Abstract: A noise-absorption structure comprising a frame over which a gastight membrane is tensioned, the outside face of the membrane receiving soundwaves, a gas such as air filling the volume defined by the frame and the membrane, and energy-dissipation means housed in the volume, which means are of the laminar gas-flow type, of the electrostatic type, or of the electromagnetic type, and area adjustable or controllable to modify the acoustic impedance of the structure as a function of the characteristics of the noise to be absorbed. The invention is particularly applicable in the aviation industry.

Abstract: A device for providing a rigid mechanical link with frequency cut-off between two structures, the device comprising a rigid tie-rod (14) the ends of which are secured to the two structures (10, 12) and a cylinder and piston assembly (16, 18) in parallel with the tie-rod (14), the two ends of the cylinder (16) being interconnected by a duct (22) which, together with the cylinder (16), is filled with a liquid of very low viscosity, the device providing filtering of a low excitation frequency applied to one of the structures and preventing the transmission of this frequency to other structures.