Records |
Author |
Van Boxem, R.; Verbeeck, J.; Partoens, B. |
Title |
Spin effects in electron vortex states |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Europhysics letters |
Abbreviated Journal |
Epl-Europhys Lett |
Volume |
102 |
Issue |
4 |
Pages |
40010-40016 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
Abstract |
The recent experimental realization of electron vortex beams opens up a wide research domain previously unexplored. The present paper explores the relativistic properties of these electron vortex beams, and quantifies deviations from the scalar wave theory. It is common in electron optics to use the Schrodinger equation neglecting spin. The present paper investigates the role of spin and the total angular momentum J(z) and how it pertains to the vortex states. As an application, we also investigate if it is possible to use holographic reconstruction to create novel total angular momentum eigenstates in a transmission electron microscope. It is demonstrated that relativistic spin coupling effects disappear in the paraxial limit, and spin effects in holographically created electron vortex beams can only be exploited by using specialized magnetic apertures. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Paris |
Editor |
|
Language |
|
Wos |
000321118600011 |
Publication Date |
2013-06-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0295-5075;1286-4854; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.957 |
Times cited |
11 |
Open Access |
|
Notes |
312483 Esteem2; N246791 Countatoms; 278510 Vortex; esteem2jra1; esteem2jra3 ECASJO_; |
Approved |
Most recent IF: 1.957; 2013 IF: 2.269 |
Call Number |
UA @ lucian @ c:irua:109852 |
Serial |
3087 |
Permanent link to this record |
|
|
|
Author |
Compernolle, T.; Van Passel, S.; Lebbe, L. |
Title |
Bioremediation : how to deal with removal efficiency uncertainty? An economic application |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Journal Of Environmental Management |
Abbreviated Journal |
J Environ Manage |
Volume |
127 |
Issue |
|
Pages |
77-85 |
Keywords |
A1 Journal article; Economics |
Abstract |
Bioremediation is a remediation strategy, which has considerable strength but also certain limitations. Complex and uncertain relationships among biomass, contaminants, and nutrients lead to an uncertain level of removal efficiency. The uncertainty inherent to a bioremediation strategy should be addressed in the remediation selection process. In order to evaluate the bioremediation strategy economically, this study takes into account the reversibility of a decision. A decision tree structures the different remediation strategies, thus giving the possible courses of action open to the decision maker. The option value indicates the importance of having the possibility to reverse a previously made decision. Compared with conventional economic evaluation tools, more information to ground the selection made is revealed. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
|
Language |
|
Wos |
000322940100010 |
Publication Date |
2013-05-15 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0301-4797 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.01 |
Times cited |
1 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 4.01; 2013 IF: 3.188 |
Call Number |
UA @ admin @ c:irua:129868 |
Serial |
6162 |
Permanent link to this record |
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|
|
Author |
Goris, B.; Roelandts, T.; Batenburg, K.J.; Heidari Mezerji, H.; Bals, S. |
Title |
Advanced reconstruction algorithms for electron tomography : from comparison to combination |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
127 |
Issue |
|
Pages |
40-47 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
In this work, the simultaneous iterative reconstruction technique (SIRT), the total variation minimization (TVM) reconstruction technique and the discrete algebraic reconstruction technique (DART) for electron tomography are compared and the advantages and disadvantages are discussed. Furthermore, we describe how the result of a three dimensional (3D) reconstruction based on TVM can provide objective information that is needed as the input for a DART reconstruction. This approach results in a tomographic reconstruction of which the segmentation is carried out in an objective manner. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000316659100007 |
Publication Date |
2012-08-02 |
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 |
63 |
Open Access |
|
Notes |
Fwo |
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:101217 |
Serial |
72 |
Permanent link to this record |
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|
|
Author |
Wang, A.; Turner, S.; Van Aert, S.; van Dyck, D. |
Title |
An alternative approach to determine attainable resolution directly from HREM images |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
133 |
Issue |
|
Pages |
50-61 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
The concept of resolution in high-resolution electron microscopy (HREM) is the power to resolve neighboring atoms. Since the resolution is related to the width of the point spread function of the microscope, it could in principle be determined from the image of a point object. However, in electron microscopy there are no ideal point objects. The smallest object is an individual atom. If the width of an atom is much smaller than the resolution of the microscope, this atom can still be considered as a point object. As the resolution of the microscope enters the sub-Å regime, information about the microscope is strongly entangled with the information about the atoms in HREM images. Therefore, we need to find an alternative method to determine the resolution in an object-independent way. In this work we propose to use the image wave of a crystalline object in zone axis orientation. Under this condition, the atoms of a column act as small lenses so that the electron beam channels through the atom column periodically. Because of this focusing, the image wave of the column can be much more peaked than the constituting atoms and can thus be a much more sensitive probe to measure the resolution. Our approach is to use the peakiness of the image wave of the atom column to determine the resolution. We will show that the resolution can be directly linked to the total curvature of the atom column wave. Moreover, we can then directly obtain the resolution of the microscope given that the contribution from the object is known, which is related to the bounding energy of the atom. The method is applied on an experimental CaTiO3 image wave. |
