As they had hoped, a narrow ultrasound beam loosened the blood vessel walls in part of a mouse's brain. (discovermagazine.com)
Sensors placed around the outer sphere and inside the sodium were used to map the magnetic field, while ultrasound beams measured the rate of flow of the fluid using the Doppler effect. (sciencedaily.com)
As the sphere turns, two tracking devices fire ultrasound beams at it from below and measure the Doppler shift of the echoes to determine the speed and direction of its spin. (scientificamerican.com)