The plasma rotation velocity were measured in HL-1M with Doppler shifts of CⅢ、 C Ⅱ、 O Ⅱ and H. line by a SKD high resolution spectrometer. The effects .of density' hydrogen pellet injection and carbon impuri...The plasma rotation velocity were measured in HL-1M with Doppler shifts of CⅢ、 C Ⅱ、 O Ⅱ and H. line by a SKD high resolution spectrometer. The effects .of density' hydrogen pellet injection and carbon impurities injected by laser-blow-off on toroidal(V) and poloidal (Vθ)rotation velocity have been observed. The Vθ measured from H. line is only half of that from C Ⅱ impurity line.展开更多
The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap meta...The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap metasurface will change this situation due to its low absorption and high efficiency. Herein, we simulate a size-adjustable metasurface of the Al doped ZnO (AZO) nanorod arrays based on finite difference time domain method (FDTD) which can realize the conversion of amplitude polarization and phase in the full visible band. The corresponding theoretical polarization conversion efficiency can reach as high as 91.48% (450 nm), 95.27% (530 nm), and 91.01% (65 nm). The modulation of focusing wavelength can be realized by directly adjusting the height of the AZO nanorod. The designed half-wave plate and metalens can be applied in the imaging power modulation halfwave conversion and enriching the spectroscopy.展开更多
Low-dimensional van der Waals materials have attracted tremendous attention due to their exceptional physical,chemical,and mechanical properties,particularly their strong anisotropy in structural,electronic,and optica...Low-dimensional van der Waals materials have attracted tremendous attention due to their exceptional physical,chemical,and mechanical properties,particularly their strong anisotropy in structural,electronic,and optical behaviors.Herein,we comprehensively studied diverse hyperbolic polaritons in quasi-one-dimensional ferroelectric material WOBr_(4),including their propagation patterns and frequencies,most notably,the electric-field and strain-driven elliptic-to-hyperbolic topological transition.Under moderate uniaxial strain or electric field,the optical absorption along the chain direction displays a threefold modulation in intensity and an approximately 1 eV frequency shift,while showing minor variation in the direction perpendicular to the chain.The pronounced tunability of anisotropic optical absorption is achieved through the regulation of 1D ferroelectric polarization by external stimuli,which controls the symmetry breaking of atomic orbitals involved in the optical transitions.We propose WOBr4 as a versatile platform for ferroelectric control of hyperbolic polaritons,offering potential for advanced applications in photovoltaics,optoelectronics,and nanophotonics.展开更多
Objective To investigate the facial spectrum and color characteristics of patients with essen-tial hypertension post administering antihypertensive drugs,establish a classification and evaluation model based on the fa...Objective To investigate the facial spectrum and color characteristics of patients with essen-tial hypertension post administering antihypertensive drugs,establish a classification and evaluation model based on the facial colors of the enrolled patients,and perform in-depth analysis on the important characteristics of their facial spectrum.Methods From September 3,2018,to March 23,2024,participants with essential hyperten-sion(receiving antihypertensive medication treatment,hypertension group)and normal blood pressure(control group)were recruited from the Cardiology Department of Shanghai Hospital of Traditional Chinese Medicine,the Coronary Care Unit of Shanghai Tenth People's Hospital,the Physical Examination Center of Shuguang Hospital Affiliated to Shanghai Uni-versity of Traditional Chinese Medicine,and the Gaohang Community Health Service Center.This study employed the propensity score matching(PSM)method to reduce study partici-pants selection bias.Spectral information in the facial visible light spectrum of the subjects was collected using a flame spectrometer,and the spectral chromaticity values were calculat-ed using the equal-interval wavelength method.The study analyzed the differences in spec-tral reflectance across various facial regions,including the entire face,forehead,glabella,nose,jaw,left and right zygomatic regions,left and right cheek regions as well as differences in parameters within the Lab color space between the two subject groups.Feature selection was conducted using least absolute shrinkage and selection operator(LASSO)regression,fol-lowed by the