The accurate analysis of the elemental composition plays a crucial role in the research of functional materials.The emitting characteristic x-ray fluorescence(XRF)photons can be used for precisely discriminating the s...The accurate analysis of the elemental composition plays a crucial role in the research of functional materials.The emitting characteristic x-ray fluorescence(XRF)photons can be used for precisely discriminating the specified element.The detection accuracy of conventional XRF methodology using semiconductor detector is limited by the energy resolution,thus posing a challenge in accurately scaling the actual energy of each XRF photon.We adopt a novel high-resolution x-ray spectrometer based on the superconducting transition-edge sensor(TES)for the XRF spectroscopy measurement of different elements.Properties including high energy resolution,high detection efficiency and precise linearity of the new spectrometer will bring significant benefits in analyzing elemental composition via XRF.In this paper,we study the Ledge emission line profiles of three adjacent rare earth elements with the evenly mixed sample of their oxide components:terbium,dysprosium and holmium.Two orders of magnitude better energy resolution are obtained compared to a commercial silicon drift detector.With this TES-based spectrometer,the spectral lines overlapped or interfered by background can be clearly distinguished,thus making the chemical component analysis more accurate and quantitative.A database of coefficient values for the line strength of the spectrum can then be constructed thereafter.Equipped with the novel XRF spectrometer and an established coefficient database,a direct analysis of the composition proportion of a certain element in an unknown sample can be achieved with high accuracy.展开更多
This study aims at investigating the effects of foliar application of aqueous solutions of La3+and Ce3+nitrates on soybean plants(Glycine max).First,we observe that Triton HW 1000 surfactant at 0.01 vol%reduces drople...This study aims at investigating the effects of foliar application of aqueous solutions of La3+and Ce3+nitrates on soybean plants(Glycine max).First,we observe that Triton HW 1000 surfactant at 0.01 vol%reduces droplets contact angle and increases their drying time.Under greenhouse conditions,the foliar treatments do not affect chlorophyll content,plant height,number of leaves,number of pods,number of seeds per pod,and average seed weight.However,the treatments induce phytotoxicity since foliar injuries appear after the spraying.Microprobe X-ray fluorescence spectroscopy combined to scanning electron microscopy shows that the leaf lesions are positively correlated to accumulation of Ce and La on the leaf surface and also promote structural alteration to the epidermal cells.X-ray absorption near edge structure shows that the La and Ce nitrates are partially bio transformed into oxides by the leaves which might explain the harmful effects.展开更多
Two dinuclear compounds [Ln2(acetate)6(H2O)4]-4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, ...Two dinuclear compounds [Ln2(acetate)6(H2O)4]-4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln(Ⅲ) ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb(Ⅲ) in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.展开更多
Separation of target elements or minerals from their host rock or ore is essential to successful mining operation. The inevitable loss of a portion of the desired material that accompanies each step in the extraction ...Separation of target elements or minerals from their host rock or ore is essential to successful mining operation. The inevitable loss of a portion of the desired material that accompanies each step in the extraction process must be documented to develop the operational protocol. Superposition of the characteristic X-ray fluorescence spectra of head (crushed rock ore particles, pre-processing) and tail (post-processing particles) samples provides a direct visual comparison of relative peak sizes, and thereby the relative concentrations, of elements of interest. If the head and tail peaks are identical, none of the element was recovered in the extraction process. At the other extreme if the tail peak “flat lines”, i.e., there is no peak, there was 100% recovery of that element. Standardless visual comparison is valid if the same mass of identical starting material is incorporated into the head and tail sample analysis pucks, and XRF analytical conditions are identical. The considerable time and expense of acquiring and calibrating the standards associated with XRF analysis of 75 or more elements are avoided, a significant advantage during initial broad screening of an experimental extraction procedure. Full quantitation by XRF or an alternate technique can proceed at a later project stage, if desired. The approach retains and presents all features of the original data, thus eliminating questions about data quality, standards and their calibration, and data manipulation in processing from raw counts to concentrations in printout tables. This form of display is ideal for both the mining professional and such less technical groups as corporate staff, investors, regulators, and the public. Examples presented herein are for heap leaching;the protocol can be applied as well to any of the other traditional ore processing and beneficiation procedures, e.g., gravity concentration, magnetic and electrical separation, froth flotation, and ore sorting.展开更多
