In this study,vehicle exhaust particles were collected three locations (the middle,entrance and outside) of the Dapu Road tunnel in downtown Shanghai,and the particle samples were characterized using SEM,XAFS,ICP-MS a...In this study,vehicle exhaust particles were collected three locations (the middle,entrance and outside) of the Dapu Road tunnel in downtown Shanghai,and the particle samples were characterized using SEM,XAFS,ICP-MS and M?ssbauer spectrometry,and the oxidative damage was assessed by plasmid DNA.Most iron-containing particles are found from vehicle exhaust,and iron oxide is the major species in all samples.Its concentration in the particles inside the tunnel is higher than that the outside particles.The iron particles inside the tunnel have higher proportion of water-soluble fraction in hydrous iron sulfate form or smaller size.ZnCl2 is the main soluble fraction in zinc-containing particles,while higher percentage of insoluble fraction existed in the particles outside of tunnel.Major species of lead-containing particles are PbSO4,Pb3(PO4)2 and PbCO3.In addition,the soluble fraction of other transition metallic elements as Ti and V is higher in the particles inside the tunnel than that outside the tunnel.The plasmid DNA assay results indicate that the particles from vehicle exhaust have a stronger oxidative damage and inflammation than that from outside of the tunnel.展开更多
The foundation of the first synchrotron radiation x-ray absorption fine structure(XAFS)station in China has been completed and the station was ready for transmission XAFS experiment.This paper reports the first XAFS s...The foundation of the first synchrotron radiation x-ray absorption fine structure(XAFS)station in China has been completed and the station was ready for transmission XAFS experiment.This paper reports the first XAFS spectrum recorded in this station and the result of performance test centered on the intensity,energy dispersion and energy accuracy of the beam line in this station.展开更多
The study on elemental speciation in atmospheric particulate matter (PM) is important for understanding the formation and origin of pollution and evaluating their toxicity. In this paper,the speci- ation of iron in at...The study on elemental speciation in atmospheric particulate matter (PM) is important for understanding the formation and origin of pollution and evaluating their toxicity. In this paper,the speci- ation of iron in atmospheric PM was investigated with extended X-ray absorption fine structure (EXAFS) spectra based on synchrotron radiation. The chemi- cal components of PM can be calculated by regres- sion analysis of EXAFS spectra. This is a non-destructive method. In order to have knowledge of the influence of chemical components on EXAFS spectra,we prepared a series of mixed reference samples,and proved the precision of method is good. The PM samples with different particle sizes and from different sampling sites were collected in Shanghai,China. The chemical components of the samples were calculated by regression analysis of EXAFS spectra. The results show that the iron in all PM samples mainly consist of Fe2O3,Fe3O4 and Fe2(SO4)3,but their proportions are different in dif- ferent samples. The changes of components among PM samples were observed preliminarily. The con- centrations of iron in the samples were determined by proton-induced X-ray emission (PIXE) technique. It is observed that the concentrations of iron in the sam- ples of iron and steel industrial district were much higher than those of other districts,and chemical components were also different from those of others.展开更多
Fractionations of rare earth elements(REEs)and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions.Significant enrichment of middle REEs(MREEs)and heavy REE...Fractionations of rare earth elements(REEs)and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions.Significant enrichment of middle REEs(MREEs)and heavy REEs(HREEs)was observed in plant roots and leaves respectively,with slight fractionation between light REEs(LREEs)and HREEs in stems.Moreover,the tetrad effect was observed in these organs.Investigations into REE speciation in roots and in the xylem sap using X-ray absorption spectroscopy(XAS)and nanometer-sized TiO2 adsorption techniques,associated with other controlled experiments,demonstrated that REE fractionations should be dominated by fixation mechanism in roots caused by cell wall absorption and phosphate precipitation,and by the combined effects of fixation mechanism and transport mechanism in aboveground parts caused by solution complexation by intrinsic organic ligands.A conceptive model was established for REE fractionations in plants based on the above studies.展开更多
Annealing crystallization of ultrafine NiB amorphous alloy prepared by the chemical reduction method was studied by DTA, XRD and XAFS techniques. The XRD and XAFS results have revealed that the crystallization process...Annealing crystallization of ultrafine NiB amorphous alloy prepared by the chemical reduction method was studied by DTA, XRD and XAFS techniques. The XRD and XAFS results have revealed that the crystallization process of ultrafine NiB amorphous alloy proceeds in two steps. First, ultrafine NiB amorphous alloy is crystallized to form metastable nanocrystalline Ni3B at an annealing temperature of 325℃. Second, the nanocrystalline Ni3B is further decomposed into crystalline Ni at 380CCC or higher tempera ture, the local structure around Ni atoms in resultant product is similar to that in Ni foil. It was found that the catalytic activity of nanocrystalline Ni3B for benzene hydro-genation is much higher than that of ultrafine NiB amorphous alloy or crystalline Ni. The result indicates that the active sites of nanocrystalline Ni3B for benzene hydrogena-tion are composed of both Ni and B with proper geometry configuration.展开更多
基金supported by Knowledge Innovation Project of Chinese Academy of Sciences (KJCX3.SYW.N3,key program)the National Natural Science Foundation of China (10490182,key program and 10675159)
文摘In this study,vehicle exhaust particles were collected three locations (the middle,entrance and outside) of the Dapu Road tunnel in downtown Shanghai,and the particle samples were characterized using SEM,XAFS,ICP-MS and M?ssbauer spectrometry,and the oxidative damage was assessed by plasmid DNA.Most iron-containing particles are found from vehicle exhaust,and iron oxide is the major species in all samples.Its concentration in the particles inside the tunnel is higher than that the outside particles.The iron particles inside the tunnel have higher proportion of water-soluble fraction in hydrous iron sulfate form or smaller size.ZnCl2 is the main soluble fraction in zinc-containing particles,while higher percentage of insoluble fraction existed in the particles outside of tunnel.Major species of lead-containing particles are PbSO4,Pb3(PO4)2 and PbCO3.In addition,the soluble fraction of other transition metallic elements as Ti and V is higher in the particles inside the tunnel than that outside the tunnel.The plasmid DNA assay results indicate that the particles from vehicle exhaust have a stronger oxidative damage and inflammation than that from outside of the tunnel.
