Dear Editor,This letter presents a novel dynamic vision enabled contactless cross-domain fault diagnosis method with neuromorphic computing.The event-based camera is adopted to capture the machine vibration states in ...Dear Editor,This letter presents a novel dynamic vision enabled contactless cross-domain fault diagnosis method with neuromorphic computing.The event-based camera is adopted to capture the machine vibration states in the perspective of vision.展开更多
Intelligent machinery fault diagnosis methods have been popularly and successfully developed in the past decades,and the vibration acceleration data collected by contact accelerometers have been widely investigated.In...Intelligent machinery fault diagnosis methods have been popularly and successfully developed in the past decades,and the vibration acceleration data collected by contact accelerometers have been widely investigated.In many industrial scenarios,contactless sensors are more preferred.The event camera is an emerging bio-inspired technology for vision sensing,which asynchronously records per-pixel brightness change polarity with high temporal resolution and low latency.It offers a promising tool for contactless machine vibration sensing and fault diagnosis.However,the dynamic vision-based methods suffer from variations of practical factors such as camera position,machine operating condition,etc.Furthermore,as a new sensing technology,the labeled dynamic vision data are limited,which generally cannot cover a wide range of machine fault modes.Aiming at these challenges,a novel dynamic vision-based machinery fault diagnosis method is proposed in this paper.It is motivated to explore the abundant vibration acceleration data for enhancing the dynamic vision-based model performance.A crossmodality feature alignment method is thus proposed with deep adversarial neural networks to achieve fault diagnosis knowledge transfer.An event erasing method is further proposed for improving model robustness against variations.The proposed method can effectively identify unseen fault mode with dynamic vision data.Experiments on two rotating machine monitoring datasets are carried out for validations,and the results suggest the proposed method is promising for generalized contactless machinery fault diagnosis.展开更多
The Three Gorges Project, also known as the Yangtze River Three Gorges Water Control Project, is located in Yichang, Hubei Province, China. The dam is one of the largest hydropower stations in the world, with an eleva...The Three Gorges Project, also known as the Yangtze River Three Gorges Water Control Project, is located in Yichang, Hubei Province, China. The dam is one of the largest hydropower stations in the world, with an elevation of 185 meters and a water storage elevation of 175 meters.展开更多
Quantum coherence in quantum optics is an essential part of optical information processing and light manipulation.Alkali metal vapors,despite the numerous shortcomings,are traditionally used in quantum optics as a wor...Quantum coherence in quantum optics is an essential part of optical information processing and light manipulation.Alkali metal vapors,despite the numerous shortcomings,are traditionally used in quantum optics as a working medium due to convenient near-infrared excitation,strong dipole transitions and long-lived coherence.Here,we proposed and experimentally demonstrated photon retention and subsequent re-emittance with the quantum coherence in a system of coherently excited molecular nitrogen ions(N_(2)^(+))which are produced using a strong 800 nm femtosecond laser pulse.Such photon retention,facilitated by quantum coherence,keeps releasing directly-unmeasurable coherent photons for tens of picoseconds,but is able to be read out by a time-delayed femtosecond pulse centered at 1580 nm via two-photon resonant absorption,resulting in a strong radiation at 329.3 nm.We reveal a pivotal role of the excited-state population to transmit such extremely weak re-emitted photons in this system.This new finding unveils the nature of the coherent quantum control in N_(2)^(+)for the potential platform for optical information storage in the remote atmosphere,and facilitates further exploration of fundamental interactions in the quantum optical platform with strong-field ionized molecules.展开更多
Remote or standoff detection of greenhouse gases,air pollutants,and biological agents with innovative ultrafast laser technology attracts growing interests in recent years.Hybrid femtosecond/picosecond coherent Raman ...Remote or standoff detection of greenhouse gases,air pollutants,and biological agents with innovative ultrafast laser technology attracts growing interests in recent years.Hybrid femtosecond/picosecond coherent Raman spectroscopy is considered as one of the most versatile techniques due to its great advantages in terms of detection sensitivity and chemical specificity.However,the simultaneous requirement for the femtosecond pump and the picosecond probe increases the complexity of optical system.Herein,we demonstrate that air lasing naturally created inside a filament can serve as an ideal light source to probe Raman coherence excited by the femtosecond pump,producing coherent Raman signal with molecular vibrational signatures.The combination of pulse self-compression effect and air lasing action during filamentation improves Raman excitation efficiency and greatly simplifies the experimental setup.The air-lasing-assisted Raman spectroscopy was applied to quantitatively detect greenhouse gases mixed in air,and it was found that the minimum detectable concentrations of CO_(2) and SF_(6) can reach 0.1%and 0.03%,respectively.The ingenious designs,especially the optimization of pump-seed delay and the choice of perpendicular polarization,ensure a high detection sensitivity and signal stability.Moreover,it is demonstrated that this method can be used for simultaneously measuring CO_(2) and SF_(6) gases and distinguishing ^(12)CO_(2) and ^(13)CO_(2).The developed scheme provides a new route for high-sensitivity standoff detection and combustion diagnosis.展开更多
基金supported in part by the National Key R&D Program of China (2022YFB3402100)the National Science Fund for Distinguished Young Scholars of China (52025056)。
文摘Dear Editor,This letter presents a novel dynamic vision enabled contactless cross-domain fault diagnosis method with neuromorphic computing.The event-based camera is adopted to capture the machine vibration states in the perspective of vision.