Address |
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Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000324471800007 |
Publication Date |
2013-05-23 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0304-3991; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
2.843 |
Times cited |
|
Open Access |
|
Notes |
FWO; Hercules; Esteem2; esteem2_jra2 |
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:109919 |
Serial |
90 |
Permanent link to this record |
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|
|
Author |
de Backer, A.; Martinez, G.T.; Rosenauer, A.; Van Aert, S. |
Title |
Atom counting in HAADF STEM using a statistical model-based approach : methodology, possibilities, and inherent limitations |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
134 |
Issue |
|
Pages |
23-33 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
In the present paper, a statistical model-based method to count the number of atoms of monotype crystalline nanostructures from high resolution high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) images is discussed in detail together with a thorough study on the possibilities and inherent limitations. In order to count the number of atoms, it is assumed that the total scattered intensity scales with the number of atoms per atom column. These intensities are quantitatively determined using model-based statistical parameter estimation theory. The distribution describing the probability that intensity values are generated by atomic columns containing a specific number of atoms is inferred on the basis of the experimental scattered intensities. Finally, the number of atoms per atom column is quantified using this estimated probability distribution. The number of atom columns available in the observed STEM image, the number of components in the estimated probability distribution, the width of the components of the probability distribution, and the typical shape of a criterion to assess the number of components in the probability distribution directly affect the accuracy and precision with which the number of atoms in a particular atom column can be estimated. It is shown that single atom sensitivity is feasible taking the latter aspects into consideration. |
Address |
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Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000324474900005 |
Publication Date |
2013-05-17 |
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 |
48 |
Open Access |
|
Notes |
FWO; Esteem2; FP 2007-2013; esteem2_jra2 |
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:109916 |
Serial |
162 |
Permanent link to this record |
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|
|
Author |
den Dekker, A.J.; Gonnissen, J.; de Backer, A.; Sijbers, J.; Van Aert, S. |
Title |
Estimation of unknown structure parameters from high-resolution (S)TEM images : what are the limits? |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
134 |
Issue |
|
Pages |
34-43 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
Statistical parameter estimation theory is proposed as a quantitative method to measure unknown structure parameters from electron microscopy images. Images are then purely considered as data planes from which structure parameters have to be determined as accurately and precisely as possible using a parametric statistical model of the observations. For this purpose, an efficient algorithm is proposed for the estimation of atomic column positions and intensities from high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) images. Furthermore, the so-called CramérRao lower bound (CRLB) is reviewed to determine the limits to the precision with which continuous parameters such as atomic column positions and intensities can be estimated. Since this lower bound can only be derived for continuous parameters, alternative measures using the principles of detection theory are introduced for problems concerning the estimation of discrete parameters such as atomic numbers. An experimental case study is presented to show the practical use of these measures for the optimization of the experiment design if the purpose is to decide between the presence of specific atom types using STEM images. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000324474900006 |
Publication Date |
2013-06-01 |
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 |
31 |
Open Access |
|
Notes |
FWO; FP 2007-2013; Esteem2; esteem2_jra2 |
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:109240 |
Serial |
1083 |
Permanent link to this record |
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|
|
Author |
Dunin-Borkowski, R.E.; Lichte, H.; Tillmann, K.; Van Aert, S.; Van Tendeloo, G. |
Title |
Introduction to a special issue in honour of W. Owen Saxton, David J. Smith and Dirk Van Dyck on the occasion of their 65th birthdays |
Type |
Editorial |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
134 |
Issue |
|
Pages |
1-1 |
Keywords |
Editorial; Electron microscopy for materials research (EMAT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
Elsevier science bv |
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000324474900001 |
Publication Date |
