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Author |
Babynina, A.; Fedoruk, M.; Kuhler, P.; Meledin, A.; Doblinger, M.; Lohmueller, T. |
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Title |
Bending Gold Nanorods with Light |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Nano letters |
Abbreviated Journal |
Nano Lett |
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Volume |
16 |
Issue |
16 |
Pages |
6485-6490 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
V-shaped gold nanoantennas are the functional components of plasmonic metasurfaces, which are capable of manipulating light in unprecedented ways. Designing a metasurface requires the custom arrangement of individual antennas with controlled shape and orientation. Here, we show how highly crystalline gold nanorods in solution can be bend, one-by one, into a V-shaped geometry and printed to the surface of a solid support through a combination of plasmonic heating and optical force. Significantly, we demonstrate that both the bending angle and the orientation of each rod-antenna can be adjusted independent from each other by tuning the laser intensity and polarization. This approach is applicable for the patterning of V-shaped plasmonic antennas on almost any substrate, which holds great potential for the fabrication of ultrathin optical components and devices. |
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Language |
English |
Wos |
000385469800072 |
Publication Date |
2016-09-06 |
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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 |
1530-6984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.712 |
Times cited |
24 |
Open Access  |
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Notes |
PMID:27598653 We would also like to thank Prof. Jochen Feldmann and Bernhard Bohn for fruitful discussions. |
Approved |
Most recent IF: 12.712 |
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Call Number |
c:irua:135172 |
Serial |
4122 |
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Author |
Kirilenko, D.A.; Brunkov, P.N. |
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Title |
Measuring the height-to-height correlation function of corrugation in suspended graphene |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
165 |
Issue |
165 |
Pages |
1-7 |
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Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
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Abstract |
Nanocorrugation of 2D crystals is an important phenomenon since it affects their electronic and mechanical properties. The corrugation may have various sources; one of them is flexural phonons that, in particular, are responsible for the thermal conductivity of graphene. A study of corrugation of just the suspended graphene can reveal much of valuable information on the physics of this complicated phenomenon. At the same time, the suspended crystal nanorelief can hardly be measured directly because of high flexibility of the 2D crystal. Moreover, the relief portion related to rapid out-of-plane oscillations (flexural phonons) is also inaccessible by such measurements. Here we present a technique for measuring the Fourier components of the height-height correlation function H(q) of suspended graphene which includes the effect of flexural phonons. The technique is based on the analysis of electron diffraction patterns. The H(q) is measured in the range of wavevectors q approximately 0.4-4.5nm(-1). At the upper limit of this range H(q) does follow the T/kappaq(4) law. So, we measured the value of suspended graphene bending rigidity kappa=1.2+/-0.4eV at ambient temperature T approximately 300K. At intermediate wave vectors, H(q) follows a slightly weaker exponent than theoretically predicted q(-3.15) but is closer to the results of the molecular dynamics simulation. At low wave vectors, the dependence becomes even weaker, which may be a sign of influence of charge carriers on the dynamics of undulations longer than 10nm. The technique presented can be used for studying physics of flexural phonons in other 2D materials. |
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Address |
Ioffe Institute, Politekhnicheskaya ul. 26, 194021 St-Petersburg, Russia; ITMO University, Kronverksky pr. 49, 197101 St. Petersburg, Russia |
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Editor |
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Language |
English |
Wos |
000375946200001 |
Publication Date |
2016-03-28 |
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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 |
0304-3991 |
ISBN |
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Additional Links |
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Impact Factor |
2.843 |
Times cited |
3 |
Open Access |
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Notes |
D.K. thanks the RFBR (Grant no. 16-32-60165) for the partial support of this research. The work was carried out in part at the Joint Research Center “Material Science and Characterization in Advanced Technologies” (St-Petersburg, Russia) under the financial support from the Ministry of Education and Science of the Russian Federation (Agreement 14.621.21.0007, 04.12.2014, id RFMEFI62114X0007, the use of the Jeol JEM-2100F microscope) and at EMAT, Universiteit Antwerpen (Antwerpen, Belgium), (the use of the FEI Tecnai G2 microscope). |
Approved |
Most recent IF: 2.843 |
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Call Number |
EMAT @ emat @ |
Serial |
4124 |
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Author |
Sobrino Fernandez, M.M.; Neek-Amal, M.; Peeters, F.M. |
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Title |
AA-stacked bilayer square ice between graphene layers |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
92 |
Issue |
92 |
Pages |
245428 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Water confined between two graphene layers with a separation of a few A forms a layered two-dimensional ice structure. Using large scale molecular dynamics simulations with the adoptable ReaxFF interatomic potential we found that flat monolayer ice with a rhombic-square structure nucleates between the graphene layers which is nonpolar and nonferroelectric. We provide different energetic considerations and H-bonding results that explain the interlayer and intralayer properties of two-dimensional ice. The controversial AA stacking found experimentally [Algara-Siller et al., Nature (London) 519, 443 (2015)] is consistent with our minimum-energy crystal structure of bilayer ice. Furthermore, we predict that an odd number of layers of ice has the same lattice structure as monolayer ice, while an even number of ice layers exhibits the square ice AA stacking of bilayer ice. |
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Place of Publication |
Lancaster, Pa |
Editor |
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Wos |
000366731800004 |
Publication Date |
2015-12-17 |
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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 |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
40 |
Open Access |
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Notes |
; This work was supported by the ESF-Eurographene project CONGRAN, and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
c:irua:130203 |
Serial |
4127 |
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Author |
Gonnissen, J.; De Backer, A.; den Dekker, A.J.; Sijbers, J.; Van Aert, S. |
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Title |
Detecting and locating light atoms from high-resolution STEM images: The quest for a single optimal design |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
170 |
Issue |
170 |
Pages |
128-138 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
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Abstract |
In the present paper, the optimal detector design is investigated for both detecting and locating light atoms from high resolution scanning transmission electron microscopy (HR STEM) images. The principles of detection theory are used to quantify the probability of error for the detection of light atoms from HR STEM images. To determine the optimal experiment design for locating light atoms, use is made of the so-called Cramer-Rao Lower Bound (CRLB). It is investigated if a single optimal design can be found for both the detection and location problem of light atoms. Furthermore, the incoming electron dose is optimised for both research goals and it is shown that picometre range precision is feasible for the estimation of the atom positions when using an appropriate incoming electron dose under the optimal detector settings to detect light atoms. |
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Address |
Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium. Electronic address: sandra.vanaert@uantwerpen.be |
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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 |
English |
Wos |
000386925500014 |
Publication Date |
2016-07-26 |
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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 |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.843 |
Times cited |
6 |
Open Access |
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Notes |
The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0368.15, G.0369.15 and G.0374.13) and a postdoctoral research grant to A. De Backer. The research leading to these results has also received funding from the European Union Seventh Framework Programme [FP7/2007-2013] under Grant agreement no. 312483 (ESTEEM2). The authors would also like to thank A. Rosenauer for providing access to the STEMsim software and Gerardo T. Martinez for fruitful discussions.; esteem2_jra2 |
Approved |
Most recent IF: 2.843 |
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Call Number |
c:irua:135337 c:irua:135337 |
Serial |
4128 |
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Author |
Gonnissen, J.; Batuk, D.; Nataf, G.F.; Jones, L.; Abakumov, A.M.; Van Aert, S.; Schryvers, D.; Salje, E.K.H. |
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Title |
Direct Observation of Ferroelectric Domain Walls in LiNbO3: Wall-Meanders, Kinks, and Local Electric Charges |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Advanced functional materials |
Abbreviated Journal |
Adv Funct Mater |
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Volume |
26 |
Issue |
26 |
Pages |
7599-7604 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Direct observations of the ferroelectric domain boundaries in LiNbO3 are performed using high-resolution high-angle annular dark field scanning transmission electron microscopy imaging, revealing a very narrow width of the domain wall between the 180° domains. The domain walls demonstrate local side-way meandering, which results in inclinations even when the overall wall orientation follows the ferroelectric polarization. These local meanders contain kinks with “head-to-head” and “tail-to-tail” dipolar configurations and are therefore locally charged. The charged meanders are confined to a few cation layers along the polarization direction and are separated by longer stretches of straight domain walls. |
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Corporate Author |
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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 |
000388166700006 |
Publication Date |
2016-09-16 |
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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 |
