Support vector machine(SVM)is easily affected by noises and outliers,and its training time dramatically increases with the growing in number of training samples.Satellite cloud image may easily be deteriorated by nois...Support vector machine(SVM)is easily affected by noises and outliers,and its training time dramatically increases with the growing in number of training samples.Satellite cloud image may easily be deteriorated by noises and intensity non-uniformity with a huge amount of data needs to be processed regularly,so it is hard to detect convective clouds in satellite image using traditional SVM.To deal with this problem,a novel method for detection of convective clouds was proposed based on fast fuzzy support vector machine(FFSVM).FFSVM was constructed by eliminating feeble samples and designing new membership function as two aspects.Firstly,according to the distribution characteristics of fuzzy inseparable sample set and the fact that the classification hyper-plane is only determined by support vectors,this paper uses SVDD,Gaussian model and border vector extraction model comprehensively to design a sample selection method in three steps,which can eliminate most of redundant samples and keep possible support vectors.Then,by defining adaptive parameters related to attenuation rate and critical membership on the basis of the distribution characteristics of training set,an adaptive membership function is designed.Finally,the FFSVM is trained by the remaining samples using adaptive membership function to detect convective clouds.The experiments on FY-2D satellite images show that the proposed method,compared with traditional FSVM,not only remarkably reduces training time,but also further improves the accuracy of convective clouds detection.展开更多
Editorial board meeting of Opto-Electronic Engineering was successfully held in Mianyang City,Sichuan province,on Sept.22,2007. Mr.Zhang Yimo, the president of Committee on Opto-electronic Technology （COT）, the Chin...Editorial board meeting of Opto-Electronic Engineering was successfully held in Mianyang City,Sichuan province,on Sept.22,2007. Mr.Zhang Yimo, the president of Committee on Opto-electronic Technology （COT）, the Chinese Optical Society, invited editorial board members, newly elected members of the editorial board and all staffs of the editorial department of Opto-Electronic Engineering attended the meeting.展开更多
The characteristics of reflected light of a 1-D guided-mode resonance filter(GMRF)are studied in this paper.A triple-layer GMRF is designed by using the finite difference time domain method under non-polarized light i...The characteristics of reflected light of a 1-D guided-mode resonance filter(GMRF)are studied in this paper.A triple-layer GMRF is designed by using the finite difference time domain method under non-polarized light illumination.Numerical results show that the reflectance spectra of TE and TM polarizations can be changed by altering the fill factor f of the GMRF.Moreover,by calculating the color of the reflected light with the chromaticity theory,we find that the color of reflected light becomes pure when f is 0.9.The results show that the color and polarization degree of the reflected light of a GMRF are tunable by altering the fill factor.展开更多
Starlight is generally unpolarized,but the light reflected from the planet is linearly polarized as the result of the Rayleigh scattering.For ground-based exoplanet imaging,atmospheres turbulence is changing from time...Starlight is generally unpolarized,but the light reflected from the planet is linearly polarized as the result of the Rayleigh scattering.For ground-based exoplanet imaging,atmospheres turbulence is changing from time to time,which induces speckle noise and hampers the high-contrast imaging of the faint exoplanets.In this paper,we propose a differential-imaging polarimeter dedicated for exoplanet high-contrast imaging.The system contains a zero-order half-wave plate(HWP)located on the optical pupil plane,which can rotate to modulate the incoming light,and a Wollaston prism(WP)is used to generate two polarized images,which is used for simultaneously polarization differential imaging and thus our system is fundamentally immune to the atmospheric turbulence induced temporally-variable wavefront aberration.Our polarimeter can be inserted near the telescope image focal plane,and provide an extra contrast for the exoplanet high-contrast imaging.To achieve best differential-imaging performance,dedicated algorithm is developed,which can effectively correct the distortion and the intensity unbalance between the two differential images.The system successfully achieves an extra contrast of^30~50 times,which can be used with current adaptive optics and coronagraph system for directly imaging of giant Jupiter-like exoplanets.展开更多
Triboluminescence,also as known as mechanoluminescence,is an attractive optical behavior that means the light emitted from specific organic and inorganic materials when they are subjected to external forces,such as cr...Triboluminescence,also as known as mechanoluminescence,is an attractive optical behavior that means the light emitted from specific organic and inorganic materials when they are subjected to external forces,such as crushing,deformation,cleaving,vibration.Inorganic triboluminescent materials show great potential for applications in sensing,such as stress sensing,damage detection.However,the triboluminescent mechanism of organic materials should be pushed further as well as their application.In this review,we summarized the history of development and possible mechanism of organic triboluminescent materials,and discussed various applications in sensing field.At the same time,inspired by the existing research progress in inorganic triboluminescent materials,we proposed the flourishing development prospects of organic triboluminescent materials in stress sensors,movement monitoring,imaging stress distribution,visualization of crack propagation,structural diagnosis,and other fields.展开更多
