toggle visibility
Search within Results:
Display Options:

Select All    Deselect All
 |   | 
Details
   print
  Records
Author Hai, G.-Q.; Peeters, F.M.
  Title Hamiltonian of a many-electron system with single-electron and electron-pair states in a two-dimensional periodic potential Type A1 Journal article
  Year 2015 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
  Volume 88 Issue (down) 88 Pages 20
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Based on the metastable electron-pair energy band in a two-dimensional (2D) periodic potential obtained previously by Hai and Castelano [J. Phys.: Condens. Matter 26, 115502 (2014)], we present in this work a Hamiltonian of many electrons consisting of single electrons and electron pairs in the 2D system. The electron-pair states are metastable of energies higher than those of the single-electron states at low electron density. We assume two different scenarios for the single-electron band. When it is considered as the lowest conduction band of a crystal, we compare the obtained Hamiltonian with the phenomenological model Hamiltonian of a boson-fermion mixture proposed by Friedberg and Lee [Phys. Rev. B 40, 6745 (1989)]. Single-electron-electron-pair and electron-pair-electron-pair interaction terms appear in our Hamiltonian and the interaction potentials can be determined from the electron-electron Coulomb interactions. When we consider the single-electron band as the highest valence band of a crystal, we show that holes in this valence band are important for stabilization of the electron-pair states in the system.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Berlin Editor
  Language Wos 000347776800005 Publication Date 2015-01-10
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1434-6028;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.461 Times cited 2 Open Access
  Notes ; This work was supported by FAPESP and CNPq (Brazil). ; Approved Most recent IF: 1.461; 2015 IF: 1.345
  Call Number c:irua:125317 Serial 1406
Permanent link to this record
 

 
Author Vasylenko, A.A.; Misko, V.R.
  Title Nonlinear transport of the Wigner crystal in symmetric and asymmetric FET-like structures : nonlinear transport of the Wigner crystal on superfluid He-4 in quasi-one-dimensional channels with symmetric and asymmetric constrictions Type A1 Journal article
  Year 2015 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
  Volume 88 Issue (down) 88 Pages 105
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract When floating on a two-dimensional surface of superfluid He-4, electrons arrange themselves in two-dimensional crystalline structure known as Wigner crystal. In channels, the boundaries interfere the crystalline order and in case of very narrow channels one observes a quasi-one-dimensional (quasi-1D) Wigner crystal formed by just a few rows of electrons and, ultimately, one row in the “quantum wire” regime. Recently, the “quantum wire” regime was accessed experimentally [D.G. Rees, H. Totsuji, K. Kono, Phys. Rev. Lett. 108, 176801 (2012)] resulting in unusual transport phenomena such as, e.g., oscillations in the electron conductance. Using molecular dynamics simulations, we study the nonlinear transport of electrons in channels with various types of constrictions: single and multiple symmetric and asymmetric geometrical constrictions with varying width and length, and saddle-point-type potentials with varying gate voltage. In particular, we analyze the average particle velocity of the particles and the corresponding electron current versus the driving force or the gate voltage. We have revealed a significant difference in the dynamics for long and short constrictions: The oscillations of the average velocity of the particles for the systems with short constrictions exhibit a clear correlation with the transitions between the states with different numbers of rows of particles; on the other hand, for the systems with longer constrictions these oscillations are suppressed. The obtained results qualitatively agree with the experimental observations. Next, we propose a FET-like structure that consists of a channel with asymmetric constrictions. We show that applying a transverse bias results either in increase of the average particle velocity or in its suppression thus allowing a flexible control tool over the electron transport. The advantage of the asymmetric FET is that it does not have a gate and it allows an easy control of relatively large electron flow. Furthermore, the asymmetric device can be used for rectification of an ac-driven electron flow. Our results bring important insights into the dynamics of electrons floating on the surface of superfluid He-4 in channels with constrictions and allow the effective control over the electron transport.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Berlin Editor
  Language Wos 000353065100002 Publication Date 2015-04-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1434-6028;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.461 Times cited Open Access
  Notes Approved Most recent IF: 1.461; 2015 IF: 1.345
  Call Number c:irua:125997 Serial 2359
Permanent link to this record
 

 
Author Berdiyorov, G.R.; Savel'ev, S.; Kusmartsev, F.V.; Peeters, F.M.
  Title Effect of ordered array of magnetic dots on the dynamics of Josephson vortices in stacked SNS Josephson junctions under DC and AC current Type A1 Journal article
  Year 2015 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
  Volume 88 Issue (down) 88 Pages 286
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We use the anisotropic time-dependent Ginzburg-Landau theory to investigate the effect of a square array of out-of-plane magnetic dots on the dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting (SNS) Josephson junctions in the presence of external DC and AC currents. Periodic pinning due to the magnetic dots distorts the triangular lattice of fluxons and results in the appearance of commensurability features in the current-voltage characteristics of the system. For the larger values of the magnetization, additional peaks appear in the voltage-time characteristics of the system due to the creation and annihilation of vortex-antivortex pairs. Peculiar changes in the response of the system to the applied current is found resulting in a “superradiant” vortex-flow state at large current values, where a rectangular lattice of moving vortices is formed. Synchronizing the motion of fluxons by adding a small ac component to the biasing dc current is realized. However, we found that synchronization becomes difficult for large magnetization of the dots due to the formation of vortex-antivortex pairs.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Berlin Editor
  Language Wos 000363960900002 Publication Date 2015-10-30
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1434-6028 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.461 Times cited 1 Open Access
  Notes ; This work was supported by EU Marie Curie (Project No. 253057). ; Approved Most recent IF: 1.461; 2015 IF: 1.345
  Call Number UA @ lucian @ c:irua:129509 Serial 4166
Permanent link to this record
 

 
Author Lu, Y.-G.; Turner, S.; Ekimov, E.A.; Verbeeck, J.; Van Tendeloo, G.
  Title Boron-rich inclusions and boron distribution in HPHT polycrystalline superconducting diamond Type A1 Journal article
  Year 2015 Publication Carbon Abbreviated Journal Carbon
  Volume 86 Issue (down) 86 Pages 156-162
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Polycrystalline boron-doped superconducting diamond, synthesized at high pressure and high temperature (HPHT) via a reaction of a single piece of crystalline boron with monolithic graphite, has been investigated by analytical transmission electron microscopy. The local boron distribution and boron environment have been studied by a combination of (scanning) transmission electron microscopy ((S)TEM) and spatially resolved electron energy-loss spectroscopy (EELS). High resolution TEM imaging and EELS elemental mapping have established, for the first time, the presence of largely crystalline diamond-diamond grain boundaries within the material and have evidenced the presence of substitutional boron dopants within individual diamond grains. Confirmation of the presence of substitutional B dopants has been obtained through comparison of acquired boron K-edge EELS fine structures with known references. This confirmation is important to understand the origin of superconductivity in polycrystalline B-doped diamond. In addition to the substitutional boron doping, boron-rich inclusions and triple-points, both amorphous and crystalline, with chemical compositions close to boron carbide B4C, are evidenced. (C) 2015 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000352922700019 Publication Date 2015-01-22
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0008-6223; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.337 Times cited 20 Open Access
  Notes FWO; 246791 COUNTATOMS; 278510 VORTEX; Hercules ECASJO_; Approved Most recent IF: 6.337; 2015 IF: 6.196
  Call Number c:irua:125994UA @ admin @ c:irua:125994 Serial 250
Permanent link to this record
 

