Abstract: A focused ultrasonic transducer includes a piezoelectric substrate having a first face and a second face, a back metal layer disposed over the first face, and a patterned metal layer disposed over the second face. The patterned metal layer includes a first plurality of concentric ring electrodes wherein each of the first plurality of concentric ring electrodes are wired to be individually accessible. A controller actuates a subset of the concentric ring electrodes such that electrical control of focal length is achieved by selecting a group of electrodes to actuate so that acoustic waves generated from selected electrodes arrive at a desired focal length in-phase and interfere constructively to create a focal spot of high acoustic intensity. The patterned metal layer optionally includes a first central electrode that is surrounded by the first plurality of concentric ring electrodes.

Abstract: A method for continuous acoustic signature recognition and classification includes a step of obtaining an audio input signal from a resonant microphone array positioned proximate to a target, the audio input signal having a plurality of channels. The target produces characterizing audio signals depending on a state or condition of the target. A plurality of features is extracted from the audio input signal with a signal processor. The plurality of features is classified to determine the state of the target. An acoustic monitoring system implementing the method is also provided.

Abstract: A device for picking and placing semiconductor chips includes a liquid having a first surface and a second surface and a layer of semiconductor chips disposed over the first surface. Characteristically, the first surface is a liquid-air interface. The device also includes a focused ultrasonic transducer positioned to focus acoustic wave on the layer of semiconductor chips such that a droplet including at least one semiconductor chip is ejected through the liquid-air per each actuation of the focused ultrasonic transducer through droplet ejection. The focused ultrasonic transducer includes a piezoelectric substrate having a top face and a bottom face, a Fresnel acoustic lens including a plurality of annular rings of air cavities disposed on the top face, and a first patterned circular electrode disposed over the top face and a second patterned circular electrode disposed over the bottom face. The first patterned circular electrode overlaps the second patterned circular electrode.

Abstract: A device for contactless, damage-free, high-precision cell and/or particle extraction and transfer through acoustic droplet ejection includes a substrate having a first surface and a second surface and a focused ultrasonic transducer positioned to focus an acoustic wave onto the substrate such that a droplet that includes at least one cell or particle is ejected from the bulk or from the first surface per each actuation of the focused ultrasonic transducer through droplet ejection. The substrate includes cells or particles inside the substrate or on top of the substrate. The focused ultrasonic transducer includes a piezoelectric substrate having a top face and a bottom face, a Fresnel acoustic lens including a plurality of annular rings of air cavities disposed on the top face, and a first patterned circular electrode disposed over the top face and a second patterned circular electrode disposed over the bottom face. The first patterned circular electrode overlaps the second patterned circular electrode.

Abstract: This document describes a single-element planar focused ultrasonic transducer with electrically tunable focal size (focal diameter in the focal plane), through modifying the design of a self-focusing acoustic transducer (SFAT). The transducer is built on a 1-mm-thick lead zirconate titanate (PZT) with (1) Fresnel acoustic lens formed with annular rings of air cavities on the top and (2) patterned annular ring electrodes on the bottom. By controlling the number of Fresnel rings being driven from the center, we were able to tune the focal size between 371 and 866 ?m, while keeping the focal length at 6 mm, with 2.32 MHz pulsed ultrasound. When tested as a droplet ejector, the transducer ejected water droplets with diameter between 294 and 560 ?m (between 13.3 and 92.0 nL in volume), depending on which set of electrodes are actuated.

Abstract: A vibration energy harvester includes a proof mass that is a magnetic array or a coil array. The magnetic array has multiple magnets. The coil array has one or more coils. The vibration energy harvester includes an enclosed chamber. The enclosed chamber has the other of the coil array or the magnetic array that is not the proof mass. The one or more copper coils and the multiple magnets are configured to generate the electrical energy from a relative movement between the one or more copper coils and the multiple magnets. The vibration energy harvester includes a liquid suspension that suspends the proof mass within the enclosed chamber.

Abstract: A focused ultrasonic transducer includes a piezoelectric substrate having a first face and a second face, a back metal layer disposed over the first face, and a patterned metal layer disposed over the second face. The patterned metal layer includes a first plurality of concentric ring electrodes wherein each of the first plurality of concentric ring electrodes are wired to be individually accessible. A controller actuates a subset of the concentric ring electrodes such that electrical control of focal length is achieved by selecting a group of electrodes to actuate so that acoustic waves generated from selected electrodes arrive at a desired focal length in-phase and interfere constructively to create a focal spot of high acoustic intensity. The patterned metal layer optionally includes a first central electrode that is surrounded by the first plurality of concentric ring electrodes.

Abstract: A vibration energy harvester includes a proof mass that is a magnetic array or a coil array. The magnetic array has multiple magnets. The coil array has one or more coils. The vibration energy harvester includes an enclosed chamber. The enclosed chamber has the other of the coil array or the magnetic array that is not the proof mass. The one or more copper coils and the multiple magnets are configured to generate the electrical energy from a relative movement between the one or more copper coils and the multiple magnets. The vibration energy harvester includes a liquid suspension that suspends the proof mass within the enclosed chamber.

Abstract: A vibration energy harvester that converts kinetic energy to electrical energy. The vibration energy harvester includes an electrically conductive coil array, a magnetic array and a self-assembled liquid bearing. The magnetic array is levitated above the electrically conductive coil array. The magnetic array and the electrically conductive coil array are configured to generate the electrical energy from a relative movement between the magnetic array and the electrically conductive coil array. The self-assembled liquid bearing separates the magnetic array from the electrically conductive coil array and levitates the magnetic array over the electrically conductive coil array.