application of various machine learning algorithms,including logistic regres-sion(LR),support vector machine(SVM),random forest(RF),Naïve Bayes(NB),and eX-treme Gradient Boosting(XGB).The reduced-dimensional dataset was split in a 7:3 ratio to establish a classification and assessment model for facial coloration related to primary hyper-tension.Additionally,model fusion techniques were applied to enhance the predictive power.The performance of the models was evaluated using metrics including the area under the curve(AUC)and accuracy.Shapley Additive exPlanations(SHAP)was used to interpret the outcomes of the models.Results A total of 114 participants were included in both hypertension and control groups.Reflectance analysis across the entire face and eight predefined areas revealed that the hypertensive group exhibited significantly higher reflectance of corresponding color light in the blue-violet region(P<0.05)and a lower reflectance in the red region(P<0.05)compared with control group.Analysis of Lab color space parameters across the entire face and eight predefined areas showed that hypertensive group had significantly lower a and b values than control group(P<0.05).LASSO regression analysis identified a total of 18 facial color features that were highly correlated with hypertension,including the a values of the chin and the right cheek,the reflectance at 380 nm and at 780 nm of the forehead.The results of the multi-mod-el classification showed that the RF classification model was the most effective,with an AUC of 0.74 and an accuracy of 0.77.The combined model of RF+LR+SVM outperformed a single model in their classification performance,achieving an AUC of 0.80 and an accuracy of 0.76.SHAP model visualization results indicated that the top three contributors to ideal prediction results based on the characteristics from the facial spectrum were the reflectance at 380 nm across the entire face and of the nose as well as the a value of the chin.Conclusion Within the same age group,patients with essential hypertension exhibited signif-icant and regular changes in facial color and facial spectral reflectance parameters after the administration of antihypertensive drugs.Furthermore,facial reflectance indicators,such as the overall reflectance at 380 nm and the a value of the chin,could offer valuable references for clinically assessing the drug efficacy and health status of patients with essential hyperten-sion.展开更多
Organic semiconductoe 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) has been synthetized with 1,8-naphthalic anhydride using chemical method.X-ray diffraction spectrum shows that it is monoclinic.Visible absorp...Organic semiconductoe 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) has been synthetized with 1,8-naphthalic anhydride using chemical method.X-ray diffraction spectrum shows that it is monoclinic.Visible absorption spectrum shows that its gap band is 2.2 eV with singlet exciton bandwidth of 0.9 eV.展开更多
A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic po...A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic pollutants during an integrated chemical oxidation and biological process. The results showed that the hydrophobic acid fraction increased after Fenton oxidation, which was likely due to the production of small-molecule organic acids. Soluble microbial products were generated during biological treatment processes,which were degraded after ozonation; meanwhile, the hydrophilic base and acid components increased. Ultraviolet-visible spectroscopic analysis indicated that peaks at the absorption wavelengths of 280 and 254 nm, which are associated with aromatic substances, were detected in the raw water. The aromatic substances were gradually removed, becoming undetectable after biological aeration filter（BAF） treatment. Fourier transform infrared spectroscopy analysis revealed that the functional groups of phenols;benzene, toluene, ethylbenzene, and xylene（BTEX）; aromatic hydrocarbons; aliphatic acids;aldehydes; and esters were present in raw wastewater. The organic substances were oxidized into small molecules after Fenton treatment. Aromatic hydrocarbons were effectively removed through bioadsorption and biodegradation after BAF process.Biodegradable organic matter was reduced and finally became undetectable after anoxic–oxic treatment in combination with a membrane bioreactor. Four fluorescent components were fractionated and obtained via excitation–emission matrix parallel factor analysis（EEM-PARAFAC）. Dissolved organic matter fractionation in conjunction with EEM-PARAFAC was able to monitor more precisely the evolution of characteristic organic contaminants.展开更多
