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Author Brosens, F.; Magnus, W.
Title Newtonian trajectories : a powerful tool for solving quantum dynamics Type A1 Journal article
Year 2010 Publication Solid state communications Abbreviated Journal Solid State Commun
Volume 150 Issue 43/44 Pages 2102-2105
Keywords A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
Abstract Since Ehrenfests theorem, the role and importance of classical paths in quantum dynamics have been examined by several means. Along this line, we show that the classical equations of motion provide a solution to quantum dynamics, if appropriately incorporated into the Wigner distribution function, exactly reformulated in a type of Boltzmann equation. Also the quantum-mechanical features of the canonical ensemble can be studied in this framework of Newtonian dynamics, if the initial distribution function is appropriately constructed from the statistical operator.
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Corporate Author Thesis
Publisher Place of Publication (down) New York, N.Y. Editor
Language Wos 000284251700006 Publication Date 2010-09-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1098; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.554 Times cited 7 Open Access
Notes ; The authors thank J.T. Devreese and J. Tempere for interesting and helpful discussions, and, in particular, L.F. Lemmens for several valuable suggestions. One of the authors (F.B.) acknowledges the FWO projects G.0115.06 and G.0365.08 as well as the WOG project WO.033.09N, for financial support. ; Approved Most recent IF: 1.554; 2010 IF: 1.981
Call Number UA @ lucian @ c:irua:85795 Serial 2338
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Author Carrillo-Nuñez, H.; Magnus, W.; Peeters, F.M.
Title A non-linear variational principle for the self-consistent solution of Poisson's equation and a transport equation in the local density approximation Type P1 Proceeding
Year 2010 Publication Abbreviated Journal
Volume Issue Pages 171-174
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Ieee Place of Publication (down) New York, N.Y. Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-4244-7699-2 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:85824 Serial 2347
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Author Fang, C.M.; Sluiter, M.H.F.; van Huis, M.; Ande, C.K.; Zandbergen, H.W.
Title Origin of predominance of cementite among iron carbides in steel at elevated temperature Type A1 Journal article
Year 2010 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 105 Issue 5 Pages 4
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A long-standing challenge in physics is to understand why cementite is the predominant carbide in steel. Here we show that the prevalent formation of cementite can be explained only by considering its stability at elevated temperature. A systematic highly accurate quantum mechanical study was conducted on the stability of binary iron carbides. The calculations show that all the iron carbides are unstable relative to the elemental solids, -Fe and graphite. Apart from a cubic Fe23C6 phase, the energetically most favorable carbides exhibit hexagonal close-packed Fe sublattices. Finite-temperature analysis showed that contributions from lattice vibration and anomalous Curie-Weis magnetic ordering, rather than from the conventional lattice mismatch with the matrix, are the origin of the predominance of cementite during steel fabrication processes.
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Corporate Author Thesis
Publisher Place of Publication (down) New York, N.Y. Editor
Language Wos 000280472900008 Publication Date 2010-07-30
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 65 Open Access
Notes Approved Most recent IF: 8.462; 2010 IF: 7.622
Call Number UA @ lucian @ c:irua:84064 Serial 2526
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Author Martens, T.; Bogaerts, A.; van Dijk, J.
Title Pulse shape influence on the atmospheric barrier discharge Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 96 Issue 13 Pages 131503,1-131503,3
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this letter we compare the effect of a radio-frequency sine, a low frequency sine, a rectangular and a pulsed dc voltage profile on the calculated electron production and power consumption in the dielectric barrier discharge. We also demonstrate using calculated potential distribution profiles of high time and space resolution how the pulsed dc discharge generates a secondary discharge pulse by deactivating the power supply.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000276275300019 Publication Date 2010-03-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 35 Open Access
Notes Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:81538 Serial 2738
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Author Saniz, R.; Dixit, H.; Lamoen, D.; Partoens, B.
Title Quasiparticle energies and uniaxial pressure effects on the properties of SnO2 Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 97 Issue Pages 261901-261901,3
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract We calculate the quasiparticle energy spectrum of SnO2 within the GW approximation, properly taking into account the contribution of core levels to the energy corrections. The calculated fundamental gap is of 3.85 eV. We propose that the difference with respect to the experimental optical gap (3.6 eV) is due to excitonic effects in the latter. We further consider the effect applied on uniaxial pressure along the c-axis. Compared to GW, the effect of pressure on the quasiparticle energies and band gap is underestimated by the local-density approximation. The quasiparticle effective masses, however, appear to be well described by the latter.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000285768100015 Publication Date 2010-12-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 23 Open Access
Notes Iwt; Fwo; Bof-Noi Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:85759 Serial 2803
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Author Depla, D.; Li, X.Y.; Mahieu, S.; van Aeken, K.; Leroy, W.P.; Haemers, J.; de Gryse, R.; Bogaerts, A.
