Abstract: An ultrasonic sensor includes a magnetic substance, a diaphragm, and an electromagnetic transducer. The electromagnetic transducer is disposed opposing the magnetic substance across an outer plate of a vehicle. The diaphragm has the shape of a thin film with a film thickness direction along an axial direction parallel to a directional axis. The diaphragm is able to ultrasonically oscillate by being joined to an outer surface of the outer plate at an outer edge in a radial direction crossing the directional axis. With the outer edge of the diaphragm joined to the outer surface of the outer plate, an internal space that expands and contracts along the axial direction in response to ultrasonic oscillation of the diaphragm is formed between the diaphragm and the outer surface of the outer plate.

Abstract: An ultrasonic sensor installable to a vehicle includes a magnetic body capable of ultrasonic vibration and an electric-magnetic converter having a conversion function between an oscillating magnetic field corresponding to the ultrasonic vibration of the magnetic body and an electric signal. The magnetic body is located on an outer surface side of an outer plate of the vehicle, which is the surface facing an external space of the vehicle. The electric-magnetic converter is located to face the magnetic body with the outer plate interposed therebetween on an inner surface side, which is a back surface of the outer surface of the outer plate.

Abstract: A process for preparing a flame retardant thermoplastic polyester which comprises reacting a low molecular weight polyester having terminal hydroxyl groups with a polyfunctional isocyanate, said low molecular weight polyester being one synthesized using as its acid component a compound selected from the group consisting of terephthalic acid and its lower alkyl esters of 1-4 carbon atoms and as its alcohol component 1,4-butanediol and a compound selected from the group consisting of an alkylene oxide adduct of 2 - 4 carbon atoms of tetrabromobisphenol A and an alkylene oxide adduct of 2 - 4 carbon atoms of tetrachlorobisphenol A.