We demonstrate a single-exposure holographic fabrication of two-dimensional photonic crystal with round- cornered triangular ＇atoms＇ arranged in a triangular lattice. Simulation results show that double absolute pho...We demonstrate a single-exposure holographic fabrication of two-dimensional photonic crystal with round- cornered triangular ＇atoms＇ arranged in a triangular lattice. Simulation results show that double absolute photonic band gaps exist in this structure. Our experimental results show that holographic lithography can be used to fabricate photonic crystals not only with various lattice structures but also with various kinds of structures of the atoms, to obtain absolute band gaps or a particular band gap structure. Furthermore, the single-exposure holographic method not only makes the fabrication process simple and convenient but also makes the structures of the atoms more perfect.展开更多
Ozone is a green house gas. Ozone absorption cross sections have been reported with discrepancies and inconsistencies. In this paper, simultaneous effects of the optical path length and temperature variations on ozone...Ozone is a green house gas. Ozone absorption cross sections have been reported with discrepancies and inconsistencies. In this paper, simultaneous effects of the optical path length and temperature variations on ozone gas absorption cross sections are investigated at different wavelengths. HITRAN 2012, the latest available line list on spectralcalc.com simulator, is used in this study to simulate ozone gas absorption cross sections in relation to the simultaneous effects of the optical path length and temperature at the wavelengths of 603 nm and 575 nm. Results obtained for gas cells with the optical path length from 10 cm to 120 cm show that the decrease in temperatures from 313 K to 103 K results in the increase in ozone gas absorption cross sections. At wavelengths of 603 nm and 575 nm, the percentage increase of ozone gas absorption cross sections is 1.22% and 0.71%, respectively. Results obtained in this study show that in the visible spectrum, at constant pressure, ozone gas absorption cross sections are dependent on the temperature and wavelength but do not depend on the optical path length. Analysis in this work addresses discrepancies in ozone gas absorption cross sections in relation to the temperature in the visible spectrum; thus, the results can be applied to get optimal configuration of high accuracy ozone gas sensors.展开更多
The colour-transition glazed brick has been made under suitable conditions and the expected result has been-obtained.The chemical compositions of the glaze have been given. The structures of Na_2O(K_2O)-CaO(MgO)-Al_2O...The colour-transition glazed brick has been made under suitable conditions and the expected result has been-obtained.The chemical compositions of the glaze have been given. The structures of Na_2O(K_2O)-CaO(MgO)-Al_2O_3 -SiO_2 system,parent glaze and colour-transition glaze have been invesitigated by SME,Visible spec- trum,IR spectrum and Raman spectrum.A brief exp- lanation to colouring mechanism of colour-transi- tion glaze was given in accordance with theory of optical absorption and scattering. For all specimens,liquid phase separation structures were observed generally be SEM and acomparison between parent glaze and colour-transi- tion glaze was made by Visible specta.Hence an inference can be drawn from these results that the liquid phase droplets contain Nd^(3+),Pr^(3+) ions, which cause coloration selective absorbing and scattering of incident light waves.展开更多
The air in African cities is increasingly polluted mainly due to human activities. A bioindication technical of urban air quality based on active remote sensing might be an alternative to existing physico-chemical met...The air in African cities is increasingly polluted mainly due to human activities. A bioindication technical of urban air quality based on active remote sensing might be an alternative to existing physico-chemical methods. Reflectance measurements in the visible spectrum have been carried out at the adaxial and abaxial sides of Ficus benjamina L. leaves in the city of Abidjan, Côte d’Ivoire, with a precision digital camera. Leaves were collected in industrial zones and in parks. The impact of air pollution on leaf physiological as well as structural characteristics in these two contrasts urban environments was determined by Dorsiventral Leaf Reflectance Correlation (DRLC) and dorsiventral leaf reflectance asymmetry quantitatively defined with Normalized Dorsiventral Asymmetry Index (NDAI). Species leaf susceptibility to air pollution from season to season was determined by NDAI seasonal variation. Leaf reflectance measurements allowed the estimation of environmental stress level among industrial areas and parks. NDAI and DLRC were significantly higher in industrial zones compared to parks. NDAI values were found significantly higher for major rainy season compared to major dry season, indicating probably that F. benjamina leaf structure changes were increased from one season to another. Thereby, assessment of urban air quality can be done using leaves reflectance in the visible spectrum.展开更多
