An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MO...An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MOF difficulties in computing solutions to problems in which surface tension forces are crucial for understanding salient flow mechanisms.The Continuous MOF(CMOF)method is motivated in this article.The CMOF reconstruction method inherently removes the"checkerboard instability"that persists when using the MOF method on surface tension driven multiphase(multimaterial)flows.The CMOF reconstruction algorithm is accelerated by coupling the CMOF method to the level set method and coupling the CMOF method to a decision tree machine learning(ML)algorithm.Multiphase flow examples are shown in the two-dimensional(2D),three-dimensional(3D)axisymmetric"RZ",and 3D coordinate systems.Examples include two material and three material multiphase flows:bubble formation,the impingement of a liquid jet on a gas bubble in a cryogenic fuel tank,freezing,and liquid lens dynamics.展开更多
Flow measurement is critical in various sectors,including industry,agriculture,medicine,and environmental monitoring.There is a growing need for compact,sensitive,scalable,and energy-efficient flow sensors,particularl...Flow measurement is critical in various sectors,including industry,agriculture,medicine,and environmental monitoring.There is a growing need for compact,sensitive,scalable,and energy-efficient flow sensors,particularly for applications in unmanned aerial vehicles,unmanned underwater vehicles,biomedicine,and bionic robotics.Inspired by biological mechanosensory structures,artificial hair and hair cell flow sensors have emerged as promising solutions.This study offers a comprehensive review of the progress,underlying principles,performance optimization techniques,and applications of hair flow sensors.We provide an overview of the biological mechanisms of hair as mechanical receptors.Subsequently,we explain the design and fabrication techniques of artificial hair flow sensors,highlighting the challenges associated with replicating and integrating hair structures.The study further explores strategies for sensor enhancement and their diverse applications.Finally,we conclude by outlining the challenges and prospects of hair sensor technology,along with its potential to address specific flow-sensing requirements.While most applications of artificial hair cell flow sensors are still in the research stage,they offer substantial potential for flow measurement.Future progress in materials science,structural design,and sensing mechanisms is anticipated to drive the development of these sensors,opening up new avenues for scientific research and commercial applications.展开更多
xIn this paper,we propose and investigate novel closed-form point estimators for the beta distribution.The estimators of the first type are a modified version of Pearson’s method of moments.The underlying idea is to ...xIn this paper,we propose and investigate novel closed-form point estimators for the beta distribution.The estimators of the first type are a modified version of Pearson’s method of moments.The underlying idea is to involve the sufficient statistics,i.e.,log-moments in the moment estimation equations and solve the mixed type of moment equations simultaneously.The estimators of the second type are based on an approximation to Fisher’s likelihood principle.The idea is to solve two score equations derived from the log-likelihood function of generalized beta distributions.Both two resulted estimators are in closed forms,strongly consistent and asymptotically normal.In addition,through theoretical analyses and extensive simulations,the proposed estimators are shown to perform very close to themaximumlikelihood estimators in both small and large samples,and they significantly outperform the method of moment estimators.展开更多
Silicon sub-bandgap photodetectors can detect light at the infrared telecommunication wavelengths but with relatively weak photo-response.In this work,we demonstrate the enhancement of sub-bandgap photodetection in si...Silicon sub-bandgap photodetectors can detect light at the infrared telecommunication wavelengths but with relatively weak photo-response.In this work,we demonstrate the enhancement of sub-bandgap photodetection in silicon by helium-ion implantation,without afecting the transparency that is an important benefcial feature of this type of photodetectors.With an implantation dose of 1×10^(13)ions/cm^(2),the minimal detectable optical power can be improved from−33.2 to−63.1 dBm,or,by 29.9 dB,at the wavelength of 1550 nm,and the photo-response at the same optical power(−10 dBm)can be enhanced by approximately 18.8 dB.Our work provides a method for strategically modifying the intrinsic trade-of between transparency and strong photo-responses of this type of photodetectors.展开更多
基金supported by the National Aeronautics and Space Administration under grant number 80NSSC20K0352.
