A5014251377- Ultrasound Imaging and Elastography
- Ultrasound and Hyperthermia Applications
- Acoustic Wave Resonator Technologies
- Analytical Chemistry and Sensors
- Microfluidic and Capillary Electrophoresis Applications
- Mechanical and Optical Resonators
- Gas Sensing Nanomaterials and Sensors
- Advanced Chemical Sensor Technologies
- Ultrasonics and Acoustic Wave Propagation
- Advanced Sensor and Energy Harvesting Materials
- Radio Frequency Integrated Circuit Design
- GaN-based semiconductor devices and materials
- Wireless Body Area Networks
- Advanced MEMS and NEMS Technologies
- Wireless Power Transfer Systems
- Ultrasound and Cavitation Phenomena
Stanford University
2014-2022
Focused ultrasound (FUS) is a powerful tool for noninvasive modulation of deep brain activity with promising therapeutic potential refractory epilepsy; however, tools examining FUS effects on specific cell types within the do not yet exist. Consequently, how heterogeneous networks can be modulated and whether parameters identified to bias these in context complex behaviors remains unknown. To address this, we developed fiber Photometry Coupled focused Ultrasound System (PhoCUS)...
Capacitive micromachined ultrasonic transducers (CMUTs) can function as extremely sensitive mass-loading chemical sensors. The resonant frequency of the CMUT changes mass is added due to chemicals absorbing into a chemical-sensitive layer on top plate. However, these sensors suffer from problem that they are not selective single chemical. As solution, we present system four with different functionalization layers. Neural networks used do pattern recognition sensor outputs in order...
CMUTs make very sensitive gravimetric chemical sensors in air. Selectivity can be improved by using arrays of these with different functionalization coatings. However, operating multiple sensor on the same chip challenging because frequency locking and greater difficulty functionalization. In prior work, or only two three have been used at once chip. Here, we present results showing simultaneous operation 8 CMUT a single chip, demonstrate ability array to recognize chemicals
Capacitive micromachined ultrasonic transducers (CMUTs) make extremely sensitive chemical sensors in air. In this work, we demonstrate a CMUT sensor chip with integrated temperature and pressure sensors. These allow the measurement of multiple environmental parameters using single influence on to be corrected for. Additionally, CMUTs are designed have low charging. We use correct for resonance frequency variations due temperature. With correction, measure drift two 19 parts per million 59...
Capacitive Micromachined Ultrasonic Transducers (CMUTs) can be used as small, highly sensitive chemical sensors in air. Single CMUT lack selectivity, but arrays of multiple to allow selective detection. In this work, we demonstrate the simultaneous operation eight on a single chip. We then use seven from array classify five different vapors and measure their concentrations. Finally, same sensor three samples coffee beans grown farms. The is able perform both classification tasks with 100%...
Focused ultrasound treats tissue deep in the body without damaging surrounding structures. Driven by large-amplitude RF electrical signals, ultrasonic transducers can generate large pressure acoustic wave. Wide-bandgap semiconductors, e.g., Gallium Nitride (GaN), greatly simplify design and reduce requisite size weight of amplifiers, so improves portability focused device. Here, we demonstrate a compact 8-phase 5 MHz Class-D resonant amplifier for cancer therapy application.
We developed previously a 2D CMUT array with capability to both do imaging and generate HIFU for ablation of targeted tissues without collateral damage. This new technology allows more compact system, when compared conventional systems composed transducers made PZT, cooling PZT additional guidance systems. In this paper we present dc RF power electronics that drive our array. The are significantly capable fast-switching between mode.
High Intensity Focused Ultrasound (HIFU) therapy requires imaging guidance to ensure that the correct area is treated. Guidance may be provided by magnetic resonance or ultrasound imaging. With piezoelectric transducers, typically done with a separate transducer array since it difficult obtain sufficient and HIFU performance same transducers. However, Capacitive Micromachined Ultrasonic Transducers (CMUTs) can have bandwidth efficiency allow both array. Additionally, CMUTs much lower...
Capacitive Micromachined Ultrasonic Transducer (CMUT) chemical sensors have demonstrated outstanding sensitivity for sensing in air. In order to achieve good low limit of detection and sensor reliability, attention must be paid the interface circuits. this work, we demonstrate how a transistor-based oscillator circuit can used noise, small size power consumption CMUT arrays. We show optimize these circuits, they enabled disabled allow multiplexing time.