2013-07-24 |
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 |
1 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:109917 |
Serial |
1721 |
Permanent link to this record |
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|
|
Author |
Heidari, H.; van den Broek, W.; Bals, S. |
Title |
Quantitative electron tomography : the effect of the three-dimensional point spread function |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
135 |
Issue |
|
Pages |
1-5 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The intensity levels in a three-dimensional (3D) reconstruction, obtained by electron tomography, can be influenced by several experimental imperfections. Such artifacts will hamper a quantitative interpretation of the results. In this paper, we will correct for artificial intensity variations by determining the 3D point spread function (PSF) of a tomographic reconstruction based on high angle annular dark field scanning transmission electron microscopy. The large tails of the PSF cause an underestimation of the intensity of smaller particles, which in turn hampers an accurate radius estimate. Here, the error introduced by the PSF is quantified and corrected a posteriori. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000326941500001 |
Publication Date |
2013-06-21 |
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 |
6 |
Open Access |
|
Notes |
Esteem2; Sunflower; esteem2_jra4 |
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:111397 |
Serial |
2756 |
Permanent link to this record |
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|
Author |
Lichtert, S.; Verbeeck, J. |
Title |
Statistical consequences of applying a PCA noise filter on EELS spectrum images |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
125 |
Issue |
|
Pages |
35-42 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Principal component analysis (PCA) noise filtering is a popular method to remove noise from experimental electron energy loss (EELS) spectrum images. Here, we investigate the statistical behaviour of this method by applying it on a simulated data set with realistic noise levels. This phantom data set provides access to the true values contained in the data set as well as to many different realizations of the noise. Using least squares fitting and parameter estimation theory, we demonstrate that even though the precision on the estimated parameters can be better as the CramérRao lower bound, a significant bias is introduced which can alter the conclusions drawn from experimental data sets. The origin of this bias is in the incorrect retrieval of the principal loadings for noisy data. Using an expression for the bias and precision of the singular values from literature, we present an evaluation criterion for these singular values based on the noise level and the amount of information present in the data set. This criterion can help to judge when to avoid PCA noise filtering in practical situations. Further we show that constructing elemental maps of PCA noise filtered data using the background subtraction method, does not guarantee an increase in the signal to noise ratio due to correlation of the spectral data as a result of the filtering process. |
Address |
|
Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000314679700006 |
Publication Date |
2012-10-27 |
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 |
54 |
Open Access |
|
Notes |
Fwo; Countatoms; Vortex; Esteem 312483; esteem2jra3 ECASJO; |
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:105293 |
Serial |
3153 |
Permanent link to this record |
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|
|
Author |
Béché, A.; Rouviere, J.L.; Barnes, J.P.; Cooper, D. |
Title |
Strain measurement at the nanoscale : comparison between convergent beam electron diffraction, nano-beam electron diffraction, high resolution imaging and dark field electron holography |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
Volume |
131 |
Issue |
|
Pages |
10-23 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Convergent beam electron diffraction (CBED), nano-beam electron diffraction (NBED or NBD), high resolution imaging (HRTEM and HRSTEM) and dark field electron holography (DFEH or HoloDark) are five TEM based techniques able to quantitatively measure strain at the nanometer scale. In order to demonstrate the advantages and disadvantages of each technique, two samples composed of epitaxial silicon-germanium layers embedded in a silicon matrix have been investigated. The five techniques are then compared in terms of strain precision and accuracy, spatial resolution, field of view, mapping abilities and ease of performance and analysis. (C) 2013 Elsevier By. All rights reserved. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000322631200002 |
Publication Date |
2013-04-06 |
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 |
73 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.843; 2013 IF: 2.745 |
Call Number |
UA @ lucian @ c:irua:109774 |
Serial |
3171 |
Permanent link to this record |
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Author |
Van Dael, M.; Van Passel, S.; Pelkmans, L.; Guisson, R.; Reumermann, P.; Luzardo, N.M.; Witters, N.; Broeze, J. |
Title |
A techno-economic evaluation of a biomass energy conversion park |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Applied Energy |
Abbreviated Journal |
Appl Energ |
Volume |
104 |
Issue |
|
Pages |
611-622 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM) |
Abstract |
