FEM simulation and comparison of PMN-PT single crystals based phased array ultrasonic transducer by alternating current poling and direct current poling

A relaxor-based ferroelectric single crystal with the nominal composition of xPb(Sm0.5Nb0.5)O3-(0.7‒x) Pb(Mg1/3Nb1/3)O3-0.3PbTiO3 (x = 0.01, 0.02, and 0.03) was grown by the vertical Bridgman process. The electrical properties and the ferroelectric domains, as well as the luminescent characteristics of the single crystals, were investigated systematically. The piezoelectric coefficient d33 of the single crystals are slightly higher than that of the undoped PMN-PT single crystal under direct current polarization, while the crystal wafers gain a much higher d33 value upon being polarized with alternating current voltage. The single crystals possess a decreased phase transition temperature of around 60 °C and a decreased Curie temperature of 92~116 °C compared with the undoped PMN-PT single crystal. The crystal wafers polarized with alternating current voltage exhibited a desirable optical transmittance, which is associated with the domain structure changes inside the crystal medium. The domain density of the crystal wafers under alternating current polarization was significantly decreased compared with the direct current polarized crystal wafers. The luminescent spectra of the crystal wafers exhibit the typical emission peaks corresponding to the characteristic transition of Sm3+ ions in the crystal lattice.

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Comparison of alternating current with direct current electroshock across the closed chest

The American Journal of Cardiology ◽

10.1016/0002-9149(62)90299-0 ◽

1962 ◽

Vol 10 (2) ◽

pp. 223-233 ◽

Cited By ~ 216

Author(s):

Bernard Lown ◽

Jose Neuman ◽

Raghavan Amarasingham ◽

Barouh V. Berkovits

Keyword(s):

Direct Current ◽

Alternating Current ◽

Closed Chest

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CONCEPTS OF ELECTRONICALLY-CONTROLLED ELECTROMECHANICAL/MECHANOELECTRICAL STEER-, AUTODRIVE- AND AUTOABSORBABLE WHEELS FOR ENVIRONMENTALLY-FRIENDLY TRI-MODE SUPERCARS

Journal of Circuits System and Computers ◽

10.1142/s0218126694000296 ◽

1994 ◽

Vol 04 (04) ◽

pp. 501-516 ◽

Cited By ~ 8

Author(s):

BOGDAN T. FIJALKOWSKI ◽

JAN W. KROSNICKI

Keyword(s):

Direct Current ◽

Integrated Circuit ◽

Environmentally Friendly ◽

Alternating Current ◽

Switching Frequency ◽

Neuro Fuzzy ◽

Interior Permanent Magnet ◽

Application Specific Integrated Circuit ◽

Computer Processor ◽

Application Specific

Concepts of the electronically-controlled electromechanical/mechanoelectrical Steer-, Autodrive- and Autoabsorbable Wheels (SA2W) with their brushless Alternating Current-to-Alternating Current (AC-AC), Alternating Current-to-Direct Current-Alternating Current (AC-DC-AC) and/or Direct Current-to-Alternating Current (DC-AC)/Alternating Current-to-Direct Current (AC-DC) macroelectronic converter commutator (macro-commutator) wheel-hub motors/generators with the Application Specific Integrated Matrixer (ASIM) macroelectronic converter commutators (ASIM macrocommutators) and Application Specific Integrated Circuit (ASIC) microelectronic Neuro-Fuzzy (NF) computer (processor) controllers (ASIC NF microcontrollers) for environmentally-friendly tri-mode supercars (advanced ultralight hybrids) have been conceived by the first author and designed by both authors with the Cracow University of Technology’s Automotive Mechatronics Research and Development (R&D) Team. These electromechanical/mechanoelectrical wheel-hub motors/generators, respectively, for instance, can be composed of the outer rotor with the Interior Permanent Magnet (IPM) poles and the inner stator that has the three-phase armature winding. The macroelectronic converter commutator establishes the AC-AC cycloconverter, AC-DC rectifier-DC-AC inverter and/or DC-AC inverter/AC-DC rectifier ASIM macrocommutator. The microelectronic NF computer (processor) controller establishes the ASIC microcomputer-based NF microcontroller. By adopting continuous semiconductor bipolar electrical valves in the high-power ASIM, it has been able to increase the commutation (switching) frequency and reduce harmonic losses of the electromechanical/mechanoelectrical wheel-hub motors/generators, respectively.

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