Title Rotating cylindrical magnetron sputtering: simulation of the reactive process Type A1 Journal article
Year 2010 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 107 Issue 11 Pages 113307,1-113307,9
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A rotating cylindrical magnetron consists of a cylindrical tube, functioning as the cathode, which rotates around a stationary magnet assembly. In stationary mode, the cylindrical magnetron behaves similar to a planar magnetron with respect to the influence of reactive gas addition to the plasma. However, the transition from metallic mode to poisoned mode and vice versa depends on the rotation speed. An existing model has been modified to simulate the influence of target rotation on the well known hysteresis behavior during reactive magnetron sputtering. The model shows that the existing poisoning mechanisms, i.e., chemisorption, direct reactive ion implantation and knock on implantation, are insufficient to describe the poisoning behavior of the rotating target. A better description of the process is only possible by including the deposition of sputtered material on the target.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000278907100020 Publication Date 2010-06-07
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 15 Open Access
Notes Approved Most recent IF: 2.068; 2010 IF: 2.079
Call Number UA @ lucian @ c:irua:82631 Serial 2930
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Author Carrillo-Nuñez, H.; Magnus, W.; Peeters, F.M.
Title A simplified quantum mechanical model for nanowire transistors based on non-linear variational calculus Type A1 Journal article
Year 2010 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 108 Issue 6 Pages 063708,1-063708,8
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A simplified quantum mechanical model is developed to investigate quantum transport features such as the electron concentration and the current flowing through a silicon nanowire metal-oxide-semiconductor field-effect transistor (MOSFET). In particular, the electron concentration is extracted from a self-consistent solution of the Schrödinger and Poisson equations as well as the ballistic Boltzmann equation which have been solved by exploiting a nonlinear variational principle within the framework of the generalized local density approximation. A suitable action functional has been minimized and details of the implementation and its numerical minimization are given. The current density and its related current-voltage characteristics are calculated from the one-dimensional ballistic steady-state Boltzmann transport equation which is solved analytically by using the method of characteristic curves. The straightforward implementation, the computational speed and the good qualitative behavior of the transport characteristics observed in our approach make it a promising simulation method for modeling quantum transport in nanowire MOSFETs.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000282646400067 Publication Date 2010-09-22
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 7 Open Access
Notes ; This work was supported by Flemish Science Foundation (FWO-VI) and the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC. ; Approved Most recent IF: 2.068; 2010 IF: 2.079
Call Number UA @ lucian @ c:irua:84943 Serial 3006
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Author Wendelen, W.; Autrique, D.; Bogaerts, A.
Title Space charge limited electron emission from a Cu surface under ultrashort pulsed laser irradiation Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 96 Issue 5 Pages 1-3
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this theoretical study, the electron emission from a copper surface under ultrashort pulsed laser irradiation is investigated using a one-dimensional particle in cell model. Thermionic emission as well as multiphoton photoelectron emission were taken into account. The emitted electrons create a negative space charge above the target; consequently the generated electric field reduces the electron emission by several orders of magnitude. The simulations indicate that the space charge effect should be considered when investigating electron emission related phenomena in materials under ultrashort pulsed laser irradiation of metals.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000274319500021 Publication Date 2010-02-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 22 Open Access
Notes Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:80995 Serial 3059
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Author Chen, L.; Kirilenko, D.; Stesmans, A.; Nguyen, X.S.; Binnemans, K.; Goderis, B.; Vanacken, J.; Lebedev, O.; Van Tendeloo, G.; Moshchalkov, V.V.
Title Symmetry and electronic states of Mn2+ in ZnS nanowires with mixed hexagonal and cubic stacking Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 97 Issue 4 Pages 041918,1-041918,3
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electron spin resonance and electronic spectroscopy techniques were used to study the symmetry and electronic structure of Mn2+ dopants in solvothermally synthesized ZnS nanowires. The average diameter of ∼ 5 nm leads to the observable quantum confinement effects in the photoluminescence excitation spectra. The results clearly demonstrate the three symmetry locations of Mn2+ incorporation. Together with the inferred Mn2+ center densities, these data indicate a much higher efficiency of Mn2+ substitution in the nanowire sample with about two times larger diameter.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000281059200038 Publication Date 2010-08-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 5 Open Access
Notes Methusalem Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:84869 Serial 3403
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Author Xavier, L.J.P.; Pereira, J.M.; Chaves, A.; Farias, G.A.; Peeters, F.M.
Title Topological confinement in graphene bilayer quantum rings Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 96 Issue 21 Pages 212108,1-212108,3
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We find localized electron and hole states in a ring-shaped potential kink in biased bilayer graphene. Within the continuum description, we show that for sharp potential steps the Dirac equation describing carrier states close to the K (or K′) point of the first Brillouin zone can be solved analytically for a circular kink/antikink dot. The solutions exhibit interfacial states which exhibit AharonovBohm oscillations as functions of the height of the potential step and/or the radius of the ring.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000278183200039 Publication Date 2010-05-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 29 Open Access
Notes ; This work was financially supported by CNPq, under Contract No. NanoBioEstruturas 555183/2005-0, FUNCAP, CAPES, the Bilateral program between Flanders and Brazil, the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:83373 Serial 3675
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Author Li, Y.; Yang, X.-Y.; Rooke, J.; Van Tendeloo, G.; Su, B.-L.
