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Author Neek-Amal, M.; Beheshtian, J.; Sadeghi, A.; Michel, K.H.; Peeters, F.M.
Title Boron nitride mono layer : a strain-tunable nanosensor Type A1 Journal article
Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 117 Issue 25 Pages 13261-13267
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract The influence of triaxial in-plane strain on the electronic properties of a hexagonal boron-nitride sheet is investigated using density functional theory. Different from graphene, the triaxial strain localizes the molecular orbitals of the boron-nitride flake in its center depending on the direction of the applied strain. The proposed technique for localizing the molecular orbitals that are close to the Fermi level in the center of boron nitride flakes can be used to actualize engineered nanosensors, for instance, to selectively detect gas molecules. We show that the central part of the strained flake adsorbs polar molecules more strongly as compared with an unstrained sheet.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000321236400041 Publication Date 2013-06-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 38 Open Access
Notes (down) ; This work was supported by the EU-Marie Curie IIF postdoc Fellowship/299855 (for M.N.-A.), the ESF EuroGRAPHENE project CONGRAN, the Flemish Science Foundation (FWO-VI), and the Methusalem Funding of the Flemish government. AS. would like to thank the Universiteit Antwerpen for its hospitality. ; Approved Most recent IF: 4.536; 2013 IF: 4.835
Call Number UA @ lucian @ c:irua:109829 Serial 249
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Author Seyed-Talebi, S.M.; Beheshtian, J.; Neek-Amal, M.
Title Doping effect on the adsorption of NH3 molecule onto graphene quantum dot : from the physisorption to the chemisorption Type A1 Journal article
Year 2013 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 114 Issue 12 Pages 124307-7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The adsorption of ammonia molecule onto a graphene hexagonal flake, aluminum (Al) and boron (B) doped graphene flakes (graphene quantum dots, GQDs) are investigated using density functional theory. We found that NH3 molecule is absorbed to the hollow site through the physisorption mechanism without altering the electronic properties of GQD. However, the adsorption energy of NH3 molecule onto the Al- and B-doped GQDs increases with respect GQD resulting chemisorption. The adsorption of NH3 onto the Al-doped and B-doped GQDs makes graphene locally buckled, i.e., B-doped and Al-doped GQDs are not planar. The adsorption mechanism onto a GQD is different than that of graphene. This study reveals important features of the edge passivation and doping effects of the adsorption mechanism of external molecules onto the graphene quantum dots. (C) 2013 AIP Publishing LLC.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000325391100057 Publication Date 2013-09-26
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 10 Open Access
Notes (down) ; This work was supported by the EU-Marie Curie IIF Fellowship/299855 for M.-N.A. ; Approved Most recent IF: 2.068; 2013 IF: 2.185
Call Number UA @ lucian @ c:irua:112201 Serial 750
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Author Arsoski, V.V.; Tadić, M.Z.; Peeters, F.M.
Title Strain and band-mixing effects on the excitonic Aharonov-Bohm effect in In(Ga)As/GaAs ringlike quantum dots Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages 085314-14
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Neutral excitons in strained axially symmetric In(Ga)As/GaAs quantum dots with a ringlike shape are investigated. Similar to experimental self-assembled quantum rings, the analyzed quantum dots have volcano-like shapes. The continuum mechanical model is employed to determine the strain distribution, and the single-band envelope function approach is adopted to compute the electron states. The hole states are determined by the axially symmetric multiband Luttinger-Kohn Hamiltonian, and the exciton states are obtained from an exact diagonalization. We found that the presence of the inner layer covering the ring opening enhances the excitonic Aharonov-Bohm (AB) oscillations. The reason is that the hole becomes mainly localized in the inner part of the quantum dot due to strain, whereas the electron resides mainly inside the ring-shaped rim. Interestingly, larger AB oscillations are found in the analyzed quantum dot than in a fully opened quantum ring of the same width. Comparison with the unstrained ringlike quantum dot shows that the amplitude of the excitonic Aharonov-Bohm oscillations are almost doubled in the presence of strain. The computed oscillations of the exciton energy levels are comparable in magnitude to the oscillations measured in recent experiments. DOI: 10.1103/PhysRevB.87.085314
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315278000003 Publication Date 2013-02-25
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 18 Open Access
Notes (down) ; This work was supported by the EU NoE: SANDiE, the Ministry of Education, Science, and Technological Development of Serbia, and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107656 Serial 3165
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Author Arsoski, V.; Tadic, M.; Peeters, F.M.
Title Electric field tuning of the optical excitonic Aharonov-Bohm effect in nanodots grown by droplet epitaxy Type A1 Journal article
Year 2013 Publication Physica scripta Abbreviated Journal Phys Scripta
Volume T157 Issue Pages 014002
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Neutral excitons in axially symmetric GaAs nanodots embedded in an (Al, Ga) As matrix, which are formed by the droplet epitaxy technique, are investigated theoretically. An electric field perpendicular to the nanodot base results in both a vertical and an in-plane exciton polarization, which is beneficial for the appearance of the excitonic Aharonov-Bohm effect. In the range of low magnetic fields (below 5 Tesla), we found that the bright and dark exciton states can cross twice. This results in oscillations of the photoluminescence intensity with magnetic field, which are a striking manifestation of the optical excitonic Aharonov-Bohm effect.
Address
Corporate Author Thesis
Publisher Place of Publication Stockholm Editor
Language Wos 000332504600003 Publication Date 2013-11-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-8949 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.28 Times cited Open Access
Notes (down) ; This work was supported by the EU Network of Excellence: SANDiE, the Ministry of Education and Science of Serbia, the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). ; Approved Most recent IF: 1.28; 2013 IF: 1.296
Call Number UA @ lucian @ c:irua:128901 Serial 4594
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Author Zhu, J.-J.; Badalyan, S.M.; Peeters, F.M.