 
Author Wang, X.; Kustov, S.; Li, K.; Schryvers, D.; Verlinden, B.; Van Humbeeck, J.
  Title Effect of nanoprecipitates on the transformation behavior and functional properties of a Ti50.8 at.% Ni alloy with micron-sized grains Type A1 Journal article
  Year 2015 Publication Acta materialia Abbreviated Journal Acta Mater
  Volume 82 Issue (down) 82 Pages 224-233
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract In order to take advantage of both grain refinement and precipitation hardening effects, nanoscaled Ni4Ti3 precipitates are introduced in a Ti50.8 at.% Ni alloy with micron-sized grains (average grain size of 1.7 μm). Calorimetry, electrical resistance studies and thermomechanical tests were employed to study the transformation behavior and functional properties in relation to the obtained microstructure. A significant suppression of martensite transformation by the obtained microstructure is observed. The thermomechanical tests show that the advantageous properties of both grain refinement and precipitation hardening are combined in the developed materials, resulting in superior shape memory characteristics and stability of pseudoelasticity. It is concluded that introducing nanoscaled Ni4Ti3 precipitates into small grains is a new approach to improve the functional properties of NiTi shape memory alloys.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000347017800021 Publication Date 2014-10-04
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 5.301 Times cited 51 Open Access
  Notes Fwo Approved Most recent IF: 5.301; 2015 IF: 4.465
  Call Number c:irua:120469 Serial 824
Permanent link to this record
 

 
Author Béché, A.; Winkler, R.; Plank, H.; Hofer, F.; Verbeeck, J.
  Title Focused electron beam induced deposition as a tool to create electron vortices Type A1 Journal article
  Year 2015 Publication Micron Abbreviated Journal Micron
  Volume 80 Issue (down) 80 Pages 34-38
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Focused electron beam induced deposition (FEBID) is a microscopic technique that allows geometrically controlled material deposition with very high spatial resolution. This technique was used to create a spiral aperture capable of generating electron vortex beams in a transmission electron microscope (TEM). The vortex was then fully characterized using different TEM techniques, estimating the average orbital angular momentum to be approximately 0.8variant Planck's over 2pi per electron with almost 60% of the beam ending up in the l=1 state.
  Address EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language English Wos 000366770100006 Publication Date 2015-09-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0968-4328; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.98 Times cited 21 Open Access
  Notes A.B and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant No. 278510 VORTEX. J.V., R.W., H.P. and F.H. acknowledge financial support from the European Union under the 7th Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative (Reference No. 312483 ESTEEM2). R.W and H.P also acknowledge financial support by the COST action CELINA (Nr. CM1301) and the EUROSTARS project TRIPLE-S (Nr. E!8213). The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government.; esteem2jra3 ECASJO; Approved Most recent IF: 1.98; 2015 IF: 1.988
  Call Number c:irua:129203 c:irua:129203UA @ admin @ c:irua:129203 Serial 3946
Permanent link to this record
 

 
Author Aerts, R.; Somers, W.; Bogaerts, A.
  Title Carbon dioxide splitting in a dielectric barrier discharge plasma : a combined experimental and computational study Type A1 Journal article
  Year 2015 Publication Chemsuschem Abbreviated Journal Chemsuschem
  Volume 8 Issue (down) 8 Pages 702-716
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract Plasma technology is gaining increasing interest for the splitting of CO2 into CO and O2. We have performed experiments to study this process in a dielectric barrier discharge (DBD) plasma with a wide range of parameters. The frequency and dielectric material did not affect the CO2 conversion and energy efficiency, but the discharge gap can have a considerable effect. The specific energy input has the most important effect on the CO2 conversion and energy efficiency. We have also presented a plasma chemistry model for CO2 splitting, which shows reasonable agreement with the experimental conversion and energy efficiency. This model is used to elucidate the critical reactions that are mostly responsible for the CO2 conversion. Finally, we have compared our results with other CO2 splitting techniques and we identified the limitations as well as the benefits and future possibilities in terms of modifications of DBD plasmas for greenhouse gas conversion in general.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Weinheim Editor
  Language Wos 000349954400019 Publication Date 2015-01-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1864-5631; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.226 Times cited 131 Open Access
  Notes Approved Most recent IF: 7.226; 2015 IF: 7.657
  Call Number c:irua:123930 Serial 279
Permanent link to this record
 

 
Author Schutyser, W.; Van den Bosch, S.; Dijkmans, J.; Turner, S.; Meledina, M.; Van Tendeloo, G.; Debecker, D.P.; Sels, B.F.
  Title Selective nickel-catalyzed conversion of model and lignin-derived phenolic compounds to cyclohexanone-based polymer building blocks Type A1 Journal article
  Year 2015 Publication Chemsuschem Abbreviated Journal Chemsuschem
  Volume 8 Issue (down) 8 Pages 1805-1818
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4-alkylguaiacols, their conversion into 4-alkylcyclohexanols, followed by dehydrogenation to form cyclohexanones, and Baeyer-Villiger oxidation to give caprolactones. The formation of alkylated cyclohexanols is one of the most difficult steps in the series. A liquid-phase process in the presence of nickel on CeO2 or ZrO2 catalysts is demonstrated herein to give the highest cyclohexanol yields. The catalytic reaction with 4-alkylguaiacols follows two parallel pathways with comparable rates: 1) ring hydrogenation with the formation of the corresponding alkylated 2-methoxycyclohexanol, and 2) demethoxylation to form 4-alkylphenol. Although subsequent phenol to cyclohexanol conversion is fast, the rate is limited for the removal of the methoxy group from 2-methoxycyclohexanol. Overall, this last reaction is the rate-limiting step and requires a sufficient temperature (> 250 degrees C) to overcome the energy barrier. Substrate reactivity (with respect to the type of alkyl chain) and details of the catalyst properties (nickel loading and nickel particle size) on the reaction rates are reported in detail for the Ni/CeO2 catalyst. The best Ni/CeO2 catalyst reaches 4-alkylcyclohexanol yields over 80 %, is even able to convert real softwood-derived guaiacol mixtures and can be reused in subsequent experiments. A proof of principle of the projected cascade conversion of lignocellulose feedstock entirely into caprolactone is demonstrated by using Cu/ZrO2 for the dehydrogenation step to produce the resultant cyclohexanones (approximate to 80%) and tin-containing beta zeolite to form 4-alkyl-e-caprolactones in high yields, according to a Baeyer-Villiger-type oxidation with H2O2.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Weinheim Editor
  Language Wos 000355220300020 Publication Date 2015-04-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1864-5631; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.226 Times cited 71 Open Access
  Notes Fwo Approved Most recent IF: 7.226; 2015 IF: 7.657
  Call Number c:irua:126406 Serial 2967
Permanent link to this record
 

