Abstract: An acoustical barrier for blocking the transfer of sound through a barrier wall. The acoustical barrier comprises a sound absorbing layer and a decoupling layer mounted to the sound absorbing layer and spacing the sound absorbing layer from the barrier wall. The decoupling layer has a constructoin defining multiple voids to reduce the quantity of material used to construct the decoupling layer and to reduce the surface area of the decoupling layer contracting the barrier wall. Preferably, the decoupling layer has multiple protrusions such as ribs between which are interstitial spaces defining the voids.

Abstract: A semiconductor amplifying apparatus and a communication terminal apparatus to satisfy a standard value for adjacent channel power and amplify the power at a high efficiency. The value of an impedance viewed from an input terminal side of an impedance circuit network connected to an input terminal of a transistor is set at a value which causes a characteristic curve for a mutual modulation distortion component included in output power of the transistor to form, in the middle thereof, a curve section in which an inclination angle of a tangential line to this characteristic curve once becomes smaller, or a curve section which protrudes downwardly.

Abstract: A brake system including a master cylinder connected to wheel brakes is supplemented by a fluid return system made up of return pumps so that the braking pressure can be adjusted in the wheel brakes. In order to extend this system to a brake system which permits the generation of wheel brake pressure without the application of the brake pedal, the suction side of at least one return pump is connected to the pressure side of a charging pump which aspirates fluid directly from the supply reservoir. To prevent the pressure in the low-pressure range of the system from rising excessively high, the charging pressure of the pump is adjusted so that it only slightly exceeds the precharging pressure of the suction side of the low-pressure accumulator.

Abstract: A piston ring having a keystone shape and an orientation feature on one of its surfaces for ensuring proper orientation of the ring during installation. The piston ring preferably has an outer peripheral surface that includes a sealing land with a nitride hardened surface to resist wear during the service life of the piston ring. A tapered surface is also provided on the outer peripheral surface adjacent to the sealing land.