Title Plasmonic excitations in Coulomb-coupled N-layer graphene structures Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 8 Pages 085401-85408
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study Dirac plasmons and their damping in spatially separated N-layer graphene structures at finite doping and temperatures. The plasmon spectrum consists of one optical excitation with square-root dispersion and N – 1 acoustical excitations with linear dispersion, which are undamped at zero temperature and finite doping within a triangular energy region outside the electron-hole continuum. In the long-wavelength limit the energy and weight of the optical plasmon modes increase, respectively, as the square root and linearly with N in agreement with recent experimental findings. The energy and weight of the upper-lying acoustical branches also increase with N. This increase is strongest for the uppermost acoustical mode, and we find that its energy can exceed at some value of momentum the plasmon energy in an individual graphene sheet. Meanwhile, the energy of the low-lying acoustical branches decreases weakly with N as compared with the single acoustical mode in double-layer graphene structures. Our numerical calculations provide a detailed understanding of the overall behavior of the wave-vector dependence of the optical and acoustical multilayer plasmon modes and show how their dispersion and damping are modified as a function of temperature, interlayer spacing, and inlayer carrier density in (un)balanced graphene multilayer structures. DOI: 10.1103/PhysRevB.87.085401
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000314682900005 Publication Date 2013-02-05
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 59 Open Access
Notes (down) ; This work was supported by the ESF-Eurocores program EuroGRAPHENE (CONGRAN project) and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107671 Serial 2645
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Author Zhang, S.H.; Xu, W.; Badalyan, S.M.; Peeters, F.M.
Title Piezoelectric surface acoustical phonon limited mobility of electrons in graphene on a GaAs substrate Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 7 Pages 075443-75445
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study the mobility of Dirac fermions in monolayer graphene on a GaAs substrate, limited by the combined action of the extrinsic potential of piezoelectric surface acoustical phonons of GaAs (PA) and of the intrinsic deformation potential of acoustical phonons in graphene (DA). In the high-temperature (T) regime, the momentum relaxation rate exhibits the same linear dependence on T but different dependencies on the carrier density n, corresponding to the mobility mu proportional to 1 root n and 1/n, respectively for the PA and DA scattering mechanisms. In the low-T Bloch-Gruneisen regime, the mobility shows the same square-root density dependence mu proportional to root n, but different temperature dependencies mu proportional to T-3 and T-4, respectively for PA and DA phonon scattering. DOI: 10.1103/PhysRevB.87.075443
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315375200008 Publication Date 2013-02-27
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 25 Open Access
Notes (down) ; This work was supported by the ESF-Eurocores program EuroGRAPHENE (CONGRAN project) and the Flemish Science Foundation (FWO-VI). ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:107655 Serial 2622
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Author Kapra, A.V.; Vodolazov, D.Y.; Misko, V.R.
Title Vortex transport in a channel with periodic constrictions Type A1 Journal article
Year 2013 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 26 Issue 9 Pages 095010-95011
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract By numerically solving the time-dependent Ginzburg-Landau equations in a type-II superconductor, characterized by a critical temperature T-c1, and the coherence length xi(1), with a channel formed by overlapping rhombuses (diamond-like channel) made of another type-II superconductor, characterized, in general, by different T-c2 and xi(2), we investigate the dynamics of driven vortex matter for varying parameters of the channel: the width of the neck connecting the diamond cells, the cell geometry, and the ratio between the coherence lengths in the bank and the channel. We analyzed samples with periodic boundary conditions (which we call 'infinite' samples) and finite-size samples (with boundaries for vortex entry/exit), and we found that by tuning the channel parameters, one can manipulate the vortex dynamics, e.g., change the transition from flux-pinned to flux-flow regime and tune the slope of the IV-curves. In addition, we analyzed the effect of interstitial vortices on these characteristics. The critical current of this device was studied as a function of the applied magnetic field, j(c)(H). The function j(c)(H) reveals a striking commensurability peak, in agreement with recent experimental observations. The obtained results suggest that the diamond channel, which combines the properties of pinning arrays and flux-guiding channels, can be a promising candidate for potential use in devices controlling magnetic flux motion.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000323073800016 Publication Date 2013-07-30
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 2 Open Access
Notes (down) ; This work was supported by the 'Odysseus' Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 2.878; 2013 IF: 2.796
Call Number UA @ lucian @ c:irua:110737 Serial 3898
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Author Pogosov, W.V.; Lin, N.; Misko, V.R.
Title Electron-hole symmetry and solutions of Richardson pairing model Type A1 Journal article
Year 2013 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 86 Issue 5 Pages 235-236
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Richardson approach provides an exact solution of the pairing Hamiltonian. This Hamiltonian is characterized by the electron-hole pairing symmetry, which is however hidden in Richardson equations. By analyzing this symmetry and using an additional conjecture, fulfilled in solvable limits, we suggest a simple expression of the ground state energy for an equally-spaced energy-level model, which is applicable along the whole crossover from the superconducting state to the pairing fluctuation regime. Solving Richardson equations numerically, we demonstrate a good accuracy of our expression.
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000320286200044 Publication Date 2013-05-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 6 Open Access
Notes (down) ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). W.V.P. acknowledges useful discussions with Monique Combescot and the support from the Dynasty Foundation, the RFBR (project No. 12-02-00339), and RFBR-CNRS programme (project No. 12-02-91055). ; Approved Most recent IF: 1.461; 2013 IF: 1.463
Call Number UA @ lucian @ c:irua:109657 Serial 935
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Author Orlova, N.V.; Shanenko, A.A.; Milošević, M.V.; Peeters, F.M.; Vagov, A.V.; Axt, V.M.
Title Ginzburg-Landau theory for multiband superconductors : microscopic derivation Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 13 Pages 134510-134518
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A procedure to derive the Ginzburg-Landau (GL) theory from the multiband BCS Hamiltonian is developed in a general case with an arbitrary number of bands and arbitrary interaction matrix. It combines the standard Gor'kov truncation and a subsequent reconstruction in order to match accuracies of the obtained terms. This reconstruction recovers the phenomenological GL theory as obtained from the Landau model of phase transitions but offers explicit microscopic expressions for the relevant parameters. Detailed calculations are presented for a three-band system treated as a prototype multiband superconductor. It is demonstrated that the symmetry in the coupling matrix may lead to the chiral ground state with the phase frustration, typical for systems with broken time-reversal symmetry. DOI: 10.1103/PhysRevB.87.134510
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000317586700002 Publication Date 2013-04-16
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 57 Open Access
Notes (down) ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). A.A.S. acknowledges useful discussions with D. Neilson. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:108464 Serial 1344
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Author Zhao, H.J.; Misko, V.R.; Peeters, F.M.