 
Author Pilehvar, S.; Jambrec, D.; Gebala, M.; Schuhmann, W.; De Wael, K.
  Title Intercalation of proflavine in ssDNA aptamers : effect on binding of the specific target chloramphenicol Type A1 Journal article
  Year 2015 Publication Electroanalysis Abbreviated Journal Electroanal
  Volume 27 Issue (down) 8 Pages 1836-1841
  Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
  Abstract The structural modification of ssDNA-based aptamers upon specific binding of its target molecule leads to changes of the charge-transfer resistance (Rct) of a negatively-charged free-diffusing redox probe. The aptamer adopts a structure due to self-hybridization which is stabilized using profalvine as intercalator. The pre-organized aptamer structure is used to detect chloramphenicol (CAP) requiring a substantial change of the aptamer structure indicated by a CAP concentration dependent increase in the Rct values. Pre-incubation of the aptamer-modified electrode with an intercalator allows for the modulation of the aptamer/target interaction and hence for a modulation of the CAP-dependent variation of the Rct values.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000359737500006 Publication Date 2015-06-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1040-0397 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.851 Times cited 5 Open Access
  Notes ; D. J., M. G., W. S. are grateful for financial support to the Deutsch-Israelische Projektkooperation (DIP) in the framework of the project “Nanoengineered optoelectronics with biomaterials and bioinspired assemblies” funded by the Deutsche Forschungsgemeinschaft. S. P. and K. D. W. are thankful to UA for DOCPRO financial support. ; Approved Most recent IF: 2.851; 2015 IF: 2.138
  Call Number UA @ admin @ c:irua:126494 Serial 5666
Permanent link to this record
 

 
Author De Schepper, E.; Van Passel, S.; Lizin, S.
  Title Economic benefits of combining clean energy technologies : the case of solar photovoltaics and battery electric vehicles Type A1 Journal article
  Year 2015 Publication International Journal Of Energy Research Abbreviated Journal Int J Energ Res
  Volume 39 Issue (down) 8 Pages 1109-1119
  Keywords A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM)
  Abstract The combined use of clean technologies can lead amongst other benefits to reduced environmental impacts, improved system efficiencies, better management of land scarcity, and diminishment of the effect of power variability of intermittent clean energy sources. Nonetheless, private investors facing budgetary constraints will only opt to invest in the combination of technologies if the latter is more profitable than the investment in a single technology. The aim of the paper is to provide a systematic model for decision makers that allows them to evaluate the profitability of any random combination of technologies under budgetary constraints, and to compare this profitability with that of the individual projects in isolation. This research goes beyond the state of art in the field of financial management and more specifically in the field of the rationing of capital amongst interdependent projects, by developing a method to calculate the payoff of interdependent projects undertaken together. Moreover, this paper develops a computational model from the investor's point of view, of which the purpose is threefold: First, the model allows to directly compare the economic payoff of individual complementary technologies with the economic payoff of their integrated combination, under budgetary constraints. Second, the model calculates economic synergies labeled benefits of combined technologies' (BOCT) when combining complementary technologies. Third, the model explains the rationalization behind the presence of BOCT. The model exemplifies an ex ante cost benefit analysis developed for business and non-governmental use. A four step methodology is proposed and illustrated by means of a case study of PV solar power and battery electric vehicles (BEVs) for a small Belgian enterprise. Results show that at low electricity prices (<Euro0.112/kWh) it is most profitable to invest in BEVs. When the price of electricity rises (>Euro0.134/kWh), investment in exclusively PV becomes most attractive. In all other cases, it is more profitable to invest in the combination of both technologies. Copyright (c) 2015 John Wiley & Sons, Ltd.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000355732200006 Publication Date 2015-03-21
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0363-907x ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.598 Times cited 14 Open Access
  Notes ; Sebastien Lizin would like to thank the Research Foundation Flanders (FWO), grant number 12G5415N, for their funding without which it would have been impossible to review this work. ; Approved Most recent IF: 2.598; 2015 IF: 2.418
  Call Number UA @ admin @ c:irua:127535 Serial 6188
Permanent link to this record
 

 
Author Batuk, D.; Batuk, M.; Abakumov, A.M.; Hadermann, J.
  Title Synergy between transmission electron microscopy and powder diffraction : application to modulated structures Type A1 Journal article
  Year 2015 Publication Acta crystallographica: section B: structural science Abbreviated Journal Acta Crystallogr B
  Volume 71 Issue (down) 71 Pages 127-143
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The crystal structure solution of modulated compounds is often very challenging, even using the well established methodology of single-crystal X-ray crystallography. This task becomes even more difficult for materials that cannot be prepared in a single-crystal form, so that only polycrystalline powders are available. This paper illustrates that the combined application of transmission electron microscopy (TEM) and powder diffraction is a possible solution to the problem. Using examples of anion-deficient perovskites modulated by periodic crystallographic shear planes, it is demonstrated what kind of local structural information can be obtained using various TEM techniques and how this information can be implemented in the crystal structure refinement against the powder diffraction data. The following TEM methods are discussed: electron diffraction (selected area electron diffraction, precession electron diffraction), imaging (conventional high-resolution TEM imaging, high-angle annular dark-field and annular bright-field scanning transmission electron microscopy) and state-of-the-art spectroscopic techniques (atomic resolution mapping using energy-dispersive X-ray analysis and electron energy loss spectroscopy).
  Address
  Corporate Author Thesis
  Publisher Place of Publication Copenhagen Editor
  Language Wos 000352166500002 Publication Date 2015-04-01
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2052-5206; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.032 Times cited 11 Open Access
  Notes Fwo G039211n Approved Most recent IF: 2.032; 2015 IF: NA
  Call Number c:irua:124411 Serial 3408
Permanent link to this record
 

 
Author Zeng, Y.-J.; Schouteden, K.; Amini, M.N.; Ruan, S.-C.; Lu, Y.-F.; Ye, Z.-Z.; Partoens, B.; Lamoen, D.; Van Haesendonck, C.
  Title Electronic band structures and native point defects of ultrafine ZnO nanocrystals Type A1 Journal article
  Year 2015 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
  Volume 7 Issue (down) 7 Pages 10617-10622
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
  Abstract Ultrafine ZnO nanocrystals with a thickness down to 0.25 nm are grown by a metalorganic chemical vapor deposition method. Electronic band structures and native point defects of ZnO nanocrystals are studied by a combination of scanning tunneling microscopy/spectroscopy and first-principles density functional theory calculations. Below a critical thickness of nm ZnO adopts a graphitic-like structure and exhibits a wide band gap similar to its wurtzite counterpart. The hexagonal wurtzite structure, with a well-developed band gap evident from scanning tunneling spectroscopy, is established for a thickness starting from similar to 1.4 nm. With further increase of the thickness to 2 nm, V-O-V-Zn defect pairs are easily produced in ZnO nanocrystals due to the self-compensation effect in highly doped semiconductors.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000355055000063 Publication Date 2015-04-29
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1944-8244;1944-8252; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.504 Times cited 15 Open Access
  Notes Hercules; EWI Approved Most recent IF: 7.504; 2015 IF: 6.723
  Call Number c:irua:126408 Serial 999
Permanent link to this record
 