As one of the most complete archaic human fossils,the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens.However,the unsystematic recovery of th...As one of the most complete archaic human fossils,the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens.However,the unsystematic recovery of this cranium and a long and confused history since the discovery impede its accurate dating.Here,we carried out a series of geochemical analyses,including non-destructive X-ray fluorescence(XRF),rare earth elements(REE),and the Sr isotopes,to test the reported provenance of the Harbin cranium and get better stratigraphic constraints.The results show that the Harbin cranium has very similar XRF element distribution patterns,REE concentration patterns,and Sr isotopic compositions to those of the Middle Pleistocene-Holocene mammalian and human fossils recently recovered from the Harbin area.The sediments adhered in the nasal cavity of the Harbin cranium have a 87Sr/86Sr ratio of 0.711898,falling in the variation range measured in a core drilled near the Dongjiang Bridge,where the cranium was discovered during its reconstruction.The regional stratigraphic correlations indicate that the Harbin cranium was probably from the upper part of the Upper Huangshan Formation of the Harbin area,which has an optically stimulated luminescence dating constraint between 138 and 309 ka.U-series disequilibrium dating(n=10)directly on the cranium suggests that the cranium is older than 146 ka.The multiple lines of evidence from our experiments consistently support the theory that the Harbin cranium is from the late Middle Pleistocene of the Harbin area.Our study also shows that geochemical approaches can provide reliable evidence for locating and dating unsystematically recovered human fossils,and potentially can be applied to other human fossils without clear provenance and stratigraphy records.展开更多
A Ce^(Ⅲ) linear complex of N-hydroxy-1,8-naphthalenedicarboximide(HL)has been synthesized with acenaphthoquinone dioxime(acndH_(2))under solvothermal conditions,in which L is generated by a series of in-situ reaction...A Ce^(Ⅲ) linear complex of N-hydroxy-1,8-naphthalenedicarboximide(HL)has been synthesized with acenaphthoquinone dioxime(acndH_(2))under solvothermal conditions,in which L is generated by a series of in-situ reactions starting from acndH2.X-ray crystallography reveals the coordination chains of Ce^(Ⅲ) ions are assembled into a 3D supramolecular framework viaπ···πinteractions.The title complex has been characterized by IR and UV-Vis spectra and thermogravimetric analysis(TGA).Furthermore,the fluorescent properties study demonstrated a ligand-based emission of the Ce^(Ⅲ) complex with~6 nm blue-shift compared with the emisision of the HL ligand.展开更多
基金the National Major Scientific Research Instrument Development Project(Grant No.11927805)the National Key Research and Development Program of China(Grant No.2022YFF0608303)+2 种基金the NSFC Young Scientists Fund(Grant No.12005134)the Shanghai-XFEL Beamline Project(SBP)(Grant No.31011505505885920161A2101001)the Shanghai Municipal Science and Technology Major Project(Grant No.2017SHZDZX02)。
文摘The accurate analysis of the elemental composition plays a crucial role in the research of functional materials.The emitting characteristic x-ray fluorescence(XRF)photons can be used for precisely discriminating the specified element.The detection accuracy of conventional XRF methodology using semiconductor detector is limited by the energy resolution,thus posing a challenge in accurately scaling the actual energy of each XRF photon.We adopt a novel high-resolution x-ray spectrometer based on the superconducting transition-edge sensor(TES)for the XRF spectroscopy measurement of different elements.Properties including high energy resolution,high detection efficiency and precise linearity of the new spectrometer will bring significant benefits in analyzing elemental composition via XRF.In this paper,we study the Ledge emission line profiles of three adjacent rare earth elements with the evenly mixed sample of their oxide components:terbium,dysprosium and holmium.Two orders of magnitude better energy resolution are obtained compared to a commercial silicon drift detector.With this TES-based spectrometer,the spectral lines overlapped or interfered by background can be clearly distinguished,thus making the chemical component analysis more accurate and quantitative.A database of coefficient values for the line strength of the spectrum can then be constructed thereafter.Equipped with the novel XRF spectrometer and an established coefficient database,a direct analysis of the composition proportion of a certain element in an unknown sample can be achieved with high accuracy.
基金Project supported by the National Council for Scientific and Technological Development (CNPq)(407380/2016-7)the Sao Paulo Research Foundation (FAPESP) in framework of Multiuser Equipment grant (2015-19121-8)+1 种基金Young Researcher Awards (2015/05942-0)the Masters scholarship for E.S.Rodrigues (2017/16375-4)。
文摘This study aims at investigating the effects of foliar application of aqueous solutions of La3+and Ce3+nitrates on soybean plants(Glycine max).First,we observe that Triton HW 1000 surfactant at 0.01 vol%reduces droplets contact angle and increases their drying time.Under greenhouse conditions,the foliar treatments do not affect chlorophyll content,plant height,number of leaves,number of pods,number of seeds per pod,and average seed weight.However,the treatments induce phytotoxicity since foliar injuries appear after the spraying.Microprobe X-ray fluorescence spectroscopy combined to scanning electron microscopy shows that the leaf lesions are positively correlated to accumulation of Ce and La on the leaf surface and also promote structural alteration to the epidermal cells.X-ray absorption near edge structure shows that the La and Ce nitrates are partially bio transformed into oxides by the leaves which might explain the harmful effects.