Abstract: A method for continuous acoustic signature recognition and classification includes a step of obtaining an audio input signal from a resonant microphone array positioned proximate to a target, the audio input signal having a plurality of channels. The target produces characterizing audio signals depending on a state or condition of the target. A plurality of features is extracted from the audio input signal with a signal processor. The plurality of features is classified to determine the state of the target. An acoustic monitoring system implementing the method is also provided.

Abstract: In some aspects of the disclosure, an apparatus includes an XYZ control stage and an acoustic transducer coupled with the XYZ control stage. The acoustic transducer includes a multi-foci Fresnel lens having multiple focal spots.

Abstract: A vibration energy harvester that converts kinetic energy to electrical energy. The vibration energy harvester includes an electrically conductive coil array, a magnetic array and a self-assembled liquid bearing. The magnetic array is levitated above the electrically conductive coil array. The magnetic array and the electrically conductive coil array are configured to generate the electrical energy from a relative movement between the magnetic array and the electrically conductive coil array. The self-assembled liquid bearing separates the magnetic array from the electrically conductive coil array and levitates the magnetic array over the electrically conductive coil array.

Abstract: A flexible, polymer-based biosensor deployable into the arterial system which can assess shear stress in the arterial geometry in the presence of time-varying component of blood flow. Also, a method of fabricating a biosensor which may be used for in vivo procedures, involving the sequential depositing onto a substrate of a silicon dioxide layer, a metal heating element on the silicon dioxide layer, and a biocompatible polymer on the heating element, followed by etching the polymer layer to provide holes to allow for electrode contact with the heating element. A second metal layer is then deposited to form electrodes, followed by a second biocompatible polymer layer to form the device structure and removing the fabricated biosensor from the substrate by etching the substrate. In addition, a method of determining intravascular shear stress by measuring the temperature, flow rate and pressure of a bodily fluid with a biocompatible biosensor is disclosed.

Abstract: This specification describes technologies relating to converting vibration energy to electrical energy through electromagnetic transduction. According to an aspect, an apparatus to convert kinetic energy to electricity through electromagnetic transduction can include: an array of magnets arranged in a first plane; and an array of coils arranged in a second plane with respect to the first plane to form a gap between the array of magnets and the array of coils. According to another aspect, an energy harvester can include: a two dimensional array of magnets; a two dimensional array of coils; a housing configured and arranged to limit a direction of motion of either the two dimensional array of magnets or the two dimensional array of coils; and additional magnets configured and arranged to form a suspension system for either the two dimensional array of magnets or the two dimensional array of coils in the direction of motion.

Abstract: This specification describes technologies relating to converting vibration energy to electrical energy through electromagnetic transduction. According to an aspect, an apparatus to convert kinetic energy to electricity through electromagnetic transduction can include: an array of magnets arranged in a first plane; and an array of coils arranged in a second plane with respect to the first plane to form a gap between the array of magnets and the array of coils. According to another aspect, an energy harvester can include: a two dimensional array of magnets; a two dimensional array of coils; a housing configured and arranged to limit a direction of motion of either the two dimensional array of magnets or the two dimensional array of coils; and additional magnets configured and arranged to form a suspension system for either the two dimensional array of magnets or the two dimensional array of coils in the direction of motion.

Abstract: A micromachined sensor for measuring vascular parameters, such as fluid shear stress, includes a substrate having a front-side surface, and a backside surface opposite the front-side surface. The sensor includes a diaphragm overlying a cavity etched within the substrate, and a heat sensing element disposed on the front-side surface of the substrate and on top of the cavity and the diaphragm. The heat sensing element is electrically couplable to electrode leads formed on the backside surface of the substrate. The sensor includes an electronic system connected to the backside surface and configured to measure a change in heat convection from the sensing element to surrounding fluid when the sensing element is heated by applying an electric current thereto, and further configured to derive from the change in heat convection vascular parameters such as the shear stress of fluid flowing past the sensing element.

Abstract: A micromachined sensor for measuring vascular parameters, such as fluid shear stress, includes a substrate having a front-side surface, and a backside surface opposite the front-side surface. The sensor includes a diaphragm overlying a cavity etched within the substrate, and a heat sensing element disposed on the front-side surface of the substrate and on top of the cavity and the diaphragm. The heat sensing element is electrically couplable to electrode leads formed on the backside surface of the substrate. The sensor includes an electronic system connected to the backside surface and configured to measure a change in heat convection from the sensing element to surrounding fluid when the sensing element is heated by applying an electric current thereto, and further configured to derive from the change in heat convection vascular parameters such as the shear stress of fluid flowing past the sensing element.

Abstract: A DNA probe synthesis system may include a target holder for holding a target chip, an ejector array chip, a wash and dry station, and conveyance means for moving the target holder and the chip between the ejector array chip and the wash and dry station. The ejector array chip may include ejectors, reservoirs for containing DNA bases, and microchannels all on the same substrate. The ejectors may be Self Focusing Acoustic Transducers (SFATs).

Abstract: Techniques, apparatus and systems that use an acoustic transducer with a Fresnel lens to focus an acoustic wave for various applications, including acoustic droplet ejectors.

Abstract: A MEMS silicon inertial sensor formed of a mass that is supported and constrained to vibrate in only specified ways. The sensors can be separately optimized from the support, to adjust the sensitivity separate from the bandwidth. The sensor can sense three dimensionally, or can only sense in a single plane.