 
Author La Porta, A.; Sanchez-Iglesias, A.; Altantzis, T.; Bals, S.; Grzelczak, M.; Liz-Marzan, L.M.
  Title Multifunctional self-assembled composite colloids and their application to SERS detection Type A1 Journal article
  Year 2015 Publication Nanoscale Abbreviated Journal Nanoscale
  Volume 7 Issue (down) 7 Pages 10377-10381
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract We present a simple method for the co-encapsulation of gold nanostars and iron-oxide nanoparticles into hybrid colloidal composites that are highly responsive to both light and external magnetic fields. Self-assembly was driven by hydrophobic interactions between polystyrene capped gold nanostars and iron oxide nanocrystals stabilized with oleic acid, upon addition of water. A block copolymer was then used to encapsulate the resulting spherical colloidal particle clusters, which thereby became hydrophilic. Electron microscopy analysis unequivocally shows that each composite particle comprises a single Au nanostar surrounded by a few hundreds of iron oxide nanocrystals. We demonstrate that this hybrid colloidal system can be used as an efficient substrate for surface enhanced Raman scattering, using common dyes as model molecular probes. The co-encapsulation of iron oxide nanoparticles renders the system magnetically responsive, so that application of an external magnetic field leads to particle accumulation and limits of detection are in the nM range.
  Address A1 Article; Electron microscopy for materials research (EMAT);
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language English Wos 000355987300010 Publication Date 2015-04-22
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.367 Times cited 51 Open Access OpenAccess
  Notes 267867 Plasmaquo; 335078 Colouratom; 262348 Esmi; ECAS_Sara; (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot); Approved Most recent IF: 7.367; 2015 IF: 7.394
  Call Number c:irua:127003 Serial 3940
Permanent link to this record
 

 
Author Mourdikoudis, S.; Chirea, M.; Zanaga, D.; Altantzis, T.; Mitrakas, M.; Bals, S.; Marzán, L.M.; Pérez-Juste, J.; Pastoriza-Santos, I.
  Title Governing the morphology of PtAu heteronanocrystals with improved electrocatalytic performance Type A1 Journal article
  Year 2015 Publication Nanoscale Abbreviated Journal Nanoscale
  Volume 7 Issue (down) 7 Pages 8739-8747
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Platinumgold heteronanostructures comprising either dimer (PtAu) or coresatellite (Pt@Au) configurations were synthesized by means of a seeded growth procedure using platinum nanodendrites as seeds. Careful control of the reduction kinetics of the gold precursor can be used to direct the nucleation and growth of gold nanoparticles on either one or multiple surface sites simultaneously, leading to the formation of either dimers or coresatellite nanoparticles, respectively, in high yields. Characterization by electron tomography and high resolution electron microscopy provided a better understanding of the actual three-dimensional particle morphology, as well as the AuPt interface, revealing quasi-epitaxial growth of Au on Pt. The prepared PtAu bimetallic nanostructures are highly efficient catalysts for ethanol oxidation in alkaline solution, showing accurate selectivity, high sensitivity, and improved efficiency by generating higher current densities than their monometallic counterparts.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Cambridge Editor
  Language Wos 000354204400011 Publication Date 2015-03-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.367 Times cited 41 Open Access OpenAccess
  Notes 335078 Colouratom; 262348 Esmi; ECAS_Sara; (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot); Approved Most recent IF: 7.367; 2015 IF: 7.394
  Call Number c:irua:126354 Serial 1360
Permanent link to this record
 

 
Author Buffière, M.; Brammertz, G.; Sahayaraj, S.; Batuk, M.; Khelifi, S.; Mangin, D.; El Mel, A.A.; Arzel, L.; Hadermann, J.; Meuris, M.; Poortmans, J.;
  Title KCN chemical etch for interface engineering in Cu2ZnSnSe4 solar cells Type A1 Journal article
  Year 2015 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
  Volume 7 Issue (down) 7 Pages 14690-14698
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract The removal of secondary phases from the surface of the kesterite crystals is one of the major challenges to improve the performances of Cu2ZnSn(S,Se)(4) (CZTSSe) thin film solar cells. In this Contribution, the KCN/KOH Chemical etching approach, originally developed for the removal of CuxSe phases in Cu(In,Ga)(S,Se)(2) thin films) is applied to CZTSe absorbers exhibiting various chemical compositions. Two distinct electrical behaviors were observed on CZTSe/CdS solar cells after treatment: (i) the improvement of the fill factor (FF) after 30 s of etching for the CZTSe absorbers showing initially a distortion of the electrical characteristic; (ii) the progressive degradation Of the FF after long treatment time for all Cu-poor CZTSe solar cell samples. The first effect can be attributed to the action of KCN on the absorber, that is found to clean the absorber free surface from most of the secondary phases surrounding the kesterite grains (e.g., Se-0, CuxSe, SnSex, SnO2, Cu2SnSe3 phases, excepting the ZnSe-based phases). The second observation was identified as a consequence of the preferential etching of Se, Sn, and Zn from the CZTSe surface by the KOH solution, combined with the modification of the alkali content of the absorber. The formation of a Cu-rich shell at the absorber/buffer layer interface, leading to the increase of the recombination rate at the interface, and the increase in the doping of the absorber layer after etching are found to be at the origin of the deterioration of the FF of the solar cells.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000358395200019 Publication Date 2015-06-03
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1944-8244;1944-8252; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.504 Times cited 34 Open Access
  Notes Approved Most recent IF: 7.504; 2015 IF: 6.723
  Call Number c:irua:127153 Serial 1755
Permanent link to this record
 