A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical(PEC)water splitting is central to improving its performance.Herein,taking the Si-based photoanodes(n^(+)p-Si/SiO_(x)/Fe/FeOx/MOO...A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical(PEC)water splitting is central to improving its performance.Herein,taking the Si-based photoanodes(n^(+)p-Si/SiO_(x)/Fe/FeOx/MOOH,M=Fe,Co,Ni)as a model system,we investigate the effect of the transition-metal electrocatalysts on the oxygen evolution reaction(OER).Among the photoanodes with the three different electrocatalysts,the best OER activity,with a low-onset potential of∼1.01 VRHE,a high photocurrent density of 24.10 mA cm^(-2)at 1.23 VRHE,and a remarkable saturation photocurrent density of 38.82 mA cm^(-2),was obtained with the NiOOH overlayer under AM 1.5G simulated sunlight(100 mW cm^(-2))in 1 M KOH electrolyte.The optimal interfacial engineering for electrocatalysts plays a key role for achieving high performance because it promotes interfacial charge transport,provides a larger number of surface active sites,and results in higher OER activity,compared to other electrocatalysts.This study provides insights into how electrocatalysts function in water-splitting devices to guide future studies of solar energy conversion.展开更多
In this paper, we demonstrate that controlled dopantoncentration is an essential issue for charge carriers transporting in red Phosphorescent Organic Light-Emitting Device （PHOLED）. Carriers transport via dopant mol...In this paper, we demonstrate that controlled dopantoncentration is an essential issue for charge carriers transporting in red Phosphorescent Organic Light-Emitting Device （PHOLED）. Carriers transport via dopant molecules in the emitting layer with a single host, however, via both dopant and host molecules when their energy levels are well aligned. Conditions for reduced driving-voltage and enhanced efficiency of red PHOLED are obtained by employing a mixed host structure. A pure red PHOLED with color coordinates of （0.67, 0.33） has been realized by using only 4 wt% dopant, The device achieves 100 cd/cm2 at 2.9 V, with correspond- ing power efficiency of 9.3im/W and external quantum efficiency of 14.3%.展开更多
In Mexico, owing to solar radiation conditions, there is great potential for PV （photovoltaic） systems. Besides, since 2007, the solar electricity interconnection agreement became official which allowed for an impor...In Mexico, owing to solar radiation conditions, there is great potential for PV （photovoltaic） systems. Besides, since 2007, the solar electricity interconnection agreement became official which allowed for an important growth of the photovoltaic industry. Due to the important development of the PV industry, there is a need for engineers trained to design, install, and evaluate PV systems The UAEMEX （autonomous university of the state of Mexico） offers a new bachelor degree of engineering program which dedicated to the development of sustainable energy systems. This kind of programs requires special equipment for experimentation and practice Specialists at UAEMEX also detected the need for a system to evaluate and demonstrate the application of PV modules, but they also found that most of the systems on the market are very expensive and unable to evaluate different arrangements. The goal of this paper is to present the design of a mobile system to evaluate PV modules and arrangements. This system is useful, not only for demonstration practices, but also for experimentation with different materials and types of PV panels. The design allows for two or four PV modules to be assembled in different positions and inclinations. The prototype is equipped with a data acquisition system that will be used to obtain the PV module performance curves. It will also be used to evaluate the atmospheric, interference and shadow effects on these modules. This prototype will be used to complement the practice learning of solar PV systems, but also to demonstrate the use of PV modules. The prototype is being design and constructed by a group of mechanical and electronic engineering students and this fact will be useful to meet the needs of basic science, math, and engineering teaching objectives in an integrated and hands-on way project. The essential features of system are described. A comparative analysis of the systems on the market is carried out. Also presented are the learning advantages for the students involved in the design and construction of this kind of systems, as well as a summary of practices that may be performed with the equipment.展开更多
基金supported in part by the National Natural Science Foundation of China under Grants (61471212)Natural Science Foundation of Zhejiang Province under Grants (LY16F010001)+1 种基金Science and Technology Program of Zhejiang Meteorological Bureau under Grants (2016YB01)Natural Science Foundation of Ningbo under Grants(2016A610091,2017A610297)
文摘Support vector machine(SVM)is easily affected by noises and outliers,and its training time dramatically increases with the growing in number of training samples.Satellite cloud image may easily be deteriorated by noises and intensity non-uniformity with a huge amount of data needs to be processed regularly,so it is hard to detect convective clouds in satellite image using traditional SVM.To deal with this problem,a novel method for detection of convective clouds was proposed based on fast fuzzy support vector machine(FFSVM).FFSVM was constructed by eliminating feeble samples and designing new membership function as two aspects.Firstly,according to the distribution characteristics of fuzzy inseparable sample set and the fact that the classification hyper-plane is only determined by support vectors,this paper uses SVDD,Gaussian model and border vector extraction model comprehensively to design a sample selection method in three steps,which can eliminate most of redundant samples and keep possible support vectors.Then,by defining adaptive parameters related to attenuation rate and critical membership on the basis of the distribution characteristics of training set,an adaptive membership function is designed.Finally,the FFSVM is trained by the remaining samples using adaptive membership function to detect convective clouds.The experiments on FY-2D satellite images show that the proposed method,compared with traditional FSVM,not only remarkably reduces training time,but also further improves the accuracy of convective clouds detection.
