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Author Nikolaev, A.V.; Verberck, B.; Ionova, G.V.
Title Molecular interaction energies and optimal configuration of a cubane dimer Type A1 Journal article
Year 2010 Publication International journal of quantum chemistry Abbreviated Journal Int J Quantum Chem
Volume (up) 110 Issue 5 Pages 1063-1069
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We have studied the dependence of the binding energy of a cubane dimer on the mutual orientation of and the distance between the composing monomers employing the second-order Møller-Plesset perturbation scheme (MP2) with the cc-pVDZ molecular basis set. We have found that the MP2 contribution from the molecular correlations is responsible for the bound state of the cubane dimer, whereas the Hartree-Fock contribution remains anti-bonding at all intermolecular distances. Starting with two molecules in the standard orientation and centers of mass at (0,0,0) and (0,0,d), respectively, the maximal binding energy is found at d = 5.125 Å and one of the monomers rotated by 45° about the z-axis. This configuration implies that the hydrogen atoms belonging to different monomers tend to repel each other. The results are in agreement with experimental data on the optimal packing of cubane molecules in the solid state.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000274720000011 Publication Date 2009-04-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-7608;1097-461X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.92 Times cited 1 Open Access
Notes ; ; Approved Most recent IF: 2.92; 2010 IF: 1.302
Call Number UA @ lucian @ c:irua:81944 Serial 2179
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Author Schattschneider, P.; Ennen, I.; Stoger-Pollach, M.; Verbeeck, J.; Mauchamp, V.; Jaouen, M.
Title Real space maps of magnetic moments on the atomic scale: theory and feasibility Type A1 Journal article
Year 2010 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume (up) 110 Issue 8 Pages 1038-1041
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The recently discovered EMCD technique (energy loss magnetic chiral dichroism) can detect atom specific magnetic moments with nanometer resolution, exploiting the spin selectivity of electronic transitions in energy loss spectroscopy. Yet, direct imaging of magnetic moments on the atomic scale is not possible. In this paper we present an extension of EMCD that can overcome this limit. As a model system we chose bcc Fe. We present image simulations of the L3 white line signal, based on the kinetic equation for the density matrix of the 200 kV probe electron. With actual progress in instrumentation (high brightness sources, aberration corrected lenses) this technique should allow direct imaging of spin moments on the atomic scale.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000281216600016 Publication Date 2009-12-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 10 Open Access
Notes --- Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:84439UA @ admin @ c:irua:84439 Serial 2830
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Author Wendelen, W.; Dzhurakhalov, A.A.; Peeters, F.M.; Bogaerts, A.
Title Combined molecular dynamics: continuum study of phase transitions in bulk metals under ultrashort pulsed laser irradiation Type A1 Journal article
Year 2010 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume (up) 114 Issue 12 Pages 5652-5660
Keywords A1 Journal article; Integrated Molecular Plant Physiology Research (IMPRES); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The phase transition processes induced by ultrashort, 100 fs pulsed laser irradiation of Au, Cu, and Ni are studied by means of a combined atomistic-continuum approach. A moderately low absorbed laser fluence range, from 200 to 600 J/m2 is considered to study phase transitions by means of a local and a nonlocal order parameter. At low laser fluences, the occurrence of layer-by-layer evaporation has been observed, which suggests a direct solid to vapor transition. The calculated amount of molten material remains very limited under the conditions studied, especially for Ni. Therefore, our results show that a kinetic equation that describes a direct solid to vapor transition might be the best approach to model laser-induced phase transitions by continuum models. Furthermore, the results provide more insight into the applicability of analytical superheating theories that were implemented in continuum models and help the understanding of nonequilibrium phase transitions.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000275855600044 Publication Date 2010-01-26
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 2 Open Access
Notes ; A.D. gratefully acknowledges Professor M. Hot (ULB, Brussels) for the basic MD-code that was modified further for the laser-induced melting processes. W.W, and A.D. are thankful to Professor L.V. Zhigilei for useful discussions and advices. The calculations were performed on the CALCUA computing facility of the University of Antwerp. This work was supported by the Belgian Science Policy (IAP). ; Approved Most recent IF: 4.536; 2010 IF: 4.524
Call Number UA @ lucian @ c:irua:81391 Serial 402
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Author Ao, Z.M.; Peeters, F.M.
