Goodness of fit is demonstrated for theoretical calculation of z-scan data based on beams propagating in the nonlinear medium and the Fresnel–Kirchhoff diffraction integral in experiments with high nonlinear refracti...Goodness of fit is demonstrated for theoretical calculation of z-scan data based on beams propagating in the nonlinear medium and the Fresnel–Kirchhoff diffraction integral in experiments with high nonlinear refraction and absorption. The constancy of nonlinear optical parameters is achieved regardless of sample thickness and laser intensity, which clarifies the physical significance of optical parameters. We have obtained γ = 2.0 × 10-19 m2/W and β = 5.0 × 10-13 m/W for carbon disulfide excited by a pulsed laser at 800 nm with pulse duration of 35 fs,which are independent of sample thickness and laser intensity. Affirming constancy of the extracted parameters to the incident light intensity may become a practice to verify the goodness of the z-scan experiment.展开更多
Urban aerosols have a large effect on the deterioration of air quality and the degradation of atmospheric visibility.Characterization of the chemical composition of PM 2.5 and in situ measurements of the optical prope...Urban aerosols have a large effect on the deterioration of air quality and the degradation of atmospheric visibility.Characterization of the chemical composition of PM 2.5 and in situ measurements of the optical properties of aerosols were conducted in July 2008 at an urban site in Guangzhou,Southern China.The mean PM 2.5 concentration for the entire period was 53.7±23.2 μg m 3.The mean PM 2.5 concentration (82.7±25.4 μg m 3) on hazy days was roughly two times higher than that on clear days (38.8±8.7 μg m 3).The total water-soluble ion species and the total average carbon accounted for 47.9%±4.3% and 35.2%±4.5%,respectively,of the major components of PM 2.5.The increase of secondary and carbonaceous aerosols,in particular ammonium sulfate,played an important role in the formation of haze pollution.The mean absorption and scattering coefficients and the single scattering albedo over the whole period were 53±20 M m 1,226±111 M m 1,and 0.80±0.04,respectively.PM 2.5 had a high linear correlation with the aerosol extinction coefficient,elemental carbon (EC) was correlated with aerosol absorption,and organic carbon (OC) and SO 4 2 were tightly linked to aerosol scattering.展开更多
In this study,the effects of quantum dot size on the binding energy,radiative lifetime,and optical absorption coefficient of exciton state in both GaN/AlxGa1-xN core/shell and AlxGa1-xN/GaN inverted core/shell quantum...In this study,the effects of quantum dot size on the binding energy,radiative lifetime,and optical absorption coefficient of exciton state in both GaN/AlxGa1-xN core/shell and AlxGa1-xN/GaN inverted core/shell quantum dot structures are studied.For the GaN/AlxGa1-xN core/shell structure,the variation trend of binding energy is the same as that of radiation lifetime,both of which increase first and then decrease with the increase of core size.For AlxGa1-xN/GaN inverted core/shell structure,the binding energy decreases first and then increases with core size increasing,and the trends of radiation lifetime varying with core size under different shell sizes are different.For both structures,when the photon energy is approximately equal to the binding energy,the peak value of the absorption coefficient appears,and there will be different peak shifts under different conditions.展开更多
Based on the Schr ¨odinger equation for envelope function in the effective mass approximation, linear and nonlinear optical absorption coefficients in a multi-subband lens quantum dot are investigated. The effect...Based on the Schr ¨odinger equation for envelope function in the effective mass approximation, linear and nonlinear optical absorption coefficients in a multi-subband lens quantum dot are investigated. The effects of quantum dot size on the interband and intraband transitions energy are also analyzed. The finite element method is used to calculate the eigenvalues and eigenfunctions. Strain and In-mole-fraction effects are also studied, and the results reveal that with the decrease of the In-mole fraction, the amplitudes of linear and nonlinear absorption coefficients increase. The present computed results show that the absorption coefficients of transitions between the first excited states are stronger than those of the ground states. In addition, it has been found that the quantum dot size affects the amplitudes and peak positions of linear and nonlinear absorption coefficients while the incident optical intensity strongly affects the nonlinear absorption coefficients.展开更多
The variations of sulfate formation and optical coefficients during SO2 heterogeneous reactions on hematite surface under different SO2 concentrations were examined using in situ diffuse reflectance infrared Fourier t...The variations of sulfate formation and optical coefficients during SO2 heterogeneous reactions on hematite surface under different SO2 concentrations were examined using in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS） and ion chromatograph （IC）. Laboratory experiments revealed that within ambient SO2 of 0.51-18.6 ppmv, sulfate product, producing velocity, absorption and backward scattering coefficients showed an increasing trend with SO2 concentration. Under given SO2 concentration, the velocity of sulfate producing performed an evolution of initial increasing, midterm decreasing and final stabilizing. The reactive uptake and Brunaner-Emmett-Teller （BET） uptake coefficients of heterogeneous reactions rose with SOz and exhibited high reactivities. Considering global warming, this result is important for the knowledge of heterogeneous reactions of SO2 on mineral particle surface in the atmosphere and the assessment of their impacts on radiative forcing.展开更多