Title Dynamics of self-organized driven particles with competing range interaction Type A1 Journal article
Year 2013 Publication Physical review : E : statistical, nonlinear, and soft matter physics Abbreviated Journal Phys Rev E
Volume 88 Issue 2 Pages 022914-22917
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Nonequilibrium self-organized patterns formed by particles interacting through competing range interaction are driven over a substrate by an external force. We show that, with increasing driving force, the preexisted static patterns evolve into dynamic patterns either via disordered phase or depinned patterns or via the formation of nonequilibrium stripes. Strikingly, the stripes are formed either in the direction of the driving force or in the transverse direction, depending on the pinning strength. The revealed dynamical patterns are summarized in a dynamical phase diagram.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication Woodbury (NY) Editor
Language Wos 000323333000014 Publication Date 2013-08-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1539-3755;1550-2376; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.366 Times cited 23 Open Access
Notes (down) ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 2.366; 2013 IF: 2.326
Call Number UA @ lucian @ c:irua:110743 Serial 783
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Author Shanenko, A.A.; Orlova, N.V.; Vagov, A.; Milošević, M.V.; Axt, V.M.; Peeters, F.M.
Title Nanofilms as quantum-engineered multiband superconductors : the Ginzburg-Landau theory Type A1 Journal article
Year 2013 Publication Europhysics letters Abbreviated Journal Epl-Europhys Lett
Volume 102 Issue 2 Pages 27003-27006
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Recently fabricated single-crystalline atomically flat metallic nanofilms are in fact quantum-engineered multiband superconductors. Here the multiband structure is dictated by the nanofilm thickness through the size quantization of the electron motion perpendicular to the nanofilm. This opens the unique possibility to explore superconductivity in well-controlled multi-band systems. However, a serious obstacle is the absence of a convenient and manageable theoretical tool to access new physical phenomena in such quasi-two-dimensional systems, including interplay of quantum confinement and fluctuations. Here we cover this gap and construct the appropriate multiband Ginzburg-Landau functional for nano-thin superconductors. Copyright (C) EPLA, 2013
Address
Corporate Author Thesis
Publisher Place of Publication Paris Editor
Language Wos 000319617700019 Publication Date 2013-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0295-5075;1286-4854; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.957 Times cited 8 Open Access
Notes (down) ; This work was supported by the “Odysseus” Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 1.957; 2013 IF: 2.269
Call Number UA @ lucian @ c:irua:109859 Serial 2257
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Author Gomez, A.; Gonzalez, E.M.; Gilbert, D.A.; Milošević, M.V.; Liu, K.; Vicent, J.L.
Title Probing the dynamic response of antivortex, interstitial and trapped vortex lattices on magnetic periodic pinning potentials Type A1 Journal article
Year 2013 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 26 Issue 8 Pages 085018-8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The dynamics of the pinned vortex, antivortex and interstitial vortex have been studied in superconducting/magnetic hybrids consisting of arrays of Co/Pd multilayer nanodots embedded in Nb films. The magnetic nanodots show out-of-plane magnetization at the remanent state. This magnetic state allows for superconducting vortex lattices of different types in an applied homogeneous magnetic field. We experimentally and theoretically show three such lattices: (i) a lattice containing only antivortices; (ii) a vortex lattice entirely pinned on the dots; and (iii) a vortex lattice with pinned and interstitial vortices. Between the flux creep (low vortex velocity) and the free flux flow (high vortex velocity) regimes the interaction between the magnetic array and the vortex lattice governs the vortex dynamics, which in turn enables distinguishing experimentally the type of vortex lattice which governs the dissipation. We show that the vortex lattice with interstitial vortices has the highest onset velocity where the lattice becomes ordered, whereas the pinned vortex lattice has the smallest onset velocity. Further, for this system, we directly estimate that the external force needed to depin vortices is 60% larger than the one needed to depin antivortices; therefore we are able to decouple the antivortex-vortex motion.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000321709400024 Publication Date 2013-07-02
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 7 Open Access
Notes (down) ; This work was supported by Spanish MINECO, grants FIS2008-06249 (Grupo Consolidado), Consolider CSD2007-00010 and CAM grant S2009/MAT-1726. MVM acknowledges support from FWO-Vlaanderen. Work at UCD was supported by the US NSF (DMR-1008791 and ECCS-0925626). ; Approved Most recent IF: 2.878; 2013 IF: 2.796
Call Number UA @ lucian @ c:irua:109785 Serial 2716
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Author Villegas, C.E.P.; Tavares, M.R.S.; Hai, G.-Q.; Peeters, F.M.
Title Sorting the modes contributing to guidance in strain-induced graphene waveguides Type A1 Journal article
Year 2013 Publication New journal of physics Abbreviated Journal New J Phys
Volume 15 Issue Pages 023015-11
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We propose a simple way of probing the number of modes contributing to the channeling in graphene waveguides which are formed by a gauge potential produced by mechanical strain. The energy mode structure for both homogeneous and non-homogeneous strain regimes is carefully studied using the continuum description of the Dirac equation. We found that high strain values privilege negative (instead of positive) group velocities throughout the guidance, sorting the types of modes flowing through it. We also show how the effect of a substrate-induced gap competes against the strain.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000314868000002 Publication Date 2013-02-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1367-2630; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.786 Times cited 7 Open Access
Notes (down) ; This work was supported by FAPESP, CNPq and the Flemish Science Foundation (FWO-VI). ; Approved Most recent IF: 3.786; 2013 IF: 3.671
Call Number UA @ lucian @ c:irua:107667 Serial 3056
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Author Berdiyorov, G.R.; Savel'ev, S.E.; Kusmartsev, F.V.; Peeters, F.M.
Title In-phase motion of Josephson vortices in stacked SNS Josephson junctions : effect of ordered pinning Type A1 Journal article
Year 2013 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech
Volume 26 Issue 12 Pages 125010-125016
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting Josephson junctions is investigated using the anisotropic time-dependent Ginzburg-Landau theory in the presence of a square/rectangular array of pinning centers (holes). For small values of the applied drive, fluxons in different junctions move out of phase, forming a periodic triangular lattice. A rectangular lattice of moving fluxons is observed at larger currents, which is in agreement with previous theoretical predictions (Koshelev and Aranson 2000 Phys. Rev. Lett. 85 3938). This 'superradiant' flux-flow state is found to be stable in a wide region of applied current. The stability range of this ordered state is considerably larger than the one obtained for the pinning-free sample. Clear commensurability features are observed in the current-voltage characteristics of the system with pronounced peaks in the critical current at (fractional) matching fields. The effect of density and strength of the pinning centers on the stability of the rectangular fluxon lattice is discussed. Predicted synchronized motion of fluxons in the presence of ordered pinning can be detected experimentally using the rf response of the system, where enhancement of the Shapiro-like steps is expected due to the synchronization.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000327447200013 Publication Date 2013-10-29
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 5 Open Access
Notes (down) ; This work was supported by EU Marie Curie (Project No: 253057) and by the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 2.878; 2013 IF: 2.796
Call Number UA @ lucian @ c:irua:112834 Serial 1573
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Author Lucena, D.; Ferreira, W.P.; Munarin, F.F.; Farias, G.A.; Peeters, F.M.