基金the National Natural Science Foundation of China (20772037)the Natural Science Foundation of Guangdong Province (06025033)
文摘Two dinuclear compounds [Ln2(acetate)6(H2O)4]-4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln(Ⅲ) ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb(Ⅲ) in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.
文摘Separation of target elements or minerals from their host rock or ore is essential to successful mining operation. The inevitable loss of a portion of the desired material that accompanies each step in the extraction process must be documented to develop the operational protocol. Superposition of the characteristic X-ray fluorescence spectra of head (crushed rock ore particles, pre-processing) and tail (post-processing particles) samples provides a direct visual comparison of relative peak sizes, and thereby the relative concentrations, of elements of interest. If the head and tail peaks are identical, none of the element was recovered in the extraction process. At the other extreme if the tail peak “flat lines”, i.e., there is no peak, there was 100% recovery of that element. Standardless visual comparison is valid if the same mass of identical starting material is incorporated into the head and tail sample analysis pucks, and XRF analytical conditions are identical. The considerable time and expense of acquiring and calibrating the standards associated with XRF analysis of 75 or more elements are avoided, a significant advantage during initial broad screening of an experimental extraction procedure. Full quantitation by XRF or an alternate technique can proceed at a later project stage, if desired. The approach retains and presents all features of the original data, thus eliminating questions about data quality, standards and their calibration, and data manipulation in processing from raw counts to concentrations in printout tables. This form of display is ideal for both the mining professional and such less technical groups as corporate staff, investors, regulators, and the public. Examples presented herein are for heap leaching;the protocol can be applied as well to any of the other traditional ore processing and beneficiation procedures, e.g., gravity concentration, magnetic and electrical separation, froth flotation, and ore sorting.
基金This project has been supported by the National Natural Science Foundation of China(41977380,41877430,41842039,41625005,41888101,41988101)the Strategic Priority Research Program of Chinese Academy of Sciences(CAS XDB26030400,XDB26030300,XDA20070203,XDA19050100)+3 种基金the People’s Government of Hebei Province(Z20177187)the China Geological Survey(DD20190601)the Science Foundation of Hebei GEO University(TS2017-001)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0705)。
文摘As one of the most complete archaic human fossils,the Harbin cranium provides critical evidence for studying the diversification of the Homo genus and the origin of Homo sapiens.However,the unsystematic recovery of this cranium and a long and confused history since the discovery impede its accurate dating.Here,we carried out a series of geochemical analyses,including non-destructive X-ray fluorescence(XRF),rare earth elements(REE),and the Sr isotopes,to test the reported provenance of the Harbin cranium and get better stratigraphic constraints.The results show that the Harbin cranium has very similar XRF element distribution patterns,REE concentration patterns,and Sr isotopic compositions to those of the Middle Pleistocene-Holocene mammalian and human fossils recently recovered from the Harbin area.The sediments adhered in the nasal cavity of the Harbin cranium have a 87Sr/86Sr ratio of 0.711898,falling in the variation range measured in a core drilled near the Dongjiang Bridge,where the cranium was discovered during its reconstruction.The regional stratigraphic correlations indicate that the Harbin cranium was probably from the upper part of the Upper Huangshan Formation of the Harbin area,which has an optically stimulated luminescence dating constraint between 138 and 309 ka.U-series disequilibrium dating(n=10)directly on the cranium suggests that the cranium is older than 146 ka.The multiple lines of evidence from our experiments consistently support the theory that the Harbin cranium is from the late Middle Pleistocene of the Harbin area.Our study also shows that geochemical approaches can provide reliable evidence for locating and dating unsystematically recovered human fossils,and potentially can be applied to other human fossils without clear provenance and stratigraphy records.
基金supported by NSF of China(21871262,21805257 and 21901242)NSF of Fujian Province(2019J01130 and 2020J05080)+1 种基金NSF of Xiamen(3502Z20206080)the Recruitment Program of Global Youth Experts。
文摘A Ce^(Ⅲ) linear complex of N-hydroxy-1,8-naphthalenedicarboximide(HL)has been synthesized with acenaphthoquinone dioxime(acndH_(2))under solvothermal conditions,in which L is generated by a series of in-situ reactions starting from acndH2.X-ray crystallography reveals the coordination chains of Ce^(Ⅲ) ions are assembled into a 3D supramolecular framework viaπ···πinteractions.The title complex has been characterized by IR and UV-Vis spectra and thermogravimetric analysis(TGA).Furthermore,the fluorescent properties study demonstrated a ligand-based emission of the Ce^(Ⅲ) complex with~6 nm blue-shift compared with the emisision of the HL ligand.