Abstract: A heat storage medium such as paraffin for a latent heat accumulator (cold accumulator), which solidifies while forming crystal structures. In order to achieve improved responsiveness on heat input, the crystal structures are modified by a structure additive preferably in terms of hollow structures, such as e.g. hollow cones.

Abstract: Storage and selective information transmission system of personal data comprising at least one optical memory card on which a defined memory field for storing a multiplicity of key terms is provided, a multiplicity of codes each assigned to at least one key term, at least one read/write device for the optical memory card having a multiplicity of key recognition functions, one key recognition function in each case pointing to one of a multiplicity of formatting functions contained in the read/write device and activating said formatting functions in interaction with the respective assigned code, each formatting function pointing to a data storage field of the optical card and being qualified, on the basis of the associated format specifications, for reading the data stored there.