Most present research into facial expression recognition focuses on the visible spectrum, which is sen- sitive to illumination change. In this paper, we focus on in- tegrating thermal infrared data with visible spectr...Most present research into facial expression recognition focuses on the visible spectrum, which is sen- sitive to illumination change. In this paper, we focus on in- tegrating thermal infrared data with visible spectrum images for spontaneous facial expression recognition. First, the ac- tive appearance model AAM parameters and three defined head motion features are extracted from visible spectrum im- ages, and several thermal statistical features are extracted from infrared （IR） images. Second, feature selection is per- formed using the F-test statistic. Third, Bayesian networks BNs and support vector machines SVMs are proposed for both decision-level and feature-level fusion. Experiments on the natural visible and infrared facial expression （NVIE） spontaneous database show the effectiveness of the proposed methods, and demonstrate thermal 1R images＇ supplementary role for visible facial expression recognition.展开更多
Well established for the visible spectrum gaps of the transition metal dichalcogenide family,valleytronics—the control of valley charge and current by light—is comparatively unexplored for the THz gaps that characte...Well established for the visible spectrum gaps of the transition metal dichalcogenide family,valleytronics—the control of valley charge and current by light—is comparatively unexplored for the THz gaps that characterize graphene and topological insulators.Hereweshow that few cycle pulses of THz light can create and control a>90%valley polarized current in graphene,with lightwave control over the current magnitude and direction.This is underpinned by a light-matter symmetry breaking in the ultrafast limit of circularly polarized light,characterized by a symmetry lowering of the excited state charge distribution.Our findings both highlight the richness of few cycle light pulses in control over quantum matter,and provide a route towards a“THz valleytronics”in meV gapped systems.展开更多
文摘The plasma rotation velocity were measured in HL-1M with Doppler shifts of CⅢ、 C Ⅱ、 O Ⅱ and H. line by a SKD high resolution spectrometer. The effects .of density' hydrogen pellet injection and carbon impurities injected by laser-blow-off on toroidal(V) and poloidal (Vθ)rotation velocity have been observed. The Vθ measured from H. line is only half of that from C Ⅱ impurity line.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2017YFB0403101).
文摘The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap metasurface will change this situation due to its low absorption and high efficiency. Herein, we simulate a size-adjustable metasurface of the Al doped ZnO (AZO) nanorod arrays based on finite difference time domain method (FDTD) which can realize the conversion of amplitude polarization and phase in the full visible band. The corresponding theoretical polarization conversion efficiency can reach as high as 91.48% (450 nm), 95.27% (530 nm), and 91.01% (65 nm). The modulation of focusing wavelength can be realized by directly adjusting the height of the AZO nanorod. The designed half-wave plate and metalens can be applied in the imaging power modulation halfwave conversion and enriching the spectroscopy.
基金supported by the Yongjiang Talent Program(No.2024A-119-G)the Foundation of Zhejiang Province Excellent Young Scientist,the National Postdoctoral Program,and the Program for Science and Technology Innovation Team in Zhejiang under Grant No.2021R01004+4 种基金H.W.and B.W.were supported by Zhejiang Provincial Natural Science Foundation of China(LD24F040001)S.X.acknowledges funding support from the Natural Science Foundation of Chongqing,China(No.CSTB2024NSCQ-MSX0424)Changsha Municipal Natural Science Foundation(No.kq2402050)S.T.was supported by the Natural Science Foundation of Zhejiang Province(No.LY24A040001)the Ningbo Youth Science and Technology Innovation Leading Talent Project(No.2023QL001).