Title Ultralong Cu(OH)(2) and CuO nanowire bundles: PEG200-directed crystal growth for enhanced photocatalytic performance Type A1 Journal article
Year 2010 Publication Journal of colloid and interface science Abbreviated Journal J Colloid Interf Sci
Volume 348 Issue 2 Pages 303-312
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Ultralong Cu(OH)(2) and CuO nanowire bundles with lengths ranging from tens to hundreds of micrometers have been selectively synthesized on a large scale by a facile solution-phase method, using PEG200 as growth-directing agent. The growth mechanisms were investigated by monitoring the nanowire evolution process. The results showed that under the action of PEG200 molecules, the Cu(OH)(2) and CuO nanowires were first formed through oriented attachment of colloidal particles, then through side self-assembly leading to nanowire bundles, and finally to CuO nanoleaves. PEG200 plays a critical role in the synthesis of nanowires as it not only prevents the random aggregation of colloidal particles toward CuO nanoleaves but also helps to orientate nanowire growth by the coalescence and alignment in one direction of the colloidal particles. The concentration of OH(-) in the reaction system is also important for nanowire growth. In the absence of PEG200, nanoleaves are formed by an Ostwald ripening process. The band-gap value estimated from a UV-Vis absorption spectrum of CuO nanowire bundles is 2.32 eV. The photodegradation of a model pollutant, rhodamine B, by CuO nanowires and nanoleaves was compared with commercial nanopowders, showing that the as-synthesized ultralong CuO polycrystalline nanowire bundles have an enhanced photocatalytic activity with 87% decomposition of rhodamine B after an 8-h reaction, which was much higher than that of single-crystal nanoleaves (61%) and commercial nanopowders (32%). The origin of the high photocatalytic activity of these new polycrystalline CuO nanowire bundles has been discussed. This present work reveals that the (0 0 2) crystallographic surface is more favorable for photocatalytic decomposition of organic compounds and that these ultralong CuO nanowire bundles are potential candidates for photocatalysts in wastewater treatment. (C) 2010 Elsevier Inc. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication (down) New York, N.Y. Editor
Language Wos 000279968700002 Publication Date 2010-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9797; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.233 Times cited 70 Open Access
Notes Approved Most recent IF: 4.233; 2010 IF: 3.068
Call Number UA @ lucian @ c:irua:95589 Serial 3795
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Author Milošević, M.V.; Peeters, F.M.
Title Vortex manipulation in a superconducting matrix with view on applications Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 96 Issue 19 Pages 192501,1-192501,3
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We show how a single flux quantum can be effectively manipulated in a superconducting film with a matrix of blind holes. Such a sample can serve as a basic memory element, where the position of the vortex in a k×l matrix of pinning sites defines the desired combination of n bits of information (2n = k×l). Vortex placement is achieved by strategically applied current and the resulting position is read out via generated voltage between metallic contacts on the sample. Such a device can also act as a controllable source of a nanoengineered local magnetic field for, e.g., spintronics applications.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000277756400040 Publication Date 2010-05-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 14 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the ESF-NES and ESF-AQDJJ networks. ; Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:83657 Serial 3869
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Author Vandenberghe, W.; Sorée, B.; Magnus, W.; Groeseneken, G.
Title Zener tunneling in semiconductors under nonuniform electric fields Type A1 Journal article
Year 2010 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 107 Issue 5 Pages 054520,1-054520,7
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Recently, a renewed interest in Zener tunneling has arisen because of its increasing impact on semiconductor device performance at nanometer dimensions. In this paper we evaluate the tunnel probability under the action of a nonuniform electric field using a two-band model and arrive at significant deviations from the commonly used Kanes model, valid for weak uniform fields only. A threshold on the junction bias where Kanes model for Zener tunneling breaks down is determined. Comparison with Kanes model particularly shows that our calculation yields a higher tunnel probability for intermediate electric fields and a lower tunnel probability for high electric fields. When performing a current calculation comparing to the WKB approximation for the case of an abrupt p-n junction significant differences concerning the shape of the I-V curve are demonstrated.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication (down) New York, N.Y. Editor
Language Wos 000275657500136 Publication Date 2010-03-11
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 22 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). These authors acknowledge the support from IMEC's Industrial Affiliation Program and the authors would like to thank Anne Verhulst for useful comments. ; Approved Most recent IF: 2.068; 2010 IF: 2.079
Call Number UA @ lucian @ c:irua:82450 Serial 3929
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Author Payette, C.; Austing, D.G.; Yu, G.; Gupta, J.A.; Nair, S.V.; Partoens, B.; Amaha, S.; Tarucha, S.
