In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interf...In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.展开更多
A noncontact photoacoustic technique using air transducers in MHz range is presented.Firstly, theoretical simulation and experimental fabrication of ultrasonic transducers in airare considered. An improvement of about...A noncontact photoacoustic technique using air transducers in MHz range is presented.Firstly, theoretical simulation and experimental fabrication of ultrasonic transducers in airare considered. An improvement of about 50 dB in the round-trip insertion loss and a frac-tional bandwidth greater than 15% are obtained by using one or two matching layers. Then,the 1 MHz photoacoustic measurement system is described and different applications are dis-cussed. The phase shifts of the received acoustic waves are extracted to obtain the surfacetopography of samples. The ion implantation dose in semiconductor is measured by detectingthe photoacoustic signal in air. Finally, a photoacoustic method for quantitative determina-tion of thin-film thicknesses is proposed.展开更多
We propose a high-speed all-optic dual-modal system that integrates spectral domain optical coherence tomography and photoacoustic microscopy(PAM).A 3*3 coupler-based interfer-ometer is used to remotely detect the sur...We propose a high-speed all-optic dual-modal system that integrates spectral domain optical coherence tomography and photoacoustic microscopy(PAM).A 3*3 coupler-based interfer-ometer is used to remotely detect the surface vibration caused by photoacoustic(PA)waves.Three outputs of the interferometer are acquired simultaneously with a multi-channel data ac-quisition card.One channel data with the highest PA signal detection sensitivity is selected for sensitivity compensation.Experiment on the phantom demonstrates that the proposed method can sucessfully compensate for the loss of intensity caused by sensitivity variation.The imaging speed of the PAM is improved compared to our previous system.The total time to image a sample with 256×256 pixels is~20s.Using the proposed system,the microvasculature in the mouse auricle is visualized and the blood flow state is accessed.展开更多
基金supported by the National Science and Technology Innovation 2030 Major Project(Grant No.2022ZD0208601)the National Natural Science Foundation of China(Grant No.52105593 and 51975513)the Natural Science Foundation of Zhejiang Province,China(No.LR20E050003)。
文摘In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.
基金Project supported by the National Foundation of China for post-doctoral researches.
文摘A noncontact photoacoustic technique using air transducers in MHz range is presented.Firstly, theoretical simulation and experimental fabrication of ultrasonic transducers in airare considered. An improvement of about 50 dB in the round-trip insertion loss and a frac-tional bandwidth greater than 15% are obtained by using one or two matching layers. Then,the 1 MHz photoacoustic measurement system is described and different applications are dis-cussed. The phase shifts of the received acoustic waves are extracted to obtain the surfacetopography of samples. The ion implantation dose in semiconductor is measured by detectingthe photoacoustic signal in air. Finally, a photoacoustic method for quantitative determina-tion of thin-film thicknesses is proposed.
基金This work was supported in part by the National Natural Science Foundation of China(Grant Nos.61771119,61901100 and 62075037)the Natural Science Foundation of Hebei Province(Grant Nos.H2019501010,F2019501132,E2020501029 and F2020501040).
文摘We propose a high-speed all-optic dual-modal system that integrates spectral domain optical coherence tomography and photoacoustic microscopy(PAM).A 3*3 coupler-based interfer-ometer is used to remotely detect the surface vibration caused by photoacoustic(PA)waves.Three outputs of the interferometer are acquired simultaneously with a multi-channel data ac-quisition card.One channel data with the highest PA signal detection sensitivity is selected for sensitivity compensation.Experiment on the phantom demonstrates that the proposed method can sucessfully compensate for the loss of intensity caused by sensitivity variation.The imaging speed of the PAM is improved compared to our previous system.The total time to image a sample with 256×256 pixels is~20s.Using the proposed system,the microvasculature in the mouse auricle is visualized and the blood flow state is accessed.