基金supported by the National Science Fund for Distinguished Young Scholars of China(52025056)the China Postdoctoral Science Foundation(2023M732789)+1 种基金the China Postdoctoral Innovative Talents Support Program(BX20230290)the Fundamental Research Funds for the Central Universities(xzy012022062).
文摘Intelligent machinery fault diagnosis methods have been popularly and successfully developed in the past decades,and the vibration acceleration data collected by contact accelerometers have been widely investigated.In many industrial scenarios,contactless sensors are more preferred.The event camera is an emerging bio-inspired technology for vision sensing,which asynchronously records per-pixel brightness change polarity with high temporal resolution and low latency.It offers a promising tool for contactless machine vibration sensing and fault diagnosis.However,the dynamic vision-based methods suffer from variations of practical factors such as camera position,machine operating condition,etc.Furthermore,as a new sensing technology,the labeled dynamic vision data are limited,which generally cannot cover a wide range of machine fault modes.Aiming at these challenges,a novel dynamic vision-based machinery fault diagnosis method is proposed in this paper.It is motivated to explore the abundant vibration acceleration data for enhancing the dynamic vision-based model performance.A crossmodality feature alignment method is thus proposed with deep adversarial neural networks to achieve fault diagnosis knowledge transfer.An event erasing method is further proposed for improving model robustness against variations.The proposed method can effectively identify unseen fault mode with dynamic vision data.Experiments on two rotating machine monitoring datasets are carried out for validations,and the results suggest the proposed method is promising for generalized contactless machinery fault diagnosis.
基金provided by the National Natural Science Foundation of China (No.41572336)。
文摘The Three Gorges Project, also known as the Yangtze River Three Gorges Water Control Project, is located in Yichang, Hubei Province, China. The dam is one of the largest hydropower stations in the world, with an elevation of 185 meters and a water storage elevation of 175 meters.
基金the National Natural Science Foundation of China(11822410,12034013,11734009,and 11974245)the National Key R&D Program of China(2017YFA0303701 and 2019YFA0705000)+10 种基金the Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)the Program of Shanghai Academic Research Leader(20XD1424200)the Natural Science Foundation of Shanghai(19ZR1475700)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB16030300)the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(QYZDJ-SSW-SLH010)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2018284)NSF(ECCS-1509268,and CMMI-1826078)AFOSR(FA9550-20-1-0366)partially supported by the Fundamental Research Funds for the Central Universitiesthe support from the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learningthe support from Shandong Quancheng Scholarship(00242019024)。
文摘Quantum coherence in quantum optics is an essential part of optical information processing and light manipulation.Alkali metal vapors,despite the numerous shortcomings,are traditionally used in quantum optics as a working medium due to convenient near-infrared excitation,strong dipole transitions and long-lived coherence.Here,we proposed and experimentally demonstrated photon retention and subsequent re-emittance with the quantum coherence in a system of coherently excited molecular nitrogen ions(N_(2)^(+))which are produced using a strong 800 nm femtosecond laser pulse.Such photon retention,facilitated by quantum coherence,keeps releasing directly-unmeasurable coherent photons for tens of picoseconds,but is able to be read out by a time-delayed femtosecond pulse centered at 1580 nm via two-photon resonant absorption,resulting in a strong radiation at 329.3 nm.We reveal a pivotal role of the excited-state population to transmit such extremely weak re-emitted photons in this system.This new finding unveils the nature of the coherent quantum control in N_(2)^(+)for the potential platform for optical information storage in the remote atmosphere,and facilitates further exploration of fundamental interactions in the quantum optical platform with strong-field ionized molecules.
基金supported by the National Natural Science Foundation of China(11822410,12034013,12074063)Key Research Program of Frontier Sciences of Chinese Academy of Sciences(QYZDJ-SSW-SLH010)+2 种基金Program of Shanghai Academic Research Leader(20XD1424200)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Youth Innovation Promotion Association of CAS(2018284).
文摘Remote or standoff detection of greenhouse gases,air pollutants,and biological agents with innovative ultrafast laser technology attracts growing interests in recent years.Hybrid femtosecond/picosecond coherent Raman spectroscopy is considered as one of the most versatile techniques due to its great advantages in terms of detection sensitivity and chemical specificity.However,the simultaneous requirement for the femtosecond pump and the picosecond probe increases the complexity of optical system.Herein,we demonstrate that air lasing naturally created inside a filament can serve as an ideal light source to probe Raman coherence excited by the femtosecond pump,producing coherent Raman signal with molecular vibrational signatures.The combination of pulse self-compression effect and air lasing action during filamentation improves Raman excitation efficiency and greatly simplifies the experimental setup.The air-lasing-assisted Raman spectroscopy was applied to quantitatively detect greenhouse gases mixed in air,and it was found that the minimum detectable concentrations of CO_(2) and SF_(6) can reach 0.1%and 0.03%,respectively.The ingenious designs,especially the optimization of pump-seed delay and the choice of perpendicular polarization,ensure a high detection sensitivity and signal stability.Moreover,it is demonstrated that this method can be used for simultaneously measuring CO_(2) and SF_(6) gases and distinguishing ^(12)CO_(2) and ^(13)CO_(2).The developed scheme provides a new route for high-sensitivity standoff detection and combustion diagnosis.