 
Author Meledina, M.; Turner, S.; Galvita, V.V.; Poelman, H.; Marin, G.B.; Van Tendeloo, G.
  Title Local environment of Fe dopants in nanoscale Fe : CeO2-x oxygen storage material Type A1 Journal article
  Year 2015 Publication Nanoscale Abbreviated Journal Nanoscale
  Volume 7 Issue (down) 7 Pages 3196-3204
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Nanoscale Fe : CeO2-x oxygen storage material for the process of chemical looping has been investigated by advanced transmission electron microscopy and electron energy-loss spectroscopy before and after a model looping procedure, consisting of redox cycles at heightened temperature. Separately, the activity of the nanomaterial has been tested in a toluene total oxidation reaction. The results show that the material consists of ceria nanoparticles, doped with single Fe atoms and small FeOx clusters. The iron ion is partially present as Fe3+ in a solid solution within the ceria lattice. Furthermore, enrichment of reduced Fe2+ species is observed in nanovoids present in the ceria nanoparticles, as well as at the ceria surface. After chemical looping, agglomeration occurs and reduced nanoclusters appear at ceria grain boundaries formed by sintering. These clusters originate from surface Fe2+ aggregation, and from bulk Fe3+, which “leaks out” in reduced state after cycling to a slightly more agglomerated form. The activity of Fe : CeO2 during the toluene total oxidation part of the chemical looping cycle is ensured by the dopant Fe in the Fe1-xCexO2 solid solution, and by surface Fe species. These measurements on a model Fe : CeO2-x oxygen storage material give a unique insight into the behavior of dopants within a nanosized ceria host, and allow to interpret a plethora of (doped) cerium oxide-based reactions.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Cambridge Editor
  Language Wos 000349473200046 Publication Date 2015-01-13
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.367 Times cited 17 Open Access
  Notes Approved Most recent IF: 7.367; 2015 IF: 7.394
  Call Number c:irua:125299 Serial 1828
Permanent link to this record
 

 
Author Chen, J.-J.; Ke, X.; Van Tendeloo, G.; Meng, J.; Zhou, Y.-B.; Liao, Z.-M.; Yu, D.-P.
  Title Magnetotransport across the metal-graphene hybrid interface and its modulation by gate voltage Type A1 Journal article
  Year 2015 Publication Nanoscale Abbreviated Journal Nanoscale
  Volume 7 Issue (down) 7 Pages 5516-5524
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract The graphene-metal contact is very important for optimizing the performance of graphene based electronic devices. However, it is difficult to probe the properties of the graphene/metal interface directly via transport measurements in traditional graphene lateral devices, because the dominated transport channel is graphene, not the interface. Here, we employ the Au/graphene/Au vertical and lateral hybrid structure to unveil the metal-graphene interface properties, where the transport is dominated by the charge carriers across the interface. The magnetoresistance (MR) of Au/monolayer graphene/Au and Au/stacked two-layered graphene/Au devices is measured and modulated by gate voltage, demonstrating that the interface is a device. The gate-tunable MR is identified from the graphene lying on the SiO2 substrate and underneath the top metal electrode. Our unique structures couple the in-plane and out-of-plane transport and display linear MR with small amplitude oscillations at low temperatures. Under a magnetic field, the electronic coupling between the graphene edge states and the electrode leads to the appearance of quantum oscillations. Our results not only provide a new pathway to explore the intrinsic transport mechanism at the graphene/metal interface but also open up new vistas of magnetoelectronics.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Cambridge Editor
  Language Wos 000351372400050 Publication Date 2015-02-19
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.367 Times cited 3 Open Access
  Notes 246791 Countatoms Approved Most recent IF: 7.367; 2015 IF: 7.394
  Call Number c:irua:125533 Serial 1931
Permanent link to this record
 

 
Author Egoavil, R.; Huehn, S.; Jungbauer, M.; Gauquelin, N.; Béché, A.; Van Tendeloo, G.; Verbeeck; Moshnyaga, V.
  Title Phase problem in the B-site ordering of La2CoMnO6 : impact on structure and magnetism Type A1 Journal article
  Year 2015 Publication Nanoscale Abbreviated Journal Nanoscale
  Volume 7 Issue (down) 7 Pages 9835-9843
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Epitaxial double perovskite La2CoMnO6 (LCMO) films were grown by metalorganic aerosol deposition on SrTiO3(111) substrates. A high Curie temperature, T-C = 226 K, and large magnetization close to saturation, M-S(5 K) = 5.8 mu(B)/f.u., indicate a 97% degree of B-site (Co,Mn) ordering within the film. The Co/Mn ordering was directly imaged at the atomic scale by scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (STEM-EDX). Local electron-energy-loss spectroscopy (EELS) measurements reveal that the B-sites are predominantly occupied by Co2+ and Mn4+ ions in quantitative agreement with magnetic data. Relatively small values of the (1/2 1/2 1/2) superstructure peak intensity, obtained by X-ray diffraction (XRD), point out the existence of ordered domains with an arbitrary phase relationship across the domain boundary. The size of these domains is estimated to be in the range 35-170 nm according to TEM observations and modelling the magnetization data. These observations provide important information towards the complexity of the cation ordering phenomenon and its implications on magnetism in double perovskites, and similar materials.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Cambridge Editor
  Language Wos 000354983100060 Publication Date 2015-05-05
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.367 Times cited 37 Open Access
  Notes 312483 ESTEEM2; FWO G004413N; 246102 IFOX; Hercules; esteem2_jra3 Approved Most recent IF: 7.367; 2015 IF: 7.394
  Call Number c:irua:126423 c:irua:126423 Serial 2586
Permanent link to this record
 

 
Author Zeng, Y.-J.; Gauquelin, N.; Li, D.-Y.; Ruan, S.-C.; He, H.-P.; Egoavil, R.; Ye, Z.-Z.; Verbeeck, J.; Hadermann, J.; Van Bael, M.J.; Van Haesendonck, C.
  Title Co-Rich ZnCoO Nanoparticles Embedded in Wurtzite Zn1-xCoxO Thin Films: Possible Origin of Superconductivity Type A1 Journal article
  Year 2015 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
  Volume 7 Issue (down) 7 Pages 22166-22171
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Co-rich ZnCoO nanoparticles embedded in wurtzite Zn0.7Co0.3O thin films are grown by pulsed laser deposition on a Si substrate. Local superconductivity with an onset Tc at 5.9 K is demonstrated in the hybrid system. The unexpected superconductivity probably results from Co(3+) in the Co-rich ZnCoO nanoparticles or from the interface between the Co-rich nanoparticles and the Zn0.7Co0.3O matrix.
  Address Solid State Physics and Magnetism Section, KU Leuven , Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language English Wos 000363001500007 Publication Date 2015-09-21
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1944-8244;1944-8252; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.504 Times cited 13 Open Access
  Notes This work has been supported by the Research Foundation − Flanders (FWO, Belgium) as well as by the Flemish Concerted Research Action program (BOF KU Leuven, GOA/14/007). N. G. and J. V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. The Qu-Ant-EM microscope was partly funded by the Flemish Hercules Foundation. The work at Shenzhen University was supported by National Natural Science Foundation of China under Grant No. 61275144 and Natural Science Foundation of SZU. Y.-J. Z. acknowledges funding under grant No. SKL2015-12 from the State Key Laboratory of Silicon Materials; ECASJO_; Approved Most recent IF: 7.504; 2015 IF: 6.723
  Call Number c:irua:129195 c:irua:129195UA @ admin @ c:irua:129195 Serial 3949
Permanent link to this record
 

