Records |
Author |
Monico, L.; Sorace, L.; Cotte, M.; de Nolf, W.; Janssens, K.; Romani, A.; Miliani, C. |
Title |
Disclosing the binding medium effects and the pigment solubility in the (photo)reduction process of chrome yellows (PbCrO4/PbCr1-xSxO4) |
Type |
A1 Journal article |
Year |
2019 |
Publication |
ACS Omega |
Abbreviated Journal ![sorted by Abbreviated Journal field, ascending order (up)](img/sort_asc.gif) |
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Volume |
4 |
Issue |
4 |
Pages |
6607-6619 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
The darkening due to chemical alteration of chrome yellows (PbCrO4/PbCr1-xSxO4) is a phenomenon threatening a large number of 19th-20th century paintings, including the Amsterdam Sunflowers by Vincent van Gogh. Our earlier studies have proven that the alteration is due to a Cr(VI) -> Cr(III) reduction with Cr(V)-species that are formed as long-lived intermediates and that bCr(1-x)S(x)O(4) (0 < x <= 0.8) types undergo reduction more readily than monoclinic, S-free, PbCrO4. In this context, there is still lack of knowledge about the effects of the chemical properties of the binding medium (i.e., chemical composition and drying process) and the solubility of chrome yellows on the overall reduction pathways. Here, we study a series of naturally and photochemically aged mock-up paints prepared by mixing chrome yellow powders (PbCrO4/PbCr0.2S0.8O4) with either linseed oil or a water-based acrylic emulsion as the binding medium. Equivalent paints made up of the highly soluble K2CrO4 were also investigated and used as benchmarks to provide a more in-depth understanding of the influence of the solubility on the chromate reduction pathways in the two different binders. A combination of synchrotron radiation-based Cr K-edge X-ray absorption near edge structure (XANES), electron paramagnetic resonance (EPR), and UV-Visible spectroscopy measurements shows that: (1) the Cr(VI) reduction results from the interaction between the pigment and the binder; (2) the process is more significant in oil, giving rise to Cr(V)- and Cr(III)-species as well as oxidized organic compounds; (3) the lightfastness of the chrome yellow pigment is enhanced in the acrylic binder; and (4) the tendency toward chromium reduction increases with increasing solubility of the pigment. Based on our findings, we propose a scheme for the mechanism of the (photo)reduction process of chrome yellows in the oil and acrylic binder. Overall, our results provide new insights into the factors driving the degradation of lead chromate-based paints in artworks and contribute to the development of strategies for preserving them over time. |
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 |
000466552500057 |
Publication Date |
2019-04-10 |
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 |
2470-1343 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
4 |
Open Access |
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Notes |
; The research was financially supported by the European research project IPERION-CH, funded by the European Commission, H2020-INFRAIA-2014-2015 (grant agreement n. 654028), and by the project AMIS, within the program Dipartimenti di Eccellenza 2018-2022, funded by MIUR and University of Perugia. The University of Perugia is also acknowledged for financial support under the program “Ricerca di Base 2017”. L.S. acknowledges the financial support of Ente CRF. For the beamtime grants received, we thank the ESRF (experiment no. HG64 and in-house beamtimes). ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:160416 |
Serial |
5577 |
Permanent link to this record |
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Author |
Almohammadi, G.; O'Modhrain, C.; Kelly, S.; Sullivan, J.A. |
Title |
Ti-doped SBA-15 catalysts used in phenol oxidation reactions |
Type |
A1 Journal article |
Year |
2020 |
Publication |
ACS Omega |
Abbreviated Journal ![sorted by Abbreviated Journal field, ascending order (up)](img/sort_asc.gif) |
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Volume |
5 |
Issue |
1 |
Pages |
791-798 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
Two Ti-SBA-15 catalysts are synthesized using techniques that should either deposit Ti atoms specifically at the SBA-15 surface or allow Ti-containing species to exist at both the surface and within the bulk of SBA-15. The materials have been characterized by Fourier transform infrared (FTIR), Raman and UV visible spectroscopies, transmission electron microscopy, scanning electron microscopy/energy-dispersive X-ray spectrometry microscopies, and N-2 physisorption experiments. They have been applied in the total oxidation of phenol under catalytic wet air oxidation (CWAO) conditions and using photo- and plasma promotion. The materials retain the structure of SBA-15 following the doping in both cases and Ti incorporation is confirmed. The nature of the incorporated Ti remains unclear-with evidence for anatase TiO2 (from Raman and UV vis analysis) and evidence for atomically dispersed Ti from FTIR. In terms of reactivity, the presence of Ti in the in situ-prepared catalyst improves reactivity in the photopromoted reaction (increasing conversion from 28 to 60%), while both Ti catalysts improve reactivity in the CWAO reaction (by 7% over the in situ catalyst and by 25% over the grafted material). The presence of Ti has no beneficial effect on conversion in the plasma-promoted reaction. Here, however, Ti does affect the nature of the oxidized intermediates formed during the total phenol oxidation. |