Biomass as a renewable energy source has many advantages and is therefore recognized as one of the main renewable energy sources to be deployed in order to attain the target of 20% renewable energy use of final energy consumption by 2020 in Europe. In this paper the concept of a biomass Energy Conversion Park (ECP) is introduced. A biomass ECP can be defined as a synergetic, multi-dimensional biomass conversion site with a highly integrated set of conversion technologies in which a multitude of regionally available biomass (residue) sources are converted into energy and materials. A techno-economic assessment is performed on a case study in the Netherlands to illustrate the concept and to comparatively assess the highly integrated system with two mono-dimensional models. The three evaluated models consist of (1) digestion of the organic fraction of municipal solid waste, (2) co-digestion of manure and co-substrates, and (3) integration. From a socio-economic point of view it can be concluded that it is economically and energetically more interesting to invest in the integrated model than in two separate models. The integration is economically feasible and environmental benefits can be realized. For example, the integrated model allows the implementation of a co-digester. Unmanaged manure would otherwise represent a constant pollution risk. However, from an investor's standpoint one should firstly invest in the municipal solid waste digester since the net present value (NPV) of this mono-dimensional model is higher than that of the multi-dimensional model. A sensitivity analysis is performed to identify the most influencing parameters. Our results are of interest for companies involved in the conversion of biomass. The conclusions are useful for policy makers when deciding on policy instruments concerning manure processing or biogas production. (C) 2012 Elsevier Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000316152700062 |
Publication Date |
2012-12-25 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0306-2619 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
7.182 |
Times cited |
45 |
Open Access |
|
Notes |
; We would like to thank the editor and the anonymous referees for their helpful suggestions and insightful comments that have significantly improved the paper. Furthermore, the authors gratefully acknowledge the financial support from INTERREG and the province of Limburg (Belgium). Also, we would like to thank all remaining partners of the ECP project (Eloi Schreurs, Dries Maes, Kristian Coppoolse, Han ten Berge, Bert Annevelink, Nathalie Devriendt, Erwin Cornelissen, Hannes Pieper, Pieter Vollaard, Jan Venselaar, and Hessel Abbink Spaink) for their support and contributions. Finally, we would like to express our gratitude towards the organization of the eighth International Conference on Renewable Resources and Biorefineries in Toulouse (France) for giving us the opportunity to present and thereby fine-tune our work. ; |
Approved |
Most recent IF: 7.182; 2013 IF: 5.261 |
Call Number |
UA @ admin @ c:irua:127552 |
Serial |
6145 |
Permanent link to this record |
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Author |
van Winsen, F.; de Mey, Y.; Lauwers, L.; Van Passel, S.; Vancauteren, M.; Wauters, E. |
Title |
Cognitive mapping : a method to elucidate and present farmers' risk perception |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Agricultural Systems |
Abbreviated Journal |
Agr Syst |
Volume |
122 |
Issue |
|
Pages |
42-52 |
Keywords |
A1 Journal article |
Abstract |
Assumptions on the perceptions of risks, made in agricultural economics literature, are recognized to be over-simplistic. For example most studies assume that risks are independent and static, while in reality most risks are interlinked and dynamic. We propose an alternative method to identify and present risk perception, closer to the actual comprehension of risk by farmers. Grounded theory is used to investigate the perceptions of risk by farmers while avoiding prior assumptions. Main findings are: (i) farmers have difficulty to rank or score probability and impact of risks in a (semi)quantitative manner; (ii) farmers attach different meanings to risk, when the focus shifts between, uncertain event, probability or value at stake and; (iii) farmers perceive risks as being interrelated. Based on these findings, we propose that farmers' risk perception can be best understood as a network of interrelated notions of uncertain events, their effects and uncertain outcomes. Furthermore, cognitive mapping is suggested to elucidate and present these networks. We test cognitive mapping, exploring dairy farmers' risk perception, and demonstrate the appropriateness of this methodology for capturing the complexity and context of perceived risk. Advantages are: (i) the qualitative approach, (ii) the focus on interrelations and context, (iii) the applicability at farm level, (iv) the farmer-driven rather than researcher-driven perspective, and (v) the elucidation of the polyvalent use of the risk concept. Cognitive maps can be used as a communication tool, a risk management tool, and a tool to stimulate bi-directional learning amongst farmers, policy makers, researchers and extension agents. (C) 2013 Elsevier Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000326910500005 |
Publication Date |
2013-09-12 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0308-521x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.571 |
Times cited |
27 |
Open Access |
|
Notes |
; We would like to acknowledge the Agency for Innovation by Science and Technology of the Flemish Government (IWT) for funding this research. Furthermore we would like to thank the anonymous reviewers for their valuable input. ; |
Approved |
Most recent IF: 2.571; 2013 IF: 2.453 |
Call Number |
UA @ admin @ c:irua:112765 |
Serial |
6168 |
Permanent link to this record |
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|
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Author |
Zwozdziak, A.; Sowka, I.; Krupińska, B.; Zwozdziak, J.; Nych, A. |
Title |
Infiltration or indoor sources as determinants of the elemental composition of particulate matter inside a school in Wroclaw, Poland? |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Building and environment |
