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Quick-scanning X-ray absorption fine structure beamline at SSRF 被引量:1
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作者 Yu Chen Qian Gao +2 位作者 Zheng Jiang Jiong Li Shuo Zhang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第6期1-13,共13页
The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millise... The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine structures.It is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection mirror.It can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 keV.The performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental science.This paper presents an overview of the beamline design and a detailed description of its performance and capabilities. 展开更多
关键词 Bending magnet beamline x-ray absorption fine structure Quick-scanning XAFS In situ Synchrotron radiation
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Landscape of s-triazine molecule on Si(100) by a theoretical x-ray photoelectron spectroscopy and x-ray absorption near-edge structure spectra study
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作者 Jing Hu Xiu-Neng Song +3 位作者 Sheng-Yu Wang Juan Lin Jun-Rong Zhang Yong Ma 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第11期437-444,共8页
The chemisorbed structure for an aromatic molecule on a silicon surface plays an important part in promoting the development of organic semiconductor material science. The carbon K-shell x-ray photoelectron spectrosc... The chemisorbed structure for an aromatic molecule on a silicon surface plays an important part in promoting the development of organic semiconductor material science. The carbon K-shell x-ray photoelectron spectroscopy(XPS) and the x-ray absorption near-edge structure(XANES) spectra of the interfacial structure of an s-triazine molecule adsorbed on Si(100) surface have been performed by the first principles, and the landscape of the s-triazine molecule on Si(100) surface has been described in detail. Both the XPS and XANES spectra have shown their dependence on different structures for the pristine s-triazine molecule and its several possible adsorbed configurations. By comparison with the XPS spectra, the XANES spectra display the strongest structural dependency of all of the studied systems and thus could be well applied to identify the chemisorbed s-triazine derivatives. The exploration of spectral components originated from non-equivalent carbons in disparate local environments has also been implemented for both the XPS and XANES spectra of s-triazine adsorbed configurations. 展开更多
关键词 S-TRIAZINE silicon surface x-ray photoelectron spectroscopy (XPS) x-ray absorption near-edge structure (XANES)
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X-ray absorption near-edge structure study on the configuration of Cu2+/histidine complexes at different pH values
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作者 于梅娟 王宇 徐伟 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第4期474-478,共5页
The local configurations around metal ions in metalloproteins are of great significance for understanding their biolog- ical functions. Cu2+/histidine (His) is a typical complex existing in many metalloproteins and... The local configurations around metal ions in metalloproteins are of great significance for understanding their biolog- ical functions. Cu2+/histidine (His) is a typical complex existing in many metalloproteins and plays an important role in lots of physiological functions. The three-dimensional (3D) structural configurations of Cu2+/His complexes at different pH values (2.5, 6.5, and 8.5) are quantitatively determined by x-ray absorption near-edge structure (XANES). Generally Cu2+/His complex keeps an octahedral configuration consisting of oxygen atoms from water molecules and oxygen or nitrogen atoms from histidine molecules coordinated around Cu2+. It is proved in this work that the oxygen atoms from water molecules, when increasing the pH value from acid to basic value, are gradually substituted by the Ocarboxy1, Nam, and Nim from hisitidine molecules. Furthermore, the symmetries of Cu2+/His complexes at pH 6.5 and pH 8.5 are found to be lower than at pH 2.5. 展开更多
关键词 x-ray absorption near-edge structure Cu2+/His pH values CONFIGURATION
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X-ray absorption near the edge structure and x-ray photoelectron spectroscopy studies on pyrite prepared by thermally sulfurizing iron films 被引量:1
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作者 张辉 刘应书 +3 位作者 王宝义 魏龙 奎热西 钱海杰 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第7期2734-2738,共5页