 
Author Warwick, M.E.A.; Kaunisto, K.; Barreca, D.; Carraro, G.; Gasparotto, A.; Maccato, C.; Bontempi, E.; Sada, C.; Ruoko, T.P.; Turner, S.; Van Tendeloo, G.;
  Title Vapor phase processing of \alpha-Fe2O3 photoelectrodes for water splitting : an insight into the structure/property interplay Type A1 Journal article
  Year 2015 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
  Volume 7 Issue (down) 7 Pages 8667-8676
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Harvesting radiant energy to trigger water photoelectrolysis and produce clean hydrogen is receiving increasing attention in the search of alternative energy resources. In this regard, hematite (alpha-Fe2O3) nanostructures with controlled nano-organization have been fabricated and investigated for use as anodes in photoelectrochemical (PEC) cells. The target systems have been grown on conductive substrates by plasma enhanced-chemical vapor deposition (PE-CVD) and subjected to eventual ex situ annealing in air to further tailor their structure and properties. A detailed multitechnique approach has enabled to elucidate between system characteristics and the generated photocurrent. The present alpha-Fe2O3 systems are characterized by a high purity and hierarchical morphologies consisting of nanopyramids/organized dendrites, offering a high contact area with the electrolyte. PEC data reveal a dramatic response enhancement upon thermal treatment, related to a more efficient electron transfer. The reasons underlying such a phenomenon are elucidated and discussed by transient absorption spectroscopy (TAS) studies of photogenerated charge carrier kinetics, investigated on different time scales for the first time on PE-CVD Fe2O3 nanostructures.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000353931300037 Publication Date 2015-04-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1944-8244;1944-8252; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.504 Times cited 51 Open Access
  Notes 246791 Countatoms; Fwo Approved Most recent IF: 7.504; 2015 IF: 6.723
  Call Number c:irua:126059 Serial 3836
Permanent link to this record
 

 
Author Zhong, R.; Peng, L.; de Clippel, F.; Gommes, C.; Goderis, B.; Ke, X.; Van Tendeloo, G.; Jacobs, P.A.; Sels, B.F.
  Title An eco-friendly soft template synthesis of mesostructured silica-carbon nanocomposites for acid catalysis Type A1 Journal article
  Year 2015 Publication ChemCatChem Abbreviated Journal Chemcatchem
  Volume 7 Issue (down) 7 Pages 3047-3058
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The synthesis of ordered mesoporous silica-carbon composites was explored by employing TEOS and sucrose as the silica and carbon precursor respectively, and the triblock copolymer F127 as a structure-directing agent via an evaporation-induced self-assembly (EISA) process. It is demonstrated that the synthesis procedures allow for control of the textural properties and final composition of these silica-carbon nanocomposites via adjustment of the effective SiO2/C weight ratio. Characterization by SAXS, N-2 physisorption, HRTEM, TGA, and C-13 and Si-29 solid-state MAS NMR show a 2D hexagonal mesostructure with uniform large pore size ranging from 5.2 to 7.6nm, comprising of separate carbon phases in a continuous silica phase. Ordered mesoporous silica and non-ordered porous carbon can be obtained by combustion of the pyrolyzed nanocomposites in air or etching with HF solution, respectively. Sulfonic acid groups can be readily introduced to such kind of silica-carbon nanocomposites by a standard sulfonation procedure with concentrated sulfuric acid. Excellent acid-catalytic activities and selectivities for the dimerization of styrene to produce 1,3-diphenyl-1-butene and dimerization of -methylstyrene to unsaturated dimers were demonstrated with the sulfonated materials.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000361189400037 Publication Date 2015-09-03
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1867-3880; 1867-3899 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.803 Times cited 13 Open Access
  Notes Approved Most recent IF: 4.803; 2015 IF: 4.556
  Call Number UA @ lucian @ c:irua:127836 Serial 4138
Permanent link to this record
 

 
Author Meng, X.; Pant, A.; Cai, H.; Kang, J.; Sahin, H.; Chen, B.; Wu, K.; Yang, S.; Suslu, A.; Peeters, F.M.; Tongay, S.;
  Title Engineering excitonic dynamics and environmental stability of post-transition metal chalcogenides by pyridine functionalization technique Type A1 Journal article
  Year 2015 Publication Nanoscale Abbreviated Journal Nanoscale
  Volume 7 Issue (down) 7 Pages 17109-17115
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
  Abstract http://cmt.ua.ac.be/hsahin/publishedpapers/46.pdf
  Address
  Corporate Author Thesis
  Publisher Place of Publication Cambridge Editor
  Language Wos http://cmt.ua.ac.be/hsahin/publishedpapers/46.pdf Publication Date 2015-09-24
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2040-3364 ISBN Additional Links UA library record; http://cmt.ua.ac.be/hsahin/publishedpapers/46.pdf; WoS full record; WoS citing articles
  Impact Factor 7.367 Times cited 11 Open Access
  Notes ; ; Approved Most recent IF: 7.367; 2015 IF: 7.394
  Call Number UA @ lucian @ c:irua:129434 Serial 4175
Permanent link to this record
 

 
Author Ao, Z.; Jiang, Q.; Li, S.; Liu, H.; Peeters, F.M.; Li, S.; Wang, G.
  Title Enhancement of the stability of fluorine atoms on defective graphene and at graphene/fluorographene interface Type A1 Journal article
  Year 2015 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
  Volume 7 Issue (down) 7 Pages 19659-19665
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
  Abstract Fluorinated graphene is one of the most important derivatives of graphene and has been found to have great potential in optoelectronic and photonic nanodevices. However, the stability of F atoms on fluorinated graphene under different conditions, which is essential to maintain the desired properties of fluorinated graphene, is still unclear. In this work, we investigate the diffusion of F atoms on pristine graphene, graphene with defects, and at graphene/fluorographene interfaces by using density functional theory calculations. We find that an isolated F atom diffuses easily on graphene, but those F atoms can be localized by inducing vacancies or absorbates in graphene and by creating graphene/fluorographene interfaces, which would strengthen the binding energy of F atoms on graphene and increase the diffusion energy barrier of F atoms remarkably.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000361252400018 Publication Date 2015-08-24
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1944-8244 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 7.504 Times cited 35 Open Access
  Notes ; We acknowledge the financial supports from the Chancellor's Research Fellowship Program of the University of Technology Sydney, the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish Government. This research was also supported by the National Computational Infrastructure (NCI) through the merit allocation scheme and used the NCI resources and facilities in Canberra, Australia. ; Approved Most recent IF: 7.504; 2015 IF: 6.723
  Call Number UA @ lucian @ c:irua:128703 Serial 4177
Permanent link to this record
 