Title Tunable diffusion of magnetic particles in a quasi-one-dimensional channel Type A1 Journal article
Year 2013 Publication Physical review : E : statistical, nonlinear, and soft matter physics Abbreviated Journal Phys Rev E
Volume 87 Issue 1 Pages 012307-12309
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The diffusion of a system of ferromagnetic dipoles confined in a quasi-one-dimensional parabolic trap is studied using Brownian dynamics simulations. We show that the dynamics of the system is tunable by an in-plane external homogeneous magnetic field. For a strong applied magnetic field, we find that the mobility of the system, the exponent of diffusion, and the crossover time among different diffusion regimes can be tuned by the orientation of the magnetic field. For weak magnetic fields, the exponent of diffusion in the subdiffusive regime is independent of the orientation of the external field. DOI: 10.1103/PhysRevE.87.012307
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication Woodbury (NY) Editor
Language Wos 000314152300005 Publication Date 2013-01-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1539-3755;1550-2376; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.366 Times cited 11 Open Access
Notes (down) ; This work was supported by CNPq, CAPES, FUNCAP (Pronex grant), the Flemish Science Foundation (FWO-Vl), the bilateral program between Flanders and Brazil, the collaborative program CNPq – FWO-Vl, and the Brazilian program Science Without Borders (CsF). Discussions with V. R. Misko are gratefully acknowledged. ; Approved Most recent IF: 2.366; 2013 IF: 2.326
Call Number UA @ lucian @ c:irua:110089 Serial 3739
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Author Smits, M.; Chan, C. kit; Tytgat, T.; Craeye, B.; Costarramone, N.; Lacombe, S.; Lenaerts, S.
Title Photocatalytic degradation of soot deposition : self-cleaning effect on titanium dioxide coated cementitious materials Type A1 Journal article
Year 2013 Publication Chemical engineering journal Abbreviated Journal Chem Eng J
Volume 222 Issue Pages 411-418
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract Diesel soot emissions deteriorate the appearance of architectural building materials by soot fouling. This soot deposition devalue the aesthetic value of the building. A solution to counteract this problem is applying titanium dioxide on building materials. TiO2 can provide air-purifying and self-cleaning properties due to its photocatalytic activity. In literature, photocatalytic soot oxidation is observed on glass or silicon substrates. However, degradation of soot by photocatalysis was not yet investigated on cementitious samples (mortar, concrete) although it is one of the most frequently used building materials. In this study, photocatalytic soot oxidation by means of TiO2 coated cementitious samples is addressed. The soot removal capacity of four types of TiO2 layers, coated on mortar samples, is evaluated by means of two detection methods. The first method is based on colorimetric measurements, while the second method uses digital image processing to calculate the area of soot coverage. The experimental data revealed that cementitious materials coated with commercially available TiO2 exhibited self-cleaning properties as it was found that all coated samples were able to remove soot. The P25 coating gave the best soot degradation performance, while the Eoxolit product showed the slowest soot degradation rate. In addition, gas chromatography measurements in a closed chamber experiment with P25 confirmed that complete mineralization of about 60% of the soot was obtained within 24 hours since CO2 was the sole observed oxidation product. Due to its realistic approach, this study proves that photocatalytic soot removal on TiO2 coated cementitious surfaces is possible in practice, which is an important step towards the practical application of self-cleaning building materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000319528900046 Publication Date 2013-03-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1385-8947; 1873-3212 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.216 Times cited 43 Open Access
Notes (down) ; This work was supported by a PhD grant (M. Smits) from the University of Antwerp, a PhD grant (T. Tytgat) funded by the Institute of Innovation by Science and Technology in Flanders (IWT) and the exchange program Tournesol (Project T2012.05) financed by the Flemish government. ; Approved Most recent IF: 6.216; 2013 IF: 4.058
Call Number UA @ admin @ c:irua:106519 Serial 5979
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Author Barba-Ortega, J.; Sardella, E.; Aguiar, J.A.; Peeters, F.M.
Title Non-conventional vortex configurations in a mesoscopic flat disk Type A1 Journal article
Year 2013 Publication Physica: C : superconductivity Abbreviated Journal Physica C
Volume 487 Issue Pages 47-55
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The influence of superficial defects on the vortex configurations of a thin superconducting disk is investigated within the time dependent Ginzburg-Landau formalism. The free energy, magnetization, vorticity, and the Cooper pair density are calculated for both metastable and stable vortex configurations and different number of defects on its surface in the presence of an external magnetic field applied perpendicular to the disk area. We show that the competition between the confinement geometry and the geometric position of the defects leads to non-conventional vortex configurations which are not compatible with the symmetry of the sample geometry. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000317743300009 Publication Date 2013-02-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4534; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.404 Times cited 17 Open Access
Notes (down) ; This work was partially supported by the Brazilian agencies CNPq, CAPES, FACEPE (APQ 0589-105/08), FAPESP, CNPq-FWO bilateral project, and Colombian Agencies Colciencias and DIB. ; Approved Most recent IF: 1.404; 2013 IF: 1.110
Call Number UA @ lucian @ c:irua:108486 Serial 2344
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Author de Sousa, A.A.; Chaves, A.; Farias, G.A.; Peeters, F.M.
Title Braess paradox at the mesoscopic scale Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 88 Issue 24 Pages 245417-6
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We theoretically demonstrate that the transport inefficiency recently found experimentally for branched-out mesoscopic networks can also be observed in a quantum ring of finite width with an attached central horizontal branch. This is done by investigating the time evolution of an electron wave packet in such a system. Our numerical results show that the conductivity of the ring does not necessary improve if one adds an extra channel. This ensures that there exists a quantum analog of the Braess paradox, originating from quantum scattering and interference.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000328680500011 Publication Date 2013-12-17
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 17 Open Access
Notes (down) ; This work was financially supported by PRONEX/CNPq/FUNCAP and the bilateral project CNPq-FWO. Discussions with J. S. Andrade, Jr. are gratefully acknowledged. A. A. S. has been financially supported by CAPES, under PDSE Contract No. BEX 7177/13-5. ; Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:113705 Serial 253
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Author Carrillo-Nunez, H.; Magnus, W.; Vandenberghe, W.G.; Sorée, B.; Peeters, F.M.
