claimed method of mfr. a hydrocarbon or heterocyclic cpd. is introduced into the light transmissive member at a predetermined rate and decomposed pyrolytically at below 1000 deg.C so that a thin layer of C is deposited which has a translucent, mirror metallic lustre characteristic.    ADVANTAGE -   Fluid made to flow in the member is heated effectively. (6pp)    (JP93031063-B)      A half-mirror shaped metal thin film is deposited on the internal wall of a translucent hollow tube. A predetermined amt. of hydrocarbon is introduced into the translucent hollow tube at 1000 deg.C or less for heat decomposition reaction.    USE -   Light energy is converted into heat energy by heating a fluid such as water, freon gas in a glass tube. The light-heat conversion material employing a carbon thin film efficiently heats the fluid in the hollow tube. (J61223453-A)    (EP196011-B1)      A method of converting energy between heat energy and electric energy by a carbon intercalation compound composed of a majority of carbon atoms having sp2-bond to maintain a graphite structure, carbon atoms having sp3-bond scattered among said majority of carbon atoms to fix intercalants, and the intercalants as energy converting material, said method comprising the steps of:    preparing a thin film of said carbon intercalation compound on a single-crystalline substrate by pyrolytical decomposition of a hydrocarbon compound and an organo metal reagent comprising heavy metal atoms; using a temperature difference in a direction perpendicular to the graphite layers of said carbon intercalation compound to generate electric energy; or using electric energy to generate a temperature difference in said direction perpendicular to the graphite layers.    (US5316858-A)      The material for converting heat energy to electric energy consists of graphite layers with heavy metal intercalated between the adjoining graphite layers. The heavy metal is selected from Bi, Pb, Sb, Sn and Hg. The thermoelectric power of the intercalated heavy metal atoms in the direction perpendicular to the graphite layers of the material is 150-50 microV/K and the conductivity and thermal conductivity are 5100-1200 ohm(-1) cm (-1) and 0.011-0.021 W cm (-1)K(-1) respectively.    The material is produced by pyrolytically decomposing a hydrocarbon or 1,2-dibromoethylene and a heavy metal organometallic cpd. at approx. 1000 deg. C.    ADVANTAGE -   The material is highly effective at energy conversion.