Metastable 40Ar* atoms are produced in the two metastable states 3p54s [3/2]2 and 3p5 4s′ [1/2]0 in a pulsed DC discharge in a beam, and are subsequently excited to the even-parity autoionizing resonance series 3pSn...Metastable 40Ar* atoms are produced in the two metastable states 3p54s [3/2]2 and 3p5 4s′ [1/2]0 in a pulsed DC discharge in a beam, and are subsequently excited to the even-parity autoionizing resonance series 3pSnp′[3/2]1,2, 3p5 np′ [1/2]1, and 3p5nf′[5/2]3 using single photon excitation with a pulsed dye laser. The excitation spectra of the even-parity autoion- izing resonance series from the metastable 40Ar* are obtained by recording the autoionized Ar+ ions with time-of-flight ion detection in the photon energy range of 32500-35600 cm-1 with an experimental bandwidth of 〈0.1 cm-1. A wealth of autoionizing resonances are newly observed, from which more precise and systematic spectroscopic data of the level energies and quantum defects are derived.展开更多
Xenon atoms were produced in their metastable states 5p^56s[3/2]2 and 5p^56s'[1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 5p^5np' [3/2] 1,[1/2] 1...Xenon atoms were produced in their metastable states 5p^56s[3/2]2 and 5p^56s'[1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 5p^5np' [3/2] 1,[1/2] 1, and 5p^5nf' [5/2] 3 using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable 129Xe were obtained by recording the autoionized Xe+ with time-of-flight ion detection in the photon energy range of 28000-42000 cm-1. A wealth of autoionizing resonances were newly observed, from which more precise and systematic spectroscopic data of the level energies and quantum defects were derived.展开更多
We have investigated individual bulk-like wires of wurtzite InP using photoluminescence, photoluminescence excitation spectroscopy and transmission electron microscopy. Using two different methods we find that the top...We have investigated individual bulk-like wires of wurtzite InP using photoluminescence, photoluminescence excitation spectroscopy and transmission electron microscopy. Using two different methods we find that the top of the valence band is split, as expected theoretically. This splitting of the valence band is peculiar to wurtzite InP and does not occur in zinc blende InP. We find the energy difference between the two bands to be 40 meV.展开更多
We investigate the dipole-dipole broadened selective reflection spectrum with the Cs atomic aensity of 10^14- 10^15 cm^-3. The dipole-dipole broadening is reduced and the hyperfine splitting is well resolved when the ...We investigate the dipole-dipole broadened selective reflection spectrum with the Cs atomic aensity of 10^14- 10^15 cm^-3. The dipole-dipole broadening is reduced and the hyperfine splitting is well resolved when the ground state atoms are excited by a detuned pump beam. The dependences of dipoleMipole broadening of Cs atoms in the 6S1/2(F= 3) → 6P3/2(F'= 4) hyperfine transition line on atomic density and the excitation factor are studied. It is found that the reduction of the dipole-dipole broadening is dependent on the pump beam power and is independent of the atomic density in this density range. These results are useful for understanding of the dynamical process in this range of atomic density.展开更多
The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor (SBR), and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances (EPS) of sludge samples were e...The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor (SBR), and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances (EPS) of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix (EEM) fluorescence spectra of the EPS in the aerobic granules. Two peaks (A and B) are attributed to the protein-like fluorophores, and the third (peak C) is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid (peak D) is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.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
In this study we have successfully characterized the fluorescent components of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn using excitation-emission matrix fluorescen...In this study we have successfully characterized the fluorescent components of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn using excitation-emission matrix fluorescence spectroscopy(EEMs) combined with parallel factor analysis(PARAFAC).PARAFAC aids the characterization of fluorescence CDOM by decomposing the fluorescence matrices into individual components.Four humic-like components(C1,C2,C3,and C4),one marine biological production component(C6),and two protein-like components(C5 and C7) were identified by PARAFAC.We researched the distributional patterns of fluorescence intensity,regression analyses between salinity,chlorophyll a concentration and fluorescence