1616-301X |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
23 |
Open Access |
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Notes |
J.G. acknowledges the support from the Research Foundation Flanders (FWO, Belgium) through various project fundings (G.0368.15N, G.0369.15N, and G.0374.13N), as well as the financial support from the European Union Seventh Framework Program (FP7/2007–2013) under Grant agreement no. 312483 (ESTEEM2). The authors thank J. Hadermann for useful suggestions on the interpretation of the HAADFSTEM images. E.K.H.S. thanks the EPSRC (EP/K009702/1) and the Leverhulme Trust (EM-2016-004) for support. G.F.N. thanks the National Research Fund, Luxembourg (FNR/P12/4853155/Kreisel) for support.; esteem2_jra2 |
Approved |
Most recent IF: 12.124 |
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Call Number |
c:irua:135336 c:irua:135336 |
Serial |
4129 |
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Author |
Spadaro, M.C.; Luches, P.; Bertoni, G.; Grillo, V.; Turner, S.; Van Tendeloo, G.; Valeri, S.; D'Addato, S. |
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Title |
Influence of defect distribution on the reducibility of CeO2-x nanoparticles |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
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Volume |
27 |
Issue |
27 |
Pages |
425705 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Ceria nanoparticles (NPs) are fundamental in heterogeneous catalysis because of their ability to store or release oxygen depending on the ambient conditions. Their oxygen storage capacity is strictly related to the exposed planes, crystallinity, density and distribution of defects. In this work a study of ceria NPs produced with a ligand-free, physical synthesis method is presented. The NP films were grown by a magnetron sputtering based gas aggregation source and studied by high resolution- and scanning-transmission electron microscopy and x-ray photoelectron spectroscopy. In particular, the influence of the oxidation procedure on the NP reducibility has been investigated. The different reducibility has been correlated to the exposed planes, crystallinity and density and distribution of structural defects. The results obtained in this work represent a basis to obtain cerium oxide NP with desired oxygen transport properties. |
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Address |
Dipartimento FIM, Universita di Modena e Reggio Emilia, via G. Campi 213/a, I-41125 Modena, Italy. CNR-NANO, via G. Campi 213/a, I-41125 Modena, Italy |
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Place of Publication |
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Language |
English |
Wos |
000385483900004 |
Publication Date |
2016-09-15 |
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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 |
0957-4484 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.44 |
Times cited |
11 |
Open Access |
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Notes |
The authors gratefully acknowledge financial support by the Italian MIUR under grant FIRB RBAP115AYN (Oxides at the nanoscale: multifunctionality and applications). The activity is performed within the COST Action CM1104 'Reducible oxide chemistry, structure and functions'. The research leading to these results has received funding also from the European Union Seventh Framework Programme under Grant Agreement 312483—ESTEEM2 (Integrated Infrastructure Initiative–I3).; esteem2_ta |
Approved |
Most recent IF: 3.44 |
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Call Number |
EMAT @ emat @ c:irua:135424 |
Serial |
4130 |
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Author |
Wang, W.; Bogaerts, A. |
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Title |
Effective ionisation coefficients and critical breakdown electric field of CO2at elevated temperature: effect of excited states and ion kinetics |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Plasma sources science and technology |
Abbreviated Journal |
Plasma Sources Sci T |
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Volume |
25 |
Issue |
25 |
Pages |
055025 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Electrical breakdown by the application of an electric field occurs more easily in hot gases than in cold gases because of the extra electron-species interactions that occur as a result of dissociation, ionization and excitation at higher temperature. This paper discusses some overlooked physics and clarifies inaccuracies in the evaluation of the effective ionization coefficients and the critical reduced breakdown electric field of CO2 at elevated temperature, considering the influence of excited states and ion kinetics. The critical reduced breakdown electric field is obtained by balancing electron generation and loss mechanisms using the electron energy distribution function (EEDF) derived from the Boltzmann transport equation under the two-term approximation. The equilibrium compositions of the hot gas mixtures are determined based on Gibbs free energy minimization considering the ground states as well as vibrationally and electronically excited states as independent species, which follow a Boltzmann distribution with a fixed excitation temperature. The interaction cross sections between electrons and the excited species, not reported previously, are properly taken into account. Furthermore, the ion kinetics, including electron–ion recombination, associative electron detachment, charge transfer and ion conversion into stable negative ion clusters, are also considered. Our results indicate that the excited species lead to a greater population of high-energy electrons at higher gas temperature and this affects the Townsend rate coefficients (i.e. of electron impact ionization and attachment), but the critical reduced breakdown electric field strength of CO2 is only affected when also properly accounting for the ion kinetics. Indeed, the latter greatly influences the effective ionization coefficients and hence the critical reduced breakdown electric field at temperatures above 1500 K. The rapid increase of the dissociative electron attachment cross-section of molecular oxygen with rising vibrational quantum number leads to a larger electron loss rate and this enhances the critical reduced breakdown electric field strength in the temperature range where the concentration of molecular oxygen is relatively high. The results obtained in this work show reasonable agreement with experimental results from literature, and are important for the evaluation of the dielectric strength of CO2 in a highly reactive environment at elevated temperature. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000385494000006 |
Publication Date |
2016-09-22 |
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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 |
1361-6595 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.302 |
Times cited |
3 |
Open Access |
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Notes |
Skłodowska-Curie Individual Fellowship ‘GlidArc’ within Horizon2020 (Grant No.657304) and the FWO project (grant G.0383.16N). The computational work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA. |
Approved |
Most recent IF: 3.302 |
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Call Number |
PLASMANT @ plasmant @ c:irua:135515 |
Serial |
4281 |
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Author |
De Backer, A.; van den Bos, K.H.W.; Van den Broek, W.; Sijbers, J.; Van Aert, S. |
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Title |
StatSTEM: An efficient approach for accurate and precise model-based quantification of atomic resolution electron microscopy images |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
171 |
Issue |
171 |
Pages |
104-116 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
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Abstract |
An efficient model-based estimation algorithm is introduced to quantify the atomic column positions and intensities from atomic resolution (scanning) transmission electron microscopy ((S)TEM) images. This algorithm uses the least squares estimator on image segments containing individual columns fully accounting for overlap between neighbouring columns, enabling the analysis of a large field of view. For this algorithm, the accuracy and precision with which measurements for the atomic column positions and scattering cross-sections from annular dark field (ADF) STEM images can be estimated, has been investigated. The highest attainable precision is reached even for low dose images. Furthermore, the advantages of the model-based approach taking into account overlap between neighbouring columns are highlighted. This is done for the estimation of the distance between two neighbouring columns as a function of their distance and for the estimation of the scattering cross-section which is compared to the integrated intensity from a Voronoi cell. To provide end-users this well-established quantification method, a user friendly program, StatSTEM, is developed which is freely available under a GNU public license. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000389106200014 |
Publication Date |
2016-09-09 |
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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 |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.843 |
Times cited |
43 |
Open Access |
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Notes |
The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0393.11, G.0064.10 and G.0374.13), a Ph.D. research grant to K.H.W. van den Bos, and a postdoctoral research grant to A. De Backer. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2 (Integrated Infrastructure Initiative-I3). A. Rosenauer is acknowledged for providing the STEMsim program.; esteem2_jra2 |
Approved |
Most recent IF: 2.843 |
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Call Number |
EMAT @ emat @ c:irua:135516 |
Serial |
4280 |
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Author |
Ozaydin, H.D.; Sahin, H.; Kang, J.; Peeters, F.M.; Senger, R.T. |
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Title |
Electronic and magnetic properties of 1T-TiSe2 nanoribbons |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
2D materials |
Abbreviated Journal |
2D Mater |
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Volume |
2 |
Issue |
2 |
Pages |
044002 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Motivated by the recent synthesis of single layer TiSe2, we used state-of-the-art density functional theory calculations, to investigate the structural and electronic properties of zigzag and armchair-edged nanoribbons (NRs) of this material. Our analysis reveals that, differing from ribbons of other ultra-thin materials such as graphene, TiSe2 NRs have some distinctive properties. The electronic band gap of the NRs decreases exponentially with the width and vanishes for ribbons wider than 20 angstrom. For ultranarrow zigzag-edged NRs we find odd-even oscillations in the band gap width, although their band structures show similar features. Moreover, our detailed magnetic-ground-state analysis reveals that zigzag and armchair edged ribbons have non-magnetic ground states. Passivating the dangling bonds with hydrogen at the edges of the structures influences the band dispersion. Our results shed light on the characteristic properties of T phase NRs of similar crystal structures. |
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Corporate Author |
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Thesis |