Title Electric field activated hydrogen dissociative adsorption to nitrogen-doped graphene Type A1 Journal article
Year 2010 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume (up) 114 Issue 34 Pages 14503-14509
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Graphane, hydrogenated graphene, was very recently synthesized and predicted to have great potential applications. In this work, we propose a new promising approach for hydrogenation of graphene based on density functional theory (DFT) calculations through the application of a perpendicular electric field after substitutionally doping by nitrogen atoms. These DFT calculations show that the doping by nitrogen atoms into the graphene layer and applying an electrical field normal to the graphene surface induce dissociative adsorption of hydrogen. The dissociative adsorption energy barrier of an H2 molecule on a pristine graphene layer changes from 2.7 to 2.5 eV on N-doped graphene, and to 0.88 eV on N-doped graphene under an electric field of 0.005 au. When increasing the electric field above 0.01 au, the reaction barrier disappears. Therefore, N doping and applying an electric field have catalytic effects on the hydrogenation of graphene, which can be used for hydrogen storage purposes and nanoelectronic applications.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000281129100027 Publication Date 2010-08-09
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 110 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-VI) and the Belgian Science Policy (IAP). ; Approved Most recent IF: 4.536; 2010 IF: 4.524
Call Number UA @ lucian @ c:irua:84588 Serial 882
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Author Nourbakhsh, A.; Cantoro, M.; Klekachev, A.; Clemente, F.; Sorée, B.; van der Veen, M.H.; Vosch, T.; Stesmans, A.; Sels, B.; de Gendt, S.
Title Tuning the Fermi level of SiO2-supported single-layer graphene by thermal annealing Type A1 Journal article
Year 2010 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume (up) 114 Issue 5 Pages 6894-6900
Keywords A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Abstract The effects of thermal annealing in inert Ar gas atmosphere of SiO2-supported, exfoliated single-layer graphene are investigated in this work. A systematic, reproducible change in the electronic properties of graphene is observed after annealing. The most prominent Raman features in graphene, the G and 2D peaks, change in accord to what is expected in the case of hole doping. The results of electrical characterization performed on annealed, back-gated field-effect graphene devices show that the neutrality point voltage VNP increases monotonically with the annealing temperature, confirming the occurrence of excess hole accumulation. No degradation of the structural properties of graphene is observed after annealing at temperatures as high as 400 °C. Thermal annealing of single-layer graphene in controlled Ar atmosphere can therefore be considered a technique to reproducibly modify the electronic structure of graphene by tuning its Fermi level.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000276562500002 Publication Date 2010-03-26
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 54 Open Access
Notes Approved Most recent IF: 4.536; 2010 IF: 4.524
Call Number UA @ lucian @ c:irua:89508 Serial 3757
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Author Arsoski, V.; Tadić, M.; Peeters, F.M.
Title Interband optical properties of concentric type-I nanorings in a normal magnetic field Type A1 Journal article
Year 2010 Publication Acta physica Polonica: A: general physics, solid state physics, applied physics Abbreviated Journal Acta Phys Pol A
Volume (up) 117 Issue 5 Pages 733-737
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Two concentric two-dimensional GaAs/(Al,Ga)As nanorings in a normal magnetic field are theoretically studied. The single-band effective mass approximation is adopted for both the electron and the hole states, and the analytical solutions are given. We find that the electronic single particle states are arranged in pairs, which exhibit anticrossings and the orbital momentum transitions in the energy spectrum when magnetic field increases. Their period is essentially determined by the radius of the outer ring. The oscillator strength for interband transitions is strongly reduced close to each anticrossing. We show that an optical excitonic Aharonov-Bohm effect may occur in concentric nanorings.
Address
Corporate Author Thesis
Publisher Place of Publication Warszawa Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0587-4246 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 0.469 Times cited Open Access
Notes Approved Most recent IF: 0.469; 2010 IF: 0.467
Call Number UA @ lucian @ c:irua:83377 Serial 1690
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Author Tadić, M.; Arsoski, V.; Čukarić, N.; Peeters, F.M.
Title The optical excitonic Aharonov-Bohm effect in a few nanometer wide type-I nanorings Type A1 Journal article
Year 2010 Publication Acta physica Polonica: A: general physics, solid state physics, applied physics Abbreviated Journal Acta Phys Pol A
Volume (up) 117 Issue 6 Pages 974-977
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The optical excitonic Aharonov-Bohm effect in type-1 three-dimensional (In, Ga)As/GaAs nanorings in theoretically explored. The single-particle states of the electron and the hole are extracted from the effective mass theory in the presence of inhomogeneous strain, and an exact numerical diagonalization approach is used to compute the exciton states and the oscillator strength fx for exciton recombination. We studied both the large lithographically-defined and small self-assembled rings. Only in smaller self-assembled nanorings we found optical excitonic AharonovBohm effect. Those oscillations are established by anticrossings between the optically active exciton states with zero orbital momentum. In lithographically defined rings, whose average radius is 33 nm, fx shows no oscillations, whereas in the smaller self-assembled nanoring with average radius of 11.5 nm oscillations in fx for the ground exciton state are found as function of the magnetic field that is superposed on a linear dependence. These oscillations are smeared out at finite temperature, thus photoluminescence intensity exhibits step-like variation with magnetic field even at temperature as small as 4.2 K.
