Abstract: A serially arranged construction of individual fuel cells implements large-scale systems for generating power. The fuel cells are packed with high density but in an exchangeable manner. Only the fuel gas is fed to the block of fuel cells by special conduits and connecting elements whereas the oxidation gas (e.g. air) is fed by an outside pressure difference between the front and rear sides of the fuel cell blocks. A large number of blocks can be mounted on a carrier plate in which fuel gas ducts are integrated to form a reinforcement and to directly feed the fuel gas into the blocks via pipe pieces mounted from the outside.

Abstract: A foldable and deployable antenna reflector includes a central panel having along its circular periphery a circular-sawtooth shaped contour with ramplike edges separated by radial cut backs and a plurality of similar, rigid segments, each having a foot edge are respectively hinged by means of a single hinge axis to the ramplike sawtooth edges.

Abstract: This invention relates to an improvement in a collapsible antenna reflector with rigid, collapsible elements for high accuracy of contour, composed of a central panel and collapsible segments mounted thereto by means of joints, the improvement comprising means mounting the individual collapsible segments (5) so that in their collapsed state their contour curvature is equidirectional, with the individual collapsible segments being mounted perpendicularly to the central panel and being arranged from its periphery obliquely to the antenna axis.