intensities of individual fluorophore,and regression analysis between salinity and fluorescence intensities percent of individual fluorophore.The results revealed that C2 and C4 showed conservative mixing behavior,while C1 and C3 possessed conservative mixing behavior in high salinity region and additional behavior in low and middle salinity region,which were considered to be derived from riverine and degradation of organic matter from resuspended and/or sinking particles and show non-conservative mixing behavior.In addition to riverine sources,the tryptophan-like C5 may receive widespread addition(likely from photo-degradation or biodegradation),while the most likely sources for the one marine humic-like C6 and tyrosine-like C7 were biological activity and microbial processing of plankton-derived CDOM,which were suggested to be of autochthonous origin and biologically labile.The application of EEM-PARAFAC modeling presents a unique opportunity to observe compositional changes,different mixing behavior and temporal variability in CDOM in the Yellow Sea and the East China Sea.展开更多
As the biggest inter-basin water transfer scheme in the world,the South-to-North Water Diversion Project(SNWD) was designed to alleviate the water crisis in North China.The main channel of the middle route of the SNWD...As the biggest inter-basin water transfer scheme in the world,the South-to-North Water Diversion Project(SNWD) was designed to alleviate the water crisis in North China.The main channel of the middle route of the SNWD is of great concern in terms of the drinking water quality.In this study,we tested the hypothesis that the dissolved organic matter(DOM) derived from the planktonic algae causes the rising levels of COD_(Mn) along the middle route by monitoring data on water quality(2015-2019,monthly resolution).The results showed that algal density in the main channel increased along the channel and was significantly correlated with COD_(Mn)(p <0.01).Five fluorescent components of DOM,including tyrosine-like(14.85%),tryptophan-like(22.48%),microbial byproduct-like(26.34%),fulvic acid-like(11.41%),and humic acid-like(24.92%) components,were detected.The level of tyrosine-like components increased along the channel and was significantly correlated with algal density(p<0.01),indicating that algae significantly changed the level of DOM in the channel.Algal decomposition and metabolism were found to be the main mechanisms that drive the changes in COD_(Mn).Therefore,controlling algal density would be an important measure to prevent further increase in CODMn and for the guarantee of excellent water quality.展开更多
In this proceeding, I review the attempts to calculate the Nucleon resonance (including Roper as first radially excited state of nucleon and other excited states) using lattice quantum chromodynamics (QCD). The la...In this proceeding, I review the attempts to calculate the Nucleon resonance (including Roper as first radially excited state of nucleon and other excited states) using lattice quantum chromodynamics (QCD). The latest preliminary results from Hadron Spectrum Collaboration (HSC) with mπ≈ 380 MeV are reported. The Sachs electric form factor of the proton and neutron and their transition with the Roper at large Q2 are also updated in this work.展开更多
文摘Metastable 40Ar* atoms are produced in the two metastable states 3p54s [3/2]2 and 3p5 4s′ [1/2]0 in a pulsed DC discharge in a beam, and are subsequently excited to the even-parity autoionizing resonance series 3pSnp′[3/2]1,2, 3p5 np′ [1/2]1, and 3p5nf′[5/2]3 using single photon excitation with a pulsed dye laser. The excitation spectra of the even-parity autoion- izing resonance series from the metastable 40Ar* are obtained by recording the autoionized Ar+ ions with time-of-flight ion detection in the photon energy range of 32500-35600 cm-1 with an experimental bandwidth of 〈0.1 cm-1. A wealth of autoionizing resonances are newly observed, from which more precise and systematic spectroscopic data of the level energies and quantum defects are derived.
基金This work was supported by the National Natural Science Foundation of China (No.20673107), the Chinese National Key Basic Research Special Foundation (No.2007CB815203), and the Chinese Academy of Science (No.KJCX2-SW-H08).
文摘Xenon atoms were produced in their metastable states 5p^56s[3/2]2 and 5p^56s'[1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 5p^5np' [3/2] 1,[1/2] 1, and 5p^5nf' [5/2] 3 using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable 129Xe were obtained by recording the autoionized Xe+ with time-of-flight ion detection in the photon energy range of 28000-42000 cm-1. A wealth of autoionizing resonances were newly observed, from which more precise and systematic spectroscopic data of the level energies and quantum defects were derived.