Address
Corporate Author Thesis
Publisher Place of Publication Warszawa Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0587-4246 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 0.469 Times cited Open Access
Notes Approved Most recent IF: 0.469; 2010 IF: 0.467
Call Number UA @ lucian @ c:irua:84080 Serial 2474
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Author Lorenz, H.; Zhao, Q.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Klötzer, B.; Rameshan, C.; Penner, S.
Title Preparation and structural characterization of SnO2 and GeO2 methanol steam reforming thin film model catalysts by (HR)TEM Type A1 Journal article
Year 2010 Publication Materials chemistry and physics Abbreviated Journal Mater Chem Phys
Volume (up) 122 Issue 2/3 Pages 623-629
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Structure, morphology and composition of different tin oxide and germanium oxide thin film catalysts for the methanol steam reforming (MSR) reaction have been studied by a combination of (high-resolution) transmission electron microscopy, selected area electron diffraction, dark-field imaging and electron energy-loss spectroscopy. Deposition of the thin films on NaCl(0 0 1) cleavage faces has been carried out by thermal evaporation of the respective SnO2 and GeO2 powders in varying oxygen partial pressures and at different substrate temperatures. Preparation of tin oxide films in high oxygen pressures (10−1 Pa) exclusively resulted in SnO phases, at and above 473 K substrate temperature epitaxial growth of SnO on NaCl(0 0 1) leads to well-ordered films. For lower oxygen partial pressures (10−3 to 10−2 Pa), mixtures of SnO and β-Sn are obtained. Well-ordered SnO2 films, as verified by electron diffraction patterns and energy-loss spectra, are only obtained after post-oxidation of SnO films at temperatures T ≥ 673 K in 105 Pa O2. Preparation of GeOx films inevitably results in amorphous films with a composition close to GeO2, which cannot be crystallized by annealing treatments in oxygen or hydrogen at temperatures comparable to SnO/SnO2. Similarities and differences to neighbouring oxides relevant for selective MSR in the third group of the periodic system (In2O3 and Ga2O3) are also discussed with the aim of cross-correlation in formation of nanomaterials, and ultimately, also catalytic properties.
Address
Corporate Author Thesis
Publisher Place of Publication Lausanne Editor
Language Wos 000278637900054 Publication Date 2010-04-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0254-0584; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.084 Times cited 15 Open Access
Notes Esteem 026019 Approved Most recent IF: 2.084; 2010 IF: 2.356
Call Number UA @ lucian @ c:irua:83099 Serial 2699
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Author Verlooy, P.L.H.; Robeyns, K.; van Meervelt, L.; Lebedev, O.I.; Van Tendeloo, G.; Martens, J.A.; Kirschhock, C.E.A.
Title Synthesis and characterization of the new cyclosilicate hydrate (hexamethyleneimine)4.[Si8O16(OH)4].12H2O Type A1 Journal article
Year 2010 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume (up) 130 Issue 1/3 Pages 14-20
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A new cyclosilicate hydrate with composition (C6H14N)4·[Si8O16(OH)4]·12H2O was crystallized and the structure determined by single-crystal X-ray diffraction. The structure, described by the tetragonal space group I41/a, with unit cell dimensions of a = 39.2150(2) Å and c = 14.1553(2) Å, contains columns of hydrogen-bonded cubic octamer silicate anions. The space between silicate columns holds hydrogen-bonded water and protonated hexamethyleneimine molecules compensating the negative charge of the silicate. The crystal water can be removed resulting in a rearrangement of the columns into orthorhombic symmetry. Removal of the organic moiety causes amorphisation. Flash evacuation results in a new microporous material with pore volumes typical of a zeolite.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000275702600003 Publication Date 2009-10-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 5 Open Access
Notes Approved Most recent IF: 3.615; 2010 IF: 3.220
Call Number UA @ lucian @ c:irua:82448 Serial 3418
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Author Gorlé, C.; van Beeck, J.; Rambaud, P.
Title Dispersion in the wake of a rectangular building : validation of two Reynolds-averaged Navier-Stokes modelling approaches Type A1 Journal article
Year 2010 Publication Boundary-layer meteorology Abbreviated Journal Bound-Lay Meteorol
Volume (up) 137 Issue 1 Pages 115-133
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract When modelling the turbulent dispersion of a passive tracer using Reynolds-averaged Navier-Stokes (RANS) simulations, two different approaches can be used. The first consists of solving a transport equation for a scalar, where the governing parameters are the mean velocity field and the turbulent diffusion coefficient, given by the ratio of the turbulent viscosity and the turbulent Schmidt number Sc (t) . The second approach uses a Lagrangian particle tracking algorithm, where the governing parameters are the mean velocity and the fluctuating velocity field, which is determined from the turbulence kinetic energy and the Lagrangian time T (L) . A comparison between the two approaches and wind-tunnel data for the dispersion in the wake of a rectangular building immersed in a neutral atmospheric boundary layer (ABL) is presented. Particular attention was paid to the influence of turbulence model parameters on the flow and concentration field. In addition, an approach to estimate Sc (t) and T (L) based on the calculated flow field is proposed. The results show that applying modified turbulence model constants to enable correct modelling of the ABL improves the prediction for the velocity and concentration fields when the modification is restricted to the region for which it was derived. The difference between simulated and measured concentrations is smaller than 25% or the uncertainty of the data on 76% of the points when solving the transport equation for a scalar with the proposed formulation for Sc (t) , and on 69% of the points when using the Lagrangian particle tracking with the proposed formulation for T (L) .