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Publisher |
IOP Publishing |
Place of Publication |
Bristol |
Editor |
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Language |
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Wos |
000368936600005 |
Publication Date |
2015-10-13 |
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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 |
2053-1583 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.937 |
Times cited |
20 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAK-BIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). HS is supported by a FWO Pegasus Long Marie Curie Fellowship. JK is supported by a FWO Pegasus Short Marie Curie Fellowship. HDO, HS and RTS acknowledge the support from TUBITAK through project 114F397. ; |
Approved |
Most recent IF: 6.937; 2015 IF: NA |
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Call Number |
UA @ lucian @ c:irua:131602 |
Serial |
4169 |
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Author |
Croitoru, M.D.; Shanenko, A.A.; Vagov, A.; Vasenko, A.S.; Milošević, M.V.; Axt, V.M.; Peeters, F.M. |
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Title |
Influence of disorder on superconducting correlations in nanoparticles |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Journal of superconductivity and novel magnetism |
Abbreviated Journal |
J Supercond Nov Magn |
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| |
Volume |
29 |
Issue |
29 |
Pages |
605-609 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate how the interplay of quantum confinement and level broadening caused by disorder affects superconducting correlations in ultra-small metallic grains. We use the electron-phonon interaction-induced electron mass renormalization and the reduced static-path approximation of the BCS formalism to calculate the critical temperature as a function of the grain size. We show how the strong electron-impurity scattering additionally smears the peak structure in the electronic density of states of a metallic grain and imposes additional limits on the critical temperature under strong quantum confinement. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000371089500013 |
Publication Date |
2016-01-08 |
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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 |
1557-1939 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.18 |
Times cited |
7 |
Open Access |
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Notes |
; This work was supported by the Belgian Science Policy (BELSPO Back to Belgium Grant), the Flemish Science Foundation (FWO-Vl), the Methusalem Foundation of the Flemish Government, TOPBOF-UA, and the bilateral project CNPq-FWO-Vl. ; |
Approved |
Most recent IF: 1.18 |
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| |
Call Number |
UA @ lucian @ c:irua:132286 |
Serial |
4195 |
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| Permanent link to this record |
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Author |
Lobato, I.; Van Dyck, D. |
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Title |
MULTEM : a new multislice program to perform accurate and fast electron diffraction and imaging simulations using graphics processing units with CUDA |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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| |
Volume |
156 |
Issue |
156 |
Pages |
9-17 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
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Abstract |
The main features and the GPU implementation of the MULTEM program are presented and described. This new program performs accurate and fast multislice simulations by including higher order expansion of the multislice solution of the high energy Schrodinger equation, the correct subslicing of the three-dimensional potential and top-bottom surfaces. The program implements different kinds of simulation for CTEM, STEM, ED, PED, CBED, ADF-TEM and ABF-HC with proper treatment of the spatial and temporal incoherences. The multislice approach described here treats the specimen as amorphous material which allows a straightforward implementation of the frozen phonon approximation. The generalized transmission function for each slice is calculated when is needed and then discarded. This allows us to perform large simulations that can include millions of atoms and keep the computer memory requirements to a reasonable level. (C) 2015 Elsevier B.V. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000361001800003 |
Publication Date |
2015-04-28 |
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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 |
0304-3991; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.843 |
Times cited |
32 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.843; 2015 IF: 2.436 |
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Call Number |
UA @ lucian @ c:irua:127848 |
Serial |
4209 |
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| Permanent link to this record |
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Author |
Neek-Amal, M; Peeters, F.M. |
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Title |
Partially hydrogenated and fluorinated graphene : structure, roughness, and negative thermal expansion |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
92 |
Issue |
92 |
Pages |
155430 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The structural properties of partially hydrogenated and fluorinated graphene with different percentages of H/F atoms are investigated using molecular dynamics simulations based on reactive force field (ReaxFF) potentials. We found that the roughness of graphene varies with the percentage (p) of H or F and in both cases is maximal around p = 50%. Similar results were obtained for partially oxidized graphene. The two-dimensional area size of partially fluorinated and hydrogenated graphene exhibits a local minimum around p = 35% coverage. The lattice thermal contraction in partially functionalized graphene is found to be one order of magnitude larger than that of fully covered graphene. We also show that the armchair structure for graphene oxide (similar to the structure of fully hydrogenated and fluorinated graphene) is unstable. Our results show that the structure of partially functionalized graphene changes nontrivially with the C : H and C : F ratio as well as with temperature. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000363294100005 |
Publication Date |
2015-10-23 |
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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 |
1098-0121; 1550-235x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation of the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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Call Number |
UA @ lucian @ c:irua:129448 |
Serial |
4221 |
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| Permanent link to this record |
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Author |
Bretos, I.; Schneller, T.; Falter, M.; Baecker, M.; Hollmann, E.; Woerdenweber, R.; Molina-Luna, L.; Van Tendeloo, G.; Eibl, O. |
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Title |
Solution-derived YBa2Cu3O7-\delta (YBCO) superconducting films with BaZrO3 (BZO) nanodots based on reverse micelle stabilized nanoparticles |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Journal of materials chemistry C : materials for optical and electronic devices |
Abbreviated Journal |
J Mater Chem C |
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| |
Volume |
3 |
Issue |
3 |
Pages |
3971-3979 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Superconducting YBa2Cu3O7-delta (YBCO) films with artificial BaZrO3 (BZO) nanodots were prepared using a chemical solution deposition method involving hybrid solutions composed of trifluoroacetate-based YBCO precursors and reverse micelle stabilized BZO nanoparticle dispersions. Microemulsion-mediated synthesis was used to obtain nano-sized (similar to 12 nm) and mono-dispersed BZO nanoparticles that preserve their features once introduced into the YBCO solution, as revealed by dynamic light scattering. Phase pure, epitaxial YBCO films with randomly oriented BZO nanodots distributed over their whole microstructure were grown from the hybrid solutions on (100) LaAlO3 substrates. The morphology of the YBCO-BZO nanocomposite films was strongly influenced by the amount of nanoparticles incorporated into the system, with contents ranging from 5 to 40 mol%. Scanning electron microscopy showed a high density of isolated second-phase defects consisting of BZO nanodots in the nanocomposite film with 10 mol% of BZO. Furthermore, a direct observation and quantitative analysis of lattice defects in the form of interfacial edge dislocations directly induced by the BZO nanodots was evidenced by transmission electron microscopy. The superconducting properties (77 K) of the YBCO films improved considerably by the presence of such nanodots, which seem to enhance the morphology of the sample and therefore the intergranular critical properties. The incorporation of preformed second-phase defects (here, BZO) during the growth of the superconducting phase is the main innovation of this novel approach for the all-solution based low-cost fabrication of long-length coated conductors. |
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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 |
000352870400018 |
Publication Date |
2015-03-06 |
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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 |
2050-7526; 2050-7534 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
5.256 |
Times cited |
19 |
Open Access |
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Notes |
This work was supported by the German Federal Ministry of Economics and Technology (BMWi) contract no. 0327433A (project ELSA). L. Molina-Luna and G. Van Tendeloo acknowledge funding from the European Research Council (ERC grant no. 24691-COUNTATOMS). The authors gratefully acknowledge J. Dornseiffer for the support with preparation of the microemulsions for the BZO nanoparticles; G. Wasse for the SEM images; and T. Po¨ssinger for the preparation of the artwork. Eurotape |
Approved |
Most recent IF: 5.256; 2015 IF: 4.696 |
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Call Number |
UA @ lucian @ c:irua:132575 |
Serial |
4245 |
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Author |
Lander, L.; Rousse, G.; Abakumov, A.M.; Sougrati, M.; Van Tendeloo, G.; Tarascon, J.-M. |
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Title |
Structural, electrochemical and magnetic properties of a novel KFeSO4F polymorph |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Journal of materials chemistry A : materials for energy and sustainability |
Abbreviated Journal |
J Mater Chem A |
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Volume |
3 |
Issue |
3 |
Pages |
19754-19764 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
