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The precision requirements for aeroengine blade machining are exceedingly stringent. This study aims to improve the accuracy of existing aeroengine blade measurement methods while achieving comprehensive measurement. Therefore, this study proposes a new concentric ring calibration method and designs a multi-layer concentric ring calibration plate. The effectiveness of this calibration method was verified through actual testing of standard ball gauges. Compared with the checkerboard-grid calibration method, the average deviation of the multilayer concentric ring calibration method for measuring the center distance of the standard sphere is 0.02352, which improves the measurement accuracy by 3-4 times. On the basis of multi-layer concentric ring calibration, this study builds a fringe projection profiler based on the three-frequency twelve-step phase shift method. Compared with the CMM, the average deviation of the blade chord length measured by this solution is 0.064, which meets the measurement index requirements of aeroengine fan blades.
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http://dx.doi.org/10.3390/s24092810 | DOI Listing |
NMR Biomed
October 2025
High-Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
The human kidneys play a pivotal role in regulating blood pressure, water, and salt homeostasis, but assessment of renal function typically requires invasive methods. Deuterium metabolic imaging (DMI) is a novel, noninvasive technique for mapping tissue-specific uptake and metabolism of deuterium-labeled tracers. This study evaluates the feasibility of renal DMI at 7-Tesla (7T) to track deuterium-labeled tracers with high spatial and temporal resolution, aiming to establish a foundation for potential clinical applications in the noninvasive investigation of renal physiology and pathophysiology.
View Article and Find Full Text PDFMaterials (Basel)
July 2025
School of Mechanical Engineering, Shenyang Ligong University, Nanping Middle Road 6, Shenyang 110159, China.
Addressing the challenges of bulky, low-efficiency sound-insulation materials at low frequencies, this work proposes an acoustic metamaterial based on curve fractal channels. Each unit cell comprises a concentric circular-ring channel recursively iterated: as the fractal order increases, the channel path length grows exponentially, enabling outstanding sound-insulation performance within a deep-subwavelength thickness. Finite-element and transfer-matrix analyses show that increasing the fractal order from one to three raises the number of bandgaps from three to five and expands total stop-band coverage from 17% to over 40% within a deep-subwavelength thickness.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
January 2025
Circularly coherent sources, which are perfectly coherent on any ring that is concentric to the beam center, can preserve the spiral phase structures of optical vortices on propagation, making them potentially useful for free-space applications such as communications and remote sensing. In this study, we theoretically examine circularly coherent vortex beams by imposing circular coherence on Laguerre-Gaussian (LG) beams. The second-order coherence properties and coherence singularities of these circularly coherent vortex beams are investigated in free-space propagation up to 3 km.
View Article and Find Full Text PDFEntropy (Basel)
July 2025
Laboratório de Física Teórica e Computacional, Departamento de Física, Universidade Federal de Pernambuco, Recife 50670-901, PE, Brazil.
We revisit the problem of random search walks in the two-dimensional (2D) space between concentric absorbing annuli, in which a searcher performs random steps until finding either the inner or the outer ring. By considering step lengths drawn from a power-law distribution, we obtain the exact analytical result for the search efficiency η in the ballistic limit, as well as an approximate expression for η in the regime of searches starting far away from both rings, and the scaling behavior of η for very small initial distances to the inner ring. Our numerical results show good overall agreement with the theoretical findings.
View Article and Find Full Text PDFEur Heart J Case Rep
July 2025
Division of Cardiovascular Medicine, University of Virginia Health System, Charlottesville, VA 22902, USA.
Background: Hypertrophic cardiomyopathy (HCM) is a relatively common genetic disorder often associated with left ventricular outflow tract (LVOT) obstruction. However, the presence of certain structural abnormalities such as supravalvular aortic stenosis (SVAS) can contribute to elevated LVOT gradients and thereby mimic obstructive HCM. This case highlights the importance of multimodality imaging in accurately determining the aetiology of LVOT obstruction, which is critical to guiding appropriate management.
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