Described herein is an implantable device having a sensor configured to detect an amount of an analyte, a pH, a temperature, strain, or a pressure; and an ultrasonic transducer with a length of about 5 mm or less in the longest dimension, configured to receive current modulated based on the analyte amount, the pH, the temperature, or the pressure detected by the sensor, and emit an ultrasonic backscatter based on the received current. The implantable device can be implanted in a subject, such as an animal or a plant. Also described herein are systems including one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transmit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Also described are methods of detecting an amount of an analyte, a pH, a temperature, a strain, or a pressure.

Described herein is an implantable device having a sensor configured to detect an amount of an analyte, a pH, a temperature, strain, or a pressure; and an ultrasonic transducer with a length of about 5 mm or less in the longest dimension, configured to receive current modulated based on the analyte amount, the pH, the temperature, or the pressure detected by the sensor, and emit an ultrasonic backscatter based on the received current. The implantable device can be implanted in a subject, such as an animal or a plant. Also described herein are systems including one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transmit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Also described are methods of detecting an amount of an analyte, a pH, a temperature, a strain, or a pressure.

A lens barrel includes: an electromechanical conversion element; an elastic body having a joining surface, a drive surface, and grooves; a motion member rotating by vibration wave of the drive surface; a rotating ring having a recess part and rotating by rotation of the motion member; a moving ring engaged to the recess part and moving to an optical axis direction by rotation of the rotating ring; and a lens held in the moving ring; wherein the element is made of a material having sodium potassium niobate, potassium niobate, sodium niobate or barium titanate, wherein a value of T/(B+C) is within a range of from 1.3 to 2.8 when: length from the drive surface to a base unit of the groove is defined as T; length from the base unit of the groove to the joining surface is defined as B; and thickness of the element is defined as C.

Methods and apparatus are provided for electrically addressing multiple ultrasonic transducers that are connected to a common electrical channel and housed within an imaging probe. An imaging probe may comprise an imaging ultrasonic transducer and a moveable element for controlling the direction of an emitted imaging beam, and an angle sensing ultrasonic transducer, where the angle sensing ultrasonic transducer is configured for determining the direction of an ultrasonic imaging beam. The angle-sensing transducer may be configured to direct an angle sensing ultrasonic beam towards an acoustically reflective substrate and provide a signal by detecting a reflected ultrasonic beam reflected from the acoustically reflective substrate, where the acoustically reflective substrate is positioned relative to the movable element such that motion of the movable element produces a change in the signal.

Methods and apparatus are provided for electrically addressing multiple ultrasonic transducers that are connected to a common electrical channel and housed within an imaging probe. An imaging probe may comprise an imaging ultrasonic transducer and a moveable element for controlling the direction of an emitted imaging beam, and an angle sensing ultrasonic transducer, where the angle sensing ultrasonic transducer is configured for determining the direction of an ultrasonic imaging beam. The angle-sensing transducer may be configured to direct an angle sensing ultrasonic beam towards an acoustically reflective substrate and provide a signal by detecting a reflected ultrasonic beam reflected from the acoustically reflective substrate, where the acoustically reflective substrate is positioned relative to the movable element such that motion of the movable element produces a change in the signal.

An ultrasonic sensor which includes a substrate where an opening section is formed, a vibration plate that is provided on the substrate so as to close the opening section, and a piezoelectric element that is layered on a surface of the vibration plate on an opposite side to the opening section and includes a first electrode, a piezoelectric element, and a second electrode, includes a reflection layer that is provided in a space around the piezoelectric element on the surface of the vibration plate on an opposite side to the opening section, to reflect other ultrasonic waves which are transmitted in a different direction from a transmitted ultrasonic wave transmitted to a measuring target side on an interface between the piezoelectric element and the reflection layer, and has a thickness so as to superimpose other ultrasonic waves on the transmitted ultrasonic wave.

A piezoelectric cooling system and method for driving the cooling system are described. The piezoelectric cooling system includes a first piezoelectric cooling element and a second piezoelectric cooling element. The first piezoelectric cooling element is configured to direct a fluid toward a surface of a heat-generating structure. The second piezoelectric cooling element is configured to direct the fluid to an outlet area after heat has been transferred to the fluid by the heat-generating structure.

A piezoelectric cooling system and method for driving the cooling system are described. The piezoelectric cooling system includes a first piezoelectric cooling element and a second piezoelectric cooling element. The first piezoelectric cooling element is configured to direct a fluid toward a surface of a heat-generating structure. The second piezoelectric cooling element is configured to direct the fluid to an outlet area after heat has been transferred to the fluid by the heat-generating structure.

Provided is a piezoelectric element vibration apparatus that generates vibration by applying a driving voltage to a piezoelectric vibrator, wherein a piezoelectric element layer is arranged on an electrode substrate made of a conductive material, an insulation member for preventing the applied driving voltage from leaking is formed on the piezoelectric element layer, and the piezoelectric element vibration apparatus has various types of forms in order to attach and install the piezoelectric vibrator. As a result, the piezoelectric element vibration apparatus has the effects wherein: installation is possible simply by attachment, thereby simplifying the assembly process; installation in any position is possible because the thickness of the piezoelectric element vibration device is made to be thin; the vibration volume can increase and the vibration noise can decrease while minimizing the thickness.

Acoustic perfusion devices for separating biological cells from other material in a fluid mixture are disclosed. The devices include an inlet port, an outlet port, and a collection port that are connected to an acoustic chamber. An ultrasonic transducer creates an acoustic standing wave in the acoustic chamber that permits a continuous flow of fluid to be recovered through the collection port while keeping the biological cells within the acoustic chamber to be returned to the bioreactor from which the fluid mixture is being drawn.