Endoscopic ultrasound (EUS), an interventional imaging technology, utilizes a circular array to delineate the cross-sectional morphology of internal organs through the gastrointestinal (GI) track. However, the performance of conventional EUS transducers has scope for improvement because of the ordinary piezoelectric parameters of Pb(Zr, Ti) [Formula: see text] (PZT) bulk ceramic as well as its inferior mechanical flexibility which can cause material cracks during the circular shaping process. To achieve both prominent imaging capabilities and high device reliability, a 128-element 6.8-MHz circular array transducer is developed using a Pb(Mg [Formula: see text]Nb [Formula: see text]) [Formula: see text]-PbTiO (PMN-PT) 1-3 composite with a coefficient of high electromechanical coupling ( [Formula: see text]) and good mechanical flexibility. The characterization results exhibit a large average bandwidth of 58%, a high average sensitivity of 100 mV, and a crosstalk of less than -37 dB near the center frequency. Imaging performance of the PMN-PT composite-based array transducer is evaluated by a wire phantom, an anechoic cyst phantom, and an ex-vivo swine intestine. This work demonstrates the superior performance of the crucial ultrasonic device based on an advanced PMN-PT composite material and may lead to the development of next-generation biomedical ultrasonic devices for clinical diagnosis and treatment.
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http://dx.doi.org/10.1109/TUFFC.2020.3005029 | DOI Listing |
J Environ Manage
January 2025
Faculty of Materials and Chemical Engineering, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
The ubiquitous presence of plastic waste presents a significant environmental challenge, characterized by its persistence and detrimental impacts on ecosystems. The valorization of plastic waste through conversion into high-value carbon materials offers a promising circular economy approach. This review critically examines the potential of plastic waste-derived activated carbon (PAC) as a sustainable and effective adsorbent for water remediation.
View Article and Find Full Text PDFWe report on the design and fabrication of a novel circular pillar array as an interfacial barrier for microfluidic microphysiological systems (MPS). Traditional barrier interfaces, such as porous membranes and microchannel arrays, present limitations due to inconsistent pore size, complex fabrication and device assembly, and lack of tunability using a scalable design. Our pillar array overcomes these limitations by providing precise control over pore size, porosity, and hydraulic resistance through simple modifications of pillar dimensions.
View Article and Find Full Text PDFIn this paper, we propose what we believe to be a novel method to enhance both the field of view and angular resolution of a microlens array-based thin virtual reality near-eye display using a polarization grating. The proposed system employs a polarization grating to steer the field angle according to the polarization states, simultaneously enhancing the field of view and angular resolution. Optical experiments and Zemax simulations validate the effectiveness of our approach, with the field of view in the experimental setup expanding from 58.
View Article and Find Full Text PDFQuantitative phase imaging (QPI) has become a valuable tool in the field of biomedical research due to its ability to quantify refractive index variations of live cells and tissues. For example, three-dimensional differential phase contrast (3D DPC) imaging uses through-focus images captured under different illumination patterns deconvoluted with a computed 3D phase transfer function (PTF) to reconstruct the 3D refractive index. In conventional 3D DPC with semi-circular illumination, partially spatially coherent illumination often diminishes phase contrast, exacerbating inherent noise, and can lead to a large number of zero values in the 3D PTF, resulting in strong low-frequency artifacts and deteriorating imaging resolution.
View Article and Find Full Text PDFIn this study, we propose a double-layer elliptical nanohole array (DLEN) and investigate its chiral properties using the finite element method. The DLEN structure simultaneously exhibited asymmetric reflection (AR), circular dichroism (CD), and asymmetric transmission (AT) effects with specific measured values. By analyzing the full cycle of plasmon resonance modes, we identified that the local rotational resonance excited by circular polarized light (CPL) is important in the conversion of right circularly polarized (RCP) and left circularly polarized (LCP) light upon reflection and transmission.
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