Investigations of fine-paste ware production and exchange in maritime Southeast Asia by electron microscopy and synchrotron X-ray absorption

The combination of synchrotron X-ray absorption and electronmicroscopy provided information on the production and exchange of fine-paste ware (FPW), dated to around the 11th to 14th centuries in peninsular Thailand and maritime Southeast Asia. White FPW sherds from Kota Cina in north Sumatra, a well-known trading city in Indonesia, have similar clay composition to those from Kok Moh on Satingphra Spit in peninsular Thailand. Also, homogeneous texture indicating high firing temperatures was found in the samples from Kota Cina as well as in those from Phra Mahathat Temple and Suan Luang Temple in Nakhon Si Thammarat Province in Thailand. However, the split Mn K-edge X-ray absorption near-edge structure (XANES) peaks are exclusively observed in the samples from Nakhon Si Thammarat. The distinctly large compositions of ?-Fe2O3 and carbon, respectively confirmed by Fe K-edge extended X-ray absorption fine structure (EXAFS) and energy dispersive spectroscopy (EDS) spectra, suggest that Nakhon Si Thammarat probably had at least a FPW production site in which the ash glazing process may have been implemented. The evidence of such process is not found in the samples from other sites in maritime Southeast Asia in this analysis.

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Characterization of U(VI)-Acidithiobacillus ferrooxidans complexes using EXAFS, transmission electron microscopy, and energy-dispersive X-ray analysis

Radiochimica Acta ◽

10.1524/ract.91.10.583.22477 ◽

2003 ◽

Vol 91 (10) ◽

Cited By ~ 61

Author(s):

Mohamed Merroun ◽

C. Hennig ◽

A. Rossberg ◽

T. Reich ◽

S. Selenska-Pobell

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Fine Structure ◽

Acidithiobacillus Ferrooxidans ◽

Energy Dispersive ◽

X Ray ◽

Transmission Electron ◽

Molecular Scale ◽

X Ray Absorption

SummaryWe used a combination of Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray (EDX) analysis to conduct molecular scale studies on U(VI) interaction with three recently described eco-types of

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Synchrotron X-Ray Absorption Spectroscopy Study of Self-Assembled Nanoparticles Synthesized from Fe(acac)3and Pt(acac)2

Journal of Nanomaterials ◽

10.1155/2012/758429 ◽

2012 ◽

Vol 2012 ◽

pp. 1-4 ◽

Cited By ~ 2

Author(s):

K. Chokprasombat ◽

C. Sirisathitkul ◽

P. Harding ◽

S. Chandarak ◽

R. Yimnirun

Keyword(s):

Electron Microscopy ◽

Fine Structure ◽

Exafs Spectrum ◽

Fept Nanoparticles ◽

Spectroscopy Study ◽

Edge Structure ◽

X Ray ◽

Monodisperse Nanoparticles ◽

X Ray Absorption ◽

Absorption Technique

The synchrotron X-ray absorption technique was used to complement electron microscopy in the investigation of nanoparticles synthesized from the coreduction of iron acetylacetonate, Fe(acac)3and platinum acetylacetonate, Pt(acac)2. A much higher Pt composition than Fe leads to an extended X-ray absorption fine structure (EXAFS) spectrum for the sample that differs from that of fcc FePt nanoparticles. Most importantly, X-ray absorption near-edge structure (XANES) spectra clearly indicate the existence ofα-Fe2O3and Pt metal. Since these monodisperse nanoparticles have a diameter of around 4 nm and tend to self-assemble into hexagonal arrangements, they can be modeled as Pt-rich cores with anα-Fe2O3shell stabilized by organic surfactants.

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Extended X-ray absorption fine structure and multiple-scattering simulation of nickel dithiolene complexes Ni[S2C2(CF3)2]2n(n= −2, −1, 0) and an olefin adduct Ni[S2C2(CF3)2]2(1-hexene)

Journal of Synchrotron Radiation ◽

10.1107/s1600577514025041 ◽

2015 ◽

Vol 22 (1) ◽

pp. 124-129 ◽

Cited By ~ 4

Author(s):

Weiwei Gu ◽

Hongxin Wang ◽

Kun Wang

Keyword(s):

Fine Structure ◽

Multiple Scattering ◽

Edge Structure ◽

X Ray ◽

Absorption Fine ◽

Square Planar ◽

Square Planar Complexes ◽

Uv Visible ◽

Edge Features ◽

X Ray Absorption

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2n(n= −2, −1, 0) (1,2,3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) (4) have been examined by NiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for1–3reveals clear pre-edge features and approximately +0.7 eV shift in the NiK-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni—S bond distances for1,2and3(2.11–2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in NiK-edge energy positions and Ni—S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni—C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct4presents no pre-edge feature, and its NiK-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex3. Consistently, EXAFS also showed that the Ni—S distances in4elongate by ∼0.046 Å in comparison with3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of3as suggested by UV/visible spectroscopy in the literature.

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