In the quest for sustainable and low-cost positive electrode materials for Li-ion batteries, we discovered, as reported herein, a new low temperature polymorph of KFeSO4F. Contrary to the high temperature phase crystallizing in a KTiOPO4-like structure, this new phase adopts a complex layer-like structure built on FeO4F2 octahedra and SO4 tetrahedra, with potassium cations located in between the layers, as solved using neutron and synchrotron diffraction experiments coupled with electron diffraction. The detailed analysis of the structure reveals an alternation of edge-and corner-shared FeO4F2 octahedra leading to a large monoclinic cell of 1771.774(7) angstrom(3). The potassium atoms are mobile within the structure as deduced by ionic conductivity measurements and confirmed by the bond valence energy landscape approach thus enabling a partial electrochemical removal of K+ and uptake of Li+ at an average potential of 3.7 V vs. Li+/Li-0. Finally, neutron diffraction experiments coupled with SQUID measurements reveal a long range antiferromagnetic ordering of the Fe2+ magnetic moments below 22 K with a possible magnetoelectric behavior. |
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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 |
000362041300018 |
Publication Date |
2015-08-17 |
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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 |
2050-7488; 2050-7496 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.867 |
Times cited |
11 |
Open Access |
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Notes |
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Approved |
Most recent IF: 8.867; 2015 IF: 7.443 |
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Call Number |
UA @ lucian @ c:irua:132566 |
Serial |
4253 |
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| Permanent link to this record |
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Author |
Mefford, J.T.; Rong, X.; Abakumov, A.M.; Hardin, W.G.; Dai, S.; Kolpak, A.M.; Johnston, K.P.; Stevenson, K.J. |
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Title |
Water electrolysis on La1-xSrxCoO3-\delta perovskite electrocatalysts |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
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Volume |
7 |
Issue |
7 |
Pages |
11053 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Perovskite oxides are attractive candidates as catalysts for the electrolysis of water in alkaline energy storage and conversion systems. However, the rational design of active catalysts has been hampered by the lack of understanding of the mechanism of water electrolysis on perovskite surfaces. Key parameters that have been overlooked include the role of oxygen vacancies, B-O bond covalency, and redox activity of lattice oxygen species. Here we present a series of cobaltite perovskites where the covalency of the Co-O bond and the concentration of oxygen vacancies are controlled through Sr2+ substitution into La1 – xSrxCoO3 – delta. We attempt to rationalize the high activities of La1 – xSrxCoO3 – delta through the electronic structure and participation of lattice oxygen in the mechanism of water electrolysis as revealed through ab initio modelling. Using this approach, we report a material, SrCoO2.7, with a high, room temperature-specific activity and mass activity towards alkaline water electrolysis. |
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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 |
000372721700001 |
Publication Date |
2016-03-23 |
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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 |
2041-1723 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
278 |
Open Access |
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Notes |
Financial support for this work was provided by the R.A. Welch Foundation (grants F-1529 and F-1319). X.R. and A.M.K. acknowledge support from the Skoltech-MIT Center for Electrochemical Energy Storage. Computations were performed using computational resources from XSEDE and NERSC. S.D. was supported as part of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences. We thank D.W. Redman for help with the RHE measurements. |
Approved |
Most recent IF: 12.124 |
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Call Number |
UA @ lucian @ c:irua:133242 |
Serial |
4276 |
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Author |
Bogaerts, A. |
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Title |
Glow discharge optical spectroscopy and mass spectrometry |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
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Keywords |
A1 Journal article; PLASMANT |
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Abstract |
Atomic Spectroscopy Optical (atomic absorption spectroscopy, AAS; atomic emission spectroscopy, AES; atomic fluorescence spectroscopy, AFS; and optogalvanic spectroscopy) and mass spectrometric (magnetic sector, quadrupole mass analyzer, QMA; quadrupole ion trap, QIT; Fourier transform ion cyclotron resonance, FTICR; and time-of-flight, TOF) instrumentation are well suited for coupling to the glow discharge (GD). The GD is a relatively simple device. A potential gradient (500–1500 V) is applied between an anode and a cathode. In most cases, the sample is also the cathode. A noble gas (mostly Ar) is introduced into the discharge region before power initiation. When a potential is applied, electrons are accelerated toward the anode. As these electrons accelerate, they collide with gas atoms. A fraction of these collisions are of sufficient energy to remove an electron from a support gas atom, forming an ion. These ions are, in turn, accelerated toward the cathode. These ions impinge on the surface of the cathode, sputtering sample atoms from the surface. Sputtered atoms that do not redeposit on the surface diffuse into the excitation/ionization regions of the plasma where they can undergo excitation and/or ionization via a number of collisional processes, and the photons or ions created in this way can be detected with optical emission spectroscopy or mass spectrometry. GD sources offer a number of distinct advantages that make them well suited for specific types of analyses. These sources afford direct analysis of solid samples, thus minimizing the sample preparation required for analysis. The nature of the plasma also provides mutually exclusive atomization and excitation processes that help to minimize the matrix effects that plague so many other elemental techniques. In recent years, there is also increasing interest for using GD sources for liquid and gas analyses. In this article, first, the principles of operation of the GD plasma are reviewed, with an emphasis on how those principles relate to optical spectroscopy and mass spectrometry. Basic applications of the GD techniques are considered next. These include bulk analysis, surface analysis, and the analysis of solution and gaseous samples. The requirements necessary to obtain optical information are addressed following the analytical applications. This article focuses on the instrumentation needed to make optical measurements using the GD as an atomization/excitation source. Finally, mass spectrometric instrumentation and interfaces are addressed as they pertain to the use of a GD plasma as an ion source. GD sources provide analytically useful gas-phase species from solid samples. These sources can be interfaced with a variety of spectroscopic and spectrometric instruments for both quantitative and qualitative analyses. |
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Place of Publication |
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Editor |
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Wos |
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Publication Date |
2006-09-11 |
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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 |
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ISBN |
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Additional Links |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
PLASMANT @ plasmant @ |
Serial |
4282 |
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Author |
Attri, P.; Yusupov, M.; Park, J.H.; Lingamdinne, L.P.; Koduru, J.R.; Shiratani, M.; Choi, E.H.; Bogaerts, A. |
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Title |
Mechanism and comparison of needle-type non-thermal direct and indirect atmospheric pressure plasma jets on the degradation of dyes |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Scientific reports |
Abbreviated Journal |
Sci Rep-Uk |
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Volume |
6 |
Issue |
6 |
Pages |
34419 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Purified water supply for human use, agriculture and industry is the major global priority nowadays. The advanced oxidation process based on atmospheric pressure non-thermal plasma (NTP) has been used for purification of wastewater, although the underlying mechanisms of degradation of organic pollutants are still unknown. In this study we employ two needle-type atmospheric pressure non-thermal plasma jets, i.e., indirect (ID-APPJ) and direct (D-APPJ) jets operating at Ar feed gas, for the treatment of methylene blue, methyl orange and congo red dyes, for two different times (i.e., 20 min and 30 min). Specifically, we study the decolorization/degradation of all three dyes using the above mentioned plasma sources, by means of UV-Vis spectroscopy, HPLC and a density meter. We also employ mass spectroscopy to verify whether only decolorization or also degradation takes place after treatment of the dyes by the NTP jets. Additionally, we analyze the interaction of OH radicals with all three dyes using reactive molecular dynamics simulations, based on the density functional-tight binding method. This investigation represents the first report on the degradation of these three different dyes by two types of NTP setups, analyzed by various methods, and based on both experimental and computational studies. |
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Address |
Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium |
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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 |
English |
Wos |
000385172300001 |
Publication Date |
2016-10-06 |
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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 |
2045-2322 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.259 |
Times cited |
23 |
Open Access |
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Notes |
We gratefully acknowledge the grant received from the SRC program of the National Research Foundation of Korea (NRF), funded by the Korean Government (MEST) (No. 20100029418). PA is thankful to FY 2015 Japan Society for the Promotion of Science (JSPS) invitation fellowship. This work was partly supported by MEXT KAKENHI Grant Number 24108009 and JSPS KAKENHI Grant Number JP16H03895. M. Y. gratefully acknowledges financial support from the Research Foundation – Flanders (FWO), grant number 1200216N. The computational work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA. |
Approved |
Most recent IF: 4.259 |
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Call Number |
PLASMANT @ plasmant @ c:irua:135847 |
Serial |
4283 |
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Author |
Wang, W.; Berthelot, A.; Kolev, S.; Tu, X.; Bogaerts, A. |
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Title |
CO2 conversion in a gliding arc plasma: 1D cylindrical discharge model |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Plasma sources science and technology |
Abbreviated Journal |
Plasma Sources Sci T |
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Volume |
25 |
Issue |
25 |
Pages |
065012 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
