Film-type shape-configurable speakers with tunable sound directivity are in high demand for wearable electronics. Flexible, thin thermoacoustic (TA) loudspeakers-which are free from bulky vibrating diaphragms-show promise in this regard. However, configuring thin TA loudspeakers into arbitrary shapes is challenging because of their low sound pressure level (SPL) under mechanical deformations and low conformability to other surfaces. By carefully controlling the heat capacity per unit area and thermal effusivity of an MXene conductor and substrates, respectively, it fabricates an ultrathin MXene-based TA loudspeaker exhibiting high SPL output (74.5 dB at 15 kHz) and stable sound performance for 14 days. Loudspeakers with the parylene substrate, whose thickness is less than the thermal penetration depth, generated bidirectional and deformation-independent sound in bent, twisted, cylindrical, and stretched-kirigami configurations. Furthermore, it constructs parabolic and spherical versions of ultrathin, large-area (20 cm × 20 cm) MXene-based TA loudspeakers, which display sound-focusing and 3D omnidirectional-sound-generating attributes, respectively.
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http://dx.doi.org/10.1002/adma.202306637 | DOI Listing |
J Acoust Soc Am
January 2025
Jianglu Mechanical Electrical Group Company Limited, Xiangtan 411105, China.
Topological acoustic waveguides have a potential for applications in the precise transmission of sound. Currently, there is more attention to multi-band in this field. However, achieving tunability of the operating band is also of great significance.
View Article and Find Full Text PDFSoft Matter
January 2025
Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, P. R. China.
Traveling waves are universal in excitable systems; yet, the microscopic dynamics of wave propagation is inaccessible in conventional excitable systems. Here, we show that active colloids of Quincke rollers driven by a periodic electric field can form condensed excitable phases. Distinct from existing excitable media, condensed excitable colloids can be tuned reversibly between active liquids and active crystals in which two distinct waves can be excited, respectively.
View Article and Find Full Text PDFNanophotonics
March 2024
Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
The acousto-optic modulation over a broad near-infrared (NIR) spectrum with high speed, excellent integrability, and relatively simple scheme is crucial for the application of next-generation opto-electronic and photonic devices. This study aims to experimentally demonstrate ultrafast acousto-optic phenomena in the broad NIR spectral range of 0.77-1.
View Article and Find Full Text PDFJ Voice
November 2024
Department of Information and Communications Engineering, Aalto University, Espoo 02150, Finland.
Phonation is the use of the laryngeal system, with the help of an air-stream provided by the respiratory system, to generate audible sounds. Humans are capable of generating voices of various phonation types (eg, breathy, neutral, and pressed), and these types are used both in singing and speaking. In this study, we propose to use features derived using the tunable Q-factor wavelet transform (TQWT) for classification of phonation types in the singing and speaking voice.
View Article and Find Full Text PDFNan Fang Yi Ke Da Xue Xue Bao
September 2024
Department of Computer Science and Technology, College of Electronic and Information Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
Objective: To construct a model with a spatial and channel reconstruction convolutional module for accurate identification and classification of lung sound data.
Methods: We propose a convolutional network architecture combining the spatial-channel reconstruction convolution (SCConv) module. A lung sound feature extraction method combining the dual tunable Q-factor wavelet transform (DTQWT) with the triple Wigner-Ville transform (WVT) was used to improve the model's ability to capture the key features of the lung sounds by adaptively focusing on the important channel and spatial features.
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