Records |
Author |
Saniz, R.; Barbiellini, B.; Denison, A.B.; Bansil, A. |
Title |
Erratum: Spontaneous magnetization and electron momentum density in three-dimensional quantum dots [Phys. Rev. B 68, 165326 (2003)] |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
11 |
Pages |
119907 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000295263600015 |
Publication Date |
2011-09-28 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
3.836 |
Times cited |
|
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:92919 |
Serial |
1081 |
Permanent link to this record |
|
|
|
Author |
Tadić, M.; Čukarić, N.; Arsoski, V.; Peeters, F.M. |
Title |
Excitonic Aharonov-Bohm effect : unstrained versus strained type-I semiconductor nanorings |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
12 |
Pages |
125307-125307,13 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We study how mechanical strain affects the magnetic field dependence of the exciton states in type-I semiconductor nanorings. Strain spatially separates the electron and hole in (In,Ga)As/GaAs nanorings which is beneficial for the occurrence of the excitonic Aharonov-Bohm (AB) effect. In narrow strained (In,Ga)As/GaAs nanorings the AB oscillations in the exciton ground-state energy are due to anticrossings with the first excited state. No such AB oscillations are found in unstrained GaAs/(Al,Ga)As nanorings irrespective of the ring width. Our results are obtained within an exact numerical diagonalization scheme and are shown to be accurately described by a two-level model with off-diagonal coupling t. The later transfer integral expresses the Coulomb coupling between states of electron-hole pairs. We also found that the oscillator strength for exciton recombination in (In,Ga)As/GaAs nanorings exhibits AB oscillations, which are superimposed on a linear increase with magnetic field. Our results agree qualitatively with recent experiments on the excitonic Aharonov-Bohm effect in type-I (In,Ga)As/GaAs nanorings. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000294777400013 |
Publication Date |
2011-09-09 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
13 |
Open Access |
|
Notes |
; This work was supported by the Ministry of Education and Science of Serbia, the Flemish Science Foundation (FWO-Vl), the EU NoE: SANDiE, and the Belgian Science Policy (IAP). The calculations were performed on the CalcUA and Seastar computer clusters of the University of Antwerp. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:92326 |
Serial |
1122 |
Permanent link to this record |
|
|
|
Author |
Hamelet, S.; Casas-Cabanas, M.; Dupont, L.; Davoisne, C.; Tarascon, J.M.; Masquelier, C. |
Title |
Existence of superstructures due to large amounts of Fe vacancies in the LiFePO4-type framework |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
23 |
Issue |
1 |
Pages |
32-38 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
LiFePO4 has been under intense scrutiny over the past decade because it stands as an attractive positive electrode material for the next generation of Li-ion batteries to power electric vehicles and hybrid electric vehicles, hence the importance of its thermal behavior. The reactivity of LiFePO4 with air at moderate temperatures is shown to be dependent on its particle size. For nanosized materials, a progressive displacement of Fe from the core structure leading to a composite made of nanosize Fe2O3 and highly defective, oxidized LixFeyPO4 compositions, among which the “ideal” formula LiFe2/3PO4. Herein we report, from both temperature-controlled X-ray diffraction and electronic diffraction microscopy, that these off-stoichiometry olivine-type compounds show a defect ordering resulting in the formation of a superstructure. Such a finding shows striking similarities with the temperature-driven oxidation of fayalite Fe2SiO4 (another olivine) to structurally defective laihunite, reported in the literature three decades ago. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
Language |
|
Wos |
000285726900007 |
Publication Date |
2010-12-14 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
30 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 9.466; 2011 IF: 7.286 |
Call Number |
UA @ lucian @ c:irua:105605 |
Serial |
1130 |
Permanent link to this record |
|
|
|
Author |
Goris, B.; Bals, S.; van den Broek, W.; Verbeeck, J.; Van Tendeloo, G. |
Title |
Exploring different inelastic projection mechanisms for electron tomography |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
111 |
Issue |
8 |
Pages |
1262-1267 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
Several different projection mechanisms that all make use of inelastically scattered electrons are used for electron tomography. The advantages and the disadvantages of these methods are compared to HAADFSTEM tomography, which is considered as the standard electron tomography technique in materials science. The different inelastic setups used are energy filtered transmission electron microscopy (EFTEM), thickness mapping based on the log-ratio method and bulk plasmon mapping. We present a comparison that can be used to select the best inelastic signal for tomography, depending on different parameters such as the beam stability and nature of the sample. The appropriate signal will obviously also depend on the exact information which is requested. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000300461100039 |
Publication Date |
2011-03-07 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.843 |
Times cited |
21 |
Open Access |
|
Notes |
Fwo; Iap; Esteem 026019 |
Approved |
Most recent IF: 2.843; 2011 IF: 2.471 |
Call Number |
UA @ lucian @ c:irua:91260UA @ admin @ c:irua:91260 |
Serial |
1151 |
Permanent link to this record |
|
|
|
Author |
Shanenko, A.A.; Milošević, M.V.; Peeters, F.M. |
Title |
Extended Ginzburg-Landau formalism for two-band superconductors |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
106 |
Issue |
4 |
Pages |
047005-047005,4 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Recent observation of unusual vortex patterns in MgB2 single crystals raised speculations about possible type-1.5 superconductivity in two-band materials, mixing the properties of both type-I and type-II superconductors. However, the strict application of the standard two-band Ginzburg-Landau (GL) theory results in simply proportional order parameters of the two bandsand does not support the type-1.5 behavior. Here we derive the extended GL formalism (accounting all terms of the next order over the small τ=1-T/Tc parameter) for a two-band clean s-wave superconductor and show that the two condensates generally have different spatial scales, with the difference disappearing only in the limit T→Tc. The extended version of the two-band GL formalism improves the validity of GL theory below Tc and suggests revisiting the earlier calculations based on the standard model. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000286734100010 |
Publication Date |