This paper reports how pyrite films were prepared by thermal sulfurization of magnetron sputtered iron films and characterized by X-ray absorption near edge structure spectra and X-ray photoelectron spectroscopy on a ... This paper reports how pyrite films were prepared by thermal sulfurization of magnetron sputtered iron films and characterized by X-ray absorption near edge structure spectra and X-ray photoelectron spectroscopy on a 4B9B beam line at the Beijing Synchrotron Radiation Facility. The band gap of the pyrite agrees well with the optical band gap obtained by a spectrophotometer. The octahedral symmetry of pyrite leads to the splitting of the d orbit into t2g and eg levels. The high spin and low spin states were analysed through the difference of electron exchange interaction and the orbital crystal field. Only when the crystal field splitting is higher than 1.5 eV, the two weak peaks above the white lines can appear, and this was approved by experiments in the present work. 展开更多
关键词 x-ray absorption near the edge structure spectra x-ray photoelectron spectroscopy iron pyrite films solar cells
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Extended X-ray absorption fine structure (EXAFS) of FAPbI_(3) for understanding local structure-stability relation in perovskite solar cells
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作者 Dong-Ho Kang Yong-Jun Park +1 位作者 Yun-Sung Jeon Nam-Gyu Park 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第4期549-554,共6页
Perovskite solar cells (PSCs) employing formamidinium lead iodide (FAPbI_(3)) have shown high efficiency.However,operational stability has been issued due to phase instability of α phase FAPbI_(3) at ambient temperat... Perovskite solar cells (PSCs) employing formamidinium lead iodide (FAPbI_(3)) have shown high efficiency.However,operational stability has been issued due to phase instability of α phase FAPbI_(3) at ambient temperature.Excess precursors in the perovskite precursor solution has been proposed to improve not only power conversion efficiency (PCE) but also device stability.Nevertheless,there is a controversial issue on the beneficial effect on PCE and/or stability between excess FAI and excess PbI_(2).We report here extended X-ray absorption fine structure (EXAFS) of FAPbI_(3) to study local structural change and explain the effect of excess precursors on photovoltaic performance and stability.Perovskite films prepared from the precursor solution with excess PbI_(2)shows better stability than those from the one with excess FAI,despite similar PCE.A rapid phase transition from α phase to non-perovskite δ phase is observed from the perovskite film formed by excess FAI.Furthermore,the (Pb-I) bond distance evaluated by the Pb L_(III)-edge EXAFS study is increased by excess FAI,which is responsible for the phase transition and poor device stability.This work can provide important insight into local structure-stability relation in the FAPbI_(3)-based PSCs. 展开更多
关键词 Extended x-ray absorption fine structure EXAFS Excess precursor Local structure STABILITY Perovskite solar cells
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Local Structure Analysis of Lead Zinc Niobate-Barium Titanate Ceramic by X-Ray Absorption Spectroscopy and Density Functional Calculation
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作者 Kanokwan Kanchiang Phakkhananan Pakawanit Rattikorn Yimnirun 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第8期113-116,共4页
The local structure of an alternative Pb(Zn1/3Nb2/3)O3-based perovskite ceramic is investigated. The 0.07BaTiO33-0.93Pb(Zn1/3Nb2/3)O3 ceramic is synthesized using a combination of Zn3Nb2O8 B-site precursor and BaT... The local structure of an alternative Pb(Zn1/3Nb2/3)O3-based perovskite ceramic is investigated. The 0.07BaTiO33-0.93Pb(Zn1/3Nb2/3)O3 ceramic is synthesized using a combination of Zn3Nb2O8 B-site precursor and BaTiO33 perovskite phase stabilizer. Then, x-ray absorption spectroscopy and density functional theory are employed to calculate the local structure configuration and formation energy of the prepared samples. Ba2+ is found to replace Pb2+ in AA-site with Zn2+ occupying BB-site in Pb(Zn1/3Nb2/3)O3, while in the neighboring structure, Ti4+4+ replaces Nb5+5+ in BB-site with Pb2+2+ occupying AA-site. With the substitution of BaTiO33 in Pb(Zn1/3Nb2/3)O3, the bond length between Zn2+ and Pb2+ is longer than that of the typical perovskite phase of Pb(Zn1/3Nb2/3)O3. This indicates the key role of BaTiO33 in decreasing the steric hindrance of Pb2+ lone pair, and the mutual interactions between Pb2+ lone pair and Zn2+ and the formation energy is seen to decrease. This finding of the formation energy and local structure configuration relationship can further extend a fundamental understanding of the role of BaTiO33 in stabilizing the perovskite phase in PbZn13Nb23O3-based materials, which in turn will lead to an improved preparation technique for desired electrical properties. 展开更多
关键词 PB Local structure Analysis of Lead Zinc Niobate-Barium Titanate Ceramic by x-ray absorption spectroscopy and Density Functional Calculation EXAFS BA XANES Zn
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Approach to Automated In-situ X-Ray Absorption Fine Structure Spectroscopy Characterization
