2results about How to "Short pulse width" patented technology

This invention discloses a high-voltage nanosecond pulse shaping device and method based on magnetic devices. The device includes: a first magnetic transmission line and a second magnetic transmission line, with their input ends connected in parallel and connected to an initial pulse source; the output end of the first magnetic transmission line is connected to a load terminal; the output end of the second magnetic transmission line is short-circuited to ground; the first magnetic transmission line includes a first magnetic ring arranged along the axial direction and an outer magnetic field coil; the second magnetic transmission line includes a second magnetic ring arranged along the axial direction. Based on the current-dependent nonlinear permeability effect of the magnetic ring, this device simultaneously achieves pulse rise time compression, fall time truncation, pulse width shortening, and suppression of pre-pulse and tail oscillations through the rising sharpening effect of the first magnetic transmission line and the falling truncation effect of the second magnetic transmission line. This overcomes the limitation of single nonlinear transmission line or magnetic switching technology, which can only optimize single pulse parameters, and can obtain high-quality pulse waveforms at the load terminal.

The invention provides a piezoelectric micromechanical ultrasonic transducer, a control method and an array. The piezoelectric micromechanical ultrasonic transducer (100) comprises: a substrate (101) provided with a back cavity (102); the composite diaphragm structure is arranged above the back cavity and comprises a piezoelectric film layer (105) used for transmitting and receiving ultrasonic waves based on the piezoelectric effect; the phase change tuning layer (110) is mechanically coupled with the piezoelectric thin film layer and is prepared from a nonvolatile material with reversible mechanical properties, the nonvolatile material has at least two stable phase forms under external excitation, and different phase forms correspond to different mechanical properties; the change of the mechanical property causes the change of the overall effective rigidity of the composite diaphragm structure; and the excitation structure (108) is coupled with the phase change tuning layer and is used for applying external excitation to the phase change tuning layer so as to drive the nonvolatile material to carry out nonvolatile switching among different phase forms, so that frequency tuning of the piezoelectric micromechanical ultrasonic transducer is realized.