A novel ultrasonic matching layer for improving coupling between piezoelectric transducers and an air load is presented and the results of a theoretical and experimental program of work are provided. A combination of a porous material that has very low acoustic impedance with a low-density rubber material forms the basis of the approach. These matching layers were first analyzed experimentally using scanning electron and optical microscopy to determine the microscopic structure. Air-coupled resonance measurements were then performed to reveal the acoustic parameters of the individual layers that were identified within this multilayered structure. These data were then incorporated into a conventional linear model, and this has been verified and used to study performance and produce designs. Close correlation between experiment and theory is demonstrated. The most efficient designs have been implemented in a pitch/catch air-coupled system, and an improvement in received signal amplitude of 30 dB was achieved when compared with the unmatched case.
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http://dx.doi.org/10.1109/tuffc.2004.1350960 | DOI Listing |
Am J Ophthalmol
January 2025
Hacettepe University School of Medicine, Department of Ophthalmology, Ankara, Turkey.
Objective: To evaluate the effects of Fanconi anemia (FA) on retinal and choroidal microvasculature using Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA).
Design: Cohort study with age-matched controls.
Subjects And Participants: This study included 11 eyes from 11 patients diagnosed with FA and 12 eyes from 12 age-matched healthy controls.
Phys Chem Chem Phys
January 2025
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, P. R. China.
It is a major challenge to obtain broadband microwave absorption (MA) properties using low dielectric or magnetic nanoparticle-decorated carbon composites due to the limited single conductive loss or polarization loss of the carbon materials used as substrates. Novel pure cellulose-derived graphite carbon (CGC) materials can be used as an exceptional substrate option due to their special defective graphitic carbon structure, which provides both conduction and polarization loss. Herein, CGC@ZnO composites were first synthesized by atomic layer deposition (ALD) for use as microwave absorbents.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Electrical Engineering, Feng Chia University, Taichung, 407802, Taiwan.
This study presents an innovative glucose detection platform, featuring a highly sensitive, non-enzymatic glucose sensor. The sensor integrates nickel nanowires and a graphene thin film deposited on the gate region of an extended-gate electric double-layer field-effect transistor (EGEDL-FET). This unique combination of materials and device structure enables superior glucose sensing performance.
View Article and Find Full Text PDFJ Comput Assist Tomogr
January 2025
Department of Radiology, College of Medicine, University of Florida, Gainesville, FL.
Purpose: This study evaluated beam quality and radiation dosimetry of a CT scanner equipped with a novel detector and filtration technology called PureVision Optics (PVO). PVO features miniaturized electronics, a detector cut with microblade technology, and increased filtration in order to increase x-ray detection and reduce image noise.
Methods: We assessed the performance of two similar 320-detector CT scanners: one equipped with PVO and one without.
We propose an alternative data-free deep learning method using a physics-informed neural network (PINN) to enable more efficient computation of light diffraction from 3D optical metasurfaces, modeling of corresponding polarization effects, and wavefront manipulation. Our model learns only from the governing physics represented by vector Maxwell's equations, Floquet-Bloch boundary conditions, and perfectly matched layers (PML). PINN accurately simulates near-field and far-field responses, and the impact of polarization, meta-atom geometry, and illumination settings on the transmitted light.
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