Abstract: A sensor (10) for determining angular velocity includes one or a plurality of piezoceramic plates (11, 12, 31 to 34), which are suitably oriented with respect to the axis of rotation and execute shear oscillations with the aid of an exciting circuit. If the sensor (10) is located in a rotating system, piezoelectric charges are generated on specific plate surfaces by generated Coriolis forces (K.sub.c). These charges represent a measure of the rotational velocity (.OMEGA.).

Abstract: An article for the recording and storage of information includes a support and a layer for storing information provided on the support. The layer is amorphous and composed of a mixture which includes an element of the group bismuth, antimony and selenium and a different element of the group selenium and tellurium. Information may be recorded on the layer by burning away selected regions thereof with high-energy radiation such as a laser beam. A preferred mixture includes bismuth and selenium with the weight ratio of bismuth to selenium being between about 1:2.5 and 1:3.5 for radiation having a wavelength corresponding to visible blue light and with the proportion of selenium being increased for longer wavelengths such as those corresponding to visible green and red light. The layer has a thickness which corresponds to a fraction of the wavelength of the radiation used for recording and the layer is optically opaque.