Title Phonon-assisted Zener tunneling in a p-n diode silicon nanowire Type A1 Journal article
Year 2013 Publication Solid state electronics Abbreviated Journal Solid State Electron
Volume 79 Issue Pages 196-200
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The Zener tunneling current flowing through a biased, abrupt p-n junction embedded in a cylindrical silicon nanowire is calculated. As the band gap becomes indirect for sufficiently thick wires, Zener tunneling and its related transitions between the valence and conduction bands are mediated by short-wavelength phonons interacting with mobile electrons. Therefore, not only the high electric field governing the electrons in the space-charge region but also the transverse acoustic (TA) and transverse optical (TO) phonons have to be incorporated in the expression for the tunneling current. The latter is also affected by carrier confinement in the radial direction and therefore we have solved the Schrodinger and Poisson equations self-consistently within the effective mass approximation for both conduction and valence band electrons. We predict that the tunneling current exhibits a pronounced dependence on the wire radius, particularly in the high-bias regime. (C) 2012 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000313611000037 Publication Date 2012-09-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1101; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.58 Times cited 2 Open Access
Notes (down) ; This work is supported by the Flemish Science Foundation (FWO-VI), and the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC. One of the authors (W. 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: 1.58; 2013 IF: 1.514
Call Number UA @ lucian @ c:irua:110104 Serial 2600
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Author Dantas, D.S.; Chaves, A.; Farias, G.A.; Ramos, A.C.A.; Peeters, F.M.
Title Low-dimensional confining structures on the surface of helium films suspended on designed cavities Type A1 Journal article
Year 2013 Publication Journal of low temperature physics Abbreviated Journal J Low Temp Phys
Volume 173 Issue 3-4 Pages 207-226
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We investigate the formation of quantum confined structures on the surface of a liquid helium film suspended on a nanostructured substrate. We show theoretically that, by nanostructuring the substrate, it is possible to change the geometry of the liquid helium surface, opening the possibility of designing and controlling the formation of valleys with different shapes. By applying an external electric field perpendicular to the substrate plane, surface electrons can be trapped into these valleys, as in a quantum dot. We investigate how the external parameters, such as the electric field strength and the height of the liquid helium bath, can be tuned to control the energy spectrum of the trapped surface electrons.
Address
Corporate Author Thesis
Publisher Place of Publication New York Editor
Language Wos 000324820300008 Publication Date 2013-08-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-2291;1573-7357; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.3 Times cited 1 Open Access
Notes (down) ; This work has received financial support from the Brazilian National Research Council (CNPq), Fundacao Cearense de Apoio ao Desenvolvimento Cientifico e Tecnologico (Funcap), CAPES and Pronex/CNPq/Funcap. This work was partially supported by the Flemish Science Foundation (FWO-Vl) and the bilateral project between CNPq and FWO-Vl. ; Approved Most recent IF: 1.3; 2013 IF: 1.036
Call Number UA @ lucian @ c:irua:111140 Serial 1845
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Author Alfeld, M.; Siddons, D.P.; Janssens, K.; Dik, J.; Woll, A.; Kirkham, R.; van de Wetering, E.
Title Visualizing the 17th century underpainting in Portrait of an Old Man by Rembrandt van Rijn using synchrotron-based scanning macro-XRF Type A1 Journal article
Year 2013 Publication Applied physics A : materials science & processing Abbreviated Journal Appl Phys A-Mater
Volume 111 Issue 1 Pages 157-164
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract In 17th century Old Master Paintings, the underpainting generally refers to the first sketch of a composition. The underpainting is applied to a prepared ground using a monochrome, brown oil paint to roughly indicate light, shade and contours. So far, methods to visualize the underpainting-other than in localized cross-sections-have been very limited. Neither infrared reflectography nor neutron induced autoradiography have proven to be practical, adequate visualization tools. Thus, although of fundamental interest in the understanding of a painting's genesis, the underpainting has virtually escaped all imaging efforts. In this contribution we will show that 17th century underpainting may consist of a highly heterogeneous mixture of pigments, including copper pigments. We suggest that this brown pigment mixture is actually the recycled left-over of a palette scraping. With copper as the heaviest exclusive elemental component, we will hence show in a case study on a Portrait of an Old Man attributed to Rembrandt van Rijn how scanning macro-XRF can be used to efficiently visualize the underpainting below the surface painting and how this information can contribute to the discussion of the painting's authenticity.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000316075700019 Publication Date 2012-12-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-8396 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.455 Times cited 26 Open Access
Notes (down) ; This research was supported by the SSD programme of BELSPO, Brussels (project S2-ART). The text also presents results of GOA 'XANES meets ELNES' (Research Fund, University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects nos. G.0704.08 and G.01769.09. Further, the research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 226716. M. Alfeld receives a Ph.D. fellowship of the Research Foundation-Flanders (FWO). Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886. We acknowledge the assistance of C. Ryan, CSIRO Australia, in the preparation of the elemental maps using GeoPIXE and Rene Gerritsen (http://www.renegerritsen.nl) in providing photographs, XRR and IRR of the painting. We thank Sullivan Entertainment for documenting part of this project in their TV documentary 'Out of the shadows'. ; Approved Most recent IF: 1.455; 2013 IF: 1.694
Call Number UA @ admin @ c:irua:108263 Serial 5908
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Author Alfeld, M.; van der Snickt, G.; Vanmeert, F.; Janssens, K.; Dik, J.; Appel, K.; van der Loeff, L.; Chavannes, M.; Meedendorp, T.; Hendriks, E.