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 |
000507578300086 |
Publication Date |
2019-12-30 |
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 |
2470-1343 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.1 |
Times cited |
|
Open Access |
|
Notes |
; The KSA Ministry of Higher Education is acknowledged for providing G.A.'s studentship, and IRC funded the plasma work under grant ref: GOIPD/2017/1000. ; |
Approved |
Most recent IF: 4.1; 2020 IF: NA |
Call Number |
UA @ admin @ c:irua:166578 |
Serial |
6629 |
Permanent link to this record |
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Author |
Bafekry, A.; Shahrokhi, M.; Shafique, A.; Jappor, H.R.; Fadlallah, M.M.; Stampfl, C.; Ghergherehchi, M.; Mushtaq, M.; Feghhi, S.A.H.; Gogova, D. |
Title |
Semiconducting chalcogenide alloys based on the (Ge, Sn, Pb) (S, Se, Te) formula with outstanding properties : a first-principles calculation study |
Type |
A1 Journal article |
Year |
2021 |
Publication |
ACS Omega |
Abbreviated Journal ![sorted by Abbreviated Journal field, ascending order (up)](img/sort_asc.gif) |
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Volume |
6 |
Issue |
14 |
Pages |
9433-9441 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Very recently, a new class of the multicationic and -anionic entropy-stabilized chalcogenide alloys based on the (Ge, Sn, Pb) (S, Se, Te) formula has been successfully fabricated and characterized experimentally [Zihao Deng et al., Chem. Mater. 32, 6070 (2020)]. Motivated by the recent experiment, herein, we perform density functional theory-based first-principles calculations in order to investigate the structural, mechanical, electronic, optical, and thermoelectric properties. The calculations of the cohesive energy and elasticity parameters indicate that the alloy is stable. Also, the mechanical study shows that the alloy has a brittle nature. The GeSnPbSSeTe alloy is a semiconductor with a direct band gap of 0.4 eV (0.3 eV using spin-orbit coupling effect). The optical analysis illustrates that the first peak of Im(epsilon) for the GeSnPbSSeTe alloy along all polarization directions is located in the visible range of the spectrum which renders it a promising material for applications in optical and electronic devices. Interestingly, we find an optically anisotropic character of this system which is highly desirable for the design of polarization-sensitive photodetectors. We have accurately predicted the thermoelectric coefficients and have calculated a large power factor value of 3.7 x 10(11) W m(-1) K-2 s(-1) for p-type. The high p-type power factor is originated from the multiple valleys near the valence band maxima. The anisotropic results of the optical and transport properties are related to the specific tetragonal alloy unit cell. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000640649500012 |
Publication Date |
2021-03-30 |
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 |
2470-1343 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:178395 |
Serial |
7017 |
Permanent link to this record |
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Author |
Ehirim, T.J.; Ozoemena, O.C.; Mwonga, P.V.; Haruna, A.B.; Mofokeng, T.P.; De Wael, K.; Ozoemena, K.I. |
Title |
Onion-like carbons provide a favorable electrocatalytic platform for the sensitive detection of tramadol drug |
Type |
A1 Journal article |
Year |
2022 |
Publication |
ACS Omega |
Abbreviated Journal ![sorted by Abbreviated Journal field, ascending order (up)](img/sort_asc.gif) |
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Volume |
7 |
Issue |
51 |
Pages |
47892-47905 |
Keywords |
A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab) |
Abstract |
This work reports the first study on the possible application of nanodiamond-derived onion-like carbons (OLCs), in comparison with conductive carbon black (CB), as an electrode platform for the electrocatalytic detection of tramadol (an important drug of abuse). The physicochemical properties of OLCs and CB were determined using X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and thermogravimetric analysis (TGA). The OLC exhibits, among others, higher surface area, more surface defects, and higher thermal stability than CB. From the electrochemical analysis (interrogated using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy), it is shown that an OLC-modified glassy carbon electrode (GCE-OLC) allows faster electron transport and electrocatalysis toward tramadol compared to a GCE-CB. To establish the underlying science behind the high performance of the OLC, theoretical calculations (density functional theory (DFT) simulations) were conducted. DFT predicts that OLC allows for weaker surface binding of tramadol (Ead = -26.656 eV) and faster kinetic energy (K.E. = -155.815 Ha) than CB (Ead = -40.174 eV and -305.322 Ha). The GCE-OLC shows a linear calibration curve for tramadol over the range of similar to 55 to 392 mu M, with high sensitivity (0.0315 mu A/mu M) and low limit of detection (LoD) and quantification (LoQ) (3.8 and 12.7 mu M, respectively). The OLC-modified screen-printed electrode (SPE-OLC) was successfully applied for the sensitive detection of tramadol in real pharmaceutical formulations and human serum. The OLC-based electrochemical sensor promises to be useful for the sensitive and accurate detection of tramadol in clinics, quality control, and routine quantification of tramadol drugs in pharmaceutical formulations. |