2011-01-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
84 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF-INSTANS network. Discussions with M. D. Croitoru are gratefully acknowledged. ; |
Approved |
Most recent IF: 8.462; 2011 IF: 7.370 |
Call Number |
UA @ lucian @ c:irua:88038 |
Serial |
1154 |
Permanent link to this record |
|
|
|
Author |
Kirsanova, M.A.; Olenev, A.V.; Abakumov, A.M.; Bykov, M.A.; Shevelkov, A.V. |
Title |
Extension of the clathrate family : the type X clathrate Ge79P29S18Te6 |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Angewandte Chemie: international edition in English |
Abbreviated Journal |
Angew Chem Int Edit |
Volume |
50 |
Issue |
10 |
Pages |
2371-2374 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Now they are 10! The title compound displays a new type of crystal structure and is labeled clathrate X according to the general classification of clathrate structures. In contrast to typical clathrates, this compound has three-coordinate atoms within the framework and combines distorted 24-vertex polyhedra (see picture, green) centered around tellurium guest atoms with very irregular 10-vertex polyhedra around sulfur atoms (yellow). |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Weinheim |
Editor |
|
Language |
|
Wos |
000288036300033 |
Publication Date |
2011-01-31 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1433-7851; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
11.994 |
Times cited |
23 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 11.994; 2011 IF: 13.455 |
Call Number |
UA @ lucian @ c:irua:88793 |
Serial |
1158 |
Permanent link to this record |
|
|
|
Author |
Gasparotto, A.; Barreca, D.; Bekermann, D.; Devi, A.; Fischer, R.A.; Fornasiero, P.; Gombac, V.; Lebedev, O.I.; Maccato, C.; Montini, T.; Van Tendeloo, G.; Tondello, E. |
Title |
F-doped Co3O4 photocatalysts for sustainable H2 generation from water/ethanol |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
Volume |
133 |
Issue |
48 |
Pages |
19362-19365 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
p-Type Co3O4 nanostructured films are synthesized by a plasma-assisted process and tested in the photocatalytic production of H2 from water/ethanol solutions under both near-UV and solar irradiation. It is demonstrated that the introduction of fluorine into p-type Co3O4 results in a remarkable performance improvement with respect to the corresponding undoped oxide, highlighting F-doped Co3O4 films as highly promising systems for hydrogen generation. Notably, the obtained yields were among the best ever reported for similar semiconductor-based photocatalytic processes. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
Language |
|
Wos |
000297606500027 |
Publication Date |
2011-11-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0002-7863;1520-5126; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.858 |
Times cited |
114 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 13.858; 2011 IF: 9.907 |
Call Number |
UA @ lucian @ c:irua:93628 |
Serial |
1164 |
Permanent link to this record |
|
|
|
Author |
Nowak, M.P.; Szafran, B.; Peeters, F.M. |
Title |
Fano resonances and electron spin transport through a two-dimensional spin-orbit-coupled quantum ring |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
23 |
Pages |
235319-235319,8 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Electron transport through a spin-orbit-coupled quantum ring is investigated within linear response theory. We show that the finite width of the ring results in the appearance of Fano resonances in the conductance. This turns out to be a consequence of the spin-orbit interaction that leads to a breaking of the parity of the states localized in the ring. The resonances appear when the system is close to maxima of Aharonov-Casher conductance oscillations where spin transfer is heavily modified. When the spin-orbit coupling strength is detuned from the Aharonov-Casher maxima the resonances are broadened resulting in a dependence of the spin transport on the electron Fermi energy in contrast to predictions from one-dimensional models. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000298605700002 |
Publication Date |
2011-12-29 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
19 |
Open Access |
|
Notes |
; This work was supported by the “Krakow Interdisciplinary PhD Project in Nanoscience and Advanced Nanostructures” operated within the Foundation for Polish Science MPD Programme cofinanced by the EU European Regional Development Fund, Project No. N N202103938 supported by the Ministry of Science and Higher Education (MNiSW) for 2010-2013, the Belgian Science Policy (IAP), and the Flemish Science Foundation (FWO-V1). This research was supported in part by PL-Grid Infrastructure. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:94292 |
Serial |
1171 |
Permanent link to this record |
|
|
|
Author |
Cao, S.; Nishida, M.; Schryvers, D. |
Title |
FIB/SEM applied to quantitative 3D analysis of precipitates in Ni-Ti |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Diffusion and defect data : solid state data : part B : solid state phenomena |
Abbreviated Journal |
|
Volume |
172/174 |
Issue |
|
Pages |
1284-1289 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Ni4Ti3 precipitates with a heterogeneous distribution growing in a polycrystalline Ni50.8Ti49.2 alloy have been investigated in a Dual-Beam FIB/SEM system. The volume ratio, mean volume, central plane diameter, thickness, aspect ratio and sphericity of the precipitates in the grain interior as well as near to the grain boundary were measured or calculated. The morphology of the precipitates was classified according to the Zingg scheme. The multistage martensitic transformation occurring in these kinds of samples is interpreted in view of the data of this heterogeneous microstructure of matrix and precipitates. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Vaduz |
Editor |
|
Language |
|
Wos |
000303359700199 |
Publication Date |
2011-07-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1662-9779; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
|
Times cited |
|
Open Access |
|
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:90152 |
Serial |
1188 |
Permanent link to this record |
|
|
|
Author |
Bertoni, G.; Verbeeck, J.; Brosens, F. |
Title |
Fitting the momentum dependent loss function in EELS |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Microscopy research and technique |
Abbreviated Journal |
Microsc Res Techniq |
Volume |
74 |
Issue |
3 |
Pages |
212-218 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Theory of quantum systems and complex systems |
Abstract |
Momentum dependent inelastic plasmon scattering can be measured by electron energy loss in a transmission electron microscope. From energy filtered diffraction, the characteristic angle of scattering and the cutoff angle are measured, using a thin film of aluminum as a model test. Rather than deconvolving the data (as done in previous works), a fitting technique is used to extract the loss function from angular resolved spectra, starting from a simple model simulation. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000288095200002 |
