Records |
Author |
Kundu, P.; Heidari, H.; Bals, S.; Ravishankar, N.; Van Tendeloo, G. |
Title |
Formation and thermal stability of gold-silica nanohybrids : insight into the mechanism and morphology by electron tomography |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Angewandte Chemie: international edition in English |
Abbreviated Journal |
Angew Chem Int Edit |
Volume |
53 |
Issue |
15 |
Pages |
3970-3974 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Gold-silica hybrids are appealing in different fields of applications like catalysis, sensorics, drug delivery, and biotechnology. In most cases, the morphology and distribution of the heterounits play significant roles in their functional behavior. Methods of synthesizing these hybrids, with variable ordering of the heterounits, are replete; however, a complete characterization in three dimensions could not be achieved yet. A simple route to the synthesis of Au-decorated SiO2 spheres is demonstrated and a study on the 3D ordering of the heterounits by scanning transmission electron microscopy (STEM) tomography is presentedat the final stage, intermediate stages of formation, and after heating the hybrid. The final hybrid evolves from a soft self-assembled structure of Au nanoparticles. The hybrid shows good thermal stability up to 400 degrees C, beyond which the Au particles start migrating inside the SiO2 matrix. This study provides an insight in the formation mechanism and thermal stability of the structures which are crucial factors for designing and applying such hybrids in fields of catalysis and biotechnology. As the method is general, it can be applied to make similar hybrids based on SiO2 by tuning the reaction chemistry as needed. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000333634800036 |
Publication Date |
2014-03-05 |
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 |
1433-7851; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
11.994 |
Times cited |
10 |
Open Access |
OpenAccess |
Notes |
This research has received funding from the European Community’s Seventh Framework Program (ERC; grant number 246791)— COUNTATOMS, COLOURATOMS, as well as from the IAP 7/05 Programme initiated by the Belgian Science Policy Office. Funding from the Department of Science and Technology (DST) is also acknowledged.; ECAS_Sara; (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot); |
Approved |
Most recent IF: 11.994; 2014 IF: 11.261 |
Call Number |
UA @ lucian @ c:irua:117186 |
Serial |
1251 |
Permanent link to this record |
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Author |
Mahr, C.; Kundu, P.; Lackmann, A.; Zanaga, D.; Thiel, K.; Schowalter, M.; Schwan, M.; Bals, S.; Wittstock, A.; Rosenauer, A. |
Title |
Quantitative determination of residual silver distribution in nanoporous gold and its influence on structure and catalytic performance |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Journal of catalysis |
Abbreviated Journal |
J Catal |
Volume |
352 |
Issue |
352 |
Pages |
52-58 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Large efforts have been made trying to understand the origin of the high catalytic activity of dealloyed nanoporous gold as a green catalyst for the selective promotion of chemical reactions at low temperatures. Residual silver, left in the sample after dealloying of a gold-silver alloy, has been shown to have a strong influence on the activity of the catalyst. But the question of how the silver is distributed within the porous structure has not finally been answered yet. We show by quantitative energy dispersive X-ray tomography measurements that silver forms clusters that are distributed irregularly, both on the surface and inside the ligaments building up the porous structure. Furthermore, we find that the role of the residual silver is ambiguous. Whereas CO oxidation is supported by more residual silver, methanol oxidation to methyl formate is hindered. Structural characterisation reveals larger ligaments and pores for decreasing residual silver concentration. |
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 |
000408299600006 |
Publication Date |
2017-05-29 |
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 |
0021-9517 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.844 |
Times cited |
42 |
Open Access |
OpenAccess |
Notes |
This work was supported by the Deutsche Forschungsgemeinschaft (DFG) under contracts no. RO2057/12-1 (SP 6) and WI4497/1-1 (SP 2) within the research unit FOR2213 (www.nagocat. de) and the European Research Council (ERC Starting Grant No. 335078-COLOURATOMS). (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); ecas_sara |
Approved |
Most recent IF: 6.844 |
Call Number |
EMAT @ emat @c:irua:144434UA @ admin @ c:irua:144434 |
Serial |
4623 |
Permanent link to this record |
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Author |
Kundu, P.; Turner, S.; Van Aert, S.; Ravishankar, N.; Van Tendeloo, G. |
Title |
Atomic structure of quantum gold nanowires : quantification of the lattice strain |
Type |
A1 Journal article |
Year |
2014 |
Publication |
ACS nano |
Abbreviated Journal |
Acs Nano |
Volume |
8 |
Issue |
1 |
Pages |