文摘An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MOF difficulties in computing solutions to problems in which surface tension forces are crucial for understanding salient flow mechanisms.The Continuous MOF(CMOF)method is motivated in this article.The CMOF reconstruction method inherently removes the"checkerboard instability"that persists when using the MOF method on surface tension driven multiphase(multimaterial)flows.The CMOF reconstruction algorithm is accelerated by coupling the CMOF method to the level set method and coupling the CMOF method to a decision tree machine learning(ML)algorithm.Multiphase flow examples are shown in the two-dimensional(2D),three-dimensional(3D)axisymmetric"RZ",and 3D coordinate systems.Examples include two material and three material multiphase flows:bubble formation,the impingement of a liquid jet on a gas bubble in a cryogenic fuel tank,freezing,and liquid lens dynamics.
基金supported by the National Key Research and Development Program(2022YFB3203600)the Key R&D Program of Zhejiang(2024C03207)the ZJUI Institute startup fund.
文摘Flow measurement is critical in various sectors,including industry,agriculture,medicine,and environmental monitoring.There is a growing need for compact,sensitive,scalable,and energy-efficient flow sensors,particularly for applications in unmanned aerial vehicles,unmanned underwater vehicles,biomedicine,and bionic robotics.Inspired by biological mechanosensory structures,artificial hair and hair cell flow sensors have emerged as promising solutions.This study offers a comprehensive review of the progress,underlying principles,performance optimization techniques,and applications of hair flow sensors.We provide an overview of the biological mechanisms of hair as mechanical receptors.Subsequently,we explain the design and fabrication techniques of artificial hair flow sensors,highlighting the challenges associated with replicating and integrating hair structures.The study further explores strategies for sensor enhancement and their diverse applications.Finally,we conclude by outlining the challenges and prospects of hair sensor technology,along with its potential to address specific flow-sensing requirements.While most applications of artificial hair cell flow sensors are still in the research stage,they offer substantial potential for flow measurement.Future progress in materials science,structural design,and sensing mechanisms is anticipated to drive the development of these sensors,opening up new avenues for scientific research and commercial applications.
基金supported by the National Natural Science Foundation of China[project number 72401253,72271154]the State Key Laboratory of Biobased Transportation Fuel Technology[project number 512302-X02301]a start-up grant from the ZJU-UIUC Institute at Zhejiang University[project number 130200-171207711].
文摘xIn this paper,we propose and investigate novel closed-form point estimators for the beta distribution.The estimators of the first type are a modified version of Pearson’s method of moments.The underlying idea is to involve the sufficient statistics,i.e.,log-moments in the moment estimation equations and solve the mixed type of moment equations simultaneously.The estimators of the second type are based on an approximation to Fisher’s likelihood principle.The idea is to solve two score equations derived from the log-likelihood function of generalized beta distributions.Both two resulted estimators are in closed forms,strongly consistent and asymptotically normal.In addition,through theoretical analyses and extensive simulations,the proposed estimators are shown to perform very close to themaximumlikelihood estimators in both small and large samples,and they significantly outperform the method of moment estimators.
基金supported by the National Key Research and Development Program of China(No.2019YFB2203600)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF003).
文摘Silicon sub-bandgap photodetectors can detect light at the infrared telecommunication wavelengths but with relatively weak photo-response.In this work,we demonstrate the enhancement of sub-bandgap photodetection in silicon by helium-ion implantation,without afecting the transparency that is an important benefcial feature of this type of photodetectors.With an implantation dose of 1×10^(13)ions/cm^(2),the minimal detectable optical power can be improved from−33.2 to−63.1 dBm,or,by 29.9 dB,at the wavelength of 1550 nm,and the photo-response at the same optical power(−10 dBm)can be enhanced by approximately 18.8 dB.Our work provides a method for strategically modifying the intrinsic trade-of between transparency and strong photo-responses of this type of photodetectors.