Publication Date |
2010-07-06 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1059-910X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.147 |
Times cited |
6 |
Open Access |
|
Notes |
Fwo; Esteem; Iap; Goa |
Approved |
Most recent IF: 1.147; 2011 IF: 1.792 |
Call Number |
UA @ lucian @ c:irua:88782UA @ admin @ c:irua:88782 |
Serial |
1222 |
Permanent link to this record |
|
|
|
Author |
Berger, J.; Milošević, M.V. |
Title |
Fluctuations in superconducting rings with two order parameters |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
21 |
Pages |
214515-214515,9 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Motivated by two-band superconductivity in, e.g., borides and pnictides, starting from the two-band Ginzburg-Landau energy functional, we discuss how the presence of two order parameters and the coupling between them influence a superconducting ring in the fluctuative regime. Our method is an extension of the von OppenRiedel formalism for rings; it is exact, but requires numerical implementation. We also study approximations for which analytic expressions can be obtained, and check their ranges of validity. We provide estimates for the temperature ranges where fluctuations are important, calculate the persistent current in MgB2 rings as a function of temperature and enclosed flux, and point out its additional dependence on the cross-section area of the wire from which the ring is made. We find temperature regions in which fluctuations enhance the persistent currents and regions where they inhibit the persistent current. The presence of two order parameters that can fluctuate independently always leads to larger averages of the order parameters at Tc, but yields larger persistent current only for appropriate parameters. In cases of very different material parameters for the two coupled condensates, the persistent current is inhibited. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000297932500004 |
Publication Date |
2011-12-12 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
|
Notes |
; This research was supported by the Israel Science Foundation, Grant No. 249/10, the Flemish Science Foundation (FWO-Vl), and the ESF network INSTANS. We are grateful to Andrei Varlamov and Felix von Oppen for their answers to our enquiries. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:93957 |
Serial |
1226 |
Permanent link to this record |
|
|
|
Author |
De Bie, C.; Verheyde, B.; Martens, T.; van Dijk, J.; Paulussen, S.; Bogaerts, A. |
Title |
Fluid modeling of the conversion of methane into higher hydrocarbons in an atmospheric pressure dielectric barrier discharge |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Plasma processes and polymers |
Abbreviated Journal |
Plasma Process Polym |
Volume |
8 |
Issue |
11 |
Pages |
1033-1058 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
A one-dimensional fluid model for a dielectric barrier discharge in methane, used as a chemical reactor for gas conversion, is developed. The model describes the gas phase chemistry governing the conversion process of methane to higher hydrocarbons. The spatially averaged densities of the various plasma species as a function of time are discussed. Besides, the conversion of methane and the yields of the reaction products as a function of the residence time in the reactor are shown and compared with experimental data. Higher hydrocarbons (C2Hy and C3Hy) and hydrogen gas are typically found to be important reaction products. Furthermore, the main underlying reaction pathways are determined. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Weinheim |
Editor |
|
Language |
|
Wos |
000297745500005 |
Publication Date |
2011-07-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1612-8850; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.846 |
Times cited |
70 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.846; 2011 IF: 2.468 |
Call Number |
UA @ lucian @ c:irua:92443 |
Serial |
1227 |
Permanent link to this record |
|
|
|
Author |
Si, X.-J.; Zhao, S.-X.; Xu, X.; Bogaerts, A.; Wang, Y.-N. |
Title |
Fluid simulations of frequency effects on nonlinear harmonics in inductively coupled plasma |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physics of plasmas |
Abbreviated Journal |
Phys Plasmas |
Volume |
18 |
Issue |
3 |
Pages |
033504-033504,9 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
A fluid model is self-consistently established to investigate the harmonic effects in an inductively coupled plasma, where the electromagnetic field is solved by the finite difference time domain technique. The spatiotemporal distribution of harmonic current density, harmonic potential, and other plasma quantities, such as radio frequency power deposition, plasma density, and electron temperature, have been investigated. Distinct differences in current density have been observed when calculated with and without Lorentz force, which indicates that the nonlinear Lorentz force plays an important role in the harmonic effects, especially at low frequencies. Moreover, the even harmonics are larger than the odd harmonics both in the current density and the potential. Finally, the dependence of various plasma quantities with and without the Lorentz force on various driving frequencies is also examined. It is shown that the deposited power density decreases and the depth of penetration increases slightly because of the Lorentz force. The electron density increases distinctly while the electron temperature remains almost the same when the Lorentz force is taken into account. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Woodbury, N.Y. |
Editor |
|
Language |
|
Wos |
000289151900073 |
Publication Date |
2011-03-18 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1070-664X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.115 |
Times cited |
7 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.115; 2011 IF: 2.147 |
Call Number |
UA @ lucian @ c:irua:87876 |
Serial |
1233 |
Permanent link to this record |
|
|
|
Author |
Navulla, A.; Tsirlin, A.A.; Abakumov, A.M.; Shpanchenko, R.V.; Zhang, H.; Dikarev, E.V. |
Title |
Fluorinated heterometallic \beta-diketonates as volatile single-source precursors for the synthesis of low-valent mixed-metal fluorides |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
Volume |
133 |
Issue |
4 |
Pages |