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作者 XIA Yinghao ZHANG Guikai +8 位作者 LIU Wenchao CAI Guolei JIN Song AN Pengfei HUANG Huan ZHENG Lirong JI Hengxing CHU Shengqi ZHANG Jing 《Chemical Research in Chinese Universities》 2025年第2期313-318,共6页
In order to expand the range of synchrotron radiation structural characterization modes,an automated in-situ X-ray absorption fine structure(XAFS)spectroscopy characterization for electrochemical research has been est... In order to expand the range of synchrotron radiation structural characterization modes,an automated in-situ X-ray absorption fine structure(XAFS)spectroscopy characterization for electrochemical research has been established.An in-situ control system equipped with an automatic trigger capability facilitates automated acquisition of XAFS and electrochemical data.Furthermore,the quick scanning XAFS(QXAFS)terminal,in-situ server and data storage were all controlled by remote users,enabling remote measurement to be achieved.Using this system,the evolution of the local structure near Fe atoms during the charging and discharging of lithium-sulfur battery(LSB)cathode materials was observed,which provides deep insights into the sulfur reaction pathway in LSBs by leveraging structural information.The system established here paves the way for fully automated and intelligent in-situ XAFS experiments. 展开更多
关键词 REMOTE AUTOMATION In-situ x-ray absorption fine structure(XAFS)spectroscopy ELECTROCHEMICAL
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Theoretical characterization of the adsorption configuration of pyrrole on Si(100)surface by x-ray spectroscopy
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作者 李好情 明静 +3 位作者 姜志昂 李海波 马勇 宋秀能 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期430-435,共6页
The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS s... The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS spectra of these adsorption configurations have been calculated by using the density functional theory(DFT)method and fullcore hole(FCH)approximation to investigate the relationship between the adsorption configurations and the spectra.The result shows that the XPS and NEXAFS spectra are structurally dependent on the configurations of pyrrole absorbed on the Si(100)surface.Compared with the XPS,the NEXAFS spectra are relatively sensitive to the adsorption configurations and can accurately identify them.The NEXAFS decomposition spectra produced by non-equivalent carbon atoms have also been calculated and show that the spectral features vary with the diverse types of carbon atoms and their structural environments. 展开更多
关键词 PYRROLE silicon surface x-ray photoelectron spectroscopy(XPS) near-edge x-ray absorption fine structure(NEXAFS)
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X-ray Spectroscopically Probing Mo_(2)C@MoSe_(2)Heterojunction Electrodes
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作者 CAO Yu-yang WEI Shi-qiang +5 位作者 JIANG Wei Peter Joseph Chimtali YAN Zi-wei ZHOU Quan CHEN Shuang-ming SONG Li 《分析测试学报》 CAS CSCD 北大核心 2024年第10期1618-1625,共8页
Due to their high electrical conductivity and layered structure,two dimensional MXene materials are re⁃garded as promising candidates for energy storage applications.However,the relatively low stability and specific c... Due to their high electrical conductivity and layered structure,two dimensional MXene materials are re⁃garded as promising candidates for energy storage applications.However,the relatively low stability and specific ca⁃pacity of MXene materials limit their further utilization.In this study,these issues are addressed using a heterostruc⁃ture strategy via a one-step selenization method to form Mo_(2)C@MoSe_(2).Synchrotron radiation X-ray spectroscopic and high-resolution transmission electron microscopy(HRTEM)characterizations revealed the heterostructure consisting of in-situ grown MoSe_(2)on Mo_(2)C MXene.Electrochemical tests proved the heterojunction electrode’s superior rate perfor⁃mance of 289.06 mAh·g^(-1)at a high current density of 5 A·g^(-1)and long cycling stability of 550 mAh·g^(-1)after 900 cycles at 1 A·g^(-1).This work highlights the useful X-ray spectroscopic analysis to directly elucidate the heterojunction structure,providing an effective reference method for probing heterostructures. 展开更多
关键词 x-ray spectroscopic MXene HETEROJUNCTION x-ray absorption fine structure lithium-ion batteries
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XAFS Study of Coordination Structure of Cu(L-His)2 in Solution
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作者 潘妍 张立云 刘扬中 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第4期451-456,I0004,共7页
