Pub Date : 2025-12-11DOI: 10.1016/j.sna.2025.117393
Yulim Seol , Jaeheon Jeong , Ji-Hye Shim , Hak-Sung Kim , Hongyun So
The increasing demand for high-density, fine-pitch semiconductor packaging has made reliable electrical probing essential for yield assurance and process monitoring. However, conventional metal-to-metal contact probing often induces severe mechanical damage to fragile microbumps, resulting in degraded electrical reliability and surface wear. In this study, we propose a microanisotropic polydimethylsiloxane (PDMS) sheet (MAPS) that enables damage-free yet electrically stable probing by introducing a compliant and anisotropically conductive interface between the probe and device under test. The MAPS, comprising a PDMS matrix and conductive fillers, was fabricated by a lithography-based soft-molding process that enables precise control of the hole diameter, pitch, and sheet thickness. In addition, no surface damage or electrical aging was observed after 2500 repeated probing cycles, confirming its long-term structural and electrical durability. These findings underscore the scalability and process compatibility of the proposed MAPS architecture for future fine-pitch applications, suggesting its considerable potential as a next-generation high-reliability electrical testing platform for advanced semiconductor packaging.
{"title":"Microstructured anisotropic PDMS sheet for damage-free electrical testing of semiconductor packages","authors":"Yulim Seol , Jaeheon Jeong , Ji-Hye Shim , Hak-Sung Kim , Hongyun So","doi":"10.1016/j.sna.2025.117393","DOIUrl":"10.1016/j.sna.2025.117393","url":null,"abstract":"<div><div>The increasing demand for high-density, fine-pitch semiconductor packaging has made reliable electrical probing essential for yield assurance and process monitoring. However, conventional metal-to-metal contact probing often induces severe mechanical damage to fragile microbumps, resulting in degraded electrical reliability and surface wear. In this study, we propose a microanisotropic polydimethylsiloxane (PDMS) sheet (MAPS) that enables damage-free yet electrically stable probing by introducing a compliant and anisotropically conductive interface between the probe and device under test. The MAPS, comprising a PDMS matrix and conductive fillers, was fabricated by a lithography-based soft-molding process that enables precise control of the hole diameter, pitch, and sheet thickness. In addition, no surface damage or electrical aging was observed after 2500 repeated probing cycles, confirming its long-term structural and electrical durability. These findings underscore the scalability and process compatibility of the proposed MAPS architecture for future fine-pitch applications, suggesting its considerable potential as a next-generation high-reliability electrical testing platform for advanced semiconductor packaging.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117393"},"PeriodicalIF":4.9,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.sna.2025.117377
Mohammad Nizar Mohamed Zukri, Muhammad Salman Al Farisi, Yoshihiro Hasegawa, Mitsuhiro Shikida
Micro-electro mechanical systems (MEMS) thermal flow sensors are increasingly used for compact, low-power flow monitoring in biomedical applications. However, silicon-based method for sensor fabrication is limited by high cost, rigidity, and multi-step cleanroom processes. This study presents a single-step fiber laser micromachining method for fabricating biocompatible, free-standing MEMS thermal flow sensors from ultrathin titanium foil. The process combines patterning and localized thinning in single-step process, with titanium serving as resistive sensing element. A dual-matrix optimization approach consisting of a Threshold Mapping Matrix (TMM) and Energy Density Matrix (EDM) was used to determine optimized parameters without repeated trial-and-error. For localized thinning, sequential R-T scans with cooling intervals reduced redeposition from the Gaussian beam profile and produced uniform thickness reduction from 50 µm to 20–30 µm. The fabricated sensors were evaluated through thermal coefficient resistance (TCR) measurement, Infrared (IR) thermography, and airflow tests under steady and cyclic conditions controlled by artificial ventilation system. The fabricated devices showed a stable TCR of 3278 ppm °C⁻¹ , a linear relationship calibration curve between velocity and resistance with R2 = 0.986 and a 54 % improvement in thermal response was achieved with the free-standing structure design compared to substrate-fixed designs. This fabrication approach removes the need for photolithography, wet/dry etching, and wafer bonding, enabling faster and lower-cost production of flexible, biocompatible flow sensors. The method can be applied to other MEMS devices that require compact size, flexibility, localized thinning and free-standing structures.
