Abstract: Provided is a burner that includes: a tubular first outer cylinder (20); a diffuser (21) disposed inside the first outer cylinder (20) and having an inner circumferential surface, a diameter of which gradually increases in a first direction; a first gas nozzle (22) configured to feed a first gas to a radial outer region of the diffuser (21) in the first direction; a second gas nozzle (23) disposed adjacent to the first gas nozzle (22) in a circumferential direction of the first outer cylinder (20) and configured to feed a second gas to the radial outer region of the diffuser (21) in the first direction; and an ignition torch (24) configured to ignite at least one of the second gas and the first gas.

Abstract: The present invention is directed to an ultrasonic device comprising a plurality of transducer elements arranged in rows and columns and acoustic insulation material maintained between each two adjacent rows of transducer elements. The ultrasonic device comprises (i) a plurality of rows of the transducer elements, each row being disposed on an imaginary circle, (ii) a plurality of circular plates each supporting one of said rows and (iii) spacers for spacing adjacent plates of the plurality of plates at a predetermined space interval, thereby forming a cylindrical array.