نتایج جستجو برای: xafs
تعداد نتایج: 791 فیلتر نتایج به سال:
x-ray absorption fine structure (xafs) spectroscopy was used to identify directly the metal speciation and local bonding environment of fe in sediments originated from dobczyce reservoir (poland); special attention was paid to analysis of samples collected from points situated at different distances from the land. the combination of traditional approach to data analysis as well as usage of mult...
x-ray absorption fine structure (xafs) spectroscopy was used to identify directly the metal speciation and local bonding environment of fe in sediments originated from dobczyce reservoir (poland); special attention was paid to analysis of samples collected from points situated at different distances from the land. the combination of traditional approach to data analysis as well as usage of mult...
X-ray Absorption Fine Structure (XAFS) is calculated for copper using the cluster based Finite Difference Method for Near-Edge Structure (FDMNES). This approach is conventionally used to produce high accuracy XAFS theory in the near edge region, however, we demonstrate that it can be readily extended to encompass an energy range of more than 1.5 keV (k 20 Å 1 ) from the K absorption edge. Such ...
Fluorescence-yield X-ray absorption fine structure (FY-XAFS) is extensively used for investigating atomic-scale local structures around specific elements in functional materials. However, conventional FY-XAFS instruments frequently cannot cover trace light elements, for example dopants in wide gap semiconductors, because of insufficient energy resolution of semiconductor X-ray detectors. Here w...
X-ray absorption fine structure(XAFS) is used to investigate the local structural change of Fe60Cu40 and FegoCu20 with the ball milling time. The XAFS results verify that the solid solution of mechanically alloyed Fe-Cu samples are inhomogeneous. We propose that the bcc to fcc structural transformation of Fe small particles of Fe60Cuq0(160h) is induced by interfacial Cu atoms dissolving in smal...
The connection between local structure and the grain size distribution in nanophase palladium is studied by XAFS and x-ray diffraction (XRD). We show that there is a reduced average coordination number in all samples; this reduction is compatible with a size effect, cmtradicting previous XAFS measurements. Both a f i t shell analysis and a full analysis up to the 8th coordination shell, includi...
It has been shown that starch can effectively stabilize nanoscale magnetite particles, and starch-stabilized magnetite nanoparticles (SMNP) are promising for in situ remediation of arsenic-contaminated soils. However, a molecular level understanding has been lacking. Here, we carried out XAFS studies to bridge this knowledge gap. Fe K-edge XAFS spectra indicated that the Fe-O and Fe-Fe coordina...
We present a comprehensive study on Ti-doped ZnO thin films using X-ray Absorption Fine Structure (XAFS) spectroscopy. Ti K edge XAFS spectra were measured to study the electronic and chemical properties of Ti ions in the thin films grown under different ambient atmospheres. A strong dependence of Ti speciation, composition, and local structures upon the ambient conditions was observed. The XAF...
A new spectroelectrochemical cell to investigate the structure of Pt/Au nanoclusters using Pt and Au K-edge X-ray absorption fine structure (XAFS) measurements under the electrochemical conditions is developed. K-edge XAFS measurements for Pt and Au require a sample as thick as 1-2 cm, which prevents homogeneous potential distribution. We can measure in situ Pt and Au K-edge XAFS spectra and de...
Structures of carbon supported Pt-Ru catalyst in a polymer-electrolyte-fuel-cell (PEFC) were analyzed by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAFS). XRD analysis identified a face-centered-cubic (fcc) alloy structure for Pt-Ru. XAFS analysis revealed that Pt and Ru atoms were, however, not randomly distributed in the Pt-Ru fcc lattice. A Pt atom was more likely surrounded ...
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