Excitation-emission matrix fluorescence spectroscopy (EEM) has been widely used to elucidate the origin and structure of humic substances in natural environments. Due to its high sensitivity, good selectivity and non-...Excitation-emission matrix fluorescence spectroscopy (EEM) has been widely used to elucidate the origin and structure of humic substances in natural environments. Due to its high sensitivity, good selectivity and non-destructive advantage, the EEM was applied to characterizing a commercial Fluka humic acid (FHA). The results showed that the EEMs of FHA has several Ex/Em peaks. Ionic strength (0- 0.05 mol/L KClO 4) exerted little effect on the fluorescence properties of FHA, while the concentrations (5-100 mg/L) of FHA and pH (2-12) had significant effects. A red shift in the longer wavelength peak region was observed when the concentrations or pH values increased. The fluorescence intensity increased with increasing pH, but slightly decreased in the case of pH= 5.0. The protonation constants (lgK’ HL) of peak B were calculated to be 3.57 and 3.13, indicating that peak B was due to carboxyl groups. The r (A/B) values range from 0.61 to 2.59. A strong linear relationship between r (A/B) and pH was also observed. This indicates that the fluorescence peaks A and B posses similar inherent fluorescence characteristics.展开更多
Samples of chromophoric dissolved organic matter （CDOM） in the East China Sea in autumn （October in 2011） were analyzed by excitation emission matrix （EEM） fluorescence spectroscopy combined with parallel factor...Samples of chromophoric dissolved organic matter （CDOM） in the East China Sea in autumn （October in 2011） were analyzed by excitation emission matrix （EEM） fluorescence spectroscopy combined with parallel factor analysis （PARAFAC）. Three terrestrial humic-like components （C1, C2 and C3） and one protein-like component （C4） were identified. Based on spatial dis- tributions, as well as relationships with salinity, the following assignments were made. The three humic-like components （CI, C2 and C3） showed conservative mixing behavior and came mainly from riverine input. The protein-like component （C4） was considered a combination of autochthonous production and terrestrial inputs and a biologically labile component. Path analysis of samples from the middle and bottom layers revealed that the causal effects on C1 were -78.46% for salinity, and -21.54% for apparent oxygen utilization （AOU）; those on C2 were -76.43% for salinity, and -23.57% for AOU; those on C3 were -70.49% for salinity, 7.01% for Chl-a, and -22.50% for AOU; those on C4 were -55.54% for salinity, 14.6% for Chl-a, and -29.86% for AOU in middle layer; and those on C4 were -57.37% for salinity, 29.02% for Chl-a, and -13.61% for AOU in bottom layer. Results indicated that CDOM in tile East China Sea was mainly affected by terrestrial inputs, and microbial ac- tivities also played a key role in biogeochemical processes of CDOM. The application of the EEM-PARAFAC model present- ed a unique opportunity to observe compositional changes in CDOM in the East China Sea. In addition, the humification index （HIX） suggested that CDOM from the East China Sea was less stable and stayed shorter in the environment.展开更多
Nowadays,the abuse of illegal drugs has been an increasingly grim problem in the world.Excitation–emission matrix fluorescence combined with parallel factor analysis was used to make a quantitative analysis of the si...Nowadays,the abuse of illegal drugs has been an increasingly grim problem in the world.Excitation–emission matrix fluorescence combined with parallel factor analysis was used to make a quantitative analysis of the simulated amphetamine-type illegal drugs.Satisfactory results were achieved for simultaneous determination of methamphetamine(MAM)and 3,4-methylenedioxymethamphetamine(MDMA)in the presence of adulterants.The average recoveries were(99.8±0.6)%and(101.6±5.7)%for MAM and MDMA,respectively.Figures of merit including root-mean-square error of calibration and prediction,sensitivity and selectivity were investigated to evaluate the performance of the proposed method.The limits of detection were 0.054 and 0.0021 g/mL for MAM and MDMA,respectively.展开更多
A novel approach is proposed for direct quantitative analysis of thiabendazole in the orange extract by using excitation-emission matrix fluorescence coupled with second-order calibration methods based on the alternat...A novel approach is proposed for direct quantitative analysis of thiabendazole in the orange extract by using excitation-emission matrix fluorescence coupled with second-order calibration methods based on the alternating trilinear decomposition(ATLD) and the alternating normalization-weighted error(ANWE) algorithms,respectively. The average recoveries of thiabendazole in the orange extract by using ATLD and ANWE with an estimated component number of two were 99.7 ± 3.3% and 103.5 ± 4.1%,respectively. Furthermore,the accuracy of the two algorithms was also evaluated through elliptical joint confidence region(EJCR) tests as well as figures of merit,such as sensitivity(SEN),selectivity(SEL) and limit of detection(LOD). The experimental results demonstrate that both algorithms have been satisfactorily applied to the determination of thiabendazole in orange extract,and the perform-ance of ANWE is slightly better than that of ATLD.展开更多
