Abstract: When a ferroelectric liquid crystal display (FLCD) panel is addressed in such a manner as to cause adjacent or successive pixels to display different levels of greyscale, the viewer may perceive a pseudo edge effect caused by the perceived error in the transmission level at the transition between the two grey levels. In order to decrease this perceived error, the panel is addressed such that, at the transition between the two grey levels, for example between the grey levels “3” and “4”, the most significant bit of the addressing scheme incorporates an analogue grey level, for example a half level. This results in a perception level exhibiting a lower absolute error in the relative grey level than would be obtained if no special measures were taken to compensate for the perceived error at the transition. This compensation technique is applicable to addressing schemes utilizing temporal dither (TD) as well as spatial dither (SD).

Abstract: Energetic materials, particularly explosives materials, are detected in samples by heating a mixture of a sample under a reduced pressure of not more than 100 mbar and detecting the chemiluminescent emission therefrom with a suitable light detector, for example a photomultiplier or photodiode. The sample is heated to a temperature in the region of from 300° C. to 500° C., conveniently in a quartz tube furnace placed within a vacuum chamber. The inlet to the tube furnace may be connected directly into the outlet from a gas chromatography apparatus such that individual compounds from a mixture may be detected as they pas sequentially through the chromatography apparatus and into the tube furnace. An inert carrier gas may be used such as nitrogen, argon or helium or a specific gas to enhance the responsiveness of the method for a particular sample material. Apparatus for carrying out the method is also provided.

Abstract: Ferroelectric liquid crystal devices are described which contain liquid crystal mixtures comprising components A and B. Component A consists of one or more optically active compounds capable of imparting a spontaneous polarization to the material. Component B is selected as one or more compounds having formula (I), wherein a, b and c are independently 0, 1, 2; R.sub.1 and R.sub.2 are C.sub.1-15 straight or branched chain alkyl or alkoxy, preferably C.sub.3-12. In the above (for component B) CH=CH linking groups may be replaced by C.sub.2 H.sub.4 and CH.sub.2 O linking groups may be replaced by OCH.sub.2.