Multiple coordination modes are present copper coordination environment varies in the CuII-histidine complex in solution and the with pH. In this work, we have investigated the coordination geometry of Cu(His)2 comp... Multiple coordination modes are present copper coordination environment varies in the CuII-histidine complex in solution and the with pH. In this work, we have investigated the coordination geometry of Cu(His)2 complex using X-ray absorption fine structure (XAFS) analysis. Copper K-edge XAFS spectra were acquired on aqueous Cu2+ samples with his- tidine at different pH values. The coordination environments were further confirmed by chemically modified histidine. Results show that the caboxylate groups coordinate at acidic condition, while amino and imidazole nitrogens get coordinated at higher pH. For the co- ordination geometry of Cu(His)2 in solution at physiological pH, the sixfold coordination is preferentially formed, while the fivefold coordination can co-exist in equilibrium. 展开更多
关键词 x-ray absorption fine structure Coordination structure COPPER Histidine Chemical modification PH
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Oxidation of antimony (Ⅲ) in soil by manganese (Ⅳ) oxide using X-ray absorption fine structure 被引量:5
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作者 Lei Fu Katsumi Shozugawa Motoyuki Matsuo 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第11期31-37,共7页
The oxidation of antimony (Ⅲ) in soils was studied using X-ray absorption fine structure (XAFS) spectra. An andosol soft sample and artificial soil samples (SiO2 blended with iron (Ⅲ) hydroxide and manganese... The oxidation of antimony (Ⅲ) in soils was studied using X-ray absorption fine structure (XAFS) spectra. An andosol soft sample and artificial soil samples (SiO2 blended with iron (Ⅲ) hydroxide and manganese (Ⅳ) oxide) were used herein. After adding antimony (Ⅲ) oxide to all soil samples, the oxidation process was observed by recording the XAFS spectra of Sb K-edge, Fe Kedge, and Mn K-edge. The results indicated that manganese (Ⅳ) oxide played an important role in the oxidation of Sb(Ⅲ); however iron (Ⅲ) hydroxide was not directly related to the reaction. During a 2-hr continuous Sb K-edge X-ray absorption near edge structure (XANES) measurement with an interval of I rain of one of the artificial soil samples (SiO2 + MnO2 + Sb2O3), a pseudo-first-order reaction was determined with an average estimated rate of 0.52 ±0.04 hr-1. Compared to the lower oxidation rate of andosol, it is suggested that because of the low concentration of Mn(Ⅳ) in natural soils, the oxidation process of Sb(Ⅲ) might be relatively slow and require more time to convert Sb(Ⅲ) to Sb(V). 展开更多
关键词 SOIL ANTIMONY OXIDATION Manganese (Ⅳ) oxide x-ray absorption fine structure (XAFS)
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Relating atomic local structures and Curie temperature of NdFeB permanent magnets:an X-ray absorption spectroscopic study 被引量:3
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作者 Mu-Nan Yang Hang Wang +3 位作者 Yong-Feng Hu Liu-Yi-Mei Yang Aimee Maclennan Bin Yang 《Rare Metals》 SCIE EI CAS CSCD 2018年第11期983-988,共6页
Relationship between atomic local structures and Curie temperature of NdFeB permanent magnets was investigated semi-quantitatively using synchrotron radiation technique. Fe K-edge X-ray absorption spectroscopy(XAS) wa... Relationship between atomic local structures and Curie temperature of NdFeB permanent magnets was investigated semi-quantitatively using synchrotron radiation technique. Fe K-edge X-ray absorption spectroscopy(XAS) was employed to study the local structure of Fe atoms for samples before and after doping Dy, Tb or Gd. It is found that the bond lengths and coordination numbers are changed. Thus, the exchange interaction between Fe atoms increases with Dy, Tb or Gd doping, resulting in the improvement of Curie temperature of NdFeB permanent magnets. The doping effect is proven by experimental measurement of the magnetic properties. Microstructural characterization using scanning electron microscopy(SEM) was also used to further analyze the effect of different rare earth elements doping on Curie temperature of NdFeB permanent magnets. 展开更多
关键词 Permanent magnet Synchrotron radiation x-ray absorption fine structure Crystal structure Curie temperature
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Synthesis, characterization and extended X-ray absorption fine structure of novel polynuclear copper complexes with new eighteen-membered macrocycle ligands
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作者 杨鲁勤 巨新 吴瑾光 《Chinese Science Bulletin》 SCIE EI CAS 1996年第12期1000-1005,共6页
Macrocycle compounds have great importance in host-guest chemistry and moleculeidentifications. 4-acetyl-bispyrazolones are a new type of polydentate ligands. Whenthey react with diamine compounds, new compounds or co... Macrocycle compounds have great importance in host-guest chemistry and moleculeidentifications. 4-acetyl-bispyrazolones are a new type of polydentate ligands. Whenthey react with diamine compounds, new compounds or complexes containing C=O andC=N groups can be obtained. These compounds can be used to study the relationship ofcoordination structure and its properties, energy transferring processes between metal 展开更多
关键词 copper complex MACROCYCLE SCHIFF-BASE PYRAZOLONE extended x-ray absorption fine structure (EXAFS).