Title Scanning XRF investigation of a Flower Still Life and its underlying composition from the collection of the Kröller-Muller Museum Type A1 Journal article
Year 2013 Publication Applied physics A : materials science & processing Abbreviated Journal Appl Phys A-Mater
Volume 111 Issue 1 Pages 165-175
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000316075700020 Publication Date 2013-01-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-8396 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.455 Times cited 35 Open Access
Notes (down) ; This research was supported by the SSD program of BELSPO, Brussels (project S2-ART). Results are also presented here from Gemeenschappelijke Onderzoeksactie (GOA) 'XANES meets ELNES' (Research Fund, University of Antwerp, Belgium) and from Fonds voor Wetenschappelijk Onderzoek (FWO) (Brussels, Belgium) project Nos. G.0704.08 and G.01769.09. The research leading to these results was funded by the European Community's Seventh Framework Program (FP7/2007-2013) under grant agreement No. 226716 and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) under the VIDI project “Looking Over the Painter's Shoulder” (grant No. 700.10.426). M. Alfeld is the recipient of a Ph.D. fellowship of the Research Foundation-Flanders (FWO). ; Approved Most recent IF: 1.455; 2013 IF: 1.694
Call Number UA @ admin @ c:irua:108264 Serial 5826
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Author Mudronja, D.; Vanmeert, F.; Hellemans, K.; Fazinic, S.; Janssens, K.; Tibljas, D.; Rogosic, M.; Jakovljevic, S.
Title Efficiency of applying ammonium oxalate for protection of monumental limestone by poultice, immersion and brushing methods Type A1 Journal article
Year 2013 Publication Applied physics A : materials science & processing Abbreviated Journal Appl Phys A-Mater
Volume 111 Issue 1 Pages 109-119
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Samples of cretaceous limestone have been treated with three application methods (poultice, immersion and brushing) using different concentrations of ammonium oxalate solution (AmOx) and varying treatment time in order to test the efficiency of surface and in-depth formation of a protective layer of calcium oxalate (CaOx). Synchrotron-based microanalytical techniques (SR-mu XRD with 12.5 mu mx7.5 mu m (HxV) probe size, SR-mu FTIR with 10 mu mx10 mu m and 8 mu mx20 mu m probe sizes) and laboratory mu FTIR, XRD and SEM have been employed for analysis of the treated samples. Synchrotron-based techniques showed variations in the CaOx distribution along the surface on a micrometer scale. All treatments resulted in the development of a CaOx layer with a maximum thickness of approximately 40 mu m. Application by the brushing method with 10 1-min applications with 5-min breaks during one hour showed a development of the calcium oxalate layer equivalent to the poultice treatment taking 10 h. This treatment could be preferred for large marble or limestone surfaces where poultice usage is economically not feasible.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000316075700014 Publication Date 2012-10-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-8396 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.455 Times cited 13 Open Access
Notes (down) ; This research was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16). The text also presents results of GOA 'XANES meets ELNES' (Research Fund, University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0704.08 and G.01769.09. The research leading to these results has received financial support by the Access to Research Infrastructures activity in the 7th Framework Programme of the EU (CHARISMA Grant Agreement No. 228330). ; Approved Most recent IF: 1.455; 2013 IF: 1.694
Call Number UA @ admin @ c:irua:108262 Serial 5584
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Author Alfeld, M.; Pedroso, J.V.; van Hommes, M.E.; van der Snickt, G.; Tauber, G.; Blaas, J.; Haschke, M.; Erler, K.; Dik, J.; Janssens, K.
Title A mobile instrument for in situ scanning macro-XRF investigation of historical paintings Type A1 Journal article
Year 2013 Publication Journal of analytical atomic spectrometry Abbreviated Journal J Anal Atom Spectrom
Volume 28 Issue 5 Pages 760-767
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Scanning macro-X-ray fluorescence analysis (MA-XRF) is rapidly being established as a technique for the investigation of historical paintings. The elemental distribution images acquired by this method allow for the visualization of hidden paint layers and thus provide insight into the artist's creative process and the painting's conservation history. Due to the lack of a dedicated, commercially available instrument the application of the technique was limited to a few groups that constructed their own instruments. We present the first commercially available XRF scanner for paintings, consisting of an X-ray tube mounted with a Silicon-Drift (SD) detector on a motorized stage to be moved in front of a painting. The scanner is capable of imaging the distribution of the main constituents of surface and sub-surface paint layers in an area of 80 by 60 square centimeters with dwell times below 10 ms and a lateral resolution below 100 mu m. The scanner features for a broad range of elements between Ti (Z = 22) and Mo (Z = 42) a count rate of more than 1000 counts per second (cps)?mass percent and detection limits of 100 ppm for measurements of 1 s duration. Next to a presentation of spectrometric figures of merit, the value of the technique is illustrated through a case study of a painting by Rembrandt's student Govert Flinck (1615-1660).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000317674200019 Publication Date 2013-03-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0267-9477 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.379 Times cited 106 Open Access
Notes (down) ; This research was supported by the Interuniversity Attraction Poles Programme – Belgian Science Policy (IUAP VI/16). The text also presents the results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. M. Alfeld receives a Ph. D. fellowship of the Research Foundation-Flanders (FWO). We thank J. Langerock for allowing us to examine the portable altar triptych shown in Fig. 5. ; Approved Most recent IF: 3.379; 2013 IF: 3.396
Call Number UA @ admin @ c:irua:108517 Serial 5453
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Author Nuyts, G.; Cagno, S.; Hellemans, K.; Veronesi, G.; Cotte, M.; Janssens, K.
Title Study of the early stages of Mn intrusion in corroded glass by means of combined SR FTIR/\muXRF imaging and XANES spectroscopy Type P1 Proceeding
Year 2013 Publication Procedia Chemistry T2 – Youth in Conservation of Cultural Heritage Conference (YOCOCU), June 18-20, 2012, University of Antwerp, Antwerp, Belgium Abbreviated Journal
Volume Issue Pages 239-247
Keywords P1 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Historical glass, especially medieval glass, can undergo weathering under the influence of time and environmental conditions. The aim of this investigation was to better understand the processes involved in this natural degradation process by studying artificially altered glass samples prepared for the use of evaluation of conservation methods. Non-durable glass sensors produced by the Fraunhofer Institute (type M1.0) were used as a starting material for artificial alteration. These were immersed in acidic (pH = 0, 2, 4) and neutral solutions (1 h – 8 h). In a second stage the glass samples were immersed in a 0.5 M MnCl2 solution (24 h, 48 h and 72 h), allowing intrusion of Mn from the solution into the gel layer. The samples were characterized at different stages with reflectance FTIR spectroscopy, mu XRF mapping and mu XANES. All measurements were carried out at ESRF, beamline ID21. Reflectance FTIR spectroscopy measurements were performed in the 800 4000 cm(-1) range. Cluster analysis of the resulting maps evidenced the rapid growth of the gel layer in strong acidic conditions. The average spectra for each cluster feature show for the original glass a strong Si-O- stretching band between 900 and 1000 cm(-1), whereas the gel layer could be identified by the increasing Si-O-Si bands around 1100 and 1250 cm(-1). mu XRF maps were recorded at different stages of the experiment at energies around the Mn-K edge (6.539 keV) and with a step size of 2 by 2 m. These confirm the leaching of K+ and Ca+2 from the glass and the intrusion of Mn from the solution. Mn was found throughout the entire gel layer, but with a concentration gradient peaking at the surface. XANES point measurements were recorded at various points where Mn was present. No spatial variation was found, but linear combination fitting of the spectra with various Mn reference compounds indicated that Mn2+Mn23+O4 is the main Mn compound in the gel layer, as was hypothesised by Watkinson et al. The standard corroded glass samples studied here can be used for the evaluation of conservation treatments in follow-up experiments. (C) 2013 The Authors. Published by Elsevier B.V. Selection and peer-review under responsibility of the IA-CS (Italian Association of Conservation Scientists) and University of Antwerp
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000321673900030 Publication Date 2013-04-17
Series Editor Series Title Abbreviated Series Title
Series Volume 8 Series Issue Edition
ISSN 1876-6196 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 4 Open Access
Notes (down) ; This research was supported by the Interuniversity Attraction Poles Programme – Belgian Science Policy (IUAP VI/16). The text also presents results of GOA XANES “meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. We gratefully acknowledge ESRF for granting beamtime (experiment EC873). ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:109871 Serial 5851
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Author Alfeld, M.; de Nolf, W.; Cagno, S.; Janssens, K.; et al.