692-694 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Hexafluoroacetylacetonates that contain lead and divalent first-row transition metals, PbM(hfac)4 (M = Ni (1), Co (2), Mn (3), Fe (4), and Zn (5)), have been synthesized. Their heterometallic structures are held together by strong Lewis acid−base interactions between metal atoms and diketonate ligands acting in chelating−bridging fashion. Compounds 1−5 are highly volatile and decompose below 350 °C. Fluorinated heterometallic β-diketonates have been used for the first time as volatile single-source precursors for the preparation of mixed-metal fluorides. Complex fluorides of composition Pb2MF6 have been obtained by decomposition of 1−5 in a two-zone furnace under low-pressure nitrogen flow. Lead−transition metal fluorides conform to orthorhombically distorted Aurivillius-type structure with layers of corner-sharing [MF6] octahedra separated by α-PbO-type (Pb2F2) blocks. Pb2NiF6 and Pb2CoF6 were found to exhibit magnetic ordering below 80 and 43 K, respectively. The ordering is antiferromagnetic, with a weak, uncompensated moment due to the canting of spins. The Pb2MF6 fluorides represent a new class of prospective magnetoelectric materials combining transition metals and lone-pair main-group cations. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
Language |
|
Wos |
000287295300015 |
Publication Date |
2010-12-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0002-7863;1520-5126; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.858 |
Times cited |
28 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 13.858; 2011 IF: 9.907 |
Call Number |
UA @ lucian @ c:irua:88820 |
Serial |
1236 |
Permanent link to this record |
|
|
|
Author |
Xu, B.; Milošević, M.V.; Lin, S.-H.; Peeters, F.M.; Jankó, B. |
Title |
Formation of multiple-flux-quantum vortices in mesoscopic superconductors from simulations of calorimetric, magnetic, and transport properties |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
107 |
Issue |
5 |
Pages |
057002,1-057002,4 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Because of strong flux confinement in mesoscopic superconductors, a giant vortex may appear in the ground state of the system in an applied magnetic field. This multiquanta vortex can then split into individual vortices (and vice versa) as a function of, e.g., applied current, magnetic field, or temperature. Here we show that such transitions can be identified by calorimetry, as the formation or splitting of a giant vortex results in a clear jump in measured heat capacity versus external drive. We attribute this phenomenon to an abrupt change in the density of states of the quasiparticle excitations in the vortex core(s), and further link it to a sharp change of the magnetic susceptibility at the transitionproving that the formation of a giant vortex can also be detected by magnetometry. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000293333100006 |
Publication Date |
2011-07-29 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
26 |
Open Access |
|
Notes |
; We thank O. Bourgeois, T. Yokoyama, M. Eschrig, and M. Ichioka for discussions. This work was supported by FWO-Vlaanderen, the Belgian Science Policy (IAP), the bilateral project Flanders-USA, NSF NIRT, ECS-0609249, and Institute of Theoretical Sciences, Notre Dame. ; |
Approved |
Most recent IF: 8.462; 2011 IF: 7.370 |
Call Number |
UA @ lucian @ c:irua:91237 |
Serial |
1263 |
Permanent link to this record |
|
|
|
Author |
Tognalii, N.G.; Cortés, E.; Hernández-Nieves, A.D.; Carro, P.; Usaj, G.; Balseiro, C.A.; Vela, M.E.; Salvarezza, R.C.; Fainstein, A. |
Title |
From single to multiple Ag-layer modification of Au nanocavity substrates : a tunable probe of the chemical surface-enhanced Raman scattering mechanism |
Type |
A1 Journal article |
Year |
2011 |
Publication |
ACS nano |
Abbreviated Journal |
Acs Nano |
Volume |
5 |
Issue |
7 |
Pages |
5433-5443 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We present experimental and computational results that enlighten the mechanisms underlying the chemical contribution to surface-enhanced Raman scattering (SERS). Gold void metallic arrays electrochemically covered either by a Ag monolayer or 10100 Ag layers were modified with a self-assembled monolayer of 4-mercaptopyridine as a molecular Raman probe displaying a rich and unexpected Raman response. A resonant increase of the Raman intensity in the red part of the spectrum is observed that cannot be related to plasmon excitations of the cavity-array. Notably, we find an additional 1020 time increase of the SERS amplification upon deposition of a single Ag layer on the Au substrate, which is, however, almost quenched upon deposition of 10 atomic layers. Further deposition of 100 atomic Ag layers results in a new increase of the SERS signal, consistent with the improved plasmonic efficiency of Ag bulk-like structures. The SERS response as a function of the Ag layer thickness is analyzed in terms of ab initio calculations and a microscopic model for the SERS chemical mechanism based on a resonant charge transfer process between the molecular HOMO state and the Fermi level in the metal surface. We find that a rearrangement of the electronic charge density related to the presence of the Ag monolayer in the Au/Ag/molecule complex causes an increase in the distance between the HOMO center of charge and the metallic image plane that is responsible for the variation of Raman enhancement between the studied substrates. Our results provide a general platform for studying the chemical contribution to SERS, and for enhancing the Raman efficiency of tailored Au-SERS templates through electrochemical modification with Ag films. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000293035200019 |
Publication Date |
2011-06-15 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1936-0851;1936-086X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.942 |
Times cited |
26 |
Open Access |
|
Notes |
; We acknowledge financial support from ANPCyT (Argentina, PICT08-1617, PICT08-2236, PICT06-621, PICT-CNPQ-08-0019, PAE 22711, PICT06-01061, PICT06-483) and Project CTQ2008-06017/BQU, Spain. N.G.T, E.C., A.D.H.N., R.C.S, G.U., C.A.B., and A.F. are also at CONICET. M.E.V. is a member of the research career of CIC BsAs. R.C.S., C.A.B., and A.F. are Guggenheim Foundation Fellows. We would like to thank Dr. M. H. Fonticelli for fruitful discussions on the electrochemical measurements and Dr. H. Pastoriza for the help with the SEM measurements. ; |
Approved |
Most recent IF: 13.942; 2011 IF: 11.421 |
Call Number |
UA @ lucian @ c:irua:91775 |
Serial |
1285 |
Permanent link to this record |
|
|
|
Author |
De Backer, L.A.; Vos, W.G.; Salgado, R.; de Backer, J.W.; Devolder, A.; Verhulst, S.L.; Claes, R.; Germonpré, P.R.; de Backer, W.A. |
Title |
Functional imaging using computer methods to compare the effect of salbutamol and ipratropium bromide in patient-specific airway models of COPD |
Type |
A1 Journal article |
Year |
2011 |
Publication |
International journal of chronic obstructive pulmonary disease |
Abbreviated Journal |
Int J Chronic Obstr |
Volume |
6 |
Issue |
|
Pages |
637-646 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Vision lab; Laboratory Experimental Medicine and Pediatrics (LEMP) |
Abstract |