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Structure and chemical valence study of Sr_(n+1)Ru_nO_(3n+1)(n= 1, 2, ∞) series
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作者 郑龙 朱小芹 +3 位作者 眭永兴 薛建忠 刘波 裴明旭 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第5期428-432,共5页
Effect of structure parameter n and its coupling with the connection mode among RuO6 octahedra of Srn+1RUnO3n+1 (n = 1, 2, ∞) are investigated. The gradually enhanced rotation and tilting effect with increasing n... Effect of structure parameter n and its coupling with the connection mode among RuO6 octahedra of Srn+1RUnO3n+1 (n = 1, 2, ∞) are investigated. The gradually enhanced rotation and tilting effect with increasing n are observed in Srn+1RUnO3n+1. Besides, the chemical valence of Ru is not changed, while the one of Sr gradually varies with increasing n, which highlights the great contribution of connection mode to the chemical environment. Our results show a strong n dependence on the connection mode between octahedra in Srn+1RUnO3n+1 (n = 1, 2, ∞). 展开更多
关键词 RUTHENATES structure parameter x-ray diffraction extended x-ray absorption fine structure
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Structural control of magnetic nanoparticles for positive nuclear magnetic resonance imaging
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作者 Zulaikha Ali Yunfei Zhang +5 位作者 Michael GKaul Billy Truong Deepika Bhanot Gerhard Adam Yuan-Yuan Li He Wei 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第10期17-28,共12页
In addition to the tens of millions of medical doses consumed annually around the world,a vast number of nuclear magnetic resonance imaging(MRI)contrast agents are being deployed in MRI research and development,offeri... In addition to the tens of millions of medical doses consumed annually around the world,a vast number of nuclear magnetic resonance imaging(MRI)contrast agents are being deployed in MRI research and development,offering precise diagnostic information,targeting capabilities,and analyte sensing.Superparamagnetic iron oxide nanoparticles(SPIONs)are notable among these agents,providing effective and versatile MRI applications while also being heavy-metal-free,bioconjugatable,and theranostic.We designed and implemented a novel two-pronged computational and experimental strategy to meet the demand for the efficient and rigorous development of SPION-based MRI agents.Our MATLAB-based modeling simulation and magnetic characterization revealed that extremely small maghemite SPIONs in the 1-3 nm range