AI Article Synopsis
- - High sensitivity in air-coupled ultrasonic sensors is crucial for effective materials testing, and charged cellular polypropylene (PP) offers advantages over traditional piezoelectric materials due to its lower acoustic impedance and comparable piezoelectric coefficient.
- - The charged cellular PP can generate internal voltage through its polarization, and applying a dc bias voltage enhances sensor sensitivity, with experiments showing increases in signal-to-noise ratio of up to 15 ± 1 dB.
- - This research introduces the first ultrasonic sensor utilizing charged cellular PP with a high-voltage module (up to 2 kV), successfully imaging the internal structure of various materials, including rotor blade segments and glued-laminated timber.
Article Abstract
High sensitivity is an important requirement for air-coupled ultrasonic sensors applied to materials testing. With a lower acoustic impedance than any piezoelectric material, charged cellular polypropylene (PP) offers better matching to air with a similar piezoelectric coefficient. The piezoelectric properties of charged cellular PP originate from their polarization, creating permanent internal voltage. The sensitivity of the sensor can be increased by applying additional dc bias voltage, as it has been done already for transmitters. This work presents the first ultrasonic sensor based on charged cellular PP including a high-voltage module providing dc bias voltage up to 2 kV. This bias voltage led to an increase in the signal-to-noise ratio of up to 15 ± 1 dB. The measurement of the received signal depending on the applied bias voltage is proposed as a new method of determining the internal voltage of ferroelectrets. The sensor combined with a cellular PP transmitter was applied to nondestructive testing of a rotor blade segment and glued-laminated timber, enabling imaging of the internal structure of these specimens with a thickness around 4 cm.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1109/TUFFC.2019.2925666 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Accurate operando measurement of AlGaN/GaN HEMTs channel temperature and optimization of thermal design.
Nanotechnology
January 2025
Electronic Sci.&Eng., Xi'an Jiaotong University, 28 Xianning West Road,Beilin District, Xi 'an, Shaanxi Province, China, Xi'an, 710049, CHINA.
The accurate estimation of the temperature distribution of the GaN based power devices and optimization of the device structure is of great significance to possibly solve the self-heating problem, which hinders the further enhancement of the device performances. We present here the operando temperature measurement with high spatial resolution using Raman spectroscopy of AlGaN/GaN high electron mobility transistors (HEMTs) with different device structures and explore the optimization of the device thermal design accordingly. The lateral and depth temperature distributions of the single-finger HEMT were characterized.
View Article and Find Full Text PDFSelective Undercut of Undoped Optical Membranes for Spin-Active Color Centers in 4H- Silicon Carbide.
ACS Nano
January 2025
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.
Silicon carbide (SiC) is a semiconductor used in quantum information processing, microelectromechanical systems, photonics, power electronics, and harsh environment sensors. However, its high-temperature stability, high breakdown voltage, wide bandgap, and high mechanical strength are accompanied by a chemical inertness, which makes complex micromachining difficult. Photoelectrochemical (PEC) etching is a simple, rapid means of wet processing SiC, including the use of dopant-selective etch stops that take advantage of the mature SiC homoepitaxy.
View Article and Find Full Text PDFBuilding Localized NADP(H) Recycling Circuits to Advance Enzyme Cascadetronics.
Angew Chem Int Ed Engl
January 2025
University of Oxford, Chemistry, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
The catalytic action of enzymes of a cascade trapped within a mesoporous electrode material is simultaneously energized, controlled and observed through the efficient, reversible electrochemical NAD(P)(H) recycling catalyzed by one of the enzymes. In their nanoconfined state, nicotinamide cofactors are tightly channeled current carriers, mediating multi-step reactions in either direction (oxidation or reduction) with a rapid response time. By incorporating a hydrogen‑borrowing enzyme pair, the internal action of which opposes the external voltage bias driving oxidation or reduction, a reduction process can be performed under overall oxidizing conditions, and vice versa.
View Article and Find Full Text PDFChirp modulation can generate a relatively flat electro-optic frequency comb (EO comb) and offers the advantage of frequency reconfigurability, demonstrating significant potential in high-precision sensing and absorption spectroscopy measurements. However, nonresonant devices such as waveguides are susceptible to limitations in modulation efficiency and bandwidth during electro-optic modulation. In this paper, by utilizing chirp modulation resonance mode, we have realized an EO comb based on a lithium niobate resonator with small tooth spacing and high flatness.
View Article and Find Full Text PDFThe explosive growth of mobile data traffic and the demands of 6 G networks for ultra-high data rates and low latency necessitate advanced infrastructure solutions. One promising approach is the implementation of radio-over-fiber (RoF)-based distributed antenna systems (DAS), which can efficiently transmit radio frequency signals over optical fiber, especially in dense indoor environments. However, analog RoF systems face challenges, including noise, nonlinearities, and power fading caused by chromatic dispersion.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!