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Author Wang, H.; Cuppens, J.; Biermans, E.; Bals, S.; Fernandez-Ballester, L.; Kvashnina, K.O.; Bras, W.; van Bael, M.J.; Temst, K.; Vantomme, A.
Title Tuning of the size and the lattice parameter of ion-beam synthesized Pb nanoparticles embedded in Si Type A1 Journal article
Year 2012 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 45 Issue 3 Pages 035301-035301,7
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The size and lattice constant evolution of Pb nanoparticles (NPs) synthesized by high fluence implantation in crystalline Si have been studied with a variety of experimental techniques. Results obtained from small-angle x-ray scattering showed that the Pb NPs grow with increasing implantation fluence and annealing duration. The theory of NP growth kinetics can be applied to qualitatively explain the size evolution of the Pb NPs during the implantation and annealing processes. Moreover, the lattice constant of the Pb NPs was evaluated by conventional x-ray diffraction. The lattice dilatation was observed to decrease with increasing size of the Pb NPs. Such lattice constant tuning can be attributed to the pseudomorphism caused by the lattice mismatch between the Pb NPs and the Si matrix.
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Corporate Author (up) Thesis
Publisher Place of Publication London Editor
Language Wos 000299308400008 Publication Date 2011-12-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727;1361-6463; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 5 Open Access
Notes Fwo; Iap Approved Most recent IF: 2.588; 2012 IF: 2.528
Call Number UA @ lucian @ c:irua:94208 Serial 3754
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Author Leinders, G.; Grendal, O.G.; Arts, I.; Bes, R.; Prozheev, I.; Orlat, S.; Fitch, A.; Kvashnina, K.; Verwerft, M.
Title Refinement of the uranium dispersion corrections from anomalous diffraction Type A1 Journal Article
Year 2024 Publication Journal of Applied Crystallography Abbreviated Journal J Appl Cryst
Volume 57 Issue 2 Pages 284-295
Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Abstract The evolution of the uranium chemical state in uranium compounds, principally in the oxides, is of concern in the context of nuclear fuel degradation under storage and repository conditions, and in accident scenarios. The U–O system shows complicated phase relations between single-valence uranium dioxide (UO<sub>2</sub>) and different mixed-valence compounds (<italic>e.g.</italic>U<sub>4</sub>O<sub>9</sub>, U<sub>3</sub>O<sub>7</sub>and U<sub>3</sub>O<sub>8</sub>). To try resolving the electronic structure associated with unique atomic positions, a combined application of diffraction and spectroscopic techniques, such as diffraction anomalous fine structure (DAFS), can be considered. Reported here is the application of two newly developed routines for assessing a DAFS data set, with the aim of refining the uranium X-ray dispersion corrections. High-resolution anomalous diffraction data were acquired from polycrystalline powder samples of UO<sub>2</sub>(containing tetravalent uranium) and potassium uranate (KUO<sub>3</sub>, containing pentavalent uranium) using synchrotron radiation in the vicinity of the U<italic>L</italic><sub>3</sub>edge (17.17 keV). Both routines are based on an iterative refinement of the dispersion corrections, but they differ in either using the intensity of a selection of reflections or doing a full-pattern (Rietveld method) refinement. The uranium dispersion corrections obtained using either method are in excellent agreement with each other, and they show in great detail the chemical shifts and differences in fine structure expected for tetravalent and pentavalent uranium. This approach may open new possibilities for the assessment of other, more complicated, materials such as mixed-valence compounds. Additionally, the DAFS methodology can offer a significant resource optimization because each data set contains both structural (diffraction) and chemical (spectroscopy) information, which can avoid the requirement to use multiple experimental stations at synchrotron sources.
Address
Corporate Author (up) Thesis
Publisher Place of Publication Editor
Language Wos 001208800100008 Publication Date 2024-04-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1600-5767 ISBN Additional Links UA library record; WoS full record
Impact Factor 6.1 Times cited Open Access
Notes FPS Economy, SF-CORMOD; Approved Most recent IF: 6.1; 2024 IF: 2.495
Call Number EMAT @ emat @c:irua:206011 Serial 9127
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