Address
Corporate Author Thesis
Publisher Place of Publication Dordrecht Editor
Language Wos 000281712500006 Publication Date 2010-06-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-8314;1573-1472; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.573 Times cited 16 Open Access
Notes Approved Most recent IF: 2.573; 2010 IF: 1.879
Call Number UA @ lucian @ c:irua:95570 Serial 736
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Author Krstajić, P.M.; Peeters, F.M.; Helm, M.
Title Landau levels and magnetopolaron effect in dilute GaAs:N Type A1 Journal article
Year 2010 Publication Solid state communications Abbreviated Journal Solid State Commun
Volume (up) 150 Issue 33/34 Pages 1575-1579
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The magnetic-field dependence of the energy spectrum of GaAs doped with nitrogen impurities is investigated. Our theoretical model is based on the phenomenological band anticrossing model (BAC) which we extended in order to include the magnetic field and electronphonon interaction. Due to the highly localized nature of the nitrogen state, we find that the energy levels are very different from those of pure GaAs. The polaron correction results in a lower cyclotron resonance energy as compared to pure GaAs. The magneto-absorption spectrum exhibits series of asymmetric peaks close to the cyclotron energy ħωc.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000280949900019 Publication Date 2010-06-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1098; ISBN Additional Links UA library record; WoS full record
Impact Factor 1.554 Times cited Open Access
Notes ; This work is supported by the Flemish Science Foundation (FWO-VI), and the Interuniversity Attraction Poles Program (IAP)-Belgian State Science Policy. M.H. is grateful to O. Drachenko and H. Schneider for numerous discussions. ; Approved Most recent IF: 1.554; 2010 IF: 1.981
Call Number UA @ lucian @ c:irua:84580 Serial 1771
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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 (up) 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.
Address
Corporate Author Thesis
Publisher Place of Publication 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 Peng, L.; Philippaerts, A.; Ke, X.; van Noyen, J.; de Cleppel, F.; Van Tendeloo, G.; Jacobs, P.A.; Sels, B.F.
Title Preparation of sulfonated ordered mesoporous carbon and its use for the esterification of fatty acids Type A1 Journal article
Year 2010 Publication Catalysis today Abbreviated Journal Catal Today
Volume (up) 150 Issue 1/2 Pages 140-146
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Mesoporous carbon, which can be replicated from mesoporous silica and whose surface is hydrophobic, can be an ideal catalyst for the esterification of fatty acids. Here we report an easy and low cost way to prepare sulfonic acid group-functionalized mesoporous carbon. A sample of calcined mesoporous silica SBA-15 was added to an aqueous sucrose solution followed by drying and calcination at different temperatures. In contrast to existing procedures, the obtained hybrid Si/C material was then first sulfonated in H2SO4, before the final removal of the silica template in order to stabilize the porous structure towards the liquid phase sulfonation treatment. Thus the silicacarbon composites, instead of the mesoporous carbon, were successfully sulfonated to introduce SO3H groups, while keeping the ordered mesoporous structure intact. The influence of carbonization temperature was investigated, suggesting an optimum temperature of 873 K. The SO3H group-functionalized mesoporous carbon, denoted as CMK-3-873-SO3H, was characterized by means of XRD, N2 physisorption, SEM, FT-IR, elemental analysis and TEM. It followed that a uniform mesoporous carbon was obtained with an average pore size of 3.89 nm, a specific surface of 807 m2/g and a SO3H group loading of 0.39 meq/g of dry material. Compared with other solid acid catalysts, the resulting material shows enhanced activity in the acid-catalyzed esterification of oleic acid with methanol, and can be used repeatedly. The increased catalytic performance is attributed to the hydrophobic surface and larger pore size of the new catalyst. It can effectively accommodate long chain fatty acids and reject formed water, making the active sites easily accessible.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000275566700024 Publication Date 2009-09-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0920-5861; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.636 Times cited 132 Open Access
Notes Approved Most recent IF: 4.636; 2010 IF: 2.993
Call Number UA @ lucian @ c:irua:81739 Serial 2706
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Author Vassiliev, S.Y.; Laurinavichute, V.K.; Abakumov, A.M.; Govorov, V.A.; Bendovskii, E.B.; Turner, S.; Filatov, A.Y.; Tarasovskii, V.P.; Borzenko, A.G.; Alekseeva, A.M.; Antipov, E.V.