文摘Editorial board meeting of Opto-Electronic Engineering was successfully held in Mianyang City,Sichuan province,on Sept.22,2007. Mr.Zhang Yimo, the president of Committee on Opto-electronic Technology （COT）, the Chinese Optical Society, invited editorial board members, newly elected members of the editorial board and all staffs of the editorial department of Opto-Electronic Engineering attended the meeting.
基金National Natural Science Foundation of China (61605035)
文摘The characteristics of reflected light of a 1-D guided-mode resonance filter(GMRF)are studied in this paper.A triple-layer GMRF is designed by using the finite difference time domain method under non-polarized light illumination.Numerical results show that the reflectance spectra of TE and TM polarizations can be changed by altering the fill factor f of the GMRF.Moreover,by calculating the color of the reflected light with the chromaticity theory,we find that the color of reflected light becomes pure when f is 0.9.The results show that the color and polarization degree of the reflected light of a GMRF are tunable by altering the fill factor.
基金the National Natural Science Foundation of China (NSFC, 11703058, 11703056, 11661161011, 11433007, 11220101001, 11328302, 11373005 and 11303064)the Opening Project of Key Laboratory of Astronomical Optics & Technology, Nanjing Institute of Astronomical Optics & Technology, Chinese Academy of Sciences (CASKLAOT-KF201606)+5 种基金the “Strategic Priority Research Program” of the ChineseAcademy of Sciences (XDA04075200)the Special Fund for astronomy of CAS (2015–2016)the Special Fund for Young Researcher of Nanjing Institute of Astronomical Optics & Technologythe International Partnership Program of the Chinese Academy of Sciences (114A32KYSB20160018)carried out at California State University Northridge with the support from NSF AST-1607921the Mt. Cuba Astronomical Foundation
文摘Starlight is generally unpolarized,but the light reflected from the planet is linearly polarized as the result of the Rayleigh scattering.For ground-based exoplanet imaging,atmospheres turbulence is changing from time to time,which induces speckle noise and hampers the high-contrast imaging of the faint exoplanets.In this paper,we propose a differential-imaging polarimeter dedicated for exoplanet high-contrast imaging.The system contains a zero-order half-wave plate(HWP)located on the optical pupil plane,which can rotate to modulate the incoming light,and a Wollaston prism(WP)is used to generate two polarized images,which is used for simultaneously polarization differential imaging and thus our system is fundamentally immune to the atmospheric turbulence induced temporally-variable wavefront aberration.Our polarimeter can be inserted near the telescope image focal plane,and provide an extra contrast for the exoplanet high-contrast imaging.To achieve best differential-imaging performance,dedicated algorithm is developed,which can effectively correct the distortion and the intensity unbalance between the two differential images.The system successfully achieves an extra contrast of^30~50 times,which can be used with current adaptive optics and coronagraph system for directly imaging of giant Jupiter-like exoplanets.