The calculation of the indirect carbon emis-sion is essential for power system policy making,carbon market development,and power grid planning.The em-bedded carbon emissions of the electricity system are commonly calc...The calculation of the indirect carbon emis-sion is essential for power system policy making,carbon market development,and power grid planning.The em-bedded carbon emissions of the electricity system are commonly calculated by carbon emission flow theory.However,the calculation procedure is time-consuming,especially for a country with 500-1000 thousand nodes,making it challenging to obtain nationwide carbon emis-sions intensity precisely.Additionally,the calculation procedure requires to gather all the grid data with high classified levels from different power grid companies,which can prevent data sharing and cooperation among different companies.This paper proposes a distributed computing algorithm for indirect carbon emission that can reduce the time consumption and provide privacy protection.The core idea is to utilize the sparsity of the nodes’flow matrix of the nationwide grid to partition the computing procedure into parallel sub-procedures exe-cuted in multiple terminals.The flow and structure data of the regional grid are transformed irreversibly for pri-vacy protection,when transmitted between terminals.A 1-master-and-N-slave layout is adopted to verify the method.This algorithm is suitable for large grid compa-nies with headquarter and branches in provinces,such as the State Grid Corporation of China.展开更多
The autofluorescence spectroscopy of biologi- cal tissues is a powerful tool for non-invasive detection of tissue pathologies and evaluation of any biochemical and morphological changes arising during the lesions＇ gr...The autofluorescence spectroscopy of biologi- cal tissues is a powerful tool for non-invasive detection of tissue pathologies and evaluation of any biochemical and morphological changes arising during the lesions＇ growth. To obtain a full picture of the whole set of endogenous fluorophores appearing in the gastrointestinal （GI） tumors investigated, the technique of excitation-emission matrix （EEM） development was applied in a broad spectral region, covering the ultraviolet and visible spectral ranges. We could thus address a set of diagnostically-important chromophores and their alterations during tumor develop- ment, namely, collagen, elastin, nicotinamide adenine dinucleotide （NADH）, flavins, porphyrins, while hemo- globin＇s absorption influence on the spectra obtained could be evaluated as well. Comparisons are presented between EEM data of normal mucosae, benign polyps and malignant carcinoma, and the origins are determined of the fluorescence signals forming these matrices.展开更多
文摘Excitation-emission matrix fluorescence spectroscopy (EEM) has been widely used to elucidate the origin and structure of humic substances in natural environments. Due to its high sensitivity, good selectivity and non-destructive advantage, the EEM was applied to characterizing a commercial Fluka humic acid (FHA). The results showed that the EEMs of FHA has several Ex/Em peaks. Ionic strength (0- 0.05 mol/L KClO 4) exerted little effect on the fluorescence properties of FHA, while the concentrations (5-100 mg/L) of FHA and pH (2-12) had significant effects. A red shift in the longer wavelength peak region was observed when the concentrations or pH values increased. The fluorescence intensity increased with increasing pH, but slightly decreased in the case of pH= 5.0. The protonation constants (lgK’ HL) of peak B were calculated to be 3.57 and 3.13, indicating that peak B was due to carboxyl groups. The r (A/B) values range from 0.61 to 2.59. A strong linear relationship between r (A/B) and pH was also observed. This indicates that the fluorescence peaks A and B posses similar inherent fluorescence characteristics.
基金supported by the National Basic Research Program of China(973 program,2010CB428701)the National Natural Science Foundation of China(41176063)
文摘Samples of chromophoric dissolved organic matter （CDOM） in the East China Sea in autumn （October in 2011） were analyzed by excitation emission matrix （EEM） fluorescence spectroscopy combined with parallel factor analysis （PARAFAC）. Three terrestrial humic-like components （C1, C2 and C3） and one protein-like component （C4） were identified. Based on spatial dis- tributions, as well as relationships with salinity, the following assignments were made. The three humic-like components （CI, C2 and C3） showed conservative mixing behavior and came mainly from riverine input. The protein-like component （C4） was considered a combination of autochthonous production and terrestrial inputs and a biologically labile component. Path analysis of samples from the middle and bottom layers revealed that the causal effects on C1 were -78.46% for salinity, and -21.54% for apparent oxygen utilization （AOU）; those on C2 were -76.43% for salinity, and -23.57% for AOU; those on C3 were -70.49% for salinity, 7.01% for Chl-a, and -22.50% for AOU; those on C4 were -55.54% for salinity, 14.6% for Chl-a, and -29.86% for AOU in middle layer; and those on C4 were -57.37% for salinity, 29.02% for Chl-a, and -13.61% for AOU in bottom layer. Results indicated that CDOM in tile East China Sea was mainly affected by terrestrial inputs, and microbial ac- tivities also played a key role in biogeochemical processes of CDOM. The application of the EEM-PARAFAC model present- ed a unique opportunity to observe compositional changes in CDOM in the East China Sea. In addition, the humification index （HIX） suggested that CDOM from the East China Sea was less stable and stayed shorter in the environment.