CO 2 conversion by a gliding arc plasma is gaining increasing interest, but the underlying mechanisms for an energy-efficient process are still far from understood. Indeed, the chemical complexity of the non-equilibrium plasma poses a challenge for plasma modeling due to the huge computational load. In this paper, a one-dimensional (1D) gliding arc model is developed in a cylindrical frame, with a detailed non-equilibrium CO 2 plasma chemistry set, including the CO 2 vibrational kinetics up to the dissociation limit. The model solves a set of time- dependent continuity equations based on the chemical reactions, as well as the electron energy balance equation, and it assumes quasi-neutrality in the plasma. The loss of plasma species and heat due to convection by the transverse gas flow is accounted for by using a characteristic frequency of convective cooling, which depends on the gliding arc radius, the relative velocity of the gas flow with respect to the arc and on the arc elongation rate. The calculated values for plasma density and plasma temperature within this work are comparable with experimental data on gliding arc plasma reactors in the literature. Our calculation results indicate that excitation to the vibrational levels promotes efficient dissociation in the gliding arc, and this is consistent with experimental investigations of the gliding arc based CO 2 conversion in the literature. Additionally, the dissociation of CO 2 through collisions with O atoms has the largest contribution to CO 2 splitting under the conditions studied. In addition to the above results, we also demonstrate that lumping the CO 2 vibrational states can bring a significant reduction of the computational load. The latter opens up the way for 2D or 3D models with an accurate description of the CO 2 vibrational kinetics. |
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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 |
000386605100002 |
Publication Date |
2016-10-18 |
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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 |
1361-6595 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.302 |
Times cited |
3 |
Open Access |
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Notes |
This research was supported by the European Marie Skłodowska-Curie Individual Fellowship ‘GlidArc’ within Horizon2020 (Grant No. 657304) and by the FWO project (grant G.0383.16N). The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UAntwerpen. |
Approved |
Most recent IF: 3.302 |
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Call Number |
PLASMANT @ plasmant @ c:irua:135990 |
Serial |
4286 |
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Author |
Perez, A.J.; Batuk, D.; Saubanère, M.; Rousse, G.; Foix, D.; Mc Calla, E.; J. Berg, E.; Dugas, R.; van den Bos, K. H. W.; Doublet, M.-L.; Gonbeau, D.; Abakumov, A.M.; Van Tendeloo, G.; Tarascon, J.-M. |
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Title |
Strong oxygen participation in the redox governing the structural and electrochemical properties of Na-rich layered oxide Na2IrO3 |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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| |
Volume |
28 |
Issue |
28 |
Pages |
8278-8288 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The recent revival of the Na-ion battery concept has prompted intense activities in the search for new Na-based layered oxide positive electrodes. The largest capacity to date was obtained for a Na-deficient layered oxide that relies on cationic redox processes only. To go beyond this limit, we decided to chemically manipulate these Na-based layered compounds in a way to trigger the participation of the anionic network. We herein report the electrochemical properties of a Na-rich phase Na2IrO3, which can reversibly cycle 1.5 Na+ per formula unit while not suffering from oxygen release nor cationic migrations. Such large capacities, as deduced by complementary XPS, X-ray/neutron diffraction and transmission electron microscopy measurements, arise from cumulative cationic and anionic redox processes occurring simultaneously at potentials as low as 3.0 V. The inability to remove more than 1.5 Na+ is rooted in the formation of an O1-type phase having highly stabilized Na sites as confirmed by DFT calculations, which could rationalize as well the competing metal/oxygen redox processes in Na2IrO3. This work will help to define the most fertile directions in the search for novel high energy Na-rich materials based on more sustainable elements than Ir. |
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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 |
000388914500021 |
Publication Date |
2016-10-17 |
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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 |
0897-4756 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
45 |
Open Access |
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Notes |
The authors thank Montse Casas-Cabanas and Marine Reynaud for discussions about the FAULTS program, Sandra Van Aert for her great help in guiding us towards the use of the statistical parameter estimation method for establishing the O-O histogram, and Thomas Hansen and Vladimir Pomjakushin for their precious help in neutron diffraction experiments. This work is based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institute, Villigen, Switzerland, and at Institut Laue Langevin, Grenoble, France. Use of the 11-BM mail service of the APS at Argonne National Laboratory was supported by the U.S. department of Energy under contract No. DE-AC02-06CH11357 and is greatly acknowledged. |
Approved |
Most recent IF: 9.466 |
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Call Number |
EMAT @ emat @ c:irua:135994 |
Serial |
4287 |
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| Permanent link to this record |
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Author |
van den Bos, K.H.W.; Krause, F.F.; Béché, A.; Verbeeck, J.; Rosenauer, A.; Van Aert, S. |
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Title |
Locating light and heavy atomic column positions with picometer precision using ISTEM |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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| |
Volume |
172 |
Issue |
172 |
Pages |
75-81 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Recently, imaging scanning transmission electron microscopy (ISTEM) has been proposed as a promising new technique combining the advantages of conventional TEM (CTEM) and STEM [1]. The ability to visualize light and heavy elements together makes it a particularly interesting new, spatially incoherent imaging mode. Here, we evaluate this technique in term of precision with which atomic column locations can be measured. By using statistical parameter estimation theory, we will show that these locations can be accurately measured with a precision in the picometer range. Furthermore, a quantitative comparison is made with HAADF STEM imaging to investigate the advantages of ISTEM. |
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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 |
000390600200009 |
Publication Date |
2016-10-09 |
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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 |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.843 |
Times cited |
8 |
Open Access |
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Notes |
The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0374.13N, G.0368.15N, G.0369.15N), and by a Ph.D. grant to K.H.W. van den Bos. The research leading to these results has received funding from the Deutsche Forschungsgemeinschaft under Contract No. RO 2057/4-2 and the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2. We thank Prof. G. Koster from the University of Twente for kindly providing us with the PbTiO3 test sample. |
Approved |
Most recent IF: 2.843 |
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Call Number |
EMAT @ emat @ c:irua:136109UA @ admin @ c:irua:136109 |
Serial |
4288 |
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| Permanent link to this record |
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Author |
Aghaei, M.; Lindner, H.; Bogaerts, A. |
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Title |
Ion Clouds in the Inductively Coupled Plasma Torch: A Closer Look through Computations |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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| |
Volume |
88 |
Issue |
88 |
Pages |
8005-8018 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
We have computationally investigated the introduction of copper elemental particles in an inductively coupled plasma torch connected to a sampling cone, including for the first time the ionization of the sample. The sample is inserted as liquid particles, which are followed inside the entire torch, i.e., from the injector inlet up to the ionization and reaching the sampler. The spatial position of the ion clouds inside the torch as well as detailed information on the copper species fluxes at the position of the sampler orifice and the exhausts of the torch are provided. The effect of on- and off-axis injection is studied. We clearly show that the ion clouds of on-axis injected material are located closer to the sampler with less radial diffusion. This guarantees a higher transport efficiency through the sampler cone. Moreover, our model reveals the optimum ranges of applied power and flow rates, which ensure the proper position of ion clouds inside the torch, i.e., close enough to the sampler to increase the fraction that can enter the mass spectrometer and with minimum loss of material toward the exhausts as well as a sufficiently high plasma temperature for efficient ionization. |
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Address |
Research Group PLASMANT, Chemistry Department, University of Antwerp , Universiteitsplein 1, 2610 Antwerp, Belgium |
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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 |
English |
Wos |
000381654800020 |
Publication Date |
2016-07-26 |
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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 |
0003-2700 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
9 |
Open Access |
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Notes |
The authors gratefully acknowledge financial support from the Fonds voor Wetenschappelijk Onderzoek (FWO), Grant Number 6713. The computational work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the UA. |
Approved |
Most recent IF: 6.32 |
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Call Number |
PLASMANT @ plasmant @ c:irua:135644 |
Serial |
4293 |
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| Permanent link to this record |
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Author |
Huygh, S.; Bogaerts, A.; Neyts, E.C. |
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Title |
How Oxygen Vacancies Activate CO2 Dissociation on TiO2 Anatase (001) |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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| |
Volume |
120 |
Issue |
120 |
Pages |
21659-21669 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The adsorption, dissociation, and diffusion of CO2 on the anatase (001) surface was studied using DFT by means of the generalized gradient approximation using the Perdew−Burcke−Ernzerhof (PBE)-functional and applying corrections for long-range dispersion interactions. Different stable adsorption configurations were identified for the fully oxidized surface. The most stable adsorption configuration is the monodentated carbonate-like structure. Small energy barriers were identified for the conversion of a physisorbed to a chemisorbed configuration.