Title Branch current behavior at two level anti-crossings in vertical quantum dot single-particle spectra Type A1 Journal article
Year 2010 Publication AIP conference proceedings Abbreviated Journal
Volume 1199 Issue Pages 271-272
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We study single-electron-elastic-resonant-tunneling through two weakly coupled vertical quantum dots and investigate the branch current behavior at anti-crossings between two single-particle energy levels in the constituent dot spectra that are induced to approach each other by application of an out-of-dot-plane magnetic field. We observe both the familiar case of monotonic transfer of the resonant current strengths between the two branches as well as the less familiar case of concurrent enhancement and suppression (ideally complete cancellation) of the resonant current in the two branches. These two situations can be explained in terms of a simple coherent tunneling model. ©2009 American Institute of Physics
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Corporate Author Thesis
Publisher Place of Publication (down) New York Editor
Language Wos 000281590800127 Publication Date 2010-01-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 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:86923 Serial 254
Permanent link to this record
 
 
Author Wendelen, W.; Autrique, D.; Bogaerts, A.
Title Space charge limited electron emission from a Cu surface under ultrashort pulsed laser irradiation Type A1 Journal article
Year 2010 Publication AIP conference proceedings Abbreviated Journal
Volume 1278 Issue Pages 407-415
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this theoretical study, the electron emission from a copper surface under ultrashort pulsed laser irradiation is investigated using a one dimensional particle in cell model. Thermionic emission as well as multi-photon photoelectron emission were taken into account. The emitted electrons create a negative space charge above the target, consequently the generated electric field reduces the electron emission by several orders of magnitude. The simulations indicate that the space charge effect should be considered when investigating electron emission related phenomena in materials under ultrashort pulsed laser irradiation of metals.the word abstract, but do replace the rest of this text. ©2010 American Institute of Physics
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Corporate Author Thesis
Publisher Place of Publication (down) New York Editor
Language Wos 000287183900042 Publication Date 2010-10-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 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:88899 Serial 3058
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Author Yang, T.; Perkisas, T.; Hadermann, J.; Croft, M.; Ignatov, A.; Greenblatt, M.
Title B-site ordered perovskite LaSrMnNbO6 : synthesis, structure and antiferromagnetism Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 183 Issue 11 Pages 2689-2694
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract LaSrMnNbO6 has been synthesized by high temperature solid state reaction under 1% H2/Ar dynamic flow. The structure is determined by Rietveld refinement of the powder X-ray diffraction data. It crystallizes in the monoclinic space group P21/n with the unit cell parameters: a=5.69187(12), b=5.74732(10), c=8.07018(15) Å and β=90.0504(29)°, which were also confirmed by electron diffraction. The Mn2+ and Nb5+ ions, whose valence states are confirmed by X-ray absorption near-edge spectroscopy, are almost completely ordered over the B-site (<1% inversion) of the perovskite structure due to the large differences of both cationic size (0.19 Å) and charge. The octahedral framework displays significant tilting distortion according to Glazers tilt system a−b−c+. Upon heating, LaSrMnNbO6 decomposes at 690 °C under O2 flow or at 775 °C in air. The magnetic susceptibility data indicate the presence of long-range antiferromagnetic ordering at TN=8 K; the experimentally observed effective paramagnetic moment, μeff=5.76 μB for high spin Mn2+ (3d5, S=5/2) is in good agreement with the calculated value (μcalcd=5.92 μB).
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Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000284179800028 Publication Date 2010-09-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 13 Open Access
Notes Esteem 026019 Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:85805 Serial 212
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Author Abakumov, A.M.; d' Hondt, H.; Rossell, M.D.; Tsirlin, A.A.; Gutnikova, O.; Filimonov, D.S.; Schnelle, W.; Rosner, H.; Hadermann, J.; Van Tendeloo, G.; Antipov, E.V.
Title Coupled anion and cation ordering in Sr3RFe4O10.5 (R=Y, Ho, Dy) anion-deficientperovskites Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 183 Issue 12 Pages 2845-2854
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The Sr3RFe4O10.5 (R=Y, Ho, Dy) anion-deficient perovskites were prepared using a solid-state reaction in evacuated sealed silica tubes. Transmission electron microscopy and 57Fe Mössbauer spectroscopy evidenced a complete A-cations and oxygen vacancies ordering. The structure model was further refined by ab initio structure relaxation, based on density functional theory calculations. The compounds crystallize in a tetragonal a≈2√2ap≈11.3 Å, с≈4сp≈16 Å unit cell (ap: parameter of the perovskite subcell) with the P42/mnm space group. Oxygen vacancies reside in the (FeO5/4□3/4) layers, comprising corner-sharing FeO4 tetrahedra and FeO5 tetragonal pyramids, which are sandwiched between the layers of the FeO6 octahedra. Smaller R atoms occupy the 9-fold coordinated position, whereas the 10-fold coordinated positions are occupied by larger Sr atoms. The Fe sublattice is ordered aniferromagnetically up to at least 500 K, while the rare-earth sublattice remains disordered down to 2 K.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000285431100014 Publication Date 2010-10-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 8 Open Access
Notes Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:88071 Serial 533
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Author Čukarić, N.; Tadić, M.; Peeters, F.M.
