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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. Four-microphone impedance-tube measurements on the third-order sample validate a peak transmission loss of 75 dB at 495 Hz, in excellent agreement with simulations. Compared to conventional zigzag and Hilbert-maze designs, this curve fractal architecture delivers enhanced low-frequency broadband insulation, structural lightweighting, and ease of fabrication, making it a promising solution for noise control in machine rooms, ducting systems, and traffic environments. The method proposed in this paper can be applied to noise reduction of transmission parts for ceramic automation production.
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http://dx.doi.org/10.3390/ma18153616 | DOI Listing |
Surg Neurol Int
July 2025
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, United States.
Background: With excitement in the medical community around artificial intelligence, machine learning (ML) techniques have been applied to correlate clinical and radiographic variables with intracranial aneurysm (IA) rupture status. In this study, we applied various ML techniques, including random forest (RF), XGBoost (XGB), support vector machines (SVM), and multi-layer perceptron (MLP), to predict IA rupture status.
Methods: The dataset consisted of 178 IAs each with 53 clinical and radiographic features for analysis.
Int J Lab Hematol
August 2025
Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA.
Introduction: Of all the cells identified in peripheral blood smears, reactive lymphocytes (RLs) and blasts are considered especially difficult to differentiate. Blasts and RLs are present in distinct diseases that carry unique prognoses and treatments; however, there are currently no definitive methods to distinguish these cells morphologically.
Methods: We developed a method to distinguish between blasts and RLs based on the quantification of fractal chromatin patterns.
Materials (Basel)
August 2025
State Key Laboratory of Precision Blasting, Jianghan University, Wuhan 430056, China.
In high geothermal tunnels (>28 °C), curing temperature critically affects early-age concrete mechanics and durability. Uniaxial compression tests under six curing conditions, combined with CT scanning and machine learning-based crack analysis, were used to evaluate the impacts of curing age, temperature, and fiber content. The test results indicate that concrete exhibits optimal development of mechanical properties under ambient temperature conditions.
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 PDFEur Radiol
August 2025
Department of Radiology, West China Hospital, Sichuan University, Chengdu, China.
Objectives: This study aimed to assess the potential role of 3-dimensional (3D) fractal dimension (FD) derived from contrast-enhanced CT images in predicting microvascular invasion (MVI) in patients with hepatocellular carcinoma (HCC).
Materials And Methods: This retrospective study included 655 patients with surgically confirmed HCC from two medical centers (training set: 406 patients; internal test set: 170 patients; external test set: 79 patients). Box-counting algorithms were used to compute 3D FD values from portal venous phase images.