文摘We have investigated individual bulk-like wires of wurtzite InP using photoluminescence, photoluminescence excitation spectroscopy and transmission electron microscopy. Using two different methods we find that the top of the valence band is split, as expected theoretically. This splitting of the valence band is peculiar to wurtzite InP and does not occur in zinc blende InP. We find the energy difference between the two bands to be 40 meV.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921603the National Natural Science Foundation of China under Grant Nos 61275209,11304189,61378015 and 11434007+1 种基金the Shanxi Scholarship Council of Chinathe Program for Changjiang Scholars and Innovative Research Team in Universities of China under Grant No IRT13076
文摘We investigate the dipole-dipole broadened selective reflection spectrum with the Cs atomic aensity of 10^14- 10^15 cm^-3. The dipole-dipole broadening is reduced and the hyperfine splitting is well resolved when the ground state atoms are excited by a detuned pump beam. The dependences of dipoleMipole broadening of Cs atoms in the 6S1/2(F= 3) → 6P3/2(F'= 4) hyperfine transition line on atomic density and the excitation factor are studied. It is found that the reduction of the dipole-dipole broadening is dependent on the pump beam power and is independent of the atomic density in this density range. These results are useful for understanding of the dynamical process in this range of atomic density.
基金Project(2006AA06Z318) supported by the National High-Tech Research and Development Program of China
文摘The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor (SBR), and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances (EPS) of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix (EEM) fluorescence spectra of the EPS in the aerobic granules. Two peaks (A and B) are attributed to the protein-like fluorophores, and the third (peak C) is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid (peak D) is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.
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 the National High-Tech Research and Development Program of China(2009AA063005)the National Basic Research Program of China(2010CD428701)
文摘In this study we have successfully characterized the fluorescent components of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn using excitation-emission matrix fluorescence spectroscopy(EEMs) combined with parallel factor analysis(PARAFAC).PARAFAC aids the characterization of fluorescence CDOM by decomposing the fluorescence matrices into individual components.Four humic-like components(C1,C2,C3,and C4),one marine biological production component(C6),and two protein-like components(C5 and C7) were identified by PARAFAC.We researched the distributional patterns of fluorescence intensity,regression analyses between salinity,chlorophyll a concentration and fluorescence intensities of individual fluorophore,and regression analysis between salinity and fluorescence intensities percent of individual fluorophore.The results revealed that C2 and C4 showed conservative mixing behavior,while C1 and C3 possessed conservative mixing behavior in high salinity region and additional behavior in low and middle salinity region,which were considered to be derived from riverine and degradation of organic matter from resuspended and/or sinking particles and show non-conservative mixing behavior.In addition to riverine sources,the tryptophan-like C5 may receive widespread addition(likely from photo-degradation or biodegradation),while the most likely sources for the one marine humic-like C6 and tyrosine-like C7 were biological activity and microbial processing of plankton-derived CDOM,which were suggested to be of autochthonous origin and biologically labile.The application of EEM-PARAFAC modeling presents a unique opportunity to observe compositional changes,different mixing behavior and temporal variability in CDOM in the Yellow Sea and the East China Sea.
基金This research was financially supported by the National Natural Science Foundation of China(No.U2040210)the National Key R&D Program(Nos.2019YFC0408904,2019YFC0408901).
文摘As the biggest inter-basin water transfer scheme in the world,the South-to-North Water Diversion Project(SNWD) was designed to alleviate the water crisis in North China.The main channel of the middle route of the SNWD is of great concern in terms of the drinking water quality.In this study,we tested the hypothesis that the dissolved organic matter(DOM) derived from the planktonic algae causes the rising levels of COD_(Mn) along the middle route by monitoring data on water quality(2015-2019,monthly resolution).The results showed that algal density in the main channel increased along the channel and was significantly correlated with COD_(Mn)(p <0.01).Five fluorescent components of DOM,including tyrosine-like(14.85%),tryptophan-like(22.48%),microbial byproduct-like(26.34%),fulvic acid-like(11.41%),and humic acid-like(24.92%) components,were detected.The level of tyrosine-like components increased along the channel and was significantly correlated with algal density(p<0.01),indicating that algae significantly changed the level of DOM in the channel.Algal decomposition and metabolism were found to be the main mechanisms that drive the changes in COD_(Mn).Therefore,controlling algal density would be an important measure to prevent further increase in CODMn and for the guarantee of excellent water quality.
基金Supported by Jefferson Science Associates, LLC under U.S. DOE (DE-AC05-06OR23177)
文摘In this proceeding, I review the attempts to calculate the Nucleon resonance (including Roper as first radially excited state of nucleon and other excited states) using lattice quantum chromodynamics (QCD). The latest preliminary results from Hadron Spectrum Collaboration (HSC) with mπ≈ 380 MeV are reported. The Sachs electric form factor of the proton and neutron and their transition with the Roper at large Q2 are also updated in this work.