Title Electron and hole states in a quantum ring grown by droplet epitaxy. Influence of the layer inside the ring opening Type A1 Journal article
Year 2010 Publication Superlattices and microstructures Abbreviated Journal Superlattice Microst
Volume 48 Issue 5 Pages 491-501
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The electronic structure of the conduction and valence bands of a quantum ring containing a layer inside the ring opening is modeled This structure (nanocup) consists of a GaAs nanodisk (the cup s bottom) and a GaAs nanoring (the cup s rim) which encircles the disk The whole system is embedded in an (Al Ga)As matrix and its shape resembles realistic ring structures grown by the droplet epitaxy technique The conduction-band states in the structure are modeled by the single-band effective-mass theory while the 4-band Luttinger-Kohn model is adopted to compute the valence-band states We analyze how the electronic structure of the nanocup evolves from the one of a quantum ring when the size of either the nanodisk or the nanoring is changed For that purpose (1) the width of the ring (2) the disk radius and (3) the disk height are separately varied For dimensions typical for experimentally realized structures we find that the electron wavefunctions are mainly localized inside the ring even when the thickness of the Inner layer is 90% of the ring thickness These calculations indicate that topological phenomena like the excitonic Aharonov-Bohm effect are negligibly affected by the presence of the layer inside the ring (C) 2010 Elsevier Ltd All rights reserved
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000284521400005 Publication Date 2010-09-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0749-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.123 Times cited 9 Open Access
Notes ; The authors would like to thank Prof B Partoens for useful discussions This work was supported by the EU NoE SANDiE the Ministry of Science of Serbia the Flemish Science Foundation (FWO-VI) and the Belgian Science Policy (IAP) ; Approved Most recent IF: 2.123; 2010 IF: 1.096
Call Number UA @ lucian @ c:irua:95551 Serial 906
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Author Mao, M.; Bogaerts, A.
Title Investigating the plasma chemistry for the synthesis of carbon nanotubes/nanofibres in an inductively coupled plasma enhanced CVD system : the effect of different gas mixtures Type A1 Journal article
Year 2010 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 43 Issue 20 Pages 205201,1-205201,20
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A hybrid model, called the hybrid plasma equipment model (HPEM), was used to study an inductively coupled plasma in gas mixtures of H2 or NH3 with CH4 or C2H2 used for the synthesis of carbon nanotubes or carbon nanofibres (CNTs/CNFs). The plasma properties are discussed for different gas mixtures at low and moderate pressures, and the growth precursors for CNTs/CNFs are analysed. It is found that C2H2, C2H4 and C2H6 are the predominant molecules in CH4 containing plasmas besides the feedstock gas, and serve as carbon sources for CNT/CNF formation. On the other hand, long-chain hydrocarbons are observed in C2H2-containing plasmas. Furthermore, the background gases CH4 and C2H2 show a different decomposition rate with H2 or NH3 addition at moderate pressures.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000277373400009 Publication Date 2010-05-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727;1361-6463; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 52 Open Access
Notes Approved Most recent IF: 2.588; 2010 IF: 2.109
Call Number UA @ lucian @ c:irua:82067 Serial 1723
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Author Mao, M.; Bogaerts, A.
Title Investigating the plasma chemistry for the synthesis of carbon nanotubes/nanofibres in an inductively coupled plasma-enhanced CVD system : the effect of processing parameters Type A1 Journal article
Year 2010 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 43 Issue 31 Pages 315203-315203,15
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A parameter study is carried out for an inductively coupled plasma used for the synthesis of carbon nanotubes or carbon nanofibres (CNTs/CNFs), by means of the Hybrid Plasma Equipment Model. The influence of processing parameters including gas ratio for four different gas mixtures typically used for CNT/CNF growth (i.e. CH4/H2, CH4/NH3, C2H2/H2 and C2H2/NH3), inductively coupled plasma (ICP) power (501000 W), operating pressure (10 mTorr1 Torr), bias power (01000 W) and temperature of the substrate (01000 °C) on the plasma chemistry is investigated and the optimized conditions for CNT/CNF growth are analysed. Summarized, our calculations suggest that a lower fraction of hydrocarbon gases (CH4 or C2H2, i.e. below 20%) and hence a higher fraction of etchant gases (H2 or NH3) in the gas mixture result in more 'clean' conditions for controlled CNT/CNF growth. The same applies to a higher ICP power, a moderate ICP gas pressure above 100 mTorr (at least for single-walled carbon nanotubes), a high bias power (for aligned CNTs) and an intermediate substrate temperature.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000280275200007 Publication Date 2010-07-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727;1361-6463; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 17 Open Access
Notes Approved Most recent IF: 2.588; 2010 IF: 2.109
Call Number UA @ lucian @ c:irua:88365 Serial 1724
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Author Pereira, J.M.; Peeters, F.M.; Chaves, A.; Farias, G.A.
