| Records |
| 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 |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
001208800100008 |
Publication Date |
2024-04-01 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1600-5767 |
ISBN |
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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 |
| Permanent link to this record |
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| Author |
de Nolf, W.; Vanmeert, F.; Janssens, K. |
| Title |
XRDUA : crystalline phase distribution maps by two-dimensional scanning and tomographic (micro) X-ray powder diffraction |
Type |
A1 Journal article |
| Year |
2014 |
Publication |
Journal of applied crystallography |
Abbreviated Journal |
|
| Volume |
47 |
Issue |
3 |
Pages |
1107-1117 |
| Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
| Abstract |
Imaging of crystalline phase distributions in heterogeneous materials, either plane projected or in virtual cross sections of the object under investigation, can be achieved by scanning X-ray powder diffraction employing X-ray micro beams and X-ray-sensitive area detectors. Software exists to convert the two-dimensional powder diffraction patterns that are recorded by these detectors to one-dimensional diffractograms, which may be analysed by the broad variety of powder diffraction software developed by the crystallography community. However, employing these tools for the construction of crystalline phase distribution maps proves to be very difficult, especially when employing micro-focused X-ray beams, as most diffraction software tools have mainly been developed having structure solution in mind and are not suitable for phase imaging purposes. XRDUA has been developed to facilitate the execution of the complete sequence of data reduction and interpretation steps required to convert large sequences of powder diffraction patterns into a limited set of crystalline phase maps in an integrated fashion. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000336738500031 |
Publication Date |
2014-05-28 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
|
| ISSN |
0021-8898 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
62 |
Open Access |
|
| Notes |
; The authors would like to thank the synchrotron beamline staff at ID15 (ESRF, Grenoble, France), MicroXAS (SLS, Villigen, Switzerland) and PO6/BL-L (Petra III/Hasylab, Hamburg, Germany) for accommodating the experiments presented in this paper. Support from FWO 'Big Science' project G0C1213N as well as from the BELSPO project 'S2ART' (SD/RI/04A) is acknowledged. ; |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:117758 |
Serial |
5920 |
| Permanent link to this record |
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| Author |
Bogomolova, A.; Hruby, M.; Panek, J.; Rabyk, M.; Turner, S.; Bals, S.; Steinhart, M.; Zhigunov, A.; Sedlacek, O.; Stepanek, P.; Filippov, S.K.; |
| Title |
Small-angle X-ray scattering and light scattering study of hybrid nanoparticles composed of thermoresponsive triblock copolymer F127 and thermoresponsive statistical polyoxazolines with hydrophobic moieties |
Type |
A1 Journal article |
| Year |
2013 |
Publication |
Journal of applied crystallography |
Abbreviated Journal |
J Appl Crystallogr |
| Volume |
46 |
Issue |
6 |
Pages |
1690-1698 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
A combination of new thermoresponsive statistical polyoxazolines, poly[(2-butyl-2-oxazoline)-stat-(2-isopropyl-2-oxazoline)] [pBuOx-co-piPrOx], with different hydrophobic moieties and F127 surfactant as a template system for the creation of thermosensitive nanoparticles for radionuclide delivery has recently been tested [Pánek, Filippov, Hrubý, Rabyk, Bogomolova, Kučka Stěpánek (2012). Macromol. Rapid Commun.33, 16831689]. It was shown that the presence of the thermosensitive F127 triblock copolymer in solution reduces nanoparticle size and polydispersity. This article focuses on a determination of the internal structure and solution properties of the nanoparticles in the temperature range from 288 to 312 K. Here, it is demonstrated that below the cloud point temperature (CPT) the polyoxazolines and F127 form complexes that co-exist in solution with single F127 molecules and large aggregates. When the temperature is raised above the CPT, nanoparticles composed of polyoxazolines and F127 are predominant in solution. These nanoparticles could be described by a spherical shell model. It was found that the molar weight and hydrophobicity of the polymer do not influence the size of the outer radius and only slightly change the inner radius of the nanoparticles. At the same time, molar weight and hydrophobicity did affect the process of nanoparticle formation. In conclusion, poly(2-oxazoline) molecules are fully incorporated inside of F127 micelles, and this result is very promising for the successful application of such systems in radionuclide delivery. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Copenhagen |
Editor |
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| Language |
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Wos |
000327070000020 |
Publication Date |
2013-11-06 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0021-8898; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
18 |
Open Access |
|
| Notes |
262348 Esmi; Fwo; Iap-Pai |
Approved |
Most recent IF: NA |
| Call Number |
UA @ lucian @ c:irua:112420 |
Serial |
3042 |
| Permanent link to this record |