 
Author Ceglia, A.; Nuyts, G.; Meulebroeck, W.; Cagno, S.; Silvestri, A.; Zoleo, A.; Nys, K.; Janssens, K.; Thienpont, H.; Terryn, H.
  Title Iron speciation in soda-lime-silica glass: a comparison of XANES and UV-vis-NIR spectroscopy Type A1 Journal article
  Year 2015 Publication Journal of analytical atomic spectrometry Abbreviated Journal J Anal Atom Spectrom
  Volume 30 Issue (down) 7 Pages 1552-1561
  Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
  Abstract Scientific analyses of ancient glasses have been carried out for many years using elemental chemical analysis. However, it is known that the control of the redox conditions in the glass melt has a strong implication on the final hue of glass because it affects Fe2+/SFe. Therefore an increasing number of studies on the redox conditions have been published in recent years by means of synchrotron based Xray absorption spectroscopy. This is a technique which is not easily accessible and requires dedicated facilities. In this paper we describe an alternative approach by means of optical absorption spectroscopy. We synthesised 10 soda-lime-silica glasses with known redox conditions and iron concentration to calibrate the absorption at 1100 nm as a function of Fe2+ concentration. The linear extinction coefficient was also determined. These glasses were also studied by means of X-ray Absorption Near Edge Structure (XANES) spectroscopy. Electron paramagnetic resonance spectroscopy was additionally used as an ancillary method to verify the quality of our data. Furthermore 28 samples from real archaeological samples were analysed by XANES and optical spectroscopy as a case study. The Fe2+/SFe values obtained were compared and demonstrated that the two techniques were in good agreement with each other. Optical spectroscopy can be applied in situ with moderate sample preparation to determine the concentration of Fe2+. To investigate the redox conditions, especially as a first screening approach, this methodology is an important tool to take into consideration before applying more sophisticated techniques such as XANES, which is more elaborate and requires high-tech resources.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000356971900009 Publication Date 2015-04-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0267-9477 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.379 Times cited 20 Open Access
  Notes ; The research leading to these results has received funding from the European Union Seventh Framework Programme FP7/2007-2013 under grant agreement no. 265010. For more information please visit the NARNIA website: http:// narnia-itn.eu/. This work was partly supported by the Research Council of Norway through its Centres of Excellence funding scheme, project number 223268/ F50. We are grateful to the ESRF for granting beamtime and Dipanjan Banerjee for his help at the beamline. We are thankful to the R&D department of AGC Glass Europe, in particular Dr Benoit Cherdon, Dr Dominique Michiels and Ms Dominique Delleuze, for preparing glass for us and providing us the chemical information. A special thanks to M. Fialin for the help with EPMA measurements in CAMPARIS. We want to express our gratitude to F. Farges and A. Berry for sharing their XANES spectra with us. Thanks to Anne Isabelle for reading this paper and giving comments. Finally we are grateful to two anonymous reviewers who contributed to improve this paper. ; Approved Most recent IF: 3.379; 2015 IF: 3.466
  Call Number UA @ admin @ c:irua:127060 Serial 5679
Permanent link to this record
 

 
Author Monico, L.; Janssens, K.; Cotte, M.; Romani, A.; Sorace, L.; Grazia, C.; Brunetti, B.G.; Miliani, C.
  Title Synchrotron-based X-ray spectromicroscopy and electron paramagnetic resonance spectroscopy to investigate the redox properties of lead chromate pigments under the effect of visible light Type A1 Journal article
  Year 2015 Publication Journal of analytical atomic spectrometry Abbreviated Journal J Anal Atom Spectrom
  Volume 30 Issue (down) 7 Pages 1500-1510
  Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
  Abstract Light-induced redox processes have been established as the cause of the chromatic alterations of a number of artists' pigments used from the 15th to the 20th century. Despite the fact that a general comprehension of the mechanisms has been provided through the characterization of photo-degraded compounds, both exhaustive information on the wavelength-dependence of the alteration process of the pigments and experimental evidence in how visible light may influence the formation pathways of specific secondary compounds are still lacking. Establishing an analytical protocol for the study of wavelength-dependence of pigments on photo-redox pathways is relevant for the safe illumination of paintings, especially in view of the possible use of spectrally tunable light sources such as white light emitting diodes (WLEDs). In this work, we propose an integrated approach based on a combination of diffuse reflectance UV-visible, synchrotron radiation (SR)-based micro X-ray fluorescence (m-XRF)/X-ray absorption near edge structure (m-XANES) and electron paramagnetic resonance (EPR) spectroscopies to study the photo-redox process of Cr(VI) -> Cr(III) for lead chromate yellows (PbCr1-xSxO4, 0 <= x <= 0.8) under exposure to different monochromatic light. In view of the thin (3-5 mm) alteration layer that is formed at the paint surface after light exposure, SR-based Cr K-edge mu-XANES/mu-XRF analysis was employed to obtain information on the abundance, nature and distribution of the alteration of Cr(III)-compounds at the micrometricscale level. On the other hand, EPR spectroscopy was used as a complementary tool to the SR-based X-ray methods due to its sensitivity for revealing species containing one or more unpaired electrons and for distinguishing different coordination geometries of paramagnetic centers, such as Cr(V)-species. Semi-quantitative indications about the darkening of the paint surface were obtained by UV-Vis spectroscopy. An abundance of reduced Cr down to around 50% was detected at the aged surface of chrome yellow paints. The reduction process was favored not only by wavelengths shorter than 460 nm (i.e., where the pigment shows its maximum absorption) but also by light in the 490-530 nm range. The first evidence of the presence of Cr(V)-intermediates in the Cr(VI) -> Cr(III) reduction reaction allowed the risks of inducing photo-degradation of the 490-530 nm wavelength range to be explained.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000356971900004 Publication Date 2015-04-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0267-9477 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.379 Times cited 17 Open Access
  Notes ; This research was supported by the Italian projects PRIN-(SICH) and PON- (ITACHA) and by Belgian Science Policy project S2-ART (BELSPO S4DA), the GOA “SOLARPAINT” (Research Fund Antwerp University, Belgium) and FWO (Brussels, Belgium) projects no. G.0C12.13, G.0704.08 and G.01769.09. ESRF is acknowledged for the grants received (experiments HG18 and HG26). L.S. and L.M. acknowledge the financial support of Ente-CRF and CNR-Short Term Mobility Programme 2013, respectively. ; Approved Most recent IF: 3.379; 2015 IF: 3.466
  Call Number UA @ admin @ c:irua:127059 Serial 5862
Permanent link to this record
 

 
Author Daems, D.; van Nuijs, A.L.N.; Covaci, A.; Hamidi-Asl, E.; Van Camp, G.; Nagels, L.J.
  Title Potentiometric detection in UPLC as an easy alternative to determine cocaine in biological samples Type A1 Journal article
  Year 2015 Publication Biomedical chromatography Abbreviated Journal
  Volume 29 Issue (down) 7 Pages 1124-1129
  Keywords A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre
  Abstract The analytical methods which are often used for the determination of cocaine in complex biological matrices are a prescreening immunoassay and confirmation by chromatography combined with mass spectrometry. We suggest an ultra-high-pressure liquid chromatography combined with a potentiometric detector, as a fast and practical method to detect and quantify cocaine in biological samples. An adsorption/desorption model was used to investigate the usefulness of the potentiometric detector to determine cocaine in complex matrices. Detection limits of 6.3ngmL(-1) were obtained in plasma and urine, which is below the maximum residue limit (MRL) of 25ngmL(-1). A set of seven plasma samples and 10 urine samples were classified identically by both methods as exceeding the MRL or being inferior to it. The results obtained with the UPLC/potentiometric detection method were compared with the results obtained with the UPLC/MS method for samples spiked with varying cocaine concentrations. The intraclass correlation coefficient was 0.997 for serum (n =7) and 0.977 for urine (n =8). As liquid chromatography is an established technique, and as potentiometry is very simple and cost-effective in terms of equipment, we believe that this method is potentially easy, inexpensive, fast and reliable. Copyright (c) 2014 John Wiley & Sons, Ltd.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000356694000020 Publication Date 2014-12-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0269-3879 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:127069 Serial 8396
Permanent link to this record
 