Title Microstructural aspects of the degradation behavior of SnO2-based anodes for aluminum electrolysis Type A1 Journal article
Year 2010 Publication Journal of the electrochemical society Abbreviated Journal J Electrochem Soc
Volume (up) 157 Issue 5 Pages C178-C186
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The performance of SnO2 ceramic anodes doped with copper and antimony oxides was examined in cryolite alumina melts under anodic polarization at different cryolite ratios, temperatures, times, and current densities. The corroded part consists of a narrow strong corrosion zone at the anode surface with damage of the intergrain contacts and a large increase in porosity, a wider moderate corrosion zone with a smaller porosity increase, and a Cu depletion zone, where the ceramic retains its initial microstructure and a slight porosity increase occurs due to the removal of the Cu-rich inclusions. Mechanical destruction of the anode was never observed in the 10100 h tests. A microstructural model of the ceramic was suggested, consisting of grains with an Sb-doped SnO2 grain core surrounded by an ~200 to 500 nm grain shell where SnO2 was simultaneously doped with Sb and Mn+ (M=Cu2+,Fe3+,Al3+). The grains were separated by a few nanometers thick Cu-enriched grain boundaries. Different secondary charge carrier (holes) concentrations and electric conductivities in the grain core and grain shell result in a higher current density at the intergrain regions that leads to their profound degradation, especially in the low temperature acidic melt.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000276555300037 Publication Date 2010-04-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-4651; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.259 Times cited 3 Open Access
Notes Approved Most recent IF: 3.259; 2010 IF: 2.427
Call Number UA @ lucian @ c:irua:82260 Serial 2040
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Author Terzano, R.; Santoro, A.; Spagnuolo, M.; Vekemans, B.; Medici, L.; Janssens, K.; Göttlicher, J.; Denecke, M.A.; Mangold, S.; Ruggiero, P.
Title Solving mercury (Hg) speciation in soil samples by synchrotron X-ray microspectroscopic techniques Type A1 Journal article
Year 2010 Publication Environmental pollution Abbreviated Journal Environ Pollut
Volume (up) 158 Issue 8 Pages 2702-2709
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Direct mercury (Hg) speciation was assessed for soil samples with a Hg concentration ranging from 7 up to 240 mg kg1. Hg chemical forms were identified and quantified by sequential extractions and bulkand micro-analytical techniques exploiting synchrotron generated X-rays. In particular, microspectroscopic techniques such as m-XRF, m-XRD and m-XANES were necessary to solve bulk Hg speciation, in both soil fractions <2 mm and <2 mm. The main Hg-species found in the soil samples were metacinnabar (b-HgS), cinnabar (a-HgS), corderoite (Hg3S2Cl2), and an amorphous phase containing Hg bound to chlorine and sulfur. The amount of metacinnabar and amorphous phases increased in the fraction <2 mm. No interaction among Hg-species and soil components was observed. All the observed Hgspecies originated from the slow weathering of an inert Hg-containing waste material (K106, U.S. EPA) dumped in the area several years ago, which is changing into a relatively more dangerous source of pollution.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000280571500026 Publication Date 2010-06-08
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 ; This research was partially financed by the MIUR (COFIN 2005) project “Innovative chemical, physical, and biological methods to characterize and remediate soils polluted by heavy metals (MICROS)”. Synchrotron experiments at HASYLAB were financially supported by the European Community-Research Infrastructure Action under the FP6 “Structuring the European Research Area” Program I(Integrating Activity on Synchrotron and Free Electron Laser Science; project: contract RII3-CT-2004-506008). This research was also performed as part of the “Interuniversity Attraction Poles” (IAP6) Program financed by the Belgian government. We thank Gerald Falkenberg and Karen Rickers-Appel for their scientific and technical support in obtaining the experimental data at Beam line L (HASYLAB, DESY, Hamburg, Germany). ; Approved Most recent IF: 5.099; 2010 IF: 3.395
Call Number UA @ admin @ c:irua:84050 Serial 5835
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Author Bencs, L.; Ravindra, K.; de Hoog, J.; Spolnik, Z.; Bleux, N.; Berghmans, P.; Deutsch, F.; Roekens, E.; Van Grieken, R.
