Electrostatic transducer of apexcardiogram

The apexcardiogram in myocardial asynergy.

SUMMARY The apexcardiogram was analyzed in 41 patients with an altered pattern of left ven-tricular contraction. Four types were distinguished: type I, an early sustained systolic bulge which occurred in 12 patients, all of whom had large aneurysms and large end-diastolic volumes; type II, a bulge confined to midsystole which occurred in 13 patients, 11 of whom had some form of ventricular asyn...

Triple resonant states and chaos control in an electrostatic transducer with two outputs

The dynamics of a non-linear electrostatic transducer with two outputs is studied. The amplitudes and stability conditions of oscillations for the Triple Resonant States are obtained and discussed. It is found that chaos can appear in the system. A retroactive control strategy is therefore applied to tune these chaotic oscillations to regular target orbits. The stability analysis of the feedbac...

Design and Fabrication of a Longitudinal-Torsional Ultrasonic Transducer

A hybrid longitudinal-torsional ultrasonic transducer is designed and fabricated in this research. The design of the transducer was performed using the FE method with ABAQUS software, with the aim of combining the longitudinal and torsional vibration modes. The transducer horn is then fabricated using a 4-axis milling machine. The PZT stacks are employed in order to excite the transducer. The t...

Design and Fabrication of a Longitudinal-Torsional Ultrasonic Transducer

A hybrid longitudinal-torsional ultrasonic transducer is designed and fabricated in this research. The design of the transducer was performed using the FE method with ABAQUS software, with the aim of combining the longitudinal and torsional vibration modes. The transducer horn is then fabricated using a 4-axis milling machine. The PZT stacks are employed in order to excite the transducer. The t...

Thirty-month follow-up of resting and postexercise apexcardiogram in asymptomatic subjects.