599-606 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Theoretical studies exist to compute the atomic arrangement in gold nanowires and the influence on their electronic behavior with decreasing diameter. Experimental studies, e.g., by transmission electron microscopy, on chemically synthesized ultrafine wires are however lacking owing to the unavailability of suitable protocols for sample preparation and the stability of the wires under electron beam irradiation. In this work, we present an atomic scale structural investigation on quantum single crystalline gold nanowires of 2 nm diameter, chemically prepared on a carbon film grid. Using low dose aberration-corrected high resolution (S)TEM, we observe an inhomogeneous strain distribution in the crystal, largely concentrated at the twin boundaries and the surface along with the presence of facets and surface steps leading to a noncircular cross section of the wires. These structural aspects are critical inputs needed to determine their unique electronic character and their potential as a suitable catalyst material. Furthermore, electron-beam-induced structural changes at the atomic scale, having implications on their mechanical behavior and their suitability as interconnects, are discussed. |
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 |
000330542900061 |
Publication Date |
2013-11-29 |
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 |
|
Edition |
|
ISSN |
1936-0851;1936-086X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.942 |
Times cited |
20 |
Open Access |
|
Notes |
FWO; Countatoms; Hercules |
Approved |
Most recent IF: 13.942; 2014 IF: 12.881 |
Call Number |
UA @ lucian @ c:irua:113856 |
Serial |
199 |
Permanent link to this record |
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Author |
Kundu, S.; Kundu, P.; Van Tendeloo, G.; Ravishankar, N. |
Title |
Au2Sx/CdS nanorods by cation exchange : mechanistic insights into the competition between cation-exchange and metal ion reduction |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Small |
Abbreviated Journal |
Small |
Volume |
10 |
Issue |
19 |
Pages |
3895-3900 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Thumbnail image of graphical abstract It is well known that metals with higher electron affinity like Au tend to undergo reduction rather than cation-exchange. It is experimentally shown that under certain conditions cation-exchange is dominant over reduction. Thermodynamic calculation further consolidates the understanding and paves the way for better predictability of cation-exchange/reduction reactions for other systems. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000344451900011 |
Publication Date |
2014-06-02 |
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 |
1613-6810; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.643 |
Times cited |
8 |
Open Access |
|
Notes |
countatoms |
Approved |
Most recent IF: 8.643; 2014 IF: 8.368 |
Call Number |
UA @ lucian @ c:irua:118010 |
Serial |
3514 |
Permanent link to this record |
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Author |
Kumar, A.; Kundu, S.; Samantaray, D.; Kundu, P.; Zanaga, D.; Bals, S.; Ravishankar, N. |
Title |
Designing diameter-modulated heterostructure nanowires of PbTe/Te by controlled dewetting |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Nano letters |
Abbreviated Journal |
Nano Lett |
Volume |
17 |
Issue |
17 |
Pages |
7226-7233 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
<script type='text/javascript'>document.write(unpmarked('Heterostructures consisting of semiconductors with controlled morphology and interfaces find applications in many fields. A range of axial, radial, and diameter-modulated nanostructures have been synthesized primarily using vapor phase methods. Here, we present a simple wet chemical routine to synthesize heterostructures of PbTe/Te using Te nanowires as templates. A morphology evolution study for the formation of these heterostructures has been performed. On the basis of these control experiments, a pathway for the formation of these nanostructures is proposed. Reduction of a Pb precursor to Pb on Te nanowire templates followed by interdiffusion of Pb/Te leads to the formation of a thin shell of PbTe on the Te wires. Controlled dewetting of the thin shell leads to the formation of cube-shaped PbTe that is periodically arranged on the Te wires. Using control experiments, we show that different reactions parameters like rate of addition of the reducing agent, concentration of Pb precursor and thickness of initial Te nanowire play a critical role in controlling the spacing between the PbTe cubes on the Te wires. Using simple surface energy arguments, we propose a mechanism for the formation of the hybrid. The principles presented are general and can be exploited for the synthesis of other nanoscale heterostructures.')); |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington |
Editor |
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Language |
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Wos |
000418393300009 |
Publication Date |
2017-11-29 |
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 |
1530-6984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
12.712 |
Times cited |
11 |
Open Access |
OpenAccess |
Notes |
; N.R acknowledges financial support from SERB, DST, Government of India. The authors acknowledge the electron microscopy facilities at the Advanced Facility for Microscopy and Microanalysis, IISc. S.B., P.K., and D.Z. acknowledge ERC Starting Grant 335078 COLOURATOMS for financial support. ; ecas_Sara |
Approved |
Most recent IF: 12.712 |
Call Number |
UA @ lucian @ c:irua:148557UA @ admin @ c:irua:148557 |
Serial |
4870 |
Permanent link to this record |
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Author |
Pramanik, G.; Humpolickova, J.; Valenta, J.; Kundu, P.; Bals, S.; Bour, P.; Dracinsky, M.; Cigler, P. |
Title |
Gold nanoclusters with bright near-infrared photoluminescence |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
Volume |
10 |
Issue |
10 |
Pages |
3792-3798 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