Presents the synthesis of Copolyimide containing triarylamine and NLO chromophore in backbone by azo coupling of 4 nitrobenzenediazonium tetrafloroborate to copoly(amic acid) in organic solvent and characterized by IR...Presents the synthesis of Copolyimide containing triarylamine and NLO chromophore in backbone by azo coupling of 4 nitrobenzenediazonium tetrafloroborate to copoly(amic acid) in organic solvent and characterized by IR and UV Vis spectra, which had high glass transition temperatrue and big second order nonlinear optical coefficient x (2) .展开更多
Two methods for particulate pigments(i.e.,quantitative filter technique,QFT,and in vivo measurement,InVivo,respectively)and two methods for dissolved pigments(i.e.,Acetone Extracts,AceEx,and high-performance liquid ch...Two methods for particulate pigments(i.e.,quantitative filter technique,QFT,and in vivo measurement,InVivo,respectively)and two methods for dissolved pigments(i.e.,Acetone Extracts,AceEx,and high-performance liquid chromatography,HPLC,respectively) were used to obtain the optical absorption coefficient spectra for cultures of four typical algal species.Through normalization and analysis of the spectra,it is shown that(1) the four methods are able to measure optical absorption spectra of particulate and/or dissolved pigments;(2)that the optical absorption spectra of particulate and dissolved pigments were consistent in terms of the peak position in the blue wavelength,and the difference of the peak position in the near infrared wavelength was ~10nm between each other;and(3)that the leveling effect of the absorption spectra of particulate pigments was significant.These four methods can all effectively measure the absorption coefficients of phytoplankton pigments,while each one has its unique advantages in different applications.Therefore,appropriate method should be carefully selected for various application due to their intrinsic difference.展开更多
The attenuation of lateral propagating light （LPL） in sea ice was measured using an artificial light source in the Canadian Arctic during the 2007/2008 winter. The apparent attenuation coefficientμ（λ）for lateral...The attenuation of lateral propagating light （LPL） in sea ice was measured using an artificial light source in the Canadian Arctic during the 2007/2008 winter. The apparent attenuation coefficientμ（λ）for lateral prop-agating light was obtained from the measured logarithmic relative variation rate. In this study an analytical solution based on the strict optical theories is developed to validate the measured result. There is a good consistency between theoretical solution and measured data, by which a quite simple but very rigorous relationship among the light source, measurement geometry, and measured irradiance is established. The attenuation coefficients acquired by measurement and theory are the diffusion attenuation as an apparent optical property of ice, independent of the light source and shining condition. The attenuation ability of sea ice should be caused by the microstructure of sea ice, such as crystal size, ice density, brine volume, air inclusion, etc. It also includes the leak from both interfaces by directional scattering. It is verified that the measuring approach is operational and accurate to measure the attenuation of the LPL. The solution from this study did not tell the connection among the extinction and the inclusions of sea ice theoretically be-cause of insufficient understanding.展开更多
We consider the effects of quantum dot radius,confinement potential depth and controllable effective mass on the optical rectification coefficient(ORC)in spherical quantum dots,which is confined with Modified Kratzer-...We consider the effects of quantum dot radius,confinement potential depth and controllable effective mass on the optical rectification coefficient(ORC)in spherical quantum dots,which is confined with Modified Kratzer-Coulomb Potential(MKCP).Using the Nikiforov-Uvarov method and compact density matrix theory,the ground state energy,ORC and wave function of electrons under the combined action of many factors are calculated.The results show that they affect the optical rectification response from different angles,including the position of peak and formant.展开更多
Frequency-domain photoacoustic (PA) technique for immediate measuring absolute optical absorption coefficient is presented. It is based on determination of the ratio of the two spectrum amplitudes of the differential ...Frequency-domain photoacoustic (PA) technique for immediate measuring absolute optical absorption coefficient is presented. It is based on determination of the ratio of the two spectrum amplitudes of the differential PA signal. The sample is placed into the lateral chamber of a three chamber PA cell. The difference of pressure variations (differential PA signal) excited in two other chambers as a result of laser pulse absorption by the sample is recorded. Presented PA technique was tested experimentally by measuring water absorption coefficient at an IR wavelength.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.91950207,61675171 and 61675169)the Shaanxi Provincial Key R&D Program(No.2018KW-009)the Fundamental Research Funds for the Central Universities(Nos.3102017HQZZ022 and 3102017zy021)
文摘Goodness of fit is demonstrated for theoretical calculation of z-scan data based on beams propagating in the nonlinear medium and the Fresnel–Kirchhoff diffraction integral in experiments with high nonlinear refraction and absorption. The constancy of nonlinear optical parameters is achieved regardless of sample thickness and laser intensity, which clarifies the physical significance of optical parameters. We have obtained γ = 2.0 × 10-19 m2/W and β = 5.0 × 10-13 m/W for carbon disulfide excited by a pulsed laser at 800 nm with pulse duration of 35 fs,which are independent of sample thickness and laser intensity. Affirming constancy of the extracted parameters to the incident light intensity may become a practice to verify the goodness of the z-scan experiment.
