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The paper presents a mathematical model, the results of computational and theoretical research, and the feasibility of creating a vibration converter with full magnetic levitation in the suspension of a high temper ature superconductor (HTSC). The axial and radial stability of the active part of the converter is provided by the interaction of the magnetic field of ring shaped permanent magnets and a hollow cylinder made of the ceramic HTSC material. The force is created by a system of current carrying coils whose magnetic field is polarized by permanent magnets and interacts with induced currents in the superconducting cylinder. The case of transition to the superconducting state of HTSC material in the field of the permanent magnets (FC mode) is considered. The data confirm the outlook for the proposed technical solutions.

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At the end of the 20th century, polymer films with piezoelectric properties were included in the range of active materials used in developing electroacoustic technical methods. For certain purposes and certain conditions of electroacoustic transducer applications, piezoelectric polymer films have considerable advan tages over the widely used piezoelectric ceramics owing to their elasticity, small specific weight, shock resistance, and possibility of fabricating piezoelectric elements with a preset shape [1]. At the same time, the high elasticity, which prevents generation of an intense driving force in these films, restricts the area of appli cation of this material to mainly receiving acoustic sig nals; i.e., to operation in the acoustoelectric or mech anoelectric transformation mode. As for the operation of piezoelectric polymer transducers in the intense radiation mode, they are only effectual for an air medium, where the evident advantage of these trans ducers is their small internal impedance (an order of magnitude smaller than that of piezoceramics) facili tating their matching with the load medium. This property of piezopolymers had been used in a number of sound engineering designs, e.g., in headphones, where the data transfer in a broad frequency band was necessary [2]. However, the transducers used in air for the purposes of communication, signalling, detection and ranging, etc., should have a sufficiently high radi ation intensity to transmit the signals the required dis tances. Both of the aforementioned qualities, namely, the broad bandwidth and the high radiation intensity, depend on the properties of the piezoactive material, as well as on the structure of the transducer.The purpose of our study was to investigate the pos sibility of constructing a low frequency ultrasonic radiator for operation in air on the basis of piezoelec tric polymer films. We experimentally verified the lin earity of the electromechanical properties of the active material, since this linearity was necessary for the operation of a radiating transducer with a sufficiently high intensity. We measured the elastic modulus Y 11 , the longitudinal wave velocity the absorption coef ficient, the permittivity, and the piezoelectric moduli d 31 and е 31 as functions of the driving field. (Here and below, axis 1 is directed along the orientation, i.e., direction of tension, of the piezoelectric film; axis 3 is directed along the width of the piezoelectric film, i.e., the electric polarization direction; and axis 2 is per pendicular to the two aforementioned axes.) The objects of our measurements were a Russian made uniaxially oriented piezoelectric film of the F2ME type [3] and a commercial piezoelectric film made by the MSI company (United States). The driving field intensity was increased from 10 5 to 5 × 10 6 V/m, the latter value corresponding to half the breakdown field for the F2ME film. In this case, the stress amplitude at resonance reached values that exceeded 5 × 10 6 N/m 2 and were close to the onset of the yield of the mate...