Abstract: A torsional vibration damper has a first flywheel mass on the drive side and a second flywheel mass which is rotatable relative to the first flywheel mass and is connected therewith via a torsional damping device. At least one of the flywheel masses is provided with a grease chamber containing a viscous medium for at least partial accommodation of the torsional damping device. There is at least one opening which is provided with a closure and axially penetrates at least one wall of the flywheel mass for filling the grease chamber with the viscous medium. The closure is formed by a cover which is accommodated at the respective flywheel mass and movable in the axial direction relative to the opening. In a sealing position the cover covers the opening, and a filling position is removable from the opening by a connection piece which can be guided through the opening for filling the grease chamber.

Abstract: A flywheel device having two flywheel masses which are deflectable relative to each other. Within one of the masses a grease chamber is provided along with packings against the emergence of viscous medium. One of the packings rests against a sealing seat which is developed on a structural part of one of the flywheel masses and another one of the packings is also provided on a structural part of the flywheel mass. Under axial initial stress the two packings are brought to rest against, in each case, one side of a bearing. At least one of the structural parts of the flywheel mass which has a sealing seat is adapted to receive both the bearing and the packing and has recesses in which the holder of the packing can be inserted for axially securing the packings with respect to the structural part on the one hand and with respect to the bearing on the other hand.

Abstract: A flywheel with two centrifugal masses has a secondary centrifugal mass assembled from two individual parts, wherein the first part is actively connected to a torsion damping device, and the second part has a friction surface for a friction clutch. To increase the useful life of the flywheel system, the two parts of the secondary centrifugal mass are held at a distance from one another, and are connected to one another in their radially inner area essentially only by means of axially projecting spacer elements, which spacer elements are distributed circumferentially, and by means of rivets or screws. The rear side of the second part of the secondary centrifugal mass can thus be air cooled by the system of air cooling passages.

Abstract: A photocathode for electroradiographic and electrofluoroscopic apparatus which contains a stack arrangement of perforated foils of a material with a high atomic number, in particular, double layer perforated foils with two electrically conducting outer layers and an insulating layer arranged in between which obtains relatively high sensitivity and high resolution permitting its use in medical diagnostic apparatus is described along with method of manufacturing the photocathode.

Abstract: The radiation resistance of silicon transistors with a silicon oxide coating is improved by irradiating the semiconductor device with electrons at an energy below 150 keV and a dose between 10.sup.9 and 10.sup.12 rad at the boundary layer between the silicon and silicon oxide coating. The temperature of the semiconductor device is maintained at a temperature of between 150.degree. and 450.degree.C during irradiation thereof.