基金supported by the Special Scientific Research Funds for Environment Protection Commonweal Section(Grant Nos.200809143and201009001)the National Basic Research Program of China(Grant No.2010CB428503)+4 种基金the National Natural Science Foundation of China(Grant No.41075096)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.IAP09320)the Research and Development Special Fund for Public Welfare Industry(Meteorology) of the China Meteorological Administration(Grant No.GYHY201006047)the Ministry of Science and Technology of China(Grant No.2010DFA22770)the Innovation Method Fund of China(Grant No.2008IM020500)
文摘Urban aerosols have a large effect on the deterioration of air quality and the degradation of atmospheric visibility.Characterization of the chemical composition of PM 2.5 and in situ measurements of the optical properties of aerosols were conducted in July 2008 at an urban site in Guangzhou,Southern China.The mean PM 2.5 concentration for the entire period was 53.7±23.2 μg m 3.The mean PM 2.5 concentration (82.7±25.4 μg m 3) on hazy days was roughly two times higher than that on clear days (38.8±8.7 μg m 3).The total water-soluble ion species and the total average carbon accounted for 47.9%±4.3% and 35.2%±4.5%,respectively,of the major components of PM 2.5.The increase of secondary and carbonaceous aerosols,in particular ammonium sulfate,played an important role in the formation of haze pollution.The mean absorption and scattering coefficients and the single scattering albedo over the whole period were 53±20 M m 1,226±111 M m 1,and 0.80±0.04,respectively.PM 2.5 had a high linear correlation with the aerosol extinction coefficient,elemental carbon (EC) was correlated with aerosol absorption,and organic carbon (OC) and SO 4 2 were tightly linked to aerosol scattering.
基金Project supported by the Natural Science Foundation of Inner Mongolia Autonomous Region,China(Grant Nos.2019MS01006 and 2020MS01008)the Science Project of the Higher Education of Inner Mongolia Autonomous Region,China(Grant No.NJZY19047)+1 种基金the Doctoral Starting-up Foundation of Inner Mongolia Agricultural University,China(Grant No.BJ2013B-2)the Grassland Talent Project,China.
文摘In this study,the effects of quantum dot size on the binding energy,radiative lifetime,and optical absorption coefficient of exciton state in both GaN/AlxGa1-xN core/shell and AlxGa1-xN/GaN inverted core/shell quantum dot structures are studied.For the GaN/AlxGa1-xN core/shell structure,the variation trend of binding energy is the same as that of radiation lifetime,both of which increase first and then decrease with the increase of core size.For AlxGa1-xN/GaN inverted core/shell structure,the binding energy decreases first and then increases with core size increasing,and the trends of radiation lifetime varying with core size under different shell sizes are different.For both structures,when the photon energy is approximately equal to the binding energy,the peak value of the absorption coefficient appears,and there will be different peak shifts under different conditions.
基金Project supported by the Ministry of Higher Education and Scientific Research in Iraq,Ibnu Sina Institute and Physics Department of Universiti Teknologi Malaysia(UTM RUG Vote No.06-H14)
文摘Based on the Schr ¨odinger equation for envelope function in the effective mass approximation, linear and nonlinear optical absorption coefficients in a multi-subband lens quantum dot are investigated. The effects of quantum dot size on the interband and intraband transitions energy are also analyzed. The finite element method is used to calculate the eigenvalues and eigenfunctions. Strain and In-mole-fraction effects are also studied, and the results reveal that with the decrease of the In-mole fraction, the amplitudes of linear and nonlinear absorption coefficients increase. The present computed results show that the absorption coefficients of transitions between the first excited states are stronger than those of the ground states. In addition, it has been found that the quantum dot size affects the amplitudes and peak positions of linear and nonlinear absorption coefficients while the incident optical intensity strongly affects the nonlinear absorption coefficients.