Title Klein tunneling in single and multiple barriers in graphene Type A1 Journal article
Year 2010 Publication Semiconductor science and technology Abbreviated Journal Semicond Sci Tech
Volume 25 Issue 3 Pages 033002,1-033002,9
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We review the transmission properties of carriers interacting with potential barriers in graphene. The tunneling of electrons and holes in quantum structures in graphene is found to display features that are in marked contrast with those of other systems. In particular, the interaction between the carriers with electrostatic potential barriers can be related to the propagation of electromagnetic waves in media with negative refraction indices, also known as metamaterials. This behavior becomes evident as one calculates the time evolution of wavepackets propagating across the barrier interface. In addition, we discuss the effect of trigonal warping on the tunneling through potential barriers.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000274318300004 Publication Date 2010-02-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0268-1242;1361-6641; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.305 Times cited 83 Open Access
Notes ; We want to acknowledge our collaborators in this work: P Vasilopoulos and M Barbier. This work was supported by the Brazilian Council for Research (CNPq), the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). ; Approved Most recent IF: 2.305; 2010 IF: 1.333
Call Number UA @ lucian @ c:irua:80961 Serial 1764
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Author Masir, M.R.; Vasilopoulos, P.; Peeters, F.M.
Title Kronig-Penney model of scalar and vector potentials in graphene Type A1 Journal article
Year 2010 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 22 Issue 46 Pages 465302,1-465302,10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We consider a one-dimensional (1D) superlattice (SL) on graphene consisting of very high and very thin (δ-function) magnetic and potential barriers with zero average potential and zero magnetic field. We calculate the energy spectrum analytically, study it in different limiting cases, and determine the condition under which an electron beam incident on an SL is highly collimated along its direction. In the absence of the magnetic SL the collimation is very sensitive to the value of W/Ws and is optimal for W/Ws = 1, where W is the distance between the positive and negative barriers and L = W + Ws is the size of the unit cell. In the presence of only the magnetic SL the collimation decreases and the symmetry of the spectrum around ky is broken for W/Ws\neq 1 . In addition, a gap opens which depends on the strength of the magnetic field. We also investigate the effect of spatially separated potential and magnetic δ-function barriers and predict a better collimation in specific cases.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000283838800004 Publication Date 2010-11-05
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 41 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-VI), the Belgian Science Policy (IAP), and the Canadian NSERC Grant No. OGP0121756. ; Approved Most recent IF: 2.649; 2010 IF: 2.332
Call Number UA @ lucian @ c:irua:85807 Serial 1767
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Author Bezjak, J.; Abakumov, A.M.; Recnik, A.; Krzmanc, M.M.; Jancar, B.; Suvorov, D.
Title The local structure and composition of Ba4Nb2O9-based oxycarbonates Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 183 Issue 8 Pages 1823-1828
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract X-ray powder-diffraction(XRD),high-resolutiontransmissionelectronmicroscopy(HRTEM),electron diffraction(ED),infraredspectroscopy(IR),thermogravimetry(TG)andmassspectroscopy(MS)were performedtoinvestigatethecompositionandthecrystalstructureoftetra-bariumdi-niobate(V) Ba4Nb2O9. TheTG,MSandIRstudiesrevealedthatthecompoundisahydratedoxycarbonate.Assuming that thecarbonatestoichiometricallyreplacesoxygen,thecompositionofthelow-temperature a-modification,obtainedbyslowcoolingfrom1100 1C, correspondstoBa4Nb2O8.8(CO3)0.2 0.1H2O, while thequenchedhigh-temperature g-modificationhastheBa4Nb2O8.42(CO3)0.58 0.38H2O composi- tion. The a-phase hasacompositeincommensuratelymodulatedstructureconsistingoftwomutually interacting[Ba]N and the[(Nb,)O3]N subsystems.Thecompositemodulatedcrystalstructureofthe a-phase canbedescribedwiththelatticeparameters a¼10.2688(1) A˚ , c¼2.82426(8) A˚ , q¼0.66774(2)c* and asuperspacegroup R3m(00g)0s. TheHRTEManalysisdemonstratesthenanoscale twinningofthetrigonaldomainsparalleltothe{100}crystallographicplanes.Thetwinningintroduces a one-dimensionaldisorderintothe[(Nb,)O3]N subsystem,whichresultsinanaverage P62c crystal structureofthe a-phase. Possibleplacesforthecarbonategroupinthestructurearediscussedusinga comparisonwithotherhexagonalperovskite-basedoxycarbonates.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000280620300013 Publication Date 2010-06-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 10 Open Access
Notes Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:84046 Serial 1830
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Author Bogaerts, A.; De Bie, C.; Eckert, M.; Georgieva, V.; Martens, T.; Neyts, E.; Tinck, S.