{"title":"Single-step laser patterning and thinning of biocompatible MEMS flow sensor","authors":"Mohammad Nizar Mohamed Zukri, Muhammad Salman Al Farisi, Yoshihiro Hasegawa, Mitsuhiro Shikida","doi":"10.1016/j.sna.2025.117377","DOIUrl":"10.1016/j.sna.2025.117377","url":null,"abstract":"<div><div>Micro-electro mechanical systems (MEMS) thermal flow sensors are increasingly used for compact, low-power flow monitoring in biomedical applications. However, silicon-based method for sensor fabrication is limited by high cost, rigidity, and multi-step cleanroom processes. This study presents a single-step fiber laser micromachining method for fabricating biocompatible, free-standing MEMS thermal flow sensors from ultrathin titanium foil. The process combines patterning and localized thinning in single-step process, with titanium serving as resistive sensing element. A dual-matrix optimization approach consisting of a Threshold Mapping Matrix (TMM) and Energy Density Matrix (EDM) was used to determine optimized parameters without repeated trial-and-error. For localized thinning, sequential R-T scans with cooling intervals reduced redeposition from the Gaussian beam profile and produced uniform thickness reduction from 50 µm to 20–30 µm. The fabricated sensors were evaluated through thermal coefficient resistance (TCR) measurement, Infrared (IR) thermography, and airflow tests under steady and cyclic conditions controlled by artificial ventilation system. The fabricated devices showed a stable TCR of 3278 ppm °C⁻¹ , a linear relationship calibration curve between velocity and resistance with <em>R</em><sup>2</sup> = 0.986 and a 54 % improvement in thermal response was achieved with the free-standing structure design compared to substrate-fixed designs. This fabrication approach removes the need for photolithography, wet/dry etching, and wafer bonding, enabling faster and lower-cost production of flexible, biocompatible flow sensors. The method can be applied to other MEMS devices that require compact size, flexibility, localized thinning and free-standing structures.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117377"},"PeriodicalIF":4.9,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145739046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.sna.2025.117386
Weihong Chen , Wei Jin , Jiaxing Gao , Xiang Li , Zhenrui Wang , He Zhang , Yu Zhang , Yifan Qin , Zhihai Liu , Longxiang Guo , Liang Zhang , Heping Shen , Libo Yuan
Both high sensitivity and high flexibility are essential characteristics for high-performance flexible sensors. However, most existing flexible pressure sensing devices employ designs that directly convert pressure into electrical signals. Constrained by material properties and structural limitations, these sensors often struggle to simultaneously achieve weak pressure detection, high flexibility, and high sensitivity. This study proposes a wearable pulse sensor based on a microfiber knot resonator (MKR), fabricated by encapsulating the resonator within a flexible polydimethylsiloxane (PDMS) substrate. The sensor leverages the strong evanescent field of the micro/nanofiber and the sensitization effect of the micro-ring structure to achieve significantly enhanced sensitivity. Concurrently, the PDMS encapsulation addresses the inherent rigidity and environmental noise susceptibility of traditional optical sensors. This approach not only improves detection accuracy but also endows the sensor with high flexibility. Experimental results demonstrate that the sensor achieves a sensitivity of 0.27 V/kPa within a pressure range of 0–20 kPa and an ultra-fast response time of 0.7 ms. Furthermore, it maintains high reproducibility over 100,000 test cycles. Additionally, by leveraging pulse wave signal feature extraction and machine learning algorithms, this sensor can continuously and accurately identify resting heart rate, healthy exercise heart rate, and unhealthy exercise heart rate with up to 95 % accuracy. This wearable sensor technology offers a novel solution for non-invasive personalized medical monitoring. With its exceptional biocompatibility, the sensor can be integrated into smart clothing and remote health monitoring systems to enable long-term dynamic physiological parameter monitoring, opening broader application prospects for precision medicine and health management.