Title Appraisal of measurement methods, chemical composition and sources of fine atmospheric particles over six different areas of Northern Belgium Type A1 Journal article
Year 2010 Publication Environmental pollution Abbreviated Journal
Volume (up) 158 Issue 11 Pages 3421-3430
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Daily and seasonal variation in the total elemental, organic carbon (OC) and elemental carbon (EC) content and mass of PM2.5 were studied at industrial, urban, suburban and agricultural/rural areas. Continuous (optical Dustscan, standard tapered element oscillating micro-balance (TEOM), TEOM with filter dynamics measurement system), semi-continuous (Partisol filter-sampling) and non-continuous (Dekati-impactor sampling and gravimetry) methods of PM2.5 mass monitoring were critically evaluated. The average elemental fraction accounted for 26% of the PM2.5 mass measured by gravimetry. Metals, like K, Mn, Fe, Cu, Zn and Pb were strongly inter-correlated, also frequently with non-metallic elements (P, S, Cl and/or Br) and EC/OC. A high OC/EC ratio (29) was generally observed. The total carbon content of PM2.5 ranged between 3 and 77% (averages: 1232%), peaking near industrial/heavy trafficked sites. Principal component analysis identified heavy oil burning, ferrous/non-ferrous industry and vehicular emissions as the main sources of metal pollution. This work compares various aerosol monitoring methods to characterize PM2.5 over six locations of different anthropogenic activities over Northern Belgium.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000282563200009 Publication Date 2010-08-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0269-7491; 1873-6424 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:84237 Serial 7488
Permanent link to this record
 
 
Author Bruegelmans, P.; Horemans, B.; Hofkens, J.; Springael, D.
Title Response to mixed substrate feeds of the structure and activity of a linuron-degrading triple-species biofilm Type A1 Journal article
Year 2010 Publication Research in microbiology Abbreviated Journal
Volume (up) 161 Issue 8 Pages 660-666
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract We sought to determine whether the pesticide-degrading performance of a multi-species bacterial biofilm is affected by co-occurrence of multiple nutrient sources Thus, the 3-(3,4-dichlorophenyl)-l-methoxy-l-methyl urea (linuron)-degrading activity of a triple-species linuron-degrading consortium, cultivated in continuous flow biofilm systems, was monitored when exposed to mixed substrate feeds which contained, in addition to linuron, readily assimilated carbon (i e citrate and trypticase soy broth) and/or nitrogen (i e ammonium) sources The addition of alternative carbon sources at different concentrations resulted in diminished linuron degradation efficiency In addition, the efficiency of removal of the linuron metabolite 3,4-dichloroaniline was affected These effects might be attributed to catabolic repression of the linuron metabolic pathway in the presence of alternative carbon substrates Moreover, each nutrient condition resulted in a particular biofilm composition and a particular spatial and structural organization, which might also be related to the performance of the biofilm community Results show that the activity of pesticide-degrading biofilms strongly depends on prevailing nutrient conditions and that the ideal biofilm configuration and activity, as observed under selective conditions, does not exist in real-life environmental conditions where mixtures of substrates are often present (C) 2010 Elsevier Masson SAS All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000283686200004 Publication Date 2010-07-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0923-2508; 1769-7123 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:91369 Serial 8477
Permanent link to this record
 
 
Author Damla, N.; Čevik, U.; Kobya, A.I.; Celik, A.; Celik, N.; Van Grieken, R.
Title Radiation dose estimation and mass attenuation coefficients of cement samples used in Turkey Type A1 Journal article
Year 2010 Publication Journal of hazardous materials Abbreviated Journal
Volume (up) 176 Issue 1/3 Pages 644-649
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Different cement samples commonly used in building construction in Turkey have been analyzed for natural radioactivity using gamma-ray spectrometry. The mean activity concentrations observed in the cement samples were 52, 40 and 324 Bq kg−1 for 226Ra, 232Th and 40K, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and world average limits. The radiological hazard parameters such as radium equivalent activities (Raeq), gamma index (Iγ) and alpha index (Iα) indices as well as terrestrial absorbed dose and annual effective dose rate were calculated and compared with the international data. The Raeq values of cement are lower than the limit of 370 Bq kg−1, equivalent to a gamma dose of 1.5 mSv y−1. Moreover, the mass attenuation coefficients were determined experimentally and calculated theoretically using XCOM in some cement samples. Also, chemical compositions analyses of the cement samples were investigated.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000274839700087 Publication Date 2009-11-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3894 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:80671 Serial 8448
Permanent link to this record
 
 
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 (up) 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).
Address
Corporate Author Thesis
Publisher Place of Publication 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 (up) 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 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 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 (up) 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 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 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 (up) 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 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
Permanent link to this record
 
 
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 (up) 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 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
Permanent link to this record
 
 
Author El Shinawi, H.; Bertha, A.; Hadermann, J.; Herranz, T.; Santos, B.; Marco, J.F.; Berry, F.J.; Greaves, C.