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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 |
000903165200001 |
Publication Date |
2022-12-15 |
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 |
2470-1343 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:193391 |
Serial |
8908 |
Permanent link to this record |
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Author |
Grubova, I.Y.; Surmenev, R.A.; Neyts, E.C.; Koptyug, A.V.; Volkova, A.P.; Surmeneva, M.A. |
Title |
Combined first-principles and experimental study on the microstructure and mechanical characteristics of the multicomponent additive-manufactured Ti-35Nb-7Zr-5Ta alloy |
Type |
A1 Journal article |
Year |
2023 |
Publication |
ACS Omega |
Abbreviated Journal ![sorted by Abbreviated Journal field, ascending order (up)](img/sort_asc.gif) |
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Volume |
8 |
Issue |
30 |
Pages |
27519-27533 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
New & beta;-stabilizedTi-based alloys are highly promising forbone implants, thanks in part to their low elasticity. The natureof this elasticity, however, is as yet unknown. We here present combinedfirst-principles DFT calculations and experiments on the microstructure,structural stability, mechanical characteristics, and electronic structureto elucidate this origin. Our results suggest that the studied & beta;Ti-35Nb-7Zr-5Ta wt % (TNZT) alloy manufacturedby the electron-beam powder bed fusion (E-PBF) method has homogeneousmechanical properties (H = 2.01 & PLUSMN; 0.22 GPa and E = 69.48 & PLUSMN; 0.03 GPa) along the building direction,which is dictated by the crystallographic texture and microstructuremorphologies. The analysis of the structural and electronic properties,as the main factors dominating the chemical bonding mechanism, indicatesthat TNZT has a mixture of strong metallic and weak covalent bonding.Our calculations demonstrate that the softening in the Cauchy pressure(C & PRIME; = 98.00 GPa) and elastic constant C ̅ ( 44 ) = 23.84 GPa is the originof the low elasticity of TNZT. Moreover, the nature of this softeningphenomenon can be related to the weakness of the second and thirdneighbor bonds in comparison with the first neighbor bonds in theTNZT. Thus, the obtained results indicate that a carefully designedTNZT alloy can be an excellent candidate for the manufacturing oforthopedic internal fixation devices. In addition, the current findingscan be used as guidance not only for predicting the mechanical propertiesbut also the nature of elastic characteristics of the newly developedalloys with yet unknown properties. |
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 |
001031269000001 |
Publication Date |
2023-07-18 |
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 |
2470-1343 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.1 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 4.1; 2023 IF: NA |
Call Number |
UA @ admin @ c:irua:198313 |
Serial |
9011 |
Permanent link to this record |
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Author |
Grzelczak, M.; Sanchez-Iglesias, A.; Heidari, H.; Bals, S.; Pastoriza-Santos, I.; Perez-Juste, J.; Liz-Marzan, L.M. |
Title |
Silver Ions Direct Twin-Plane Formation during the Overgrowth of Single-Crystal Gold Nanoparticles |
Type |
A1 Journal article |
Year |
2016 |
Publication |
ACS Omega |
Abbreviated Journal ![sorted by Abbreviated Journal field, ascending order (up)](img/sort_asc.gif) |
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Volume |
1 |
Issue |
1 |
Pages |
177-181 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
It is commonly agreed that the crystalline structure of seeds dictates the crystallinity of final nanoparticles in a seeded-growth process. Although the formation of monocrystalline particles does require the use of single-crystal seeds, twin planes may stem from either single-or polycrystalline seeds. However, experimental control over twin-plane formation remains difficult to achieve synthetically. Here, we show that a careful interplay between kinetics and selective surface passivation offers a unique handle over the emergence of twin planes (in decahedra and triangles) during the growth over single-crystalline gold nanoparticles of quasi-spherical shape. Twinning can be suppressed under conditions of slow kinetics in the presence of silver ions, yielding single-crystalline particles with high-index facets. |
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 |
000391203300002 |
Publication Date |
2016-08-03 |
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 |
2470-1343;2470-1343; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
18 |
Open Access |
OpenAccess |
Notes |
; This work was supported by the Spanish Ministerio de Economia y Competitividad MINECO (grants: MAT2013-46101-R, MAT2013-49375-EXP, MAT2013-45168-R). Financial support is acknowledged by the European Research Council (ERC Advanced Grant # 267867, PLASMAQUO; ERC Starting Grant #335078-COLOURATOM). ; ecas_Sara |
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:140398 |
Serial |
4446 |
Permanent link to this record |