Title Modeling of the plasma chemistry and plasmasurface interactions in reactive plasmas Type A1 Journal article
Year 2010 Publication Pure and applied chemistry Abbreviated Journal Pure Appl Chem
Volume 82 Issue 6 Pages 1283-1299
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this paper, an overview is given of modeling activities going on in our research group, for describing the plasma chemistry and plasmasurface interactions in reactive plasmas. The plasma chemistry is calculated by a fluid approach or by hybrid Monte Carlo (MC)fluid modeling. An example of both is illustrated in the first part of the paper. The example of fluid modeling is given for a dielectric barrier discharge (DBD) in CH4/O2, to describe the partial oxidation of CH4 into value-added chemicals. The example of hybrid MCfluid modeling concerns an inductively coupled plasma (ICP) etch reactor in Ar/Cl2/O2, including also the description of the etch process. The second part of the paper deals with the treatment of plasmasurface interactions on the atomic level, with molecular dynamics (MD) simulations or a combination of MD and MC simulations.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000279063900010 Publication Date 2010-04-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-3075;0033-4545; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.626 Times cited 13 Open Access
Notes Approved Most recent IF: 2.626; 2010 IF: 2.134
Call Number UA @ lucian @ c:irua:82108 Serial 2134
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Author Napierala, C.; Lepoittevin, C.; Edely, M.; Sauques, L.; Giovanelli, F.; Laffez, P.; Van Tendeloo, G.
Title Moderate pressure synthesis of rare earth nickelate with metal-insulator transition using polymeric precursors Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 183 Issue 7 Pages 1663-1669
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Rare earth nickelates exhibit a reversible metalsemiconductor phase transition that is, in the infrared range, responsible for a thermo-optical contrast. The state of the art synthesis of these compounds usually requires high oxygen pressure to stabilize Ni in the oxidation state 3+. In this work, using polymeric precursor associated with moderate pressure annealing, we show that it is possible to obtain fully oxidized rare earth nickelate with metalinsulator transition. Using thermogravimetric analysis, X-ray diffraction and transmission electronic microscopy we compare different samples synthesized at different oxygen pressures and demonstrate their structural similarity. Thermo-optical properties were measured, in the infrared range, using reflectance measurements and confirmed the metalinsulator transition at 60 °C in both samples.TEM observations lead to the conclusion that the structure commonly obtained at 175 bar is perfectly observed in the 20 bar sample without major structural defects. The two samples exhibit a thermochromic behavior and thermo-optical properties of the two samples are equivalent.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000279711200028 Publication Date 2010-05-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 3 Open Access
Notes Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:83679 Serial 2156
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Author de Clippel, F.; Harkiolakis, A.; Ke, X.; Vosch, T.; Van Tendeloo, G.; Baron, G.V.; Jacobs, P.A.; Denayer, J.F.M.; Sels, B.F.
Title Molecular sieve properties of mesoporous silica with intraporous nanocarbon Type A1 Journal article
Year 2010 Publication Chemical communications Abbreviated Journal Chem Commun
Volume 46 Issue 6 Pages 928-930
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Biporous carbonsilica materials (CSM) with molecular sieve properties and high sorption capacity were developed by synthesizing nano-sized carbon crystallites in the mesopores of Al-MCM-41.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000274070800024 Publication Date 2009-12-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-7345;1364-548X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.319 Times cited 21 Open Access
Notes Fwo; Iap Approved Most recent IF: 6.319; 2010 IF: 5.787
Call Number UA @ lucian @ c:irua:80994 Serial 2182
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Author Khalil-Allafi, J.; Amin-Ahmadi, B.
Title Multiple-step martensitic transformations in the Ni51Ti49 single crystal Type A1 Journal article
Year 2010 Publication Journal of materials science Abbreviated Journal J Mater Sci
Volume 45 Issue 23 Pages 6440-6445
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Multiple-step martensitic transformations of an aged Ni51Ti49 single crystal using calorimetric method were investigated. Results show that for short aging times (1045 min) multiple-step martensitic transformations on cooling occur in two steps. Applying intermediate aging times (1.254 h) results in three steps and long aging times (more than 8 h) lead to two-step martensitic transformations again. This behavior has not been recognized in NiTi single crystals in literatures. It can be related to the heterogeneity of composition and stress fields around Ni4Ti3 precipitates.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000282429400021 Publication Date 2010-06-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-2461;1573-4803; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.599 Times cited 5 Open Access
Notes Approved Most recent IF: 2.599; 2010 IF: 1.859
Call Number UA @ lucian @ c:irua:122046 Serial 2231
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Author Hadermann, J.; Abakumov, A.M.; Perkisas, T.; d' Hondt, H.; Tan, H.; Verbeeck, J.; Filonenko, V.P.; Antipov, E.V.; Van Tendeloo, G.