Title Synthesis and characterization of La1+xSr2-xCoMnO7-\delta (x=0,0.2; \delta=0,1) Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume (up) 183 Issue 6 Pages 1347-1353
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The n=2 Ruddlesden-Popper phases LaSr(2)CoMnO(7) and La(1 2)Sr(1 8)CoMnO(7) have been synthesized by a sol-gel method The O6-type phases LaSr(2)CoMnO(6) and La(1 2)Sr(1 8)CoMnO(6) were produced by reduction of the 07 phases under a hydrogen atmosphere The materials crystallize in the tetragonal I4/mmm space group with no evidence of long-range cation order in the neutron and electron diffraction data Oxygen vacancies in the reduced materials are located primarily at the common apex of the double perovskite layers giving rise to square pyramidal coordination around cobalt and manganese ions. The oxidation states Co(3+)/Mn(4+) and Co(2+)/Mn(3+) predominate in the as-prepared and reduced materials, respectively The materials are spin glasses at low temperature and the dominant magnetic interactions change from ferro- to antiferromagnetic following reduction (C) 2010 Elsevier Inc All rights reserved
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000278750100021 Publication Date 2010-04-17
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 5 Open Access
Notes Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:99209 Serial 3417
Permanent link to this record
 
 
Author Morozov, V.A.; Arakcheeva, A.V.; Konovalova, V.V.; Pattison, P.; Chapuis, G.; Lebedev, O.I.; Fomichev, V.V.; Van Tendeloo, G.
Title LiZnNb4O11.5 : a novel oxygen deficient compound in the Nb-rich part of the Li2O-ZnO-Nb2O5 system Type A1 Journal article
Year 2010 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume (up) 183 Issue 2 Pages 408-418
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A novel lithium zinc niobium oxide LiZnNb(4)O(11.5) (LZNO) has been found in the Nb-rich part of Li(2)O-ZnO-Nb(2)O(5) system. LZNO, with an original alpha-PbO(2) related structure, has been synthesized by the routine ceramic technique and characterized by X-ray diffraction and transmission electron microscopy (TEM). Reflections belonging to the LZNO phase, observed in X-ray powder diffraction (XRPD) and electron diffraction, have been indexed as monoclinic with unit cell parameters a=17.8358(9)angstrom, b=15.2924(7)angstrom, c=5.0363(3)angstrom and gamma=96.607(5)degrees or as alpha-PbO(2)-like with lattice constants a=4.72420(3)angstrom, b=5.72780(3)angstrom, c=5.03320(3)angstrom, gamma=90.048(16)degrees and modulation vector q=0.3a*+1.1b* indicating a commensurately modulated alpha-PbO(2) related structure. The monoclinic cell is a supercell related to the latter. Using synchrotron powder diffraction data, the structure has been solved and refined as a commensurate modulation (superspace group P112(1)/n(alpha beta 0)00) as well as a supercell (space group P2(1)/b). The superspace description allows us to consider the LZNO structure as a member of the proposed alpha-PbO(2)-Z (3 + 1)D structure type, which unifies both incommensurately and commensurately modulated structures. HRTEM reveals several types of defects in LZNO and structural models for these defects are proposed. Two new phases in Li(2)O-ZnO-Nb(2)O(5) system are predicted on the basis of this detailed HRTEM analysis. (C) 2009 Elsevier Inc. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000274497600020 Publication Date 2009-12-17
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 9 Open Access
Notes Iap-Vi Approved Most recent IF: 2.299; 2010 IF: 2.261
Call Number UA @ lucian @ c:irua:95646 Serial 3542
Permanent link to this record
 
 
Author Van Meensel, J.; Lauwers, L.; Van Huylenbroeck, G.; Van Passel, S.
Title Comparing frontier methods for economic-environmental trade-off analysis Type A1 Journal article
Year 2010 Publication European Journal Of Operational Research Abbreviated Journal Eur J Oper Res
Volume (up) 207 Issue 2 Pages 1027-1040
Keywords A1 Journal article; Economics
Abstract This paper uses a mechanistic frontier approach as a reference to evaluate the ability of conventional parametric (SFA) and non-parametric (DEA) frontier approaches for analyzing economicenvironmental trade-offs. Conventional frontier approaches are environmentally adjusted through incorporating the materials balance principle. The analysis is worked out for the Flemish pig finishing case, which is both representative and didactic. Results show that, on average, SFA and DEA yield adequate economicenvironmental trade-offs. Both methods are good estimators for technical efficiency. Cost allocative and environmental allocative efficiency scores are less robust, due to the well-known methodological advantages and disadvantages of SFA and DEA. For particular firms, SFA, DEA and the mechanistic approach may yield different economicenvironmental trade-offs. One has therefore to be careful when using conventional frontier approaches for firm-specific decision support. The mechanistic approach allows for optimizing performances per average present finisher, which is the production unit in pig finishing. Conventional frontier methods do not allow for this optimization since the number of average present finishers varies along the production functions. Since the mechanistic production function is based on underlying growth, feed uptake and mortality functions, additional firm-specific indicators can also be calculated at each point of the production function.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000281107200045 Publication Date 2010-05-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0377-2217 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.297 Times cited 18 Open Access
Notes ; This research is funded by the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT Vlaanderen). ; Approved Most recent IF: 3.297; 2010 IF: 2.159
Call Number UA @ admin @ c:irua:136761 Serial 6171
Permanent link to this record
 
 
Author Titantah, J.T.; Lamoen, D.; Schowalter, M.; Rosenauer, A.