Background: Salbutamol and ipratropium bromide improve lung function in patients with chronic obstructive pulmonary disease (COPD). However, their bronchodilating effect has not yet been compared in the central and distal airways. Functional imaging using computational fluid dynamics offers the possibility of making such a comparison. The objective of this study was to assess the effects of salbutamol and ipratropium bromide on the geometry and computational fluid dynamics-based resistance of the central and distal airways.Methods: Five patients with Global Initiative for Chronic Obstructive Lung Disease Stage III COPD were randomized to a single dose of salbutamol or ipratropium bromide in a crossover manner with a 1-week interval between treatments. Patients underwent lung function testing and a multislice computed tomography scan of the thorax that was used for functional imaging. Two hours after dosing, the patients again underwent lung function tests and repeat computed tomography.Results: Lung function parameters, including forced expiratory volume in 1 second, vital capacity, overall airway resistance, and specific airway resistance, changed significantly after administration of each product. On functional imaging, the bronchodilating effect was greater in the distal airways, with a corresponding drop in airway resistance, compared with the central airways. Salbutamol and ipratropium bromide were equally effective at first glance when looking at lung function tests, but when viewed in more detail with functional imaging, hyporesponsiveness could be shown for salbutamol in one patient. Salbutamol was more effective in the other patients.Conclusion: This pilot study gives an innovative insight into the modes of action of salbutamol and ipratropium bromide in patients with COPD, using the new techniques of functional imaging and computational fluid dynamics. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000208709800068 |
Publication Date |
2011-11-28 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1178-2005; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.157 |
Times cited |
25 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 3.157; 2011 IF: NA |
Call Number |
UA @ lucian @ c:irua:93165 |
Serial |
1300 |
Permanent link to this record |
|
|
|
Author |
Esken, D.; Turner, S.; Wiktor, C.; Kalidindi, S.B.; Van Tendeloo, G.; Fischer, R.A. |
Title |
GaN@ZIF-8 : selective formation of gallium nitride quantum dots inside a zinc methylimidazolate framework |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
Volume |
133 |
Issue |
41 |
Pages |
16370-16373 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The microporous zeolitic imidazolate framework [Zn(MeIM)2; ZIF-8; MeIM = imidazolate-2-methyl] was quantitatively loaded with trimethylamine gallane [(CH3)3NGaH3]. The obtained inclusion compound [(CH3)3NGaH3]@ZIF-8 reveals three precursor molecules per host cavity. Treatment with ammonia selectively yields the caged cyclotrigallazane intermediate (H2GaNH2)3@ZIF-8, and further annealing gives GaN@ZIF-8. This new composite material was characterized with FT-IR spectroscopy, solid-state NMR spectroscopy, powder X-ray diffraction, elemental analysis, (scanning) transmission electron microscopy combined with electron energy-loss spectroscopy, photoluminescence (PL) spectroscopy, and N2 sorption measurements. The data give evidence for the presence of GaN nanoparticles (13 nm) embedded in the cavities of ZIF-8, including a blue-shift of the PL emission band caused by the quantum size effect. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
Language |
|
Wos |
000295997500014 |
Publication Date |
2011-09-13 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0002-7863;1520-5126; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.858 |
Times cited |
82 |
Open Access |
|
Notes |
Hercules |
Approved |
Most recent IF: 13.858; 2011 IF: 9.907 |
Call Number |
UA @ lucian @ c:irua:93582 |
Serial |
1315 |
Permanent link to this record |
|
|
|
Author |
Vandenberghe, W.; Sorée, B.; Magnus, W.; Fischetti, M.V. |
Title |
Generalized phonon-assisted Zener tunneling in indirect semiconductors with non-uniform electric fields : a rigorous approach |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
Volume |
109 |
Issue |
12 |
Pages |
124503-124503,12 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
A general framework to calculate the Zener current in an indirect semiconductor with an externally applied potential is provided. Assuming a parabolic valence and conduction band dispersion, the semiconductor is in equilibrium in the presence of the external field as long as the electron-phonon interaction is absent. The linear response to the electron-phonon interaction results in a non-equilibrium system. The Zener tunneling current is calculated from the number of electrons making the transition from valence to conduction band per unit time. A convenient expression based on the single particle spectral functions is provided, enabling the evaluation of the Zener tunneling current under any three-dimensional potential profile. For a one-dimensional potential profile an analytical expression is obtained for the current in a bulk semiconductor, a semiconductor under uniform field, and a semiconductor under a non-uniform field using the WKB (Wentzel-Kramers-Brillouin) approximation. The obtained results agree with the Kane result in the low field limit. A numerical example for abrupt p-n diodes with different doping concentrations is given, from which it can be seen that the uniform field model is a better approximation than the WKB model, but a direct numerical treatment is required for low bias conditions. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000292331200134 |
Publication Date |
2011-06-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0021-8979; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.068 |
Times cited |
41 |
Open Access |
|
Notes |
; William Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). ; |
Approved |
Most recent IF: 2.068; 2011 IF: 2.168 |
Call Number |
UA @ lucian @ c:irua:90808 |
Serial |
1325 |
Permanent link to this record |
|
|
|
Author |
Engbarth, M.A.; Bending, S.J.; Milošević, M.V. |
Title |
Geometry-driven vortex states in type-I superconducting Pb nanowires |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
83 |
Issue |
22 |
Pages |
224504-224504,7 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Hall probe magnetometry has been used to investigate the magnetization of individual cylindrically shaped Pb nanowires grown by electrocrystallization on a highly oriented pyrolytic graphite electrode. These measurements have been interpreted by comparison with three-dimensional Ginzburg-Landau (GL) calculations for nanowires with our sample parameters. We find that the measured superheating field and the critical field for surface superconductivity are strongly influenced by the temperature-dependent coherence length, ξ(T) and penetration depth λ(T) and their relationship to the nanowire diameter. As the temperature is increased toward Tc this drives a change in the superconductor-normal transition from first order irreversible to first order reversible and finally second order reversible. We find that the geometrical flux confinement in our type-I nanowires leads to the formation of a one-dimensional row of single-quantum vortices. While GL calculations show a quite uniform distribution of vortices in thin nanowires, clear vortex bunching is found as the diameter increases, suggesting a transition to a more classical type-I behavior. Subtle changes in minor magnetization loops also indicate that slightly different flux configurations can form with the same vorticity, which depend on the sample history. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000291888300012 |
