Abstract: A fatigue detection device includes an ultrasonic device configured to transmit an ultrasonic wave into a living body, then receive the ultrasonic wave reflected by a tissue in the living body to output a received signal, and at least one processor, wherein the processor obtains the received signal output from the ultrasonic device, and detects a fatigue state of the tissue from a change in the received signal when a load is applied to the living body.

Abstract: An ultrasonic sensor includes: a substrate having a first surface and a second surface at an opposite side from the first surface, the substrate having an opening penetrating the substrate from the first surface to the second surface; a vibration plate covering a first surface side of the opening; piezoelectric elements provided at a surface of the vibration plate at an opposite side from the opening and each including a first electrode, a piezoelectric layer, and a second electrode; and an elastic layer in contact with the vibration plate in the opening, in which a portion in which the first electrode, the piezoelectric layer, and the second electrode overlap is defined as an active portion, and a plurality of the active portions face the one opening, and a thickness of the elastic layer is equal to or larger than half a thickness of the substrate and less than the thickness of the substrate, and the thickness of the elastic layer in each of the active portions is uniform.

Abstract: A thickness calculation method includes: a signal acquisition step of acquiring a reception signal by transmitting an ultrasonic wave from an ultrasonic probe into a living body and receiving the ultrasonic wave reflected in the living body by the ultrasonic probe; a boundary candidate extraction step of extracting a plurality of boundary candidates from the reception signal; a feature information acquisition step of acquiring feature information based on a change in the reception signal; a state determination step of inputting the feature information and the boundary candidate to a machine learning model that receives the feature information and the boundary candidate and outputs boundary information indicating whether the boundary candidate is a boundary of a tissue in the living body, and acquiring the boundary information; and a thickness calculation step of calculating a thickness of the tissue based on the boundary information.

Abstract: An ultrasonic thickness measurement device includes: an ultrasonic probe including eight or less ultrasonic elements each including a transmission element and a receiving element, the transmission element and the receiving element being ultrasonic elements; and a controller configured to determine a thickness of target body tissue from tomographic image data of a body of a subject acquired based on a received signal that is received by each of the receiving elements of each of the ultrasonic elements. The controller determines the thickness from the tomographic image data based on each of the received signals that is received by each of the ultrasonic elements.

Abstract: A fluid device includes: a flow path through which a fluid flows; and an ultrasonic wave transmitter configured to transmit an ultrasonic wave to generate a standing wave to the fluid in the flow path along a first direction orthogonal to a flowing direction of the fluid. The ultrasonic wave transmitter is in contact with the fluid and faces an antinode region corresponding to any antinode in the standing wave.

Abstract: A fluid device includes: a flow path through which a fluid flows; and an ultrasonic element configured to transmit an ultrasonic wave to the fluid to generate a standing wave in the fluid in the flow path along a first direction orthogonal to a flowing direction of the fluid. The ultrasonic element includes a vibrator having a fluid contact surface that comes into contact with the fluid, and a piezoelectric element that is provided at the vibrator and that is configured to flexurally vibrate the vibrator in a normal direction of the fluid contact surface. When a thickness of the vibrator in the normal direction is t, a sound velocity of a medium of the fluid is C, an average sound velocity of a longitudinal wave transmitted in the vibrator is C?, a dimension of the flow path in the first direction is L, and a mode order of the standing wave is n, the following expression is satisfied.

Abstract: A fluid device includes: a flow path through which a fluid flows; a pressure chamber spaced apart from the flow path in a first direction (Y direction) orthogonal to a flowing direction of the fluid in the flow path; a communication path that is formed along the Y direction and that communicates the flow path with the pressure chamber; and an ultrasonic wave transmitter configured to transmit ultrasonic waves to the fluid in the pressure chamber to generate a standing wave along the Y direction in the flow path.