{"title":"Micro-nano fiber pressure sensor based on PDMS packaging microfiber knot for pulse wave monitoring","authors":"Weihong Chen , Wei Jin , Jiaxing Gao , Xiang Li , Zhenrui Wang , He Zhang , Yu Zhang , Yifan Qin , Zhihai Liu , Longxiang Guo , Liang Zhang , Heping Shen , Libo Yuan","doi":"10.1016/j.sna.2025.117386","DOIUrl":"10.1016/j.sna.2025.117386","url":null,"abstract":"<div><div>Both high sensitivity and high flexibility are essential characteristics for high-performance flexible sensors. However, most existing flexible pressure sensing devices employ designs that directly convert pressure into electrical signals. Constrained by material properties and structural limitations, these sensors often struggle to simultaneously achieve weak pressure detection, high flexibility, and high sensitivity. This study proposes a wearable pulse sensor based on a microfiber knot resonator (MKR), fabricated by encapsulating the resonator within a flexible polydimethylsiloxane (PDMS) substrate. The sensor leverages the strong evanescent field of the micro/nanofiber and the sensitization effect of the micro-ring structure to achieve significantly enhanced sensitivity. Concurrently, the PDMS encapsulation addresses the inherent rigidity and environmental noise susceptibility of traditional optical sensors. This approach not only improves detection accuracy but also endows the sensor with high flexibility. Experimental results demonstrate that the sensor achieves a sensitivity of 0.27 V/kPa within a pressure range of 0–20 kPa and an ultra-fast response time of 0.7 ms. Furthermore, it maintains high reproducibility over 100,000 test cycles. Additionally, by leveraging pulse wave signal feature extraction and machine learning algorithms, this sensor can continuously and accurately identify resting heart rate, healthy exercise heart rate, and unhealthy exercise heart rate with up to 95 % accuracy. This wearable sensor technology offers a novel solution for non-invasive personalized medical monitoring. With its exceptional biocompatibility, the sensor can be integrated into smart clothing and remote health monitoring systems to enable long-term dynamic physiological parameter monitoring, opening broader application prospects for precision medicine and health management.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117386"},"PeriodicalIF":4.9,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-10DOI: 10.1016/j.sna.2025.117380
Akanksha Mishra , Anupam Kushwaha , Roli Verma
Paper-based sensors (PS) offer low-cost and portable platforms for environmental monitoring but are limited by low visual sensitivity to subtle color changes. In this study, we present a machine learning (ML)-assisted colorimetric paper sensor system for real-time water pollution monitoring, specifically targeting Pb²⁺ and Fe ions. Copper oxide nanoparticles (CuO NPs) were deposited onto filter paper to construct colorimetric sensing strips. Images of the paper sensors were acquired using four different smartphones and under six distinct lighting conditions on four types of filter papers, generating a dataset of 1600 images per analyte, wich was further augmented for robust model development. Comprehensive feature extraction yielded 27 global colorimetric descriptors from RGB, HSV, and L*a*b color spaces. Three classification algorithms, Support Vector Machine (SVM), Logistic Regression (LR), and Random Forest (RF) were used to classify the concentration levels of Pb2 + and Fe3+ ions ranging from 20 mM to 1 µM. The RF classifier achieved highest cross-validation accuracy of 99 % for Pb²⁺ and 98 % for Fe³ ⁺. Quantitative regression using Random Forest yielded R² values of 0.9644 and 0.9588 for Pb²⁺ and Fe³ ⁺, respectively. For real-world validation, the system accurately classified sensor responses from Gomti river water samples spiked with heavy metal ions, confirming model robustness for heterogeneous sample conditions. This study underscores the potential of combining machine learning methodologies with colorimetric analysis for real-time monitoring of water pollution. Such an integrated approach offers rapid and cost-effective assessment capabilities, presenting a promising solution for environmental pollution testing to ensure water quality.
