Abstract: A device (1) for preventing the growth of the bacteria or removing the bacteria bred on the inner wall surfaces of the ducts (8, 9, 10) of a dental unit, comprising a transponder (3) having a control unit (2) generating electric signals including audible frequency components, a coil (3a), and a case (3b) for storing the coil (3a) and mounting means (5) for mounting the transponder (3) on the outer wall surface of the duct (8), whereby an audible frequency electric signal allowed to transmit through the ducts (8, 9, 10) is generated by applying the electric signals to the coil (3a).

Abstract: A device (1) for preventing the growth of the bacteria or removing the bacteria bred on the inner wall surfaces of the ducts (8, 9, 10) of a dental unit, comprising a transponder (3) having a control unit (2) generating electric signals including audible frequency components, a coil (3a), and a case (3b) for storing the coil (3a) and mounting means (5) for mounting the transponder (3) on the outer wall surface of the duct (8), whereby an audible frequency electric signal allowed to transmit through the ducts (8, 9, 10) is generated by applying the electric signals to the coil (3a).

Abstract: In a melt blowing die tip having a generally triangular nose portion with a knife-edge forming the extremity of the die tip, a channel extending lengthwise of the die tip, a row of small openings extending from the channel to the knife-edge extremity of the die tips, and a plurality of tie bars of generally elliptical cross section integral with the die tip and bridging the channel to strengthen the die tip to withstand the internal, outwardly directed pressure exerted by molten polymer forced into the channel from the die body and flowing to be extruded through the die openings.