CO2 dissociation is found to be unfeasible on the stoichiometric surface. The introduction of oxygen vacancy defects gives rise to new highly stable adsorption configurations with a stronger activation of the C−O bonds. This leads to the possibility of exothermic dissociation of CO2 with barriers up to 22.2 kcal/mol,
corresponding to chemical lifetimes of less than 4 s at 300 K. These reactions cause a CO molecule to be formed, which will easily desorb, and the reduced surface to become oxidized. It is clear that oxygen vacancy defects play a key role in the catalytic activity of an anatase (001) surface. Oxygen vacancies play an important role in the dissociation of CO2 on the anatase (001) surface, and will play a significant role in complex problems, such as the catalytic conversion of CO2 to value-added chemicals. |
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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 |
000384626800055 |
Publication Date |
2016-09-02 |
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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 |
1932-7447 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
49 |
Open Access |
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Notes |
Stijn Huygh is funded as an aspirant of the Research Foundation Flanders (FWO, project number 11C0115N). This work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the UAntwerpen. |
Approved |
Most recent IF: 4.536 |
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Call Number |
PLASMANT @ plasmant @ c:irua:136164 |
Serial |
4291 |
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| Permanent link to this record |
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Author |
Schouteden, K.; Govaerts, K.; Debehets, J.; Thupakula, U.; Chen, T.; Li, Z.; Netsou, A.; Song, F.; Lamoen, D.; Van Haesendonck, C.; Partoens, B.; Park, K. |
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Title |
Annealing-Induced Bi Bilayer on Bi2Te3 Investigated via Quasi-Particle-Interference Mapping |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
ACS nano |
Abbreviated Journal |
Acs Nano |
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| |
Volume |
10 |
Issue |
10 |
Pages |
8778-8787 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
Topological insulators (TIs) are renowned for their exotic topological surface states (TSSs) that reside in the top atomic layers, and hence, detailed knowledge of the surface top atomic layers is of utmost importance. Here we present the remarkable morphology changes of Bi2Te3 surfaces, which have been freshly cleaved in air, upon subsequent systematic annealing in ultrahigh vacuum and the resulting effects on the local and area-averaging electronic properties of the surface states, which are investigated by combining scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and Auger electron spectroscopy (AES) experiments with density functional theory (DFT) calculations. Our findings demonstrate that the annealing induces the formation of a Bi bilayer atop the Bi2Te3 surface. The adlayer results in n-type doping, and the atomic defects act as scattering centers of the TSS electrons. We also investigated the annealing-induced Bi bilayer surface on Bi2Te3 via voltage-dependent quasi-particle-interference (QPI) mapping of the surface local density of states and via comparison with the calculated constant-energy contours and QPI patterns. We observed closed hexagonal patterns in the Fourier transform of real-space QPI maps with secondary outer spikes. DFT calculations attribute these complex QPI patterns to the appearance of a “second” cone due to the surface charge transfer between the Bi bilayer and the Bi2Te3. Annealing in ultrahigh vacuum offers a facile route for tuning of the topological properties and may yield similar results for other topological materials. |
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Address |
Department of Physics, Virginia Tech , Blacksburg, Virginia 24061, United States |
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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 |
English |
Wos |
000384399300073 |
Publication Date |
2016-09-02 |
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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 |
1936-0851 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.942 |
Times cited |
15 |
Open Access |
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Notes |
The research in Leuven and Antwerp was supported by the Research FoundationFlanders (FWO, Belgium). The research in Leuven received additional support from the Flemish Concerted Research Action Program (BOF KULeuven, Project GOA/14/007) and the KULeuven Project GOA “Fundamental Challenges in Semiconductor Research”. Z.L. acknowledges the support from the China Scholarship Council (2011624021) and from KU Leuven Internal Funds (PDM). K.S. and J.D. acknowledge additional support from the FWO. T.C. and F.S. acknowledge the financial support of the National Key Projects for Basic Research of China (Grants 2013CB922103 and 2011CB922103), the National NaturalScience Foundation of China (Grant s 91421109, 11134005,11522432, and 11274003), the Natural Science Foundation ofJiangsu Province (Grant BK20130054), and the FundamentalResearch Funds for the Central Universities. K.P. wassupported by the U.S. National Science Foundation (DMR-1206354) and San Diego Supercomputer Center (SDSC)Comet and Gordon (DMR060009N). |
Approved |
Most recent IF: 13.942 |
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Call Number |
EMAT @ emat @ c:irua:136269 |
Serial |
4294 |
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Author |
Meledin, A.; Turner, S.; Cayado, P.; Mundet, B.; Solano, E.; Ricart, S.; Ros, J.; Puig, T.; Obradors, X.; Van Tendeloo, G. |
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Title |
Unique nanostructural features in Fe, Mn-doped YBCO thin films |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
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| |
Volume |
29 |
Issue |
29 |
Pages |
125009 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
An attempt to grow a thin epitaxial composite film of YBa2Cu3O7−δ (YBCO) with spinel MnFe2O4 (MFO) nanoparticles on a LAO substrate using the CSD approach resulted in a decomposition of the spinel and various doping modes of YBCO with the Fe and Mn cations. These nanostructural effects lead to a lowering of T c and a slight J c increase in field. Using a combination of advanced transmission electron microscopy (TEM) techniques such as atomic resolution high-angle annular dark field scanning TEM, energy dispersive x-ray spectroscopy and electron energy-loss spectroscopy we have been able to decipher and characterize the effects of the Fe and Mn doping on the film architecture. The YBaCuFeO5 anion-deficient double perovskite phase was detected in the form of 3D inclusions as well as epitaxially grown lamellas within the YBCO matrix. These nano-inclusions play a positive role as pinning centers responsible for the J c/J sf (H) dependency smoothening at high magnetic fields in the YBCO-MFO films with respect to the pristine YBCO films. |
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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 |
000387680100001 |
Publication Date |
2016-10-31 |
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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 |
0953-2048 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.878 |
Times cited |
6 |
Open Access |
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Notes |
The authors gratefully acknowledge Prof. Dr. A. Abakumov and Dr. J. Gazquez for discussions and corrections. Part of this work was performed within the framework of the EUROTAPES project (FP7-NMP.2011.2.2-1 Grant no. 280432), funded by the European Union. ICMAB research was financed by the Ministry of Economy and Competitiveness, and FEDER funds under the projects MAT2011-28874-C02-01, MAT2014-51778-C2-1-R, ENE2014-56109-C3-3-R and Consolider Nanoselect CSD2007-00041, and by Generalitat de Catalunya (2009 SGR 770, 2015 SGR 753 and Xarmae). ICMAB acknowledges support from Severo Ochoa Program (MINECO, Grant SEV-2015-0496). |
Approved |
Most recent IF: 2.878 |
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Call Number |
EMAT @ emat @ c:irua:136444 |
Serial |
4295 |
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Author |
Kolchina, L. M.; Lyskov, N.V.; Kuznetsov, A.N.; Kazakov, S.M.; Galin, M.Z.; Meledin, A.; Abakumov, A.M.; Bredikhin, S.I.; Mazo, G.N.; Antipov, E.V. |
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Title |
Evaluation of Ce-doped Pr2CuO4for potential application as a cathode material for solid oxide fuel cells |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
RSC advances |
Abbreviated Journal |
Rsc Adv |