文摘Low-dimensional van der Waals materials have attracted tremendous attention due to their exceptional physical,chemical,and mechanical properties,particularly their strong anisotropy in structural,electronic,and optical behaviors.Herein,we comprehensively studied diverse hyperbolic polaritons in quasi-one-dimensional ferroelectric material WOBr_(4),including their propagation patterns and frequencies,most notably,the electric-field and strain-driven elliptic-to-hyperbolic topological transition.Under moderate uniaxial strain or electric field,the optical absorption along the chain direction displays a threefold modulation in intensity and an approximately 1 eV frequency shift,while showing minor variation in the direction perpendicular to the chain.The pronounced tunability of anisotropic optical absorption is achieved through the regulation of 1D ferroelectric polarization by external stimuli,which controls the symmetry breaking of atomic orbitals involved in the optical transitions.We propose WOBr4 as a versatile platform for ferroelectric control of hyperbolic polaritons,offering potential for advanced applications in photovoltaics,optoelectronics,and nanophotonics.
基金National Natural Science Foundation of China(82104738 and 82004255)Key Discipline Construction Project of High-level Traditional Chinese Medicine of the National Administration of Traditional Chinese Medicine-Traditional Chinese Medical Diagnostics(ZYYZDXK-2023069).
文摘Objective To investigate the facial spectrum and color characteristics of patients with essen-tial hypertension post administering antihypertensive drugs,establish a classification and evaluation model based on the facial colors of the enrolled patients,and perform in-depth analysis on the important characteristics of their facial spectrum.Methods From September 3,2018,to March 23,2024,participants with essential hyperten-sion(receiving antihypertensive medication treatment,hypertension group)and normal blood pressure(control group)were recruited from the Cardiology Department of Shanghai Hospital of Traditional Chinese Medicine,the Coronary Care Unit of Shanghai Tenth People's Hospital,the Physical Examination Center of Shuguang Hospital Affiliated to Shanghai Uni-versity of Traditional Chinese Medicine,and the Gaohang Community Health Service Center.This study employed the propensity score matching(PSM)method to reduce study partici-pants selection bias.Spectral information in the facial visible light spectrum of the subjects was collected using a flame spectrometer,and the spectral chromaticity values were calculat-ed using the equal-interval wavelength method.The study analyzed the differences in spec-tral reflectance across various facial regions,including the entire face,forehead,glabella,nose,jaw,left and right zygomatic regions,left and right cheek regions as well as differences in parameters within the Lab color space between the two subject groups.Feature selection was conducted using least absolute shrinkage and selection operator(LASSO)regression,fol-lowed by the application of various machine learning algorithms,including logistic regres-sion(LR),support vector machine(SVM),random forest(RF),Naïve Bayes(NB),and eX-treme Gradient Boosting(XGB).The reduced-dimensional dataset was split in a 7:3 ratio to establish a classification and assessment model for facial coloration related to primary hyper-tension.Additionally,model fusion techniques were applied to enhance the predictive power.The performance of the models was evaluated using metrics including the area under the curve(AUC)and accuracy.Shapley Additive exPlanations(SHAP)was used to interpret the outcomes of the models.Results A total of 114 participants were included in both hypertension and control groups.Reflectance analysis across the entire face and eight predefined areas revealed that the hypertensive group exhibited significantly higher reflectance of corresponding color light in the blue-violet region(P<0.05)and a lower reflectance in the red region(P<0.05)compared with control group.Analysis of Lab color space parameters across the entire face and eight predefined areas showed that hypertensive group had significantly lower a and b values than control group(P<0.05).LASSO regression analysis identified a total of 18 facial color features that were highly correlated with hypertension,including the a values of the chin and the right cheek,the reflectance at 380 nm and at 780 nm of the forehead.The results of the multi-mod-el classification showed that the RF classification model was the most effective,with an AUC of 0.74 and an accuracy of 0.77.The combined model of RF+LR+SVM outperformed a single model in their classification performance,achieving an AUC of 0.80 and an accuracy of 0.76.SHAP model visualization results indicated that the top three contributors to ideal prediction results based on the characteristics from the facial spectrum were the reflectance at 380 nm across the entire face and of the nose as well as the a value of the chin.Conclusion Within the same age group,patients with essential hypertension exhibited signif-icant and regular changes in facial color and facial spectral reflectance parameters after the administration of antihypertensive drugs.Furthermore,facial reflectance indicators,such as the overall reflectance at 380 nm and the a value of the chin,could offer valuable references for clinically assessing the drug efficacy and health status of patients with essential hyperten-sion.
