We present experimental demonstration of specific resonance mode enhancement and suppression in circular and rectangular piezoelectric wafers with engineered non-uniform polarization profiles. The polarization profiles are designed based on the electromechanical impedance response of non-uniformly polarized wafers as obtained from the theory. The circular wafers are fabricated with non-uniform polarization profiles that involve a central polarized region surrounded by an unpolarized region. The radius of the polarization zone is designed based on the condition for specific mode enhancement obtained from the electromechanical impedance response of non-uniformly polarized wafers. We actually show how the condition can not only be used to enhance but also to suppress electromechanical resonances. Two kinds of wafers are designed and fabricated to specifically suppress second and third radial modes respectively. Similarly, rectangular wafers are designed with two different kinds of non-uniform polarization profiles - the first of which enhances the second in-plane extensional mode in the impedance spectrum and the second polarization profile suppresses all the electromechanical resonances pertaining to the in-plane extensional modes and selectively excites only the in-plane bending modes. The proposed approach of using non-uniformly polarized wafers finds application in designing multi-frequency sensors/transducers, frequency-tuned receivers, acoustic beamforming, and other non-traditional applications such as information storage.
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http://dx.doi.org/10.1016/j.ultras.2022.106878 | DOI Listing |
In this study, we utilized a discrete point configuration method in conjunction with genetic algorithm (GA) and particle swarm optimization (PSO) to design broadband polarization-maintaining anti-resonant fibers (PM-ARFs). The resulting structure features a confinement loss (CL) below 0.17 dB/m, birefringence of approximately 8.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Vascular Surgery, RWTH Aachen University Hospital, 52074 Aachen, Germany.
Thoracoabdominal aortic aneurysms (TAAAs) are rare but serious conditions characterized by dilation of the aorta characterized by remodeling of the vessel wall, with changes in the elastin and collagen content. Individuals with Marfan syndrome have a genetic predisposition for elastic fiber fragmentation and elastin degradation and are prone to early aneurysm formation and progression. Our objective was to analyze the medial collagen characteristics through histological, polarized light microscopy, and electron microscopy methods across the thoracic and abdominal aorta in twenty-five patients undergoing open surgical repair, including nine with Marfan syndrome.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Institute of Physics, Kazan Federal University, 18 Kremlevskaya St., Kazan 420008, Russia.
The spectral characteristics of cyclosporin C (CsC) with the addition of Dy ions in acetonitrile (CDCN) and CsC with Dy incorporated into dodecylphosphocholine (DPC) micelle in deuterated water were investigated by high-resolution NMR spectroscopy. The study was focused on the interaction between Dy ions and CsC molecules in different environments. Using a combination of one-dimensional and two-dimensional NMR techniques, we obtained information on the spatial features of the peptide molecule and the interaction between CsC and the metal ion.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
College of Materials Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China; Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 211816, China. Electronic address:
Sodium metal is heralded as a premier anode candidate poised to supplant lithium in next-generation rechargeable batteries due to its abundant availability, cost-effectiveness, and superior energy density. Due to the highly reactive nature of metallic sodium, an unstable solid electrolyte interphase (SEI) forms spontaneously on the Na metal anode. This instability leads to non-uniform sodium deposition during cycling, promoting dendrite growth and the accumulation of "dead" sodium.
View Article and Find Full Text PDFThe interaction between dual counter-propagating high-order circularly symmetric Bessel beams (CSBBs) and multi-layered chiral particles is investigated. Within the framework of generalized Lorenz-Mie theory (GLMT), the distribution characteristics of the superposition of two beams are studied based on the vector superposition theorem. The near-field, internal field, and far-field radar cross section (RCS) of the dual-layered chiral sphere illuminated by dual CSBBs are obtained according to the boundary conditions.
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