Title New perovskite-based manganite Pb2Mn2O5 Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 183 Issue 183 Pages 2190-2195
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A new perovskite based compound Pb2Mn2O5 has been synthesized using a high pressure high temperature technique. The structure model of Pb2Mn2O5 is proposed based on electron diffraction, high angle annular dark field scanning transmission electron microscopy and high resolution transmission electron microscopy. The compound crystallizes in an orthorhombic unit cell with parameters a=5.736(1)Å≈√2a p p p (a p the parameter of the perovskite subcell) and space group Pnma. The Pb2Mn2O5 structure consists of quasi two-dimensional perovskite blocks separated by 1/2[110] p (1̄01) p crystallographic shear planes. The blocks are connected to each other by chains of edge-sharing MnO5 distorted tetragonal pyramids. The chains of MnO5 pyramids and the MnO6 octahedra of the perovskite blocks delimit six-sided tunnels accommodating double chains of Pb atoms. The tunnels and pyramidal chains adopt two mirror-related configurations (left L and right R) and layers consisting of chains and tunnels of the same configuration alternate in the structure according to an -LRLR-sequence. The sequence is sometimes locally violated by the appearance of -LL- or -RR-fragments. A scheme is proposed with a JahnTeller distortion of the MnO6 octahedra with two long and two short bonds lying in the ac plane, along two perpendicular orientations within this plane, forming a d-type pattern.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000282139600041 Publication Date 2010-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 8 Open Access
Notes Fwo; Bof; Esteem 026019 Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:85472UA @ admin @ c:irua:85472 Serial 2332
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Author Lindner, H.; Autrique, D.; Pisonero, J.; Günther, D.; Bogaerts, A.
Title Numerical simulation analysis of flow patterns and particle transport in the HEAD laser ablation cell with respect to inductively coupled plasma spectrometry Type A1 Journal article
Year 2010 Publication Journal of analytical atomic spectrometry Abbreviated Journal J Anal Atom Spectrom
Volume 25 Issue 3 Pages 295-304
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The present study analyses a specific laser ablation cell, the High Efficiency Aerosol Dispersion (HEAD) cell (see J. Pisonero et al., J. Anal. At. Spectrom., 2006, 21, 922931), by means of computational fluid dynamics (CFD) simulations. However, this cell consists of different modular parts, therefore, the results are probably of interest for the further development of other ablation cells. In the HEAD cell, the ablation spot is positioned below an orifice in the ceiling of the sample chamber. The particle transport through this orifice has been analysed for a ceiling height of 0.8 mm. The critical velocity for the onset of particle losses was found to be independent on the ejection angle at the crater spot. The deceleration of the particles can be described as the stopping in an effectively steady gas. Particle losses were negligible in this modular part of the cell at the evaluated laser ablation conditions. The transport efficiency through the Venturi chamber was investigated for different sample gas flow rates. In this case, it was found that small particles were predominantly lost at low flow rates, the large particles at higher flow rates. Making use of the simulation results, it was possible to design a modification of the HEAD cell that results in extremely short calculated washout times. The simulations yielded a signal of less than 10 ms, which was produced by more than 99% of the introduced mass.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000274961600005 Publication Date 2010-02-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0267-9477;1364-5544; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.379 Times cited 16 Open Access
Notes Approved Most recent IF: 3.379; 2010 IF: 4.372
Call Number UA @ lucian @ c:irua:80871 Serial 2403
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Author Bultinck, E.; Mahieu, S.; Depla, D.; Bogaerts, A.
Title The origin of Bohm diffusion, investigated by a comparison of different modelling methods Type A1 Journal article
Year 2010 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 43 Issue 29 Pages 292001,1-292001,5
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract 'Bohm diffusion' causes the electrons to diffuse perpendicularly to the magnetic field lines. However, its origin is not yet completely understood: low and high frequency electric field fluctuations are both named to cause Bohm diffusion. The importance of including this process in a Monte Carlo (MC) model is demonstrated by comparing calculated ionization rates with particle-in-cell/Monte Carlo collisions (PIC/MCC) simulations. A good agreement is found with a Bohm diffusion parameter of 0.05, which corresponds well to experiments. Since the PIC/MCC method accounts for fast electric field fluctuations, we conclude that Bohm diffusion is caused by fast electric field phenomena.
Address
Corporate Author Thesis
Publisher Place of Publication (down) London Editor
Language Wos 000279638700001 Publication Date 2010-07-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727;1361-6463; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 16 Open Access
Notes Approved Most recent IF: 2.588; 2010 IF: 2.109
Call Number UA @ lucian @ c:irua:83109 Serial 2521
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