基金supported by National Natural Science Foundation of China[grant number 81373239].
文摘Nowadays,the abuse of illegal drugs has been an increasingly grim problem in the world.Excitation–emission matrix fluorescence combined with parallel factor analysis was used to make a quantitative analysis of the simulated amphetamine-type illegal drugs.Satisfactory results were achieved for simultaneous determination of methamphetamine(MAM)and 3,4-methylenedioxymethamphetamine(MDMA)in the presence of adulterants.The average recoveries were(99.8±0.6)%and(101.6±5.7)%for MAM and MDMA,respectively.Figures of merit including root-mean-square error of calibration and prediction,sensitivity and selectivity were investigated to evaluate the performance of the proposed method.The limits of detection were 0.054 and 0.0021 g/mL for MAM and MDMA,respectively.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20775025 and 20435010)973 Advanced Research Project (Grant No. 2007CB- 216404)
文摘A novel approach is proposed for direct quantitative analysis of thiabendazole in the orange extract by using excitation-emission matrix fluorescence coupled with second-order calibration methods based on the alternating trilinear decomposition(ATLD) and the alternating normalization-weighted error(ANWE) algorithms,respectively. The average recoveries of thiabendazole in the orange extract by using ATLD and ANWE with an estimated component number of two were 99.7 ± 3.3% and 103.5 ± 4.1%,respectively. Furthermore,the accuracy of the two algorithms was also evaluated through elliptical joint confidence region(EJCR) tests as well as figures of merit,such as sensitivity(SEN),selectivity(SEL) and limit of detection(LOD). The experimental results demonstrate that both algorithms have been satisfactorily applied to the determination of thiabendazole in orange extract,and the perform-ance of ANWE is slightly better than that of ATLD.
基金supported by the Science and Technol-ogy Project of State Grid Cooperation of China(No.5700-202290184A-1-1-ZN).
文摘The calculation of the indirect carbon emis-sion is essential for power system policy making,carbon market development,and power grid planning.The em-bedded carbon emissions of the electricity system are commonly calculated by carbon emission flow theory.However,the calculation procedure is time-consuming,especially for a country with 500-1000 thousand nodes,making it challenging to obtain nationwide carbon emis-sions intensity precisely.Additionally,the calculation procedure requires to gather all the grid data with high classified levels from different power grid companies,which can prevent data sharing and cooperation among different companies.This paper proposes a distributed computing algorithm for indirect carbon emission that can reduce the time consumption and provide privacy protection.The core idea is to utilize the sparsity of the nodes’flow matrix of the nationwide grid to partition the computing procedure into parallel sub-procedures exe-cuted in multiple terminals.The flow and structure data of the regional grid are transformed irreversibly for pri-vacy protection,when transmitted between terminals.A 1-master-and-N-slave layout is adopted to verify the method.This algorithm is suitable for large grid compa-nies with headquarter and branches in provinces,such as the State Grid Corporation of China.
文摘The autofluorescence spectroscopy of biologi- cal tissues is a powerful tool for non-invasive detection of tissue pathologies and evaluation of any biochemical and morphological changes arising during the lesions＇ growth. To obtain a full picture of the whole set of endogenous fluorophores appearing in the gastrointestinal （GI） tumors investigated, the technique of excitation-emission matrix （EEM） development was applied in a broad spectral region, covering the ultraviolet and visible spectral ranges. We could thus address a set of diagnostically-important chromophores and their alterations during tumor develop- ment, namely, collagen, elastin, nicotinamide adenine dinucleotide （NADH）, flavins, porphyrins, while hemo- globin＇s absorption influence on the spectra obtained could be evaluated as well. Comparisons are presented between EEM data of normal mucosae, benign polyps and malignant carcinoma, and the origins are determined of the fluorescence signals forming these matrices.