Publication Date |
2011-06-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
19 |
Open Access |
|
Notes |
; We acknowledge valuable conversations with F. V. Kusmartsev and W. M. Wu at Loughborough University, UK. This work was supported by the EPSRC-UK under Grant No. EP/E039944/1, and the Flemish Science Foundation (FWO). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:90927 |
Serial |
1331 |
Permanent link to this record |
|
|
|
Author |
Galván Moya, J.E.; Peeters, F.M. |
Title |
Ginzburg-Landau theory of the zigzag transition in quasi-one-dimensional classical Wigner crystals |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
13 |
Pages |
134106,1-134106,10 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We present a mean-field description of the zigzag phase transition of a quasi-one-dimensional system of strongly interacting particles, with interaction potential r−ne−r/λ, that are confined by a power-law potential (yα). The parameters of the resulting one-dimensional Ginzburg-Landau theory are determined analytically for different values of α and n. Close to the transition point for the zigzag phase transition, the scaling behavior of the order parameter is determined. For α=2, the zigzag transition from a single to a double chain is of second order, while for α>2, the one-chain configuration is always unstable and, for α<2, the one-chain ordered state becomes unstable at a certain critical density, resulting in jumps of single particles out of the chain. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000296289500004 |
Publication Date |
2011-10-18 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:93583 |
Serial |
1345 |
Permanent link to this record |
|
|
|
Author |
Masir, M.R.; Vasilopoulos, P.; Peeters, F.M. |
Title |
Graphene in inhomogeneous magnetic fields : bound, quasi-bound and scattering states |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
Volume |
23 |
Issue |
31 |
Pages |
315301,1-315301,14 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The electron states in graphene-based magnetic dot and magnetic ring structures and combinations of both are investigated. The corresponding spectra are studied as a function of the radii, the strengths of the inhomogeneous magnetic field and of a uniform background field, the strength of an electrostatic barrier and the angular momentum quantum number. In the absence of an external magnetic field we have only long-lived quasi-bound and scattering states and we assess their influence on the density of states. In addition, we consider elastic electron scattering by a magnetic dot, whose average B vanishes, and show that the Hall and longitudinal resistivities, as a function of the Fermi energy, exhibit a pronounced oscillatory structure due to the presence of quasi-bound states. Depending on the dot parameters this oscillatory structure differs substantially for energies below and above the first Landau level. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
London |
Editor |
|
Language |
|
Wos |
000293008900002 |
Publication Date |
2011-07-16 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.649 |
Times cited |
38 |
Open Access |
|
Notes |
; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE, the Canadian NSERC grant no. OGP0121756 and the Belgian Science Policy (IAP). We acknowledge discussions and correspondence with Professor A Matulis. ; |
Approved |
Most recent IF: 2.649; 2011 IF: 2.546 |
Call Number |
UA @ lucian @ c:irua:91176 |
Serial |
1372 |
Permanent link to this record |
|
|
|
Author |
de Clippel, F.; Harkiolakis, A.; Vosch, T.; Ke, X.; Giebeler, L.; Oswald, S.; Houthoofd, K.; Jammaer, J.; Van Tendeloo, G.; Martens, J.A.; Jacobs, P.A.; Baron, G.V.; Sels, B.F.; Denayer, J.F.M. |
Title |
Graphitic nanocrystals inside the pores of mesoporous silica : synthesis, characterization and an adsorption study |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Microporous and mesoporous materials: zeolites, clays, carbons and related materials |
Abbreviated Journal |
Micropor Mesopor Mat |
Volume |
144 |
Issue |
1/3 |
Pages |
120-133 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
This work presents a new carbonsilica hybrid material, denoted as CSM, with remarkable sorption properties. It consists of intraporous graphitic nanocrystals grown in the pores of mesoporous silica. CSM is obtained by a subtle incipient wetness impregnation of Al-containing mesoporous silica with furfuryl alcohol (FA)/hemelitol solutions. Both the volume match of the impregnation solution with that of the silica template pore volume, and the presence of Al3+ in the silica, are crucial to polymerize FA selectively inside the mesopores. Carbonization of the intraporous polymer was then performed by pyrolysis under He up to 1273 K. The resulting CSMs were examined by SEM, HRTEM, 27Al MAS NMR, N2 adsorption, XRD, TGA, TPD, XPS, pycnometry and Raman spectroscopy. Mildly oxidized graphitic-like carbon nanoblocks, consisting of a few graphene-like sheets, were thus identified inside the template mesopores. Random stacking of these carbon crystallites generates microporosity resulting in biporous materials at low carbon content and microporous materials at high carbon loadings. Very narrow pore distributions were obtained when pyrolysis was carried out under slow heating rate, viz. 1 K min−1. Adsorption and shape selective properties of the carbon filled mesoporous silica were studied by performing pulse chromatography and breakthrough experiments, and by measuring adsorption isotherms of linear and branched alkanes. Whereas the parent mesoporous silica shows unselective adsorption, their CSM analogues preferentially adsorb linear alkanes. The sorption capacity and selectivity can be adjusted by changing the pore size of the template or by varying the synthesis conditions. A relation between the carbon crystallites size and the shape selective behaviour of the corresponding CSM for instance is demonstrated. Most interestingly, CSM shows separation factors for linear and branched alkanes up to values comparable to those of zeolitic molecular sieves. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000293435400016 |
Publication Date |
2011-04-15 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1387-1811; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.615 |
Times cited |
15 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.615; 2011 IF: 3.285 |
Call Number |
UA @ lucian @ c:irua:92325 |