possess significantly reduced transversal relaxation rates(R_(2))and are therefore preferred for positive(T_(1)-weighted)MRI.Moreover,X-ray diffraction and X-ray absorption fine structure analyses demonstrated that the diffraction pattern and radial distribution function of our SPIONs matched those of the targeted maghemite crystals.In addition,simulations of the X-ray near-edge structure spectra indicated that our synthesized SPIONs,even at 1 nm,maintained a spherical structure.Furthermore,in vitro and in vivo MRI investigations showed that our 1-nm SPIONs effectively highlighted whole-body blood vessels and major organs in mice and could be cleared through the kidney route to minimize potential post-imaging side effects.Overall,our innovative approach enabled a swift discovery of the desired SPION structure,followed by targeted synthesis,synchrotron radiation spectroscopic studies,and MRI evaluations.The efficient and rigorous development of our high-performance SPIONs can set the stage for a computational and experimental platform for the development of future MRI agents. 展开更多
关键词 Magnetic nanoparticles structure control Nuclear magnetic resonance imaging Modeling simulation x-ray absorption fine structure
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基于同步辐射技术研究锌在废弃稀土矿区土壤中的吸附及垂向迁移特征
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作者 李洋 欧丽 +4 位作者 黄琨 刘鹏 刘燕红 李曼曼 唐金平 《吉林大学学报(地球科学版)》 北大核心 2025年第1期233-244,共12页
为了研究锌(Zn)在赣南稀土矿区土壤的吸附及垂向迁移特征,以及为矿山开采地区土壤及水体Zn污染防治、修复及风险评估提供理论依据,首先采用静态批实验,研究某废弃稀土矿区垂直剖面不同深度土壤对Zn的吸附特征;然后采用X射线衍射(XRD)及... 为了研究锌(Zn)在赣南稀土矿区土壤的吸附及垂向迁移特征,以及为矿山开采地区土壤及水体Zn污染防治、修复及风险评估提供理论依据,首先采用静态批实验,研究某废弃稀土矿区垂直剖面不同深度土壤对Zn的吸附特征;然后采用X射线衍射(XRD)及X射线吸收谱(XAFS)研究土壤主要物相组成及土壤中Zn的赋存形态变化,探讨Zn在土壤中的吸附机制及可迁移性。结果表明:剖面3层土壤对Zn的吸附平衡过程较快,土壤对Zn的吸附能力呈现出从表层土到深层土再到中层土逐渐减弱的趋势,准二级动力学模型及Langmuir方程能较好地描述土壤吸附Zn的过程;元素Fe、Mn在土壤中主要以Fe的氢氧化物及混合价态锰氧化物形式存在,剖面各层土壤理化性质差异影响土壤对Zn的吸附行为,相比于黏土矿物,Fe、Mn氧化物对土壤吸附Zn的影响更加显著;吸附反应前后土壤中Zn的局部配位模式由Zn-O四面体转变为Zn-O四面体和八面体的混合配位模式,反应后土壤表面可能形成了类似硫酸盐的外层络合物,反应前后土壤中的Zn由碱式碳酸盐转变为以硫酸盐与碱式碳酸盐的混合形式存在;受土壤pH影响,土壤滞留Zn能力有限,土壤中的有效态Zn易伴随降雨冲刷向下层土壤迁移,土壤中Zn质量分数随深度增加而增加。 展开更多
关键词 土壤 吸附 迁移 X射线吸收谱 稀土矿区 同步辐射
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土壤中砷吸附机理及其影响因素研究进展 被引量:37
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作者 罗磊 张淑贞 马义兵 《土壤》 CAS CSCD 北大核心 2008年第3期351-359,共9页