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Volume |
6 |
Issue |
6 |
Pages |
101029-101037 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Pr2−xCexCuO4 (x = 0.05; 0.1; 0.15) samples were synthesized and systematically characterized towards application as a cathode material for solid oxide fuel cells (SOFCs). High-temperature electrical conductivity, thermal expansion, and electrocatalytic activity in the oxygen reduction reaction (ORR) were examined. The electrical conductivity of Pr2−xCexCuO4 oxides demonstrates semiconducting behavior up to 900 °C. Small Ce-doping (2.5 at%) allows an increase in electrical conductivity from 100 to 130 S cm−1 in air at 500–800 °C. DFT calculations revealed that the density of states directly below the Fermi level, comprised mainly of Cu 3d and O 2p states, is significantly affected by atoms in rare earth positions, which might give an indication of a correlation between calculated electronic structures and measured conducting properties. Ce-doping in Pr2−xCexCuO4 slightly increases TEC from 11.9 × 10−6 K−1 for x = 0 to 14.2 × 10−6 K−1 for x = 0.15. Substitution of 2.5% of Pr atoms in Pr2CuO4 by Ce is effective to enhance the electrochemical performance of the material as a SOFC cathode in the ORR (ASR of Pr1.95Ce0.05CuO4 electrode applied on Ce0.9Gd0.1O1.95 electrolyte is 0.39 Ω cm2 at 750 °C in air). The peak power density achieved for the electrolyte-supported fuel cell with the Pr1.95Ce0.05CuO4 cathode is 150 mW cm−2 at 800 °C |
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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 |
000387427700044 |
Publication Date |
2016-10-19 |
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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 |
2046-2069 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.108 |
Times cited |
7 |
Open Access |
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Notes |
his work was partially supported by Russian Foundation for Basic Research (grant no. 153820247), Skolkovo Institute of Science and Technology (Center of electrochemical energy), and MSUdevelopment Program up to 2020. K.L.M. is grateful to Haldor Topsøe A/S for the financial support. |
Approved |
Most recent IF: 3.108 |
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Call Number |
EMAT @ emat @ c:irua:136441 |
Serial |
4296 |
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Author |
Callewaert, V.; Saniz, R.; Barbiellini, B.; Partoens, B. |
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Title |
Surface states and positron annihilation spectroscopy: results and prospects from a first-principles approach |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
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Volume |
791 |
Issue |
791 |
Pages |
012036 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The trapping of positrons at the surface of a material can be exploited to study quite selectively the surface properties of the latter by means of positron annihilation spectroscopy techniques. To support these, it is desirable to be able to theoretically predict the existence of such positronic surface states and to describe their annihilation characteristics with core or valence surface electrons in a reliable way. Here, we build on the well-developed first-principles techniques for the study of positrons in bulk solids as well as on previous models for surfaces, and investigate two schemes that can improve the theoretical description of the interaction of positrons with surfaces. One is based on supplementing the local-density correlation potential with the corrugated image potential at the surface, and the other is based on the weighted-density approximation to correlation. We discuss our results for topological insulators, graphene layers, and quantum dots, with emphasis on the information that can be directly related to experiment. We also discuss some open theoretical problems that should be addressed by future research. |
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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 |
000400610500036 |
Publication Date |
2017-02-22 |
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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 |
1742-6588 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
1 |
Open Access |
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Notes |
We acknowledge financial support from FWO-Vlaanderen (projects G.0150.13 and G.0224.14N). This work was carried out using the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), funded by the Hercules foundation and the Flemish Government (EWI Department). The work at Northeastern University was supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences grant number DE-FG02-07ER46352 (core research), and benefited from Northeastern University’s Advanced Scientific Computation Center (ASCC), the NERSC supercomputing center through DOE grant number DE-AC02- 05CH11231, and support (applications to layered materials) from the DOE EFRC: Center for the Computational Design of Functional Layered Materials (CCDM) under DE-SC0012575. |
Approved |
Most recent IF: NA |
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Call Number |
CMT @ cmt @ c:irua:140847 |
Serial |
4425 |
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| Permanent link to this record |
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Author |
Mikhailova, D.; Karakulina, O.M.; Batuk, D.; Hadermann, J.; Abakumov, A.M.; Herklotz, M.; Tsirlin, A.A.; Oswald, S.; Giebeler, L.; Schmidt, M.; Eckert, J.; Knapp, M.; Ehrenberg, H. |
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Title |
Layered-to-Tunnel Structure Transformation and Oxygen Redox Chemistry in LiRhO2upon Li Extraction and Insertion |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
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Volume |
55 |
Issue |
55 |
Pages |
7079-7089 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Layered Li(M,Li)O2 (where M is a transition metal) ordered rock-salt-type structures are used in advanced metal-ion batteries as one of the best hosts for the reversible intercalation of Li ions. Besides the conventional redox reaction involving oxidation/reduction of the M cation upon Li extraction/insertion, creating oxygen-located holes because of the partial oxygen oxidation increases capacity while maintaining the oxidized oxygen species in the lattice through high covalency of the M–O bonding. Typical degradation mechanism of the Li(M,Li)O2 electrodes involves partially irreversible M cation migration toward the Li positions, resulting in gradual capacity/voltage fade. Here, using LiRhO2 as a model system (isostructural and isoelectronic to LiCoO2), for the first time, we demonstrate an intimate coupling between the oxygen redox and M cation migration. A formation of the oxidized oxygen species upon electrochemical Li extraction coincides with transformation of the layered Li1–xRhO2 structure into the γ-MnO2-type rutile–ramsdellite intergrowth LiyRh3O6 structure with rutile-like [1 × 1] channels along with bigger ramsdellite-like [2 × 1] tunnels through massive and concerted Rh migration toward the empty positions in the Li layers. The oxidized oxygen dimers with the O–O distances as short as 2.26 Å are stabilized in this structure via the local Rh–O configuration reminiscent to that in the μ-peroxo-μ-hydroxo Rh complexes. The LiyRh3O6 structure is remarkably stable upon electrochemical cycling illustrating that proper structural implementation of the oxidized oxygen species can open a pathway toward deliberate employment of the anion redox chemistry in high-capacity/high-voltage positive electrodes for metal-ion batteries. Upon chemical or electrochemical oxidation, layered LiRhO2 shows a unique structural transformation that involves both cation migration and oxidation of oxygen resulting in a stable tunnel-like rutile−ramsdellite intergrowth LiyRh3O6 structure. This structure demonstrates excellent performance with the steady and reversible capacity of ∼200 mAh/g. The stability of LiyRh3O6 is rooted in the accommodation of partially oxidized oxygen species through the formation of short O−O distances that are compatible with the connectivity of RhO6 octahedra. |
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Wos |
000380181400035 |
Publication Date |
2016-07-18 |
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ISSN |
0020-1669 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.857 |
Times cited |
12 |
Open Access |
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Notes |
Bundesministerium fur Bildung und Forschung, 03SF0477B ; Fonds Wetenschappelijk Onderzoek, G040116N ; |
Approved |
Most recent IF: 4.857 |
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Call Number |
EMAT @ emat @ c:irua:140848 |
Serial |
4424 |
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Author |