Serial |
1380 |
Permanent link to this record |
|
|
|
Author |
Kapra, A.V.; Misko, V.R.; Vodolazov, D.Y.; Peeters, F.M. |
Title |
The guidance of vortex-antivortex pairs by in-plane magnetic dipoles in a superconducting finite-size film |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
Volume |
24 |
Issue |
2 |
Pages |
024014-024014,8 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The possibility of manipulating vortex matter by using various artificial pinning arrays is of significant importance for possible applications in nano and micro fluxonics devices. By numerically solving the time-dependent GinzburgLandau equations, we study the vortexantivortex (vav) dynamics in a hybrid structure consisting of a finite-size superconductor with magnetic dipoles on top which generate vav pairs in the presence of an external current. The vav dynamics is analyzed for different arrangements and magnetic moments of the dipoles, as a function of angle α between the direction of the magnetic dipole and that of the Lorentz force produced by the applied current. The interplay of the attractive interaction between a vav pair and the Lorentz force leads either to the separation of (anti)vortices and their motion in opposite directions or to their annihilation. We found a critical angle αc, below which vortices and antivortices are repelled, while for larger angles they annihilate. In case of a single (few) magnetic dipole(s), this magnetic dipole induced vav guidance is influenced by the self-interaction of the vav pairs with their images in a finite-size sample, while for a periodic array of dipoles the guidance is determined by the interaction of a vav pair with other dipoles and vav pairs created by them. This effect is tunable through the external current and the magnetization and size of the magnetic dipoles. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Bristol |
Editor |
|
Language |
|
Wos |
000286379900015 |
Publication Date |
2011-01-20 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0953-2048;1361-6668; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.878 |
Times cited |
28 |
Open Access |
|
Notes |
; This work was supported by the 'Odysseus' program of the Flemish Government and the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles (IAP) Programme-Belgian State-Belgian Science Policy, and the FWO-Vl. DYV acknowledges support from the Russian Fund for Basic Research and Russian Agency of Education under the Federal Programme 'Scientific and educational personnel of innovative Russia in 2009-2013'. ; |
Approved |
Most recent IF: 2.878; 2011 IF: 2.662 |
Call Number |
UA @ lucian @ c:irua:88732 |
Serial |
1399 |
Permanent link to this record |
|
|
|
Author |
Vodolazov, D.Y.; Peeters, F.M. |
Title |
Heating of quasiparticles driven by oscillations of the order parameter in short superconducting microbridges |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
83 |
Issue |
22 |
Pages |
224523-224523,6 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We predict heating of quasiparticles driven by order parameter oscillations in the resistive state of short superconducting microbridges. The finite relaxation time of the magnitude of the order parameter |Δ| and the dependence of the spectral functions both on |Δ| and the supervelocity Q are the origin of this effect. Our results are opposite to those of Aslamazov and Larkin [ Zh. Eks. Teor. Fiz. 70 1340 (1976)] and Schmid et al. [ Phys. Rev. B 21 5076 (1980)] where cooling of quasiparticles was found. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000292218200010 |
Publication Date |
2011-06-29 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
|
Notes |
; This work was supported by the Russian Foundation for Basic Research, Russian Agency of Education under the Federal Target Programme “Scientific and educational personnel of innovative Russia in 2009-2013,” Flemish Science Foundation (FWO-Vl), and the Belgian Science Policy (IAP). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:90924 |
Serial |
1415 |
Permanent link to this record |
|
|
|
Author |
Dong, H.M.; Xu, W.; Peeters, F.M. |
Title |
High-field transport properties of graphene |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
Volume |
110 |
Issue |
6 |
Pages |
063704,1-063704,6 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We present a theoretical investigation on the transport properties of graphene in the presence of high dc driving fields. Considering electron interactions with impurities and acoustic and optical phonons in graphene, we employ the momentum- and energy-balance equations derived from the Boltzmann equation to self-consistently evaluate the drift velocity and temperature of electrons in graphene in the linear and nonlinear response regimes. We find that the current-voltage relation exhibits distinctly nonlinear behavior, especially in the high electric field regime. Under the action of high-fields the large source-drain (sd) current density can be achieved and the current saturation in graphene is incomplete with increasing the sd voltage Vsd up to 3 V. Moreover, for high fields, Vsd>0.1 V, the heating of electrons in graphene occurs. It is shown that the sd current and electron temperature are sensitive to electron density and lattice temperature in the graphene device. This study is relevant to the application of graphene as high-field nano-electronic devices such as graphene field-effect transistors. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000295619300059 |
Publication Date |
2011-09-19 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0021-8979; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.068 |
Times cited |
17 |
Open Access |
|
Notes |
; This work was supported by the National Natural Science Foundation of China (Grant No. 10974206) and the Department of Science and Technology of Yunnan Province. ; |
Approved |
Most recent IF: 2.068; 2011 IF: 2.168 |
Call Number |
UA @ lucian @ c:irua:93614 |
Serial |
1433 |
Permanent link to this record |
|
|
|
Author |
de Backer, A.; Van Aert, S.; van Dyck, D. |
Title |
High precision measurements of atom column positions using model-based exit wave reconstruction |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
111 |
Issue |
9/10 |
Pages |
1475-1482 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
In this paper, it has been investigated how to measure atom column positions as accurately and precisely as possible using a focal series of images. In theory, it is expected that the precision would considerably improve using a maximum likelihood estimator based on the full series of focal images. As such, the theoretical lower bound on the variances of the unknown atom column positions can be attained. However, this approach is numerically demanding. Therefore, maximum likelihood estimation has been compared with the results obtained by fitting a model to a reconstructed exit wave rather than to the full series of focal images. Hence, a real space model-based exit wave reconstruction technique based on the channelling theory is introduced. Simulations show that the reconstructed complex exit wave contains the same amount of information concerning the atom column positions as the full series of focal images. Only for thin samples, which act as weak phase objects, this information can be retrieved from the phase of the reconstructed complex exit wave. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000300461200004 |
