Abstract: Electrically conductive polymers, especially polypyrroles, are formed with a charged polymeric dopant supplying the necessary counter-ions to stabilise the charged conductive form of the conductive polymer. The physical properties of the conductive polymer can thus be usefully modified in ways different from those achieved by non-polymeric dopants or by forming the conductive polymers in pre-existing bodies of non dopant (i.e. uncharged) polymers.

Abstract: A marker assembly 1 comprises a support layer 2 that has a surface which is provided with a porous coating 3 of a curable material, e.g. a particulate epoxy coating. The coating may be printed on using for example an ink jet printer to form indicia 6, and may be cured after the indicia have been formed in order to render them substantially indelible. The opposite side of the support layer 2 may be provided with suitable means for supporting the maker on a surface, e.g. a layer 4 of adhesive. The marker may be formed from a dimensionally stable or dimensionally heat-recoverable material.

Abstract: The invention provides an infra-red target detection system in which an array of infra-red detectors is scanned vertically in swathes and horizontal scanning is effected by sampling the output of each detector in turn. Addresses of target detections in the vertical and horizontal are stored and read out into an X and Y co-ordinate target position store if a detection resulting from scanning in the vertical corresponds to a detection resulting from scanning in the horizontal.