Title Ab initio based atomic scattering amplitudes and {002} electron structure factors of InxGa1-xAs/GaAs quantum wells Type A1 Journal article
Year 2010 Publication Journal of physics : conference series Abbreviated Journal
Volume (up) 209 Issue 1 Pages 012040,1-012040,6
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The atomic scattering amplitudes of the various atoms of the systems Ga1−xInxAs, GaAs1−xNx and InAs1−xNx are calculated using the density functional theory (DFT) approach. The scattering amplitudes of N, Ga, As and In in the model systems are compared with the frequently used Doyle and Turner values. Deviation from the latter values is found for small scattering vectors (s<0.3Å−1) and for these scattering vectors dependence on the orientation of the scattering vector and the chemical environment is reported. We suggest a parametrization of these modified scattering amplitudes (MASAs) for small scattering vectors (s<1.0Å−1). The MASAs are exploited within zero pressure classical Metropolis Monte Carlo (MC), finite temperature calculations to investigate the effect of quantum well size on the electron {002} structure factor (SF) of Ga1−xInxAs quantum wells.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000283739100040 Publication Date 2010-02-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6596; 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:85760 Serial 28
Permanent link to this record
 
 
Author Müller, K.; Schowalter, M.; Rosenauer, A.; Jansen, J.; Tsuda, K.; Titantah, J.T.; Lamoen, D.
Title Refinement of chemically sensitive structure factors using parallel and convergent beam electron nanodiffraction Type A1 Journal article
Year 2010 Publication Journal of physics : conference series Abbreviated Journal
Volume (up) 209 Issue 1 Pages 012025-012025,4
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We introduce a new method to measure structure factors from parallel beam electron diffraction (PBED) patterns. Bloch wave refinement routines were developed which can minimise the difference between simulated and experimental Bragg intensities via variation of structure factors, Debye parameters, specimen thickness and -orientation. Due to plane wave illumination, the PBED refinement is highly efficient not only in computational respect, but also concerning the experimental effort since energy filtering is shown to have no significant effect on the refinement results. The PBED method was applied to simulated GaAs diffraction patterns to derive systematic errors and rules for the identification of plausible refinement results. The evaluation of experimental GaAs PBED patterns yields a 200 X-ray structure factor of -6.33±0.14. Additionally, we obtained -6.35±0.13 from two-dimensional convergent beam electron diffraction refinements. Both results confirm density functional theory calculations published by Rosenauer et al. and indicate the inaccuracy of isolated atom scattering data, which is crucial e.g. for the composition evaluation by lattice fringe analysis.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos Publication Date 2010-02-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6596; ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:85761 Serial 2855
Permanent link to this record
 
 
Author Amin-Ahmadi, B.; Aashuri, H.
Title Semisolid structure for M2 high speed steel prepared by cooling slope Type A1 Journal article
Year 2010 Publication Journal of materials processing technology Abbreviated Journal J Mater Process Tech
Volume (up) 210 Issue 12 Pages 1632-1635
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Effects of cooling slope angle and the temperature of molten metal on the globular structure of M2 high speed steel after holding at the semisolid state have been investigated. The globular structure was achieved by pouring the molten metal at 1595 °C on the ceramic cooling slope with the length of 200 mm and the angle of 25°. The globular structure of M2 high speed steel in the form of rolledannealed and as cast condition after holding at semisolid state has been achieved. The size of globular grains of cooling slope sample was smaller than that of the rolledannealed and as cast samples. Solid particles of rolledannealed sample after holding at semisolid state had better roundness compared with cooling slope sample. Dissolution of carbides in the austenite phase at grain boundaries leads to formation of globular particles in the semisolid state. MC-type and M6C-type eutectic carbides reprecipitate during cooling cycle along grain boundaries.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000280498200011 Publication Date 2010-06-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0924-0136; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.147 Times cited 12 Open Access
Notes Approved Most recent IF: 3.147; 2010 IF: 1.570
Call Number UA @ lucian @ c:irua:122042 Serial 2983
Permanent link to this record
 
 
Author Li, B.; Magnus, W.; Peeters, F.M.
Title Tunable exciton Aharonov-Bohm effect in a quantum ring Type A1 Journal article
Year 2010 Publication Journal of physics : conference series T2 – Proceedings of the 11th International Conference on Optics of Excitons in Confined Systems, September 7-11, 2009, Spain / Vina, L. [edit.]; et al. [edit.] Abbreviated Journal
Volume (up) 210 Issue 1 Pages 012030,1-01203,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We studied the optical Aharonov-Bohm effect for an exciton in a semiconductor quantum ring. A perpendicular electric field applied to a quantum ring with large height, is able to tune the exciton ground state energy such that it exhibits a weak observable Aharonov-Bohm oscillations. This Aharonov-Bohm effect is tunable in strength and period.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000289715800242 Publication Date 2010-03-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 3 Open Access
Notes ; ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:89950 Serial 3741
Permanent link to this record