 
Author Van de Vijver, E.; Van Meirvenne, M.; Vandenhaute, L.; Delefortrie, S.; De Smedt, P.; Saey, T.; Seuntjens, P.
  Title Urban soil exploration through multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar Type A1 Journal article
  Year 2015 Publication Environmental science : processes & impacts Abbreviated Journal
  Volume 17 Issue (down) 7 Pages 1271-1281
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
  Abstract In environmental assessments, the characterization of urban soils relies heavily on invasive investigation, which is often insufficient to capture their full spatial heterogeneity. Non-invasive geophysical techniques enable rapid collection of high-resolution data and provide a cost-effective alternative to investigate soil in a spatially comprehensive way. This paper presents the results of combining multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar to characterize a former garage site contaminated with petroleum hydrocarbons. The sensor combination showed the ability to identify and accurately locate building remains and a high-density soil layer, thus demonstrating the high potential to investigate anthropogenic disturbances of physical nature. In addition, a correspondence was found between an area of lower electrical conductivity and elevated concentrations of petroleum hydrocarbons, suggesting the potential to detect specific chemical disturbances. We conclude that the sensor combination provides valuable information for preliminary assessment of urban soils.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000357793300008 Publication Date 2015-06-04
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2050-7887; 2050-7895 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:127130 Serial 8715
Permanent link to this record
 

 
Author van Dyck, D.; Lobato, I.; Chen, F.-R.; Kisielowski, C.
  Title Do you believe that atoms stay in place when you observe them in HREM? Type A1 Journal article
  Year 2015 Publication Micron Abbreviated Journal Micron
  Volume 68 Issue (down) 68 Pages 158-163
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
  Abstract Recent advancements in aberration-corrected electron microscopy allow for an evaluation of unexpectedly large atom displacements beyond a resolution limit of similar to 0.5 angstrom, which are found to be dose-rate dependent in high resolution images. In this paper we outline a consistent description of the electron scattering process, which explains these unexpected phenomena. Our approach links thermal diffuse scattering to electron beam-induced object excitation and relaxation processes, which strongly contribute to the image formation process. The effect can provide an explanation for the well-known contrast mismatch (“Stobbs factor”) between image calculations and experiments. (C) 2014 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000348016500023 Publication Date 2014-09-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0968-4328; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.98 Times cited 11 Open Access
  Notes Approved Most recent IF: 1.98; 2015 IF: 1.988
  Call Number c:irua:123802 Serial 745
Permanent link to this record
 

 
Author Kirilenko, D.A.; Dideykin, A.T.; Aleksenskiy, A.E.; Sitnikova, A.A.; Konnikov, S.G.; Vul', A.Y.
  Title One-step synthesis of a suspended ultrathin graphene oxide film: Application in transmission electron microscopy Type A1 Journal article
  Year 2015 Publication Micron Abbreviated Journal Micron
  Volume 68 Issue (down) 68 Pages 23-26
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Ultrathin graphene films find their use as advantageous support for nano- and biomaterials investigations. Thin film causes a very slight deterioration to measured signals, thus providing more details of the object's structure at nanoscale. The ultimate thinness of graphene works in the best way for this purpose. However, obtaining suspended thin film of a large-area, which is convenient for applications, is often a relatively complicated and time-consuming task. Here we present a one-step 1-min technique for synthesis of an extremely thin (about 1-2 nm) continuous film suspended over cells of a conventional copper grid (50-400 mu m mesh). This technique enables us to acquire a large-area film which is water-resistant, stable in organic solvents and can act as a support when studying nanoparticles or biomaterials. Moreover, the very mechanism of the film formation can be interesting from the point of view of other applications of ultrathin graphene oxide papers. (C) 2014 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000348016500004 Publication Date 2014-08-30
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0968-4328; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.98 Times cited 13 Open Access
  Notes Approved Most recent IF: 1.98; 2015 IF: 1.988
  Call Number c:irua:123800 Serial 2467
Permanent link to this record
 

 
Author Adam, N.; Leroux, F.; Knapen, D.; Bals, S.; Blust, R.
  Title The uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna under chronic exposure scenarios Type A1 Journal article
  Year 2015 Publication Water research Abbreviated Journal Water Res
  Volume 68 Issue (down) 68 Pages 249-261
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Veterinary physiology and biochemistry
  Abstract In this study, the uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna was tested. Daphnids were exposed during 10 days to sublethal concentrations of ZnO and CuO nanoparticles and corresponding metal salts (ZnCl2 and CuCl2.2H2O), after which they were transferred to unexposed medium for another 10 days. At different times during the exposure and none-exposure, the total and internal zinc or copper concentration of the daphnids was determined and the nanoparticles were localized in the organism using electron microscopy. The exposure concentrations were characterized by measuring the dissolved, nanoparticle and aggregated fraction in the medium. The results showed that the ZnO nanoparticles quickly dissolved after addition to the medium. Contrarily, only a small fraction (corresponding to the dissolved metal salt) of the CuO nanoparticles dissolved, while most of these nanoparticles formed large aggregates. Despite an initial increase in zinc and copper concentration during the first 48 hour to 5 day exposure, the body concentration reached a plateau level that was comparable for the ZnO nanoparticles and ZnCl2, but much higher for the CuO nanoparticles (with visible aggregates accumulating in the gut) than CuCl2.2H2O. During the remaining exposure and subsequent none-exposure phase, the zinc and copper concentration decreased fast to concentrations comparable with the unexposed daphnids. The results indicate that D. magna can regulate its internal zinc and copper concentration after exposure to ZnO and CuO nanoparticles, similar as after exposure to metal salts. The combined dissolution, accumulation and toxicity results confirm that the toxicity of ZnO and CuO nanoparticles is caused by the dissolved fraction. Keywords nano; zinc; copper; dissolution; aggregation; electron microscopy
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000347756900022 Publication Date 2014-10-14
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0043-1354; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.942 Times cited 51 Open Access OpenAccess
  Notes ; The authors would like to thank Valentine Mubiana and Steven Joosen (Sphere, UA) for performing the ICP-MS and ICP-OES measurements and Prof. Dr. Gustaaf Van Tendeloo for making the collaboration between the EMAT and Sphere group possible. This study is part of the ENNSATOX-project, which was funded by the EU (NMP4-SL-2009-229244). The authors report no conflicts of interest. ; Approved Most recent IF: 6.942; 2015 IF: 5.528
  Call Number c:irua:119366 c:irua:119366 Serial 3822
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: