Abstract: A recording medium including: an image storing medium for storing an image information; and a display section installed on a surface of said image storing medium, wherein said display section includes a radio IC chip.

Abstract: An economical data processing system, including: a means to form a virtual space in use with a network which includes a plurality of computers connected to each other; a means to form virtual currency which represents a value index in the virtual space; and a virtual currency storing means to store the virtual currency. In the economical data processing system, the virtual currency is delivered in the virtual space.

Abstract: The main photosensitive ingredient of the photosensitive composition is prepared by subjecting a polymer, which is obtained by homopolymerizing, or copolymerizing with another copolymerizable monomer, a monomer of the general formula ##STR1## in which R represents a hydrogen atom, a halogen atom, or an alkyl group, Y represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted naphthylene group, p is 0 or 1, and when p=1, X represents a divalent organic group, to reaction with p-azidocinnamylidene-.alpha.-cyanoacetic chloride in the presence of an organic or inorganic base.

Abstract: New liquid developers for electrophotography comprise (a) a coloring agent, (b) a charge control agent and (c) one or more of a polyethylene, a polypropylene, an ethylene copolymer and a propylene copolymer, with or without (d) a hydrocarbon resin soluble in a hydrocarbon solvent and containing a 1,3-pentadiene moiety, in an electro-insulating liquid. These developers have an excellent etching resistance and a high dispersion stability.