{"title":"Machine learning enabled colorimetric paper strip sensor for the detection of ultra-low concentrations of heavy metal ions","authors":"Akanksha Mishra , Anupam Kushwaha , Roli Verma","doi":"10.1016/j.sna.2025.117380","DOIUrl":"10.1016/j.sna.2025.117380","url":null,"abstract":"<div><div>Paper-based sensors (PS) offer low-cost and portable platforms for environmental monitoring but are limited by low visual sensitivity to subtle color changes. In this study, we present a machine learning (ML)-assisted colorimetric paper sensor system for real-time water pollution monitoring, specifically targeting Pb²⁺ and Fe ions. Copper oxide nanoparticles (CuO NPs) were deposited onto filter paper to construct colorimetric sensing strips. Images of the paper sensors were acquired using four different smartphones and under six distinct lighting conditions on four types of filter papers, generating a dataset of 1600 images per analyte, wich was further augmented for robust model development. Comprehensive feature extraction yielded 27 global colorimetric descriptors from RGB, HSV, and L*a*b color spaces. Three classification algorithms, Support Vector Machine (SVM), Logistic Regression (LR), and Random Forest (RF) were used to classify the concentration levels of Pb<sup>2 +</sup> and Fe<sup>3+</sup> ions ranging from 20 mM to 1 µM. The RF classifier achieved highest cross-validation accuracy of 99 % for Pb²⁺ and 98 % for Fe³ ⁺. Quantitative regression using Random Forest yielded R² values of 0.9644 and 0.9588 for Pb²⁺ and Fe³ ⁺, respectively. For real-world validation, the system accurately classified sensor responses from Gomti river water samples spiked with heavy metal ions, confirming model robustness for heterogeneous sample conditions. This study underscores the potential of combining machine learning methodologies with colorimetric analysis for real-time monitoring of water pollution. Such an integrated approach offers rapid and cost-effective assessment capabilities, presenting a promising solution for environmental pollution testing to ensure water quality.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117380"},"PeriodicalIF":4.9,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1016/j.sna.2025.117378
Yubin Yuan , Shujing Zhao , Qiang Wu , Zifan Li , Chuanyu Han , Xin Li , Long Hu , Mingchao Yang , Weihua Liu , Li Geng
Biological perception systems are renowned for their ability to process environmental stimuli with remarkable energy efficiency, primarily through spike-based communication and event-driven mechanisms. Inspired by these, in this paper, we propose an infrared artificial neuromorphic perception neuron (IR-ANPN) designed to detect infrared (IR) light, enabling sensory perception beyond the visible spectrum. The IR-ANPN is designed based on a one-transistor-one-memristor (1T1M) architecture, which consists of a PbS quantum dots-decorated Indium Gallium Zinc Oxide (IGZO) thin film transistor (PbS-QDs/IGZO TFT) and an NbOx Mott memristor. The PbS-QDs/IGZO TFT is responsible for detecting infrared light stimuli, while the NbOx Mott memristor converts these stimuli into neuromorphic spikes. The IR-ANPN can operate in an event-driven mode, which means it transmits spikes only when exposed to IR light, ensuring energy efficiency by remaining dormant in the absence of relevant stimuli. The paper also showcases the potential of the IR-ANPN by constructing a neuromorphic infrared detection array. Combined with a spiking neural network (SNN), the system achieves 92 % recognition accuracy on the MNIST dataset by encoding pixel intensity as spiking frequency. The IR-ANPN architecture enhances sensory capabilities through a neuromorphic approach, enabling the detection of non-visible wavelengths with remarkable energy efficiency and laying the foundation for future intelligent sensing technologies.
{"title":"1T1M neuromorphic infrared perception based on PbS-QDs decorated IGZO TFT and NbOx Mott Memristor with event-driven property","authors":"Yubin Yuan , Shujing Zhao , Qiang Wu , Zifan Li , Chuanyu Han , Xin Li , Long Hu , Mingchao Yang , Weihua Liu , Li Geng","doi":"10.1016/j.sna.2025.117378","DOIUrl":"10.1016/j.sna.2025.117378","url":null,"abstract":"<div><div>Biological perception systems are renowned for their ability to process environmental stimuli with remarkable energy efficiency, primarily through spike-based communication and event-driven mechanisms. Inspired by these, in this paper, we propose an infrared artificial neuromorphic perception neuron (IR-ANPN) designed to detect infrared (IR) light, enabling sensory perception beyond the visible spectrum. The IR-ANPN is designed based on a one-transistor-one-memristor (1T1M) architecture, which consists of a PbS quantum dots-decorated Indium Gallium Zinc Oxide (IGZO) thin film transistor (PbS-QDs/IGZO TFT) and an NbO<sub>x</sub> Mott memristor. The PbS-QDs/IGZO TFT is responsible for detecting infrared light stimuli, while the NbO<sub>x</sub> Mott memristor converts these stimuli into neuromorphic spikes. The IR-ANPN can operate in an event-driven mode, which means it transmits spikes only when exposed to IR light, ensuring energy efficiency by remaining dormant in the absence of relevant stimuli. The paper also showcases the potential of the IR-ANPN by constructing a neuromorphic infrared detection array. Combined with a spiking neural network (SNN), the system achieves 92 % recognition accuracy on the MNIST dataset by encoding pixel intensity as spiking frequency. The IR-ANPN architecture enhances sensory capabilities through a neuromorphic approach, enabling the detection of non-visible wavelengths with remarkable energy efficiency and laying the foundation for future intelligent sensing technologies.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117378"},"PeriodicalIF":4.9,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1016/j.sna.2025.117384