Publication Date |
2011-07-28 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.843 |
Times cited |
8 |
Open Access |
|
Notes |
Fwo |
Approved |
Most recent IF: 2.843; 2011 IF: 2.471 |
Call Number |
UA @ lucian @ c:irua:91879 |
Serial |
1438 |
Permanent link to this record |
|
|
|
Author |
Turner, S.; Lazar, S.; Freitag, B.; Egoavil, R.; Verbeeck, J.; Put, S.; Strauven, Y.; Van Tendeloo, G. |
Title |
High resolution mapping of surface reduction in ceria nanoparticles |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
Volume |
3 |
Issue |
8 |
Pages |
3385-3390 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Surface reduction of ceria nano octahedra with predominant {111} and {100} type surfaces is studied using a combination of aberration-corrected Transmission Electron Microscopy (TEM) and spatially resolved electron energy-loss spectroscopy (EELS) at high energy resolution and atomic spatial resolution. The valency of cerium ions at the surface of the nanoparticles is mapped using the fine structure of the Ce M4,5 edge as a fingerprint. The valency of the surface cerium ions is found to change from 4+ to 3+ owing to oxygen deficiency (vacancies) close to the surface. The thickness of this Ce3+ shell is measured using atomic-resolution Scanning Transmission Electron Microscopy (STEM)-EELS mapping over a {111} surface (the predominant facet for this ceria morphology), {111} type surface island steps and {100} terminating planes. For the {111} facets and for {111} surface islands, the reduction shell is found to extend over a single fully reduced surface plane and 12 underlying mixed valency planes. For the {100} facets the reduction shell extends over a larger area of 56 oxygen vacancy-rich planes. This finding provides a plausible explanation for the higher catalytic activity of the {100} surface facets in ceria. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Cambridge |
Editor |
|
Language |
|
Wos |
000293521700057 |
Publication Date |
2011-06-30 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
2040-3364;2040-3372; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
7.367 |
Times cited |
127 |
Open Access |
|
Notes |
Fwo |
Approved |
Most recent IF: 7.367; 2011 IF: 5.914 |
Call Number |
UA @ lucian @ c:irua:90361UA @ admin @ c:irua:90361 |
Serial |
1458 |
Permanent link to this record |
|
|
|
Author |
Földi, P.; Szaszkó-Bogár, V.; Peeters, F.M. |
Title |
High-temperature conductance of a two-dimensional superlattice controlled by spin-orbit interaction |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
83 |
Issue |
11 |
Pages |
115313-115313,6 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Rashba-type spin-orbit interaction (SOI) controlled band structure of a two-dimensional superlattice allows for the modulation of the conductance of finite size devices by changing the strength of the SOI. We consider rectangular arrays and find that the temperature dependence of the conductance disappears for high temperatures, but the strength of the SOI still affects the conductance at these temperatures. The modulation effect can be seen even in the presence of strong dephasing, which can be important for practical applications. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000288242800007 |
Publication Date |
2011-03-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
8 |
Open Access |
|
Notes |
; We thank M. G. Benedict and F. Bartha for useful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the Hungarian Scientific Research Fund (OTKA) under Contracts No. T81364 and M045596 and by the “TAMOP-4.2.1/B-09/1/KONV-2010-0005 project: Creating the Center of Excellence at the University of Szeged” supported by the EU and the European Regional Development Fund. P.F. was supported by a J. Bolyai grant of the Hungarian Academy of Sciences. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:88778 |
Serial |
1466 |
Permanent link to this record |
|
|
|
Author |
King, G.; Abakumov, A.M.; Woodward, P.M.; Llobet, A.; Tsirlin, A.A.; Batuk, D.; Antipov, E.V. |
Title |
The high-temperature polymorphs of K3AlF6 |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
Volume |
50 |
Issue |
16 |
Pages |
7792-7801 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The crystal structures of the three high-temperature polymorphs of K3AlF6 have been solved from neutron powder diffraction, synchrotron X-ray powder diffraction, and electron diffraction data. The β-phase (stable between 132 and 153 °C) and γ-phase (stable between 153 to 306 °C) can be described as unusually complex superstructures of the double-perovskite structure (K2KAlF6) which result from noncooperative tilting of the AlF6 octahedra. The β-phase is tetragonal, space group I4/m, with lattice parameters of a = 13.3862(5) Å and c = 8.5617(3) Å (at 143 °C) and Z = 10. In this phase, one-fifth of the AlF6 octahedra are rotated about the c-axis by 45° while the other four-fifths remain untilted. The large 45° rotations result in edge sharing between these AlF6 octahedra and the neighboring K-centered polyhedra, resulting in pentagonal bipyramidal coordination for four-fifths of the K+ ions that reside on the B-sites of the perovskite structure. The remaining one-fifth of the K+ ions on the B-sites retain octahedral coordination. The γ-phase is orthorhombic, space group Fddd, with lattice parameters of a = 36.1276(4) Å, b = 17.1133(2) Å, and c = 12.0562(1) Å (at 225 °C) and Z = 48. In the γ-phase, one-sixth of the AlF6 octahedra are randomly rotated about one of two directions by 45° while the other five-sixths remain essentially untilted. These rotations result in two-thirds of the K+ ions on the B-site obtaining 7-fold coordination while the other one-third remain in octahedral coordination. The δ-phase adopts the ideal cubic double-perovskite structure, space group Fmm, with a = 8.5943(1) Å at 400 °C. However, pair distribution function analysis shows that locally the δ-phase is quite different from its long-range average crystal structure. The AlF6 octahedra undergo large-amplitude rotations which are accompanied by off-center displacements of the K+ ions that occupy the 12-coordinate A-sites. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Easton, Pa |
Editor |
|
Language |
|
Wos |
000293493100052 |
Publication Date |
2011-07-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0020-1669;1520-510X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.857 |
Times cited |
19 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 4.857; 2011 IF: 4.601 |
Call Number |
UA @ lucian @ c:irua:91131 |
Serial |
1468 |
Permanent link to this record |