文摘Organic semiconductoe 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) has been synthetized with 1,8-naphthalic anhydride using chemical method.X-ray diffraction spectrum shows that it is monoclinic.Visible absorption spectrum shows that its gap band is 2.2 eV with singlet exciton bandwidth of 0.9 eV.
基金supported by the National Water Pollution Control and Treatment Science and Technology Major Project of China(No.2017ZX07402002)
文摘A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic pollutants during an integrated chemical oxidation and biological process. The results showed that the hydrophobic acid fraction increased after Fenton oxidation, which was likely due to the production of small-molecule organic acids. Soluble microbial products were generated during biological treatment processes,which were degraded after ozonation; meanwhile, the hydrophilic base and acid components increased. Ultraviolet-visible spectroscopic analysis indicated that peaks at the absorption wavelengths of 280 and 254 nm, which are associated with aromatic substances, were detected in the raw water. The aromatic substances were gradually removed, becoming undetectable after biological aeration filter（BAF） treatment. Fourier transform infrared spectroscopy analysis revealed that the functional groups of phenols;benzene, toluene, ethylbenzene, and xylene（BTEX）; aromatic hydrocarbons; aliphatic acids;aldehydes; and esters were present in raw wastewater. The organic substances were oxidized into small molecules after Fenton treatment. Aromatic hydrocarbons were effectively removed through bioadsorption and biodegradation after BAF process.Biodegradable organic matter was reduced and finally became undetectable after anoxic–oxic treatment in combination with a membrane bioreactor. Four fluorescent components were fractionated and obtained via excitation–emission matrix parallel factor analysis（EEM-PARAFAC）. Dissolved organic matter fractionation in conjunction with EEM-PARAFAC was able to monitor more precisely the evolution of characteristic organic contaminants.
基金Supported by the National Natural Science Foundation of China under Grant No 10674183, the National Basic Research Program of China under Grant No 2004CB719804, and PhD Foundation of the Ministry of Education of China （20060558068）.
文摘We demonstrate a single-exposure holographic fabrication of two-dimensional photonic crystal with round- cornered triangular ＇atoms＇ arranged in a triangular lattice. Simulation results show that double absolute photonic band gaps exist in this structure. Our experimental results show that holographic lithography can be used to fabricate photonic crystals not only with various lattice structures but also with various kinds of structures of the atoms, to obtain absolute band gaps or a particular band gap structure. Furthermore, the single-exposure holographic method not only makes the fabrication process simple and convenient but also makes the structures of the atoms more perfect.
基金supported by Universiti Teknologi Malaysia under Research University Grant Scheme under Grant No.05J60 and No.04H35Ministry of Higher Education under Fundamental Research Grant Scheme under Grant No.4F317 and No.4F565Nigerian Education Trust Fund under Tertiary Education Trust Fund
文摘Ozone is a green house gas. Ozone absorption cross sections have been reported with discrepancies and inconsistencies. In this paper, simultaneous effects of the optical path length and temperature variations on ozone gas absorption cross sections are investigated at different wavelengths. HITRAN 2012, the latest available line list on spectralcalc.com simulator, is used in this study to simulate ozone gas absorption cross sections in relation to the simultaneous effects of the optical path length and temperature at the wavelengths of 603 nm and 575 nm. Results obtained for gas cells with the optical path length from 10 cm to 120 cm show that the decrease in temperatures from 313 K to 103 K results in the increase in ozone gas absorption cross sections. At wavelengths of 603 nm and 575 nm, the percentage increase of ozone gas absorption cross sections is 1.22% and 0.71%, respectively. Results obtained in this study show that in the visible spectrum, at constant pressure, ozone gas absorption cross sections are dependent on the temperature and wavelength but do not depend on the optical path length. Analysis in this work addresses discrepancies in ozone gas absorption cross sections in relation to the temperature in the visible spectrum; thus, the results can be applied to get optimal configuration of high accuracy ozone gas sensors.