土壤中砷(As)的生物可利用性、迁移、转化及归宿在很大程度上依赖于其在土壤中的吸附反应。本文首先概述了土壤中As污染物的主要形态、价态及其与吸附的关系,较为系统地介绍了土壤中As吸附的主要影响因素和土壤中As吸附机理等方面的最... 土壤中砷(As)的生物可利用性、迁移、转化及归宿在很大程度上依赖于其在土壤中的吸附反应。本文首先概述了土壤中As污染物的主要形态、价态及其与吸附的关系,较为系统地介绍了土壤中As吸附的主要影响因素和土壤中As吸附机理等方面的最新研究进展,并重点对X-射线吸收精细结构光谱(XAFS)、红外光谱(IR)等现代分析技术和方法在As吸附研究中的应用和进展进行了论述。由于土壤组分与结构的复杂性,As在环境介质中的吸附机理研究目前仍集中在单纯矿物上的吸附行为,为As在土壤中的吸附研究提供了理论基础。X-射线吸收精细结构光谱及红外光谱研究结果证明As在土壤中的吸附主要与含Fe、Al等矿物结合,形成以双齿双核结构为主的配位结构:其吸附机理与土壤矿物及As污染物的价态、吸附浓度等有关,主要包括表面络合反应和表面沉淀作用;但是土壤中As吸附机理研究还需要进一步深入研究。文章最后分析了有关土壤中As吸附研究的发展趋势和重要动向。 展开更多
关键词 吸附 土壤 X-射线吸收精细结构光谱
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还原条件对CO_2加氢用Fe/TiO_2催化剂结构的影响 被引量:9
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作者 索掌怀 寇元 王弘立 《催化学报》 SCIE CAS CSCD 北大核心 2001年第4期348-352,共5页
考察了 5 %Fe/TiO2 催化剂在CO2 加氢制低碳烃中的催化活性 .最佳结果显示 ,CO2 转化率为 19 1% ,C2 +烃选择性为 5 0 1% .用X射线粉末衍射、激光拉曼光谱、穆斯堡尔谱及FeK 吸收边扩展X射线吸收精细结构等研究了该催化剂在还原条件下... 考察了 5 %Fe/TiO2 催化剂在CO2 加氢制低碳烃中的催化活性 .最佳结果显示 ,CO2 转化率为 19 1% ,C2 +烃选择性为 5 0 1% .用X射线粉末衍射、激光拉曼光谱、穆斯堡尔谱及FeK 吸收边扩展X射线吸收精细结构等研究了该催化剂在还原条件下的体相及表面结构 .结果表明 ,在Fe/TiO2 中 ,主要存在超顺磁的Fe0 ,α Fe,配位不饱和的Fe2 +物种及体相FeTiO3.还原温度对Fe/TiO2 催化剂的体相和表面结构及催化性能有显著的影响 .高温还原会破坏催化剂的表面结构 ,导致催化活性显著下降 .将催化活性与体相及表面结构相关联 ,提出Fe0 与配位不饱和的Fe2 +物种之间的协同作用是催化剂显示较高活性的重要原因 . 展开更多
关键词 氧化钛 氧化铁 二氧化碳 加氢 激光拉曼光谱 斯堡尔谱 扩展X射线吸收精细结构 体相结构 表面结构 负载型催化剂 低碳烃
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近边X射线吸收精细结构光谱法研究土壤腐殖质组分含碳官能团组成及磷酸根影响 被引量:6
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作者 罗磊 吕继涛 +2 位作者 许闯 郭智 张淑贞 《分析化学》 SCIE EI CAS CSCD 北大核心 2013年第8期1279-1282,共4页
应用同步辐射近边X射线吸收精细结构(NEXAFS)光谱技术研究了土壤腐殖质各组分(富里酸、胡敏酸及胡敏素等)的含碳官能团组成信息,并通过分析PO43-存在条件下胡敏酸、胡敏素的官能团组成变化特征,探讨了PO43-与土壤腐殖质之间的微观作用... 应用同步辐射近边X射线吸收精细结构(NEXAFS)光谱技术研究了土壤腐殖质各组分(富里酸、胡敏酸及胡敏素等)的含碳官能团组成信息,并通过分析PO43-存在条件下胡敏酸、胡敏素的官能团组成变化特征,探讨了PO43-与土壤腐殖质之间的微观作用机制。结果表明,土壤腐殖质不同组分的官能团分布具有类似的光谱特征,但组成比例存在明显差异。随着腐殖质组分的酸不溶性增加,胡敏酸、胡敏素疏水性脂肪基官能团比例显著高于富里酸,芳构化程度也明显增加,而亲水性羧基官能团比例趋于降低;PO43-通过静电作用、取代反应可以选择性释放胡敏酸中部分小分子羧基官能团,从而改变胡敏酸官能团的组成特征。此研究结果对于应用NEXAFS研究有机碳官能团形态、结构及理解PO43-在土壤微界面上的反应机制具有重要意义。 展开更多
关键词 富里酸 胡敏酸 胡敏素 官能团 磷酸根 近边X射线吸收精细结构光谱
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Fe/ZrO_(2)催化剂的Mssbauer谱及XAFS表征 被引量:3
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作者 索掌怀 王弘立 寇元 《催化学报》 SCIE CAS CSCD 北大核心 2000年第6期586-590,共5页
考察了经不同温度还原的Fe/ZrO2 催化剂在CO2 加氢制低碳烃反应中的催化活性 ,最佳结果为CO2 转化率2 7 0 % ,对C2 + 烃的选择性 5 6 7% .采用XRD ,57FeM ssbauer谱 ,FeK 吸收边的X射线吸收近边结构 (XANES)及扩展X射线吸收精细结构 (... 考察了经不同温度还原的Fe/ZrO2 催化剂在CO2 加氢制低碳烃反应中的催化活性 ,最佳结果为CO2 转化率2 7 0 % ,对C2 + 烃的选择性 5 6 7% .采用XRD ,57FeM ssbauer谱 ,FeK 吸收边的X射线吸收近边结构 (XANES)及扩展X射线吸收精细结构 (EXAFS)等表征方法研究了催化剂的表面结构 .结果表明 ,在ZrO2 表面上主要存在α Fe及配位不饱和的Fe3 + 两种物种 .催化剂表面明显呈氧缺位、零价铁相对富集的状态 .还原温度对表面结构有显著的影响 ,最佳还原温度与表面Fe O键的键长有关 .结合这种催化剂在CO2 加氢制低碳烃反应中的催化活性 ,认为α Fe与配位不饱和的Fe3 + 展开更多
关键词 氧化锆 氧化铁 穆斯堡尔谱 催化剂 XAFS 结构
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