Title Revealing hidden paint layers in oil paintings by means of scanning macro-XRF : a mock-up study based on Rembrandt's “An old man in military costume” Type A1 Journal article
Year 2013 Publication Journal of analytical atomic spectrometry Abbreviated Journal J Anal Atom Spectrom
Volume 28 Issue 1 Pages 40-51
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Over the past several decades the oeuvre of Rembrandt has been the subject of extensive art historical and scientific investigations. One of the most striking features to emerge is his frequent re-use of canvases and panels. The painting An Old Man in Military Costume (78.PB.246), in the collection of the J. Paul Getty Museum, is an example of such a re-used panel. Conventional imaging techniques revealed the presence of a second portrait under the surface portrait, but the details of this hidden portrait have not yet been revealed. Vermilion (HgS) has been identified to have been used nearly exclusively in the flesh tones of the lower painting, suggesting that element-specific XRF imaging might successfully image the hidden portrait. To test this hypothesis, a full-scale mock-up of the painting was created, including a “free impression” of the hidden portrait, reproducing as closely as possible the pigments and paint stratigraphy of the original painting. XRF imaging of the mock-up painting was conducted using three different XRF imaging systems: a mobile X-ray tube based system and two synchrotron-based setups (one equipped with multiple SDDs and one equipped with a Maia detector). The sensitivity, limits of detection and imaging capabilities of each system under the chosen experimental conditions are evaluated and compared. The results indicate that an investigation of the original painting by this method would have an excellent chance of success.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000314903400003 Publication Date 2012-11-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0267-9477 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.379 Times cited Open Access
Notes (down) ; This research was supported by the Interuniversity Attraction Poles Programme – Belgian Science Policy (IUAP VI/16). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. Further, the research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 226716. M. Alfeld receives a Ph.D. fellowship of the Research Foundation – Flanders (FWO). The authors gratefully acknowledge Yvonne Szafran and the staff of the Paintings Conservation Department of the J. Paul Getty Museum for making available their infrared reflectography (IRR) and X-radiographic images of the painting, and also the neutron activation analysis (NAA) images acquired in 1996 at NIST by Dr Henry Prask in collaboration with Mark Leonard, former head of the J. Paul Getty Museum Paintings Conservation Department. We are also grateful to Peter Reischig, a graduate intern at the Getty Conservation Institute and a Ph.D. candidate at Delft University of Technology for his assistance. ; Approved Most recent IF: 3.379; 2013 IF: 3.396
Call Number UA @ admin @ c:irua:107704 Serial 5818
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Author Monico, L.; Janssens, K.; Miliani, C.; van der Snickt, G.; Brunetti, B.G.; Guidi, M.C.; Radepont, M.; Cotte, M.
Title Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : 4 : artificial aging of model samples of co-precipitates of lead chromate and lead sulfate Type A1 Journal article
Year 2013 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 85 Issue 2 Pages 860-867
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Previous investigations about the darkening of chrome yellow pigments revealed that this form of alteration is attributable to a reduction of the original Cr(VI) to Cr(III), and that the presence of sulfur-containing compounds, most often sulfates, plays a key role during this process. We recently demonstrated that different crystal forms of chrome yellow pigments (PbCrO4 and PbCr1xSxO4) are present in paintings by Vincent van Gogh. In the present work, we show how both the chemical composition and the crystalline structure of lead chromate-based pigments influence their stability. For this purpose, oil model samples made with in-house synthesized powders of PbCrO4 and PbCr1xSxO4 were artificially aged and characterized. We observed a profound darkening only for those paint models made with PbCr1xSxO4, rich in SO42 (x ≥ 0.4), and orthorhombic phases (>30 wt %). Cr and S K-edge micro X-ray absorption near edge structure investigations revealed in an unequivocal manner the formation of up to about 60% of Cr(III)-species in the outer layer of the most altered samples; conversely, independent of the paint models chemical composition, no change in the S-oxidation state was observed. Analyses employing UVvisible diffuse reflectance and Fourier transform infrared spectroscopy were performed on unaged and aged model samples in order to obtain additional information on the physicochemical changes induced by the aging treatment.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000313668400032 Publication Date 2012-10-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 49 Open Access
Notes (down) ; This research was supported by grants from ESRF (experiment EC-799), the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16), and the BELSPO-SDD S2-ART (SD/RI/04) project. The text also presents results from GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) projects G.0704.08 and G.01769.09. The EU FP7 programme CHARISMA (Grant Agreement 228330) and MIUR (PRIN08, Materiali e sistemi innovativi per la conservazione dell'arte contemporanea 2008 FFXXN9) are also acknowledged. ; Approved Most recent IF: 6.32; 2013 IF: 5.825
Call Number UA @ admin @ c:irua:110471 Serial 5569
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Author Van Slycken, S.; Witters, N.; Meers, E.; Peene, A.; Michels, E.; Adriaensen, K.; Ruttens, A.; Vangronsveld, J.; Du Laing, G.; Wierinck, I.; Van Dael, M.; Van Passel, S.; Tack, F.M.G.
Title Safe use of metal-contaminated agricultural land by cultivation of energy maize (Zea mays) Type A1 Journal article
Year 2013 Publication Environmental Pollution Abbreviated Journal Environ Pollut
Volume 178 Issue Pages 375-380
Keywords A1 Journal article; Economics
Abstract Production of food crops on trace element-contaminated agricultural lands in the Campine region (Belgium) can be problematic as legal threshold values for safe use of these crops can be exceeded. Conventional sanitation of vast areas is too expensive and alternatives need to be investigated. Zea mays on a trace element-contaminated soil in the region showed an average yield of 53 ± 10 Mg fresh or 20 ± 3 Mg dry biomass ha−1. Whole plant Cd concentrations complied with legal threshold values for animal feed. Moreover, threshold values for use in anaerobic digestion were met. Biogas production potential did not differ between maize grown on contaminated and non-contaminated soils. Results suggested favorable perspectives for farmers to generate non-food crops profitably, although effective soil cleaning would be very slow. This demonstrates that a valuable and sustainable alternative use can be generated for moderately contaminated soils on which conventional agriculture is impaired.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000320487700050 Publication Date 2013-04-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0269-7491 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.099 Times cited 30 Open Access
Notes (down) ; This research was funded by the Institute for the promotion of Innovation by Science and Technology in Flanders (IWT-Flanders, Grant IWT/CLO/50702). We want to thank OVAM, as the planting and management of this site is part of a demonstration project in the context of the INTERREG-project BENEKEMPEN. Also many thanks to laboratory staff of the departments and to Pioneer and KWS for providing the seeds. ; Approved Most recent IF: 5.099; 2013 IF: 3.902
Call Number UA @ admin @ c:irua:129870 Serial 6247
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Author Hellar-Kihampa, H.; De Wael, K.; Lugwisha, E.; Govindan, M.; Covaci, A.; Van Grieken, R.
Title Spatial monitoring of organohalogen compounds in surface water and sediments of a rural-urban river basin in Tanzania Type A1 Journal article
Year 2013 Publication The science of the total environment Abbreviated Journal Sci Total Environ
Volume 447 Issue Pages 186-197
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre
Abstract The presence of persistent organic pollutants in Tanzanian environment is not well monitored despite the existing pollution potential from a number of sources. In this study, we investigated for the first time, the concentration profiles of different organohalogen compounds such as organochlorine pesticide residues (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in environmental samples (water and sediments) from the Pangani river basin (PRB). The PRB is one of the largest drainage basins in Tanzania, with its watershed exposed to multiple input sources of trace organic contaminants. Surface water and sediments were sampled from 12 representative stations of diverse characteristics and land-use practices, in three distinct seasons, and extracted by liquidliquid and Soxhlet extraction methods, respectively. Water samples were analyzed by GC-ECD for OCPs only, while sediment samples were analyzed for OCPs, PCBs and PBDEs by GC/MS. Seven compounds, dominated by HCH isomers (5104460 pg/L) and DDT analogs (1601460 pg/L),were detected in the water samples. These concentrations are far below the WHO guidelines for drinking water quality. A total of 42 compounds (8 OCPs, 28 PCB congeners and 6 PBDE congeners) were detected in the sediment samples. Their respective total concentration ranges were 24510,230; 35711,000 and 382175 pg/g dry weight. The spatial distribution patterns and Hierarchical Cluster Analysis reflected the impact of historical agricultural usage in sugarcane plantations (OCPs), and urbanization (PCBs and PBDEs). Risk assessment using sediment quality guidelines indicated no ecotoxicological risks. The results we have found provide preliminary data on levels of the organic contaminants in Pangani river basin as a new insight on the environmental quality of the area.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000317538100022 Publication Date 2013-02-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0048-9697 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.9 Times cited 42 Open Access
Notes (down) ; This research project was funded by the International Foundation for Science (IFS, Project Number W/4945-1). The authors wish to acknowledge the contribution of the Pangani Basin Water Office (PBWO) in Moshi, Tanzania; especially Ms. Arafa Maggidi in provision of valuable information and assistance with the sampling campaigns, and Salim Lyimo in mapping of the study area. The contributions of Mr. Peter Machibya of the Department of Geology, University of Dar es Salaam, Tanzania in sediment characterization; and Mr. Emmanuel Gwae, of the Government Chemists Laboratory Agency (GCLA) Dar es Salaam, Tanzania, for instrumental analysis of the water samples, are highly appreciated. Harieth Hellar-Kihampa acknowledges financial support from the Belgian Technical Agency (BTC). Govindan Malarvannan and Adrian Covaci acknowledge financial support from the University of Antwerp. ; Approved Most recent IF: 4.9; 2013 IF: 3.163
Call Number UA @ admin @ c:irua:105260 Serial 5836
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Author Hauchecorne, B.; Lenaerts, S.
Title Unravelling the mysteries of gas phase photocatalytic reaction pathways by studying the catalyst surface : a literature review of different Fourier transform infrared spectroscopic reaction cells used in the field Type A1 Journal article
Year 2013 Publication Journal of photochemistry and photobiology: C: photochemistry reviews Abbreviated Journal J Photoch Photobio C
Volume 14 Issue Pages 72-85
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract Unlike the profound knowledge of the reaction mechanisms occurring in water phase photocatalysis, still fairly little is known on the reaction mechanisms occurring on the catalyst surface when dealing with gaseous pollutants. Unfortunately, there are some differences between both reactions. For one, there are no abundant hydroxyl radicals present in the gas phase, so that possibly other species prove to be important in abating the pollutant. In order to unravel the mysteries of gas phase photocatalytic reaction pathways, in situ techniques must be used to allow the detection and identification of reaction intermediates on a working catalyst. Several techniques were already used in the past, of which Fourier transform infrared spectroscopy seems to be the most versatile. This review will therefore give a selective overview of different spectroscopic reaction cells constructed for the in situ study of photocatalytic gas phase reactions.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000314669600005 Publication Date 2012-09-28
Series Editor Series Title Abbreviated Series Title
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ISSN 1389-5567 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.317 Times cited 8 Open Access
Notes (down) ; The University of Antwerp is greatly acknowledged for the fellowship granted to Birger Hauchecorne. The authors would also like to thank Sammy W. Verbruggen for his help in providing several papers of interest. ; Approved Most recent IF: 12.317; 2013 IF: 11.625
Call Number UA @ admin @ c:irua:106518 Serial 6001
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