Ultrasonic focusing transducers have broad prospects in advanced ultrasonic non-destructive testing fields. However, conventional focusing methods that use acoustic concave lenses can disrupt the acoustic impedance matching condition, thereby adversely affecting the sensitivity of the transducers. In this paper, an active focusing planar ultrasonic transducer is designed and presented to achieve a focusing effect with a higher sensitivity. An electrode pattern consisting of multiple concentric rings is designed, which is inspired by the structure of Fresnel Zone Plates (FZP). The structural parameters are optimized using finite element simulation methods. A prototype of the transducer is manufactured with electrode patterns made of conductive silver paste using silk screen-printing technology. Conventional focusing transducers using an acoustic lens and an FZP baffle are also manufactured, and their focusing performances are comparatively tested. The experimental results show that our novel transducer has a focal length of 16 mm and a center frequency of 1.16 MHz, and that the sensitivity is improved by 23.3% compared with the conventional focusing transducers. This research provides a new approach for the design of focusing transducers.
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http://dx.doi.org/10.3390/s24134082 | DOI Listing |
J Phys Chem A
January 2025
Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China.
Plasmon resonance plays an important role in improving the detection of biomolecules, and it is one of the focuses of research to use metal plasmon resonance to achieve fluorescence enhancement and to improve detection sensitivity. However, the problems of nondynamic tuning and fluorescence quenching of metal plasmon resonance need to be solved. Graphene surface plasmon resonance can be dynamically controlled, and the graphene adsorption of fluorescent molecules can avoid fluorescence quenching and greatly improve the fluorescence emission intensity.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of Mechanical, Robotics and Energy Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
In composite structures, the precise identification and localization of damage is necessary to preserve structural integrity in applications across such fields as aeronautical, civil, and mechanical engineering. This study presents a deep learning (DL)-assisted framework for simultaneous damage localization and severity assessment in composite structures using Lamb waves (LWs). Previous studies have often focused on either damage detection or localization in composite structures.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
Department of Electromechanical Engineering, Faculty of Science and Technology, University of Macau, Avenida da Universidade, Taipa, Macau, China.
With advancements in small-scale research fields, precision manipulation has become crucial for interacting with small objects. As research progresses, the demand for higher precision in manipulation has led to the emergence of ultrahigh-precision engineering (UHPE), which exhibits significant potential for various applications. Traditional rigid-body manipulators suffer from issues like backlash and friction, limiting their effectiveness at smaller-scale applications.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
Department of Microsystem Technology, University of Applied Sciences Berlin, 12459 Berlin, Germany.
Shock wave boundary/layer interactions (SWBLIs) are critical in high-speed aerodynamic flows, particularly within supersonic regimes, where unsteady dynamics can induce structural fatigue and degrade vehicle performance. Conventional measurement techniques, such as pressure-sensitive paint (PSP), face limitations in frequency response, calibration complexity, and intrusive instrumentation. Similarly, MEMS-based sensors, like Kulite sensors, present challenges in terms of intrusiveness, cost, and integration complexity.
View Article and Find Full Text PDFUltrason Imaging
January 2025
Biomedical Ultrasound Imaging Laboratory, Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology, Madras, Chennai, India.
Imaging depth remains a restriction for Synthetic Aperture (SA) approaches, even though SA techniques have been shown to overcome some of the drawbacks of Conventional Focused Beamforming (CFB) technique. This limitation is attributed to lesser energy per transmit in SA techniques compared to that of CFB technique. Therefore, in this paper, a systematic investigation is done to evaluate the improvement in imaging depth and image quality of B-mode ultrasound images in the case of SA technique using PZT transducer by boosting the input voltage to the transducer, while measuring the acoustic exposure parameters recommended in international standards.
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