The increase in nonradiative pathways with decreasing emission energy reduces the luminescence quantum yield (QY) of near-infrared photoluminescent (NIR PL) metal nanoclusters. Efficient surface ligand chemistry can significantly improve the luminescence QY of NIR PL metal nanoclusters. In contrast to the widely reported but modestly effective thiolate ligand-to-metal core charge transfer, we show that metal-to-ligand charge transfer (MLCT) can be used to greatly enhance the luminescence QY of NIR PL gold nanoclusters (AuNCs). We synthesized water-soluble and colloidally stable NIR PL AuNCs with unprecedentedly high QY (similar to 25%) upon introduction of triphenylphosphonium moieties into the surface capping layer. By using a combination of spectroscopic and theoretical methods, we provide evidence for gold core-to-ligand charge transfer occurring in AuNCs. We envision that this work can stimulate the development of these unusually bright AuNCs for promising optoelectronic, bioimaging, and other applications. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000426148500026 |
Publication Date |
2018-01-08 |
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 |
2040-3364 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
7.367 |
Times cited |
97 |
Open Access |
OpenAccess |
Notes |
; The authors acknowledge support from the GACR project Nr. 18-12533S. J. V. acknowledges funding from the Ministry of Education, Youth and Sports of the Czech Republic via the V4+Japan project No. 8F15001 (cofinanced by the International Visegrad Fund). P. B. acknowledges GACR project No. 16-05935S and Ministry of Education, Youth and Sports of the Czech Republic project No. LTC17012. ; |
Approved |
Most recent IF: 7.367 |
Call Number |
UA @ lucian @ c:irua:149901UA @ admin @ c:irua:149901 |
Serial |
4935 |
Permanent link to this record |
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Author |
Boschker, H.T.S.; Cook, P.L.M.; Polerecky, L.; Eachambadi, R.T.; Lozano, H.; Hidalgo-Martinez, S.; Khalenkow, D.; Spampinato, V.; Claes, N.; Kundu, P.; Wang, D.; Bals, S.; Sand, K.K.; Cavezza, F.; Hauffman, T.; Bjerg, J.T.; Skirtach, A.G.; Kochan, K.; McKee, M.; Wood, B.; Bedolla, D.; Gianoncelli, A.; Geerlings, N.M.J.; Van Gerven, N.; Remaut, H.; Geelhoed, J.S.; Millan-Solsona, R.; Fumagalli, L.; Nielsen, L.P.; Franquet, A.; Manca, J.V.; Gomila, G.; Meysman, F.J.R. |
Title |
Efficient long-range conduction in cable bacteria through nickel protein wires |
Type |
A1 Journal article |
Year |
2021 |
Publication |
Nature Communications |
Abbreviated Journal |
Nat Commun |
Volume |
12 |
Issue |
1 |
Pages |
3996 |
Keywords ![sorted by Keywords field, ascending order (up)](img/sort_asc.gif) |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Filamentous cable bacteria display long-range electron transport, generating electrical currents over centimeter distances through a highly ordered network of fibers embedded in their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a biological material, but their chemical structure and underlying electron transport mechanism remain unresolved. Here, we combine high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate that the periplasmic wires consist of a conductive protein core surrounded by an insulating protein shell layer. The core proteins contain a sulfur-ligated nickel cofactor, and conductivity decreases when nickel is oxidized or selectively removed. The involvement of nickel as the active metal in biological conduction is remarkable, and suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures. |
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 |
000669944900006 |
Publication Date |
2021-06-28 |
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 |
2041-1723 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
12.124 |
Times cited |
23 |
Open Access |
OpenAccess |
Notes |
The authors thank Marlies Neiemeisland for assistance with Raman microscopy, Michiel Kienhuis for assistance with NanoSIMS analysis, Peter Hildebrandt and Diego Millo for helping with the interpretation of the Raman spectra, IONTOF for the Orbitrap Hybrid- SIMS analysis, and Rene Fabregas for helping with finite-element numerical modeling for SDM. H.T.S.B. and F.J.R.M. were financially supported by the Netherlands Organization for Scientific Research (VICI grant 016.VICI.170.072). Research Foundation Flanders supported F.J.R.M., J.V.M., and R.T.E. through FWO grant G031416N, and F.J.R.M. and J.S.G. through FWO grant G038819N. N.M.J.G. is the recipient of a Ph.D. scholarship for teachers from NWO in the Netherlands (grant 023.005.049). The NanoSIMS facility at Utrecht University was financed through a large infrastructure grant by the Netherlands Organization for Scientific Research (NWO, grant no. 175.010.2009.011) and through a Research Infrastructure Fund by the Utrecht University Board. A.G.S. is supported by the Special Research Fund (BOF) of Ghent University (BOF14/IOP/003, BAS094-18, 01IO3618) and FWO (G043219). The ToF-SIMS was funded by FWO Hercules grant (ZW/13/07) to J.V.M. and A.F. H.L., R.M.S., and G.G. were funded by the European Union H2020 Framework Programme (MSCA-ITN-2016) under grant agreement n 721874.EU, the Spanish Agencia Estatal de Investigación and EU FEDER under grant agreements TEC2016-79156-P and TEC2015-72751-EXP, the Generalitat de Catalunya through 2017-SGR1079 grant and CERCA Program. G.G. was recipient of an ICREA Academia Award, and H.L. of a FPI fellowship (BES-2015-074799) from the Agencia Estatal de Investigación/Fondo Social Europeo. L.F. received funding from the European Research Council (grant agreement No. 819417) under the European Union’s Horizon 2020 research and innovation programme. |
Approved |
Most recent IF: 12.124 |
Call Number |
EMAT @ emat @c:irua:179813 |
Serial |
6803 |
Permanent link to this record |