Jun Dong , Xinyue Li , Shaolong Tu , Qingyan Han , Chengyun Zhang , Kaili Ren , Tuo Li , Wei Gao , Jianxia Qi
Surface-enhanced Raman scattering (SERS) was extensively employed in the domains of target analysis and detection owing to its benefits of high sensitivity and nondestructive detection. In this study, polystyrene (PS) microspheres served as templates. PS microspheres were systematically assembled on silicon wafer surfaces using air-liquid interfacial self-assembly. Subsequently, a PMMA-anisole solution was spin-coated to fill the interstices of the microspheres. Following the removal of the templates using cyclohexane ultrasonication method, gold nanoparticles were deposited onto the substrates utilizing the three-phase self-assembly procedure to construct the AuNPs@PMMA sphere-cavity array substrate. When the PMMA-anisole solution concentration was 1 %, the spinning speed was 5500 r/min, and the annealing temperature was 120 °C, the most regular nanostructure of the spherical cavity substrate was achieved. The Raman activity of the fabricated substrates was investigated with the selection of Rhodamine (R6G), Crystal Violet (CV) and Aspartame (APM) as target molecules. The experimental results indicated that AuNPs@PMMA sphere-cavity array substrate exhibiting high sensitivity, excellent uniformity, and stability, and the detection limits for R6G and CV were 10−11 M and 10−10 M, respectively. In addition, the substrate achieved a low detection limit of 0.0313 g/L for aspartame (APM), demonstrating the potential application of the substrate in food safety testing.
{"title":"Stencil-patterned AuNPs@PMMA spherical-cavity substrates for ultrasensitive SERS detection","authors":"Jun Dong , Xinyue Li , Shaolong Tu , Qingyan Han , Chengyun Zhang , Kaili Ren , Tuo Li , Wei Gao , Jianxia Qi","doi":"10.1016/j.sna.2025.117384","DOIUrl":"10.1016/j.sna.2025.117384","url":null,"abstract":"<div><div>Surface-enhanced Raman scattering (SERS) was extensively employed in the domains of target analysis and detection owing to its benefits of high sensitivity and nondestructive detection. In this study, polystyrene (PS) microspheres served as templates. PS microspheres were systematically assembled on silicon wafer surfaces using air-liquid interfacial self-assembly. Subsequently, a PMMA-anisole solution was spin-coated to fill the interstices of the microspheres. Following the removal of the templates using cyclohexane ultrasonication method, gold nanoparticles were deposited onto the substrates utilizing the three-phase self-assembly procedure to construct the AuNPs@PMMA sphere-cavity array substrate. When the PMMA-anisole solution concentration was 1 %, the spinning speed was 5500 r/min, and the annealing temperature was 120 °C, the most regular nanostructure of the spherical cavity substrate was achieved. The Raman activity of the fabricated substrates was investigated with the selection of Rhodamine (R6G), Crystal Violet (CV) and Aspartame (APM) as target molecules. The experimental results indicated that AuNPs@PMMA sphere-cavity array substrate exhibiting high sensitivity, excellent uniformity, and stability, and the detection limits for R6G and CV were 10<sup>−11</sup> M and 10<sup>−10</sup> M, respectively. In addition, the substrate achieved a low detection limit of 0.0313 g/L for aspartame (APM), demonstrating the potential application of the substrate in food safety testing.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117384"},"PeriodicalIF":4.9,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.sna.2025.117373
Huanying Kan , Changquan Li , Bin Ju , Xiao Zheng , Wenjie Xue , Chao Tian , Weiwei Shao , Siliang Lu , Yongbin Liu
In interventional ultrasound surgery, an ultrasound transducer is delivered to the target area through a slight guide needle to display internal structures in real time. Therefore, minimizing dimensions of the transducer without compromising imaging quality holds substantial research value. To address this challenge, we proposed an active-backing ultrasonic transducer (ABUT) in which the conventional backing layer is replaced by an active backing structure, enabling substantial size reduction. A theory of vibration displacement compensation and a corresponding mathematical model were then proposed to analyze the working principle of ABUT. Subsequently, parameters of the ABUT were optimized. Simulation results showed that, the difference in acoustic pressure levels between the front and rear of the ABUT can reach 12 dB. The acoustic attenuation effect outperformed that of a conventional backing layer. Finally, the acoustic emission and attenuation performance of ABUT were verified through experiments. The experimental results showed that, the acoustic pressure attenuation value per unit thickness of active-backing layer was four times greater than that of conventional backing layer. This result demonstrated that the 0.4-mm-thick active-backing layer exhibits superior acoustic attenuation compared to the 1-mm-thick conventional backing layer, ultimately enabling a 35 % reduction in the thickness of transducer.
{"title":"Design and analysis of micro-scale ultrasonic transducers with active-backing structures","authors":"Huanying Kan , Changquan Li , Bin Ju , Xiao Zheng , Wenjie Xue , Chao Tian , Weiwei Shao , Siliang Lu , Yongbin Liu","doi":"10.1016/j.sna.2025.117373","DOIUrl":"10.1016/j.sna.2025.117373","url":null,"abstract":"<div><div>In interventional ultrasound surgery, an ultrasound transducer is delivered to the target area through a slight guide needle to display internal structures in real time. Therefore, minimizing dimensions of the transducer without compromising imaging quality holds substantial research value. To address this challenge, we proposed an active-backing ultrasonic transducer (ABUT) in which the conventional backing layer is replaced by an active backing structure, enabling substantial size reduction. A theory of vibration displacement compensation and a corresponding mathematical model were then proposed to analyze the working principle of ABUT. Subsequently, parameters of the ABUT were optimized. Simulation results showed that, the difference in acoustic pressure levels between the front and rear of the ABUT can reach 12 dB. The acoustic attenuation effect outperformed that of a conventional backing layer. Finally, the acoustic emission and attenuation performance of ABUT were verified through experiments. The experimental results showed that, the acoustic pressure attenuation value per unit thickness of active-backing layer was four times greater than that of conventional backing layer. This result demonstrated that the 0.4-mm-thick active-backing layer exhibits superior acoustic attenuation compared to the 1-mm-thick conventional backing layer, ultimately enabling a 35 % reduction in the thickness of transducer.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117373"},"PeriodicalIF":4.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.sna.2025.117381
Linghan Shen , Kai Luo , Luming Li , Mingyong Zhou
Flexible conductive films have been increasingly demanded for wearable devices that are widely applied. However, existing fabrication methods are limited by uneven particle distribution, complex processes, and material selectivity. Herein, a particle manipulation method based on surface acoustic wave (SAW) technology was proposed to align spherical silver (Ag) particles and fabricate a flexible conductive film with a linear arrangement structure. The process for fabricating conductive films was optimized by investigating the influence of the dielectrophoresis (DEP) effect, along with the effects of chamber height and solution solid content, on the alignment of Ag particles. Besides, the conductivity of the films and their applications in flexible sensing including wrist bending, finger short-term and continuous pressing actions were explored. Results showed that the acoustic radiation force dominates the aggregation of spherical-like Ag particles into periodic stripe patterns along the acoustic pressure node lines at locations distal to the substrate. Ag particles at the potential nodes are dominated by the dielectrophoretic force, leading to the formation of chain-like structures, which can be eliminated by utilizing the electric field shielding layer. The optimized film has a high conductivity of 4774 S/m and exhibits stable resistance characteristics during flexible deformation. The resistance change can be attributed to the changes in particle spacing, the breakage and recovery of conductive paths caused by deformation. The current work provides a new scheme for the fabrication of conductive films with high process controllability in the field of flexible sensing.
{"title":"Surface acoustic wave-assisted fabrication of Ag/PEGDA conductive films for flexible sensing applications","authors":"Linghan Shen , Kai Luo , Luming Li , Mingyong Zhou","doi":"10.1016/j.sna.2025.117381","DOIUrl":"10.1016/j.sna.2025.117381","url":null,"abstract":"<div><div>Flexible conductive films have been increasingly demanded for wearable devices that are widely applied. However, existing fabrication methods are limited by uneven particle distribution, complex processes, and material selectivity. Herein, a particle manipulation method based on surface acoustic wave (SAW) technology was proposed to align spherical silver (Ag) particles and fabricate a flexible conductive film with a linear arrangement structure. The process for fabricating conductive films was optimized by investigating the influence of the dielectrophoresis (DEP) effect, along with the effects of chamber height and solution solid content, on the alignment of Ag particles. Besides, the conductivity of the films and their applications in flexible sensing including wrist bending, finger short-term and continuous pressing actions were explored. Results showed that the acoustic radiation force dominates the aggregation of spherical-like Ag particles into periodic stripe patterns along the acoustic pressure node lines at locations distal to the substrate. Ag particles at the potential nodes are dominated by the dielectrophoretic force, leading to the formation of chain-like structures, which can be eliminated by utilizing the electric field shielding layer. The optimized film has a high conductivity of 4774 S/m and exhibits stable resistance characteristics during flexible deformation. The resistance change can be attributed to the changes in particle spacing, the breakage and recovery of conductive paths caused by deformation. The current work provides a new scheme for the fabrication of conductive films with high process controllability in the field of flexible sensing.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"398 ","pages":"Article 117381"},"PeriodicalIF":4.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.sna.2025.117379
Shanshan Dong , Zixin Ju , Yanping Liu , Bingang Xu , Hong Hu
Fiber- and yarn-based strain sensors are promising for wearable biomonitoring, human-computer interaction, and robotic perception due to their simple sensing mechanisms, material flexibility, and structural adaptability. The unique deformation mechanism of auxetic structures enhances the sensitivity and comfort of one-dimensional sensors, garnering substantial research interest. In this study, we design and fabricate a structurally stable auxetic braided strain yarn sensor (ABSYS) optimized for industrial-scale automated production. The ABSYS is constructed by wrapping rigid conductive multifilament and highly elastic nylon-spandex covered yarn around an elastic core yarn in a mesh pattern using circular braiding technology. It demonstrates a pronounced auxetic effect and exceptional sensing performance. When seamlessly embedded into fabric, the ABSYS exhibits a broad working range of 2–60 %, a rapid response time of 0.018 s, and reliable stability, effectively capturing a broad spectrum of human motion. Moreover, the sensor works while maintaining wearer comfort and fabric aesthetics, offering a practical and scalable solution for next-generation strain-sensing wearables.
{"title":"A highly stable auxetic braided smart yarn for seamless motion-sensing textiles","authors":"Shanshan Dong , Zixin Ju , Yanping Liu , Bingang Xu , Hong Hu","doi":"10.1016/j.sna.2025.117379","DOIUrl":"10.1016/j.sna.2025.117379","url":null,"abstract":"<div><div>Fiber- and yarn-based strain sensors are promising for wearable biomonitoring, human-computer interaction, and robotic perception due to their simple sensing mechanisms, material flexibility, and structural adaptability. The unique deformation mechanism of auxetic structures enhances the sensitivity and comfort of one-dimensional sensors, garnering substantial research interest. In this study, we design and fabricate a structurally stable auxetic braided strain yarn sensor (ABSYS) optimized for industrial-scale automated production. The ABSYS is constructed by wrapping rigid conductive multifilament and highly elastic nylon-spandex covered yarn around an elastic core yarn in a mesh pattern using circular braiding technology. It demonstrates a pronounced auxetic effect and exceptional sensing performance. When seamlessly embedded into fabric, the ABSYS exhibits a broad working range of 2–60 %, a rapid response time of 0.018 s, and reliable stability, effectively capturing a broad spectrum of human motion. Moreover, the sensor works while maintaining wearer comfort and fabric aesthetics, offering a practical and scalable solution for next-generation strain-sensing wearables.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117379"},"PeriodicalIF":4.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Two-dimensional semiconducting materials with oxide functionalities exhibit strong triboelectric properties, facilitating their use in flexible nanogenerators. This work reports the synthesis and integration of -PVA for high-performance flexible triboelectric nanogenerators (FTENGs). The -PVA was prepared using MXene, which was synthesized using a MAX phase precursor through the etching method. The yields a layered structure and a direct band gap of 2.56 eV. The spectroscopic analyses confirm the presence of a hydroxyl group (-OH) and prominent D and G vibrational modes. Then the FTENGs were fabricated, comprising of -PVA and Copper or ITO-PET electrodes. The -PVA and ITO-PET-based FTENG delivers a maximum output voltage of 100.8 V and a current of 103.3 nA, with a current density of 430.7 nA/ at 6 Hz, which surpasses the output performance of -PVA and Copper-based FTENG. The device output performance is then analysed under UV light illumination of wavelength 254 nm, which produces an output voltage of 3.4 V. This output voltage is due to the triboelectric effect and photogenerated charge carriers produced due to the wide bandgap of . This enhanced output is due to the high dielectric constant of the nanocomposite film, which is 424.8, supporting its application in tribotronic systems and as a self-powered UV sensor.