文摘The foundation of the first synchrotron radiation x-ray absorption fine structure(XAFS)station in China has been completed and the station was ready for transmission XAFS experiment.This paper reports the first XAFS spectrum recorded in this station and the result of performance test centered on the intensity,energy dispersion and energy accuracy of the beam line in this station.
基金the Chinese Academy of Sciences （approval code KJCX2-SW-No1） the National Natural Science Foundation of China （Grant No. 10490182）.
文摘The study on elemental speciation in atmospheric particulate matter (PM) is important for understanding the formation and origin of pollution and evaluating their toxicity. In this paper,the speci- ation of iron in atmospheric PM was investigated with extended X-ray absorption fine structure (EXAFS) spectra based on synchrotron radiation. The chemi- cal components of PM can be calculated by regres- sion analysis of EXAFS spectra. This is a non-destructive method. In order to have knowledge of the influence of chemical components on EXAFS spectra,we prepared a series of mixed reference samples,and proved the precision of method is good. The PM samples with different particle sizes and from different sampling sites were collected in Shanghai,China. The chemical components of the samples were calculated by regression analysis of EXAFS spectra. The results show that the iron in all PM samples mainly consist of Fe2O3,Fe3O4 and Fe2(SO4)3,but their proportions are different in dif- ferent samples. The changes of components among PM samples were observed preliminarily. The con- centrations of iron in the samples were determined by proton-induced X-ray emission (PIXE) technique. It is observed that the concentrations of iron in the sam- ples of iron and steel industrial district were much higher than those of other districts,and chemical components were also different from those of others.
基金the Key Project of the National Natural Science Foundation of China(Grant Nos.40571146 and 20577053)
文摘Fractionations of rare earth elements(REEs)and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions.Significant enrichment of middle REEs(MREEs)and heavy REEs(HREEs)was observed in plant roots and leaves respectively,with slight fractionation between light REEs(LREEs)and HREEs in stems.Moreover,the tetrad effect was observed in these organs.Investigations into REE speciation in roots and in the xylem sap using X-ray absorption spectroscopy(XAS)and nanometer-sized TiO2 adsorption techniques,associated with other controlled experiments,demonstrated that REE fractionations should be dominated by fixation mechanism in roots caused by cell wall absorption and phosphate precipitation,and by the combined effects of fixation mechanism and transport mechanism in aboveground parts caused by solution complexation by intrinsic organic ligands.A conceptive model was established for REE fractionations in plants based on the above studies.
基金the National NaturalScience Foundation of China (Grant No. 29673038) and "the One-hundred People Plan" of the Chinese Academy of Sciences.
文摘Annealing crystallization of ultrafine NiB amorphous alloy prepared by the chemical reduction method was studied by DTA, XRD and XAFS techniques. The XRD and XAFS results have revealed that the crystallization process of ultrafine NiB amorphous alloy proceeds in two steps. First, ultrafine NiB amorphous alloy is crystallized to form metastable nanocrystalline Ni3B at an annealing temperature of 325℃. Second, the nanocrystalline Ni3B is further decomposed into crystalline Ni at 380CCC or higher tempera ture, the local structure around Ni atoms in resultant product is similar to that in Ni foil. It was found that the catalytic activity of nanocrystalline Ni3B for benzene hydro-genation is much higher than that of ultrafine NiB amorphous alloy or crystalline Ni. The result indicates that the active sites of nanocrystalline Ni3B for benzene hydrogena-tion are composed of both Ni and B with proper geometry configuration.