Cassidy, S.J.; Batuk, M.; Batuk, D.; Hadermann, J.; Woodruff, D.N.; Thompson, A.L.; Clarke, S.J. |
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Title |
Complex Microstructure and Magnetism in Polymorphic CaFeSeO |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
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Volume |
55 |
Issue |
55 |
Pages |
10714-10726 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The structural complexity of the antiferromagnetic oxide selenide CaFeSeO is described. The compound contains puckered FeSeO layers composed of FeSe2O2 tetrahedra sharing all their vertexes. Two polymorphs coexist that can be derived from an archetype BaZnSO structure by cooperative tilting of the FeSe2O2 tetrahedra. The polymorphs differ in the relative arrangement of the puckered layers of vertex-linked FeSe2O2 tetrahedra. In a noncentrosymmetric Cmc21 polymorph (a = 3.89684(2) A, b = 13.22054(8) A, c = 5.93625(2) A) the layers are related by the C-centering translation, while in a centrosymmetric Pmcn polymorph, with a similar cell metric (a = 3.89557(6) A, b = 13.2237(6) A, c = 5.9363(3) A), the layers are related by inversion. The compound shows long-range antiferromagnetic order below a Neel temperature of 159(1) K with both polymorphs showing antiferromagnetic coupling via Fe-O-Fe linkages and ferromagnetic coupling via Fe-Se-Fe linkages within the FeSeO layers. The magnetic susceptibility also shows evidence for weak ferromagnetism which is modeled in the refinements of the magnetic structure as arising from an uncompensated spin canting in the noncentrosymmetric polymorph. There is also a spin glass component to the magnetism which likely arises from the disordered regions of the structure evident in the transmission electron microscopy. |
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Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QR, United Kingdom |
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English |
Wos |
000385785700085 |
Publication Date |
2016-10-05 |
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ISSN |
0020-1669 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.857 |
Times cited |
6 |
Open Access |
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Notes |
We acknowledge the financial support of the EPSRC (Grants EP/I017844/1 and EP/M020517/1), the Leverhulme Trust (RPG-2014-221), and the Diamond Light Source (studentship support for S. J. Cassidy). We thank the ESTEEM2 network for enabling the electron microscopy investigations and the ISIS facility and the Diamond Light Source Ltd. for the award of beam time. We thank Dr. P. Manuel for assistance on WISH, Dr. R. I. Smith for assistance on GEM and POLARIS, and Dr. C. Murray and Dr. A. Baker for assistance on I11. |
Approved |
Most recent IF: 4.857 |
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Call Number |
EMAT @ emat @ c:irua:136823 |
Serial |
4312 |
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Author |
Zhang, F.; Inokoshi, M.; Batuk, M.; Hadermann, J.; Naert, I.; Van Meerbeek, B.; Vleugels, J. |
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Title |
Strength, toughness and aging stability of highly-translucent Y-TZP ceramics for dental restorations |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Dental Materials |
Abbreviated Journal |
Dent Mater |
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Volume |
32 |
Issue |
32 |
Pages |
e327-e337 |
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Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
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Abstract |
OBJECTIVE: The aim was to evaluate the optical properties, mechanical properties and aging stability of yttria-stabilized zirconia with different compositions, highlighting the influence of the alumina addition, Y2O3 content and La2O3 doping on the translucency. METHODS: Five different Y-TZP zirconia powders (3 commercially available and 2 experimentally modified) were sintered under the same conditions and characterized by X-ray diffraction with Rietveld analysis and scanning electron microscopy (SEM). Translucency (n=6/group) was measured with a color meter, allowing to calculate the translucency parameter (TP) and the contrast ratio (CR). Mechanical properties were appraised with four-point bending strength (n=10), single edge V-notched beam (SEVNB) fracture toughness (n=8) and Vickers hardness (n=10). The aging stability was evaluated by measuring the tetragonal to monoclinic transformation (n=3) after accelerated hydrothermal aging in steam at 134 degrees C, and the transformation curves were fitted by the Mehl-Avrami-Johnson (MAJ) equation. Data were analyzed by one-way ANOVA, followed by Tukey's HSD test (alpha=0.05). RESULTS: Lowering the alumina content below 0.25wt.% avoided the formation of alumina particles and therefore increased the translucency of 3Y-TZP ceramics, but the hydrothermal aging stability was reduced. A higher yttria content (5mol%) introduced about 50% cubic zirconia phase and gave rise to the most translucent and aging-resistant Y-TZP ceramics, but the fracture toughness and strength were considerably sacrificed. 0.2mol% La2O3 doping of 3Y-TZP tailored the grain boundary chemistry and significantly improved the aging resistance and translucency. Although the translucency improvement by La2O3 doping was less effective than for introducing a substantial amount of cubic zirconia, this strategy was able to maintain the mechanical properties of typical 3Y-TZP ceramics. SIGNIFICANCE: Three different approaches were compared to improve the translucency of 3Y-TZP ceramics. |
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KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, Belgium |
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English |
Wos |
000389516400003 |
Publication Date |
2016-10-06 |
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ISSN |
0109-5641 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.07 |
Times cited |
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Notes |
The authors acknowledge the Research Fund of KU Leu- ven under project 0T/10/052 and the Fund for Scientific Research Flanders (FWO-Vlaanderen) under grant G.0431.10N. F. Zhang thanks the Research Fund of KU Leuven for her post- doctoral fellowship (PDM/15/153). We thank M. Peumans for the translucency measurements. |
Approved |
Most recent IF: 4.07 |
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Call Number |
EMAT @ emat @ c:irua:136821 |
Serial |
4313 |
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Author |
Juchtmans, R.; Guzzinati, G.; Verbeeck, J. |
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Title |
Extension of Friedel's law to vortex-beam diffraction |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Physical Review A |
Abbreviated Journal |
Phys Rev A |
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Volume |
94 |
Issue |
94 |
Pages |
033858 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Friedel's law states that the modulus of the Fourier transform of real functions is centrosymmetric, while the phase is antisymmetric. As a consequence of this, elastic scattering of plane-wave photons or electrons within the first-order Born-approximation, as well as Fraunhofer diffraction on any aperture, is bound to result in centrosymmetric diffraction patterns. Friedel's law, however, does not apply for vortex beams, and centrosymmetry in general is not present in their diffraction patterns. In this work we extend Friedel's law for vortex beams by showing that the diffraction patterns of vortex beams with opposite topological charge, scattered on the same two-dimensional potential, always are centrosymmetric to one another, regardless of the symmetry of the scattering object. We verify our statement by means of numerical simulations and experimental data. Our research provides deeper understanding in vortex-beam diffraction and can be used to design new experiments to measure the topological charge of vortex beams with diffraction gratings or to study general vortex-beam diffraction. |
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000384374500010 |
Publication Date |
2016-09-30 |
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ISSN |
2469-9926 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.925 |
Times cited |
13 |
Open Access |
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Notes |
The authors acknowledge support from the FWO (Aspirant Fonds Wetenschappelijk Onderzoek – Vlaanderen) and the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2 and ERC Starting Grant No. 278510 VORTEX.; ECASJO_; |
Approved |
Most recent IF: 2.925 |
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Call Number |
EMAT @ emat @ c:irua:137200UA @ admin @ c:irua:137200 |
Serial |
4314 |
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