基金supported by the National Natural Science Foundation of China (No. 40533017, 20377008,40605001)the National Key Technology R&D Program(No. 2006BAC12B001)the State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC-KF-2006-05) of China
文摘The variations of sulfate formation and optical coefficients during SO2 heterogeneous reactions on hematite surface under different SO2 concentrations were examined using in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS） and ion chromatograph （IC）. Laboratory experiments revealed that within ambient SO2 of 0.51-18.6 ppmv, sulfate product, producing velocity, absorption and backward scattering coefficients showed an increasing trend with SO2 concentration. Under given SO2 concentration, the velocity of sulfate producing performed an evolution of initial increasing, midterm decreasing and final stabilizing. The reactive uptake and Brunaner-Emmett-Teller （BET） uptake coefficients of heterogeneous reactions rose with SOz and exhibited high reactivities. Considering global warming, this result is important for the knowledge of heterogeneous reactions of SO2 on mineral particle surface in the atmosphere and the assessment of their impacts on radiative forcing.
文摘Presents the synthesis of Copolyimide containing triarylamine and NLO chromophore in backbone by azo coupling of 4 nitrobenzenediazonium tetrafloroborate to copoly(amic acid) in organic solvent and characterized by IR and UV Vis spectra, which had high glass transition temperatrue and big second order nonlinear optical coefficient x (2) .
基金Supported by the National Natural Science Foundation of China(No.41276184)the Key Laboratory of Marine Remote Sensing and Acoustics(Nanjing University of Information Science and Technology),Jiangsu Province,China(No.KHYS1404)
文摘Two methods for particulate pigments(i.e.,quantitative filter technique,QFT,and in vivo measurement,InVivo,respectively)and two methods for dissolved pigments(i.e.,Acetone Extracts,AceEx,and high-performance liquid chromatography,HPLC,respectively) were used to obtain the optical absorption coefficient spectra for cultures of four typical algal species.Through normalization and analysis of the spectra,it is shown that(1) the four methods are able to measure optical absorption spectra of particulate and/or dissolved pigments;(2)that the optical absorption spectra of particulate and dissolved pigments were consistent in terms of the peak position in the blue wavelength,and the difference of the peak position in the near infrared wavelength was ~10nm between each other;and(3)that the leveling effect of the absorption spectra of particulate pigments was significant.These four methods can all effectively measure the absorption coefficients of phytoplankton pigments,while each one has its unique advantages in different applications.Therefore,appropriate method should be carefully selected for various application due to their intrinsic difference.
基金The Global Change Research Program of China under contract No.2015CB953900the Key Program of National Natural Science Foundation of China under contract No.41330960
文摘The attenuation of lateral propagating light （LPL） in sea ice was measured using an artificial light source in the Canadian Arctic during the 2007/2008 winter. The apparent attenuation coefficientμ（λ）for lateral prop-agating light was obtained from the measured logarithmic relative variation rate. In this study an analytical solution based on the strict optical theories is developed to validate the measured result. There is a good consistency between theoretical solution and measured data, by which a quite simple but very rigorous relationship among the light source, measurement geometry, and measured irradiance is established. The attenuation coefficients acquired by measurement and theory are the diffusion attenuation as an apparent optical property of ice, independent of the light source and shining condition. The attenuation ability of sea ice should be caused by the microstructure of sea ice, such as crystal size, ice density, brine volume, air inclusion, etc. It also includes the leak from both interfaces by directional scattering. It is verified that the measuring approach is operational and accurate to measure the attenuation of the LPL. The solution from this study did not tell the connection among the extinction and the inclusions of sea ice theoretically be-cause of insufficient understanding.
基金Project supported by Support National Natural Science Foundation of China(Grant Nos.52174161,12174161,51702003,61775087,and 11674312)the Natural Science Foundation of Anhui Province(No.1508085QF140)Plan Fund for Outstanding Young Talents in Colleges and Universities(No.gxyq ZD2018039)。
文摘We consider the effects of quantum dot radius,confinement potential depth and controllable effective mass on the optical rectification coefficient(ORC)in spherical quantum dots,which is confined with Modified Kratzer-Coulomb Potential(MKCP).Using the Nikiforov-Uvarov method and compact density matrix theory,the ground state energy,ORC and wave function of electrons under the combined action of many factors are calculated.The results show that they affect the optical rectification response from different angles,including the position of peak and formant.
文摘Frequency-domain photoacoustic (PA) technique for immediate measuring absolute optical absorption coefficient is presented. It is based on determination of the ratio of the two spectrum amplitudes of the differential PA signal. The sample is placed into the lateral chamber of a three chamber PA cell. The difference of pressure variations (differential PA signal) excited in two other chambers as a result of laser pulse absorption by the sample is recorded. Presented PA technique was tested experimentally by measuring water absorption coefficient at an IR wavelength.