{"title":"Physics-guided high performance N-TiO2@MXene–PVA nanocomposite based triboelectric nanogenerators for self-powered UV-sensor","authors":"Sheetal Sharma , Vinod Kumar Singh , Manoj Kumar Gupta","doi":"10.1016/j.sna.2025.117376","DOIUrl":"10.1016/j.sna.2025.117376","url":null,"abstract":"<div><div>Two-dimensional semiconducting materials with oxide functionalities exhibit strong triboelectric properties, facilitating their use in flexible nanogenerators. This work reports the synthesis and integration of <span><math><mrow><mrow><mi>N</mi><mtext>-</mtext><msub><mi>TiO</mi><mrow><mn>2</mn></mrow></msub><mrow><mo>@</mo></mrow><mi>MXene</mi></mrow></mrow></math></span>-PVA for high-performance flexible triboelectric nanogenerators (FTENGs). The <span><math><mrow><mrow><mi>N</mi><mtext>-</mtext><msub><mi>TiO</mi><mrow><mn>2</mn></mrow></msub><mrow><mo>@</mo></mrow><mi>MXene</mi></mrow></mrow></math></span>-PVA was prepared using <span><math><mrow><msub><mi>Ti</mi><mrow><mn>3</mn></mrow></msub><msub><mi>C</mi><mrow><mn>2</mn></mrow></msub><msub><mi>T</mi><mrow><mi>x</mi></mrow></msub></mrow></math></span> MXene, which was synthesized using a MAX phase precursor through the etching method. The <span><math><mrow><mrow><mi>N</mi><mtext>-</mtext><msub><mi>TiO</mi><mrow><mn>2</mn></mrow></msub><mrow><mo>@</mo></mrow><mi>MXene</mi></mrow></mrow></math></span> yields a layered structure and a direct band gap of 2.56 eV. The spectroscopic analyses confirm the presence of a hydroxyl group (-OH) and prominent D and G vibrational modes. Then the FTENGs were fabricated, comprising of <span><math><mrow><mrow><mi>N</mi><mtext>-</mtext><msub><mi>TiO</mi><mrow><mn>2</mn></mrow></msub><mrow><mo>@</mo></mrow><mi>MXene</mi></mrow></mrow></math></span>-PVA and Copper or ITO-PET electrodes. The <span><math><mrow><mrow><mi>N</mi><mtext>-</mtext><msub><mi>TiO</mi><mrow><mn>2</mn></mrow></msub><mrow><mo>@</mo></mrow><mi>MXene</mi></mrow></mrow></math></span>-PVA and ITO-PET-based FTENG delivers a maximum output voltage of 100.8 V and a current of 103.3 nA, with a current density of 430.7 nA/<span><math><msup><mrow><mi>cm</mi></mrow><mn>2</mn></msup></math></span> at 6 Hz, which surpasses the output performance of <span><math><mrow><mrow><mi>N</mi><mtext>-</mtext><msub><mi>TiO</mi><mrow><mn>2</mn></mrow></msub><mrow><mo>@</mo></mrow><mi>MXene</mi></mrow></mrow></math></span>-PVA and Copper-based FTENG. The device output performance is then analysed under UV light illumination of wavelength 254 nm, which produces an output voltage of 3.4 V. This output voltage is due to the triboelectric effect and photogenerated charge carriers produced due to the wide bandgap of <span><math><mrow><mrow><mi>N</mi><mtext>-</mtext><msub><mi>TiO</mi><mrow><mn>2</mn></mrow></msub><mrow><mo>@</mo></mrow><mi>MXene</mi></mrow></mrow></math></span>. This enhanced output is due to the high dielectric constant of the nanocomposite film, which is 424.8, supporting its application in tribotronic systems and as a self-powered UV sensor.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117376"},"PeriodicalIF":4.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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