文摘The colour-transition glazed brick has been made under suitable conditions and the expected result has been-obtained.The chemical compositions of the glaze have been given. The structures of Na_2O(K_2O)-CaO(MgO)-Al_2O_3 -SiO_2 system,parent glaze and colour-transition glaze have been invesitigated by SME,Visible spec- trum,IR spectrum and Raman spectrum.A brief exp- lanation to colouring mechanism of colour-transi- tion glaze was given in accordance with theory of optical absorption and scattering. For all specimens,liquid phase separation structures were observed generally be SEM and acomparison between parent glaze and colour-transi- tion glaze was made by Visible specta.Hence an inference can be drawn from these results that the liquid phase droplets contain Nd^(3+),Pr^(3+) ions, which cause coloration selective absorbing and scattering of incident light waves.
文摘The air in African cities is increasingly polluted mainly due to human activities. A bioindication technical of urban air quality based on active remote sensing might be an alternative to existing physico-chemical methods. Reflectance measurements in the visible spectrum have been carried out at the adaxial and abaxial sides of Ficus benjamina L. leaves in the city of Abidjan, Côte d’Ivoire, with a precision digital camera. Leaves were collected in industrial zones and in parks. The impact of air pollution on leaf physiological as well as structural characteristics in these two contrasts urban environments was determined by Dorsiventral Leaf Reflectance Correlation (DRLC) and dorsiventral leaf reflectance asymmetry quantitatively defined with Normalized Dorsiventral Asymmetry Index (NDAI). Species leaf susceptibility to air pollution from season to season was determined by NDAI seasonal variation. Leaf reflectance measurements allowed the estimation of environmental stress level among industrial areas and parks. NDAI and DLRC were significantly higher in industrial zones compared to parks. NDAI values were found significantly higher for major rainy season compared to major dry season, indicating probably that F. benjamina leaf structure changes were increased from one season to another. Thereby, assessment of urban air quality can be done using leaves reflectance in the visible spectrum.
文摘Most present research into facial expression recognition focuses on the visible spectrum, which is sen- sitive to illumination change. In this paper, we focus on in- tegrating thermal infrared data with visible spectrum images for spontaneous facial expression recognition. First, the ac- tive appearance model AAM parameters and three defined head motion features are extracted from visible spectrum im- ages, and several thermal statistical features are extracted from infrared （IR） images. Second, feature selection is per- formed using the F-test statistic. Third, Bayesian networks BNs and support vector machines SVMs are proposed for both decision-level and feature-level fusion. Experiments on the natural visible and infrared facial expression （NVIE） spontaneous database show the effectiveness of the proposed methods, and demonstrate thermal 1R images＇ supplementary role for visible facial expression recognition.
基金funding through project-ID 328545488 TRR227(projects A04)Shallcrosswould like to thank DFG for funding through project-ID 522036409 SH 498/7-1+1 种基金Sharma and Shallcross would like to thank the Leibniz Professorin Program(SAW P118/2021)The authors acknowledge the North-German Supercomputing Alliance(HLRN)for providing HPC resources that have contributed to the research results reported in this paper.
文摘Well established for the visible spectrum gaps of the transition metal dichalcogenide family,valleytronics—the control of valley charge and current by light—is comparatively unexplored for the THz gaps that characterize graphene and topological insulators.Hereweshow that few cycle pulses of THz light can create and control a>90%valley polarized current in graphene,with lightwave control over the current magnitude and direction.This is underpinned by a light-matter symmetry breaking in the ultrafast limit of circularly polarized light,characterized by a symmetry lowering of the excited state charge distribution.Our findings both highlight the richness of few cycle light pulses in control over quantum matter,and provide a route towards a“THz valleytronics”in meV gapped systems.
基金financially supported by the National Key Research and Development Program of China(2019YFA0705900)funded by the Ministry of Science and Technology(MOST)the National Natural Science Foundation of China(52073281,22135007 and 21875244)the Natural Science Foundation of Jilin Province(20230101122JC)。