基金Project(51703253)supported by the National Natural Science Foundation of ChinaProject(2020GXLH-Z-010)supported by Key Research and Development Program of Shaanxi Province,China+6 种基金Project(2020JQ-168)supported by Shaanxi Science and Technology Fund,ChinaProject(201906010091)supported by Pearl River Nova Program of Guangzhou,ChinaProject(cstc2020jcyj-msxm X0931)supported by Chongqing Science and Technology Fund,ChinaProject(2021A1515010633)supported by Guangdong Basic and Applied Basic Research Foundation,ChinaProject(202003N4060)supported by the Ningbo Natural Science Foundation,ChinaProject(SZKFJJ202001)supported by Henan Key Laboratory of Special Protective Materials,ChinaProject(2020Z073053007)supported by Aerospace Science Foundation of China。
文摘Triboluminescence,also as known as mechanoluminescence,is an attractive optical behavior that means the light emitted from specific organic and inorganic materials when they are subjected to external forces,such as crushing,deformation,cleaving,vibration.Inorganic triboluminescent materials show great potential for applications in sensing,such as stress sensing,damage detection.However,the triboluminescent mechanism of organic materials should be pushed further as well as their application.In this review,we summarized the history of development and possible mechanism of organic triboluminescent materials,and discussed various applications in sensing field.At the same time,inspired by the existing research progress in inorganic triboluminescent materials,we proposed the flourishing development prospects of organic triboluminescent materials in stress sensors,movement monitoring,imaging stress distribution,visualization of crack propagation,structural diagnosis,and other fields.
文摘A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical(PEC)water splitting is central to improving its performance.Herein,taking the Si-based photoanodes(n^(+)p-Si/SiO_(x)/Fe/FeOx/MOOH,M=Fe,Co,Ni)as a model system,we investigate the effect of the transition-metal electrocatalysts on the oxygen evolution reaction(OER).Among the photoanodes with the three different electrocatalysts,the best OER activity,with a low-onset potential of∼1.01 VRHE,a high photocurrent density of 24.10 mA cm^(-2)at 1.23 VRHE,and a remarkable saturation photocurrent density of 38.82 mA cm^(-2),was obtained with the NiOOH overlayer under AM 1.5G simulated sunlight(100 mW cm^(-2))in 1 M KOH electrolyte.The optimal interfacial engineering for electrocatalysts plays a key role for achieving high performance because it promotes interfacial charge transport,provides a larger number of surface active sites,and results in higher OER activity,compared to other electrocatalysts.This study provides insights into how electrocatalysts function in water-splitting devices to guide future studies of solar energy conversion.
基金the National Hi-Tech Research and Development Program of China，the Ministry of Science and Technology of China，the National Natural Science Foundation of China，the Research Fund for the Doctoral Program of Higher Education，the Scientific and Technological Developing Scheme of Jilin Province
文摘In this paper, we demonstrate that controlled dopantoncentration is an essential issue for charge carriers transporting in red Phosphorescent Organic Light-Emitting Device （PHOLED）. Carriers transport via dopant molecules in the emitting layer with a single host, however, via both dopant and host molecules when their energy levels are well aligned. Conditions for reduced driving-voltage and enhanced efficiency of red PHOLED are obtained by employing a mixed host structure. A pure red PHOLED with color coordinates of （0.67, 0.33） has been realized by using only 4 wt% dopant, The device achieves 100 cd/cm2 at 2.9 V, with correspond- ing power efficiency of 9.3im/W and external quantum efficiency of 14.3%.
文摘In Mexico, owing to solar radiation conditions, there is great potential for PV （photovoltaic） systems. Besides, since 2007, the solar electricity interconnection agreement became official which allowed for an important growth of the photovoltaic industry. Due to the important development of the PV industry, there is a need for engineers trained to design, install, and evaluate PV systems The UAEMEX （autonomous university of the state of Mexico） offers a new bachelor degree of engineering program which dedicated to the development of sustainable energy systems. This kind of programs requires special equipment for experimentation and practice Specialists at UAEMEX also detected the need for a system to evaluate and demonstrate the application of PV modules, but they also found that most of the systems on the market are very expensive and unable to evaluate different arrangements. The goal of this paper is to present the design of a mobile system to evaluate PV modules and arrangements. This system is useful, not only for demonstration practices, but also for experimentation with different materials and types of PV panels. The design allows for two or four PV modules to be assembled in different positions and inclinations. The prototype is equipped with a data acquisition system that will be used to obtain the PV module performance curves. It will also be used to evaluate the atmospheric, interference and shadow effects on these modules. This prototype will be used to complement the practice learning of solar PV systems, but also to demonstrate the use of PV modules. The prototype is being design and constructed by a group of mechanical and electronic engineering students and this fact will be useful to meet the needs of basic science, math, and engineering teaching objectives in an integrated and hands-on way project. The essential features of system are described. A comparative analysis of the systems on the market is carried out. Also presented are the learning advantages for the students involved in the design and construction of this kind of systems, as well as a summary of practices that may be performed with the equipment.