Abbreviated Journal |
|
Volume |
66 |
Issue |
|
Pages |
173-180 |
Keywords |
A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
Children's exposure to air pollution requires a focus on air quality in places where they spend most time, e.g. in schools. Therefore, understanding how indoor elemental concentrations relate the outdoor ones is necessary to create healthy indoor school environment. The aims of this study were to examine the elemental composition of particulate matter (PM1, PM2.5, PM10) in the school and also to investigate to what degree indoor elemental concentrations are affected by outdoor air or generated inside the school. The measurements were performed inside and outside the public school building in the centre of the city. It was observed that concentrations of most elements were higher at school than outside. The dominant elements in PM1 both indoors and outdoors were S, Cl, K, and Zn. PM2.5 and PM10 fractions inside the school were clearly enriched in elements of mineral origin, additionally S, Zn, K and Cl were also present in high concentrations both indoors and outdoors. Results suggested that a significant contribution to indoor Zn, Pb and S concentrations in the PM2.5 fraction was from penetration of outdoor air. 88%, 80% and 90% of the observed total variations in indoor concentrations of Zn, Pb, and S were explained by the linear relationship between indoor and outdoor concentrations. The lack of correlation between indoor and outdoor concentrations obtained for Si, Ca, Ti, Sr indicated that these metals were more likely to originate from indoor sources. (C) 2013 Elsevier Ltd. All rights reserved. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000321423500017 |
Publication Date |
2013-05-09 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0360-1323 |
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:109788 |
Serial |
8087 |
Permanent link to this record |
|
|
|
Author |
Snoeckx, R.; Setareh, M.; Aerts, R.; Simon, P.; Maghari, A.; Bogaerts, A. |
Title |
Influence of N2 concentration in a CH4/N2 dielectric barrier discharge used for CH4 conversion into H2 |
Type |
A1 Journal article |
Year |
2013 |
Publication |
International journal of hydrogen energy |
Abbreviated Journal |
Int J Hydrogen Energ |
Volume |
38 |
Issue |
36 |
Pages |
16098-16120 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
We present a combined study of experimental and computational work for a dielectric barrier discharge (DBD) used for CH4 conversion into H2. More specifically, we investigated the influence of N2 as an impurity (150,000 ppm) and as additive gas (199%) on the CH4 conversion and H2 yield. For this purpose, a zero-dimensional chemical kinetics model is applied to study the plasma chemistry. The calculated conversions and yields for various gas mixing ratios are compared to the obtained experimental values, and good agreement is achieved. The study reveals the significance of the View the MathML source and View the MathML source metastable states for the CH4 conversion into H2, based on a kinetic analysis of the reaction chemistry. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Oxford |
Editor |
|
Language |
|
Wos |
000327904500027 |
Publication Date |
2013-10-23 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0360-3199; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.582 |
Times cited |
40 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.582; 2013 IF: 2.930 |
Call Number |
UA @ lucian @ c:irua:111372 |
Serial |
1642 |
Permanent link to this record |
|
|
|
Author |
Xiao, Y.M.; Xu, W.; Zhang, Y.Y.; Peeters, F.M. |
Title |
Optoelectronic properties of ABC-stacked trilayer graphene |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
Volume |
250 |
Issue |
1 |
Pages |
86-94 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We present a theoretical study on the optoelectronic properties of ABC-stacked trilayer graphene (TLG). The optical conductance and light transmittance are evaluated through using the energy-balance equation derived from the Boltzmann equation for an air/graphene/dielectric-wafer system in the presence of linearly polarized radiation field. The results obtained from two band structure models are examined and compared. For short wavelength radiation, the universal optical conductance sigma(0) = 3e(2)/(4h) can be obtained. Importantly, there exists an optical absorption window in the radiation wavelength range 10-200 mu m, which is induced by different transition energies required for inter- and intra-band optical absorption channels. As a result, we find that the position and width of this window depend sensitively on temperature and carrier density of the system, especially the lower frequency edge. There is a small characteristic absorption peak at about 82 mu m where the largest interband transition states exist in the ABC-stacked TLG model, in contrast to the relatively smooth curves in a simplified model. These theoretical results indicate that TLG has some interesting and important physical properties which can be utilized to realize infrared or THz optoelectronic devices. |
Address |
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Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Berlin |
Editor |
|
Language |
|
Wos |
000313347500011 |
Publication Date |
2012-08-08 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.674 |
Times cited |
6 |
Open Access |
|
Notes |
; This work was supported by the National Natural Science Foundation of China (grant no. 10974206), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. One of us (F.M.P.) was a Specially Appointed Foreign Professor of the Chinese Academy of Sciences. ; |
Approved |
Most recent IF: 1.674; 2013 IF: 1.605 |
Call Number |
UA @ lucian @ c:irua:110109 |
Serial |
2495 |
Permanent link to this record |
|
|
|
Author |
Buekenhoudt, A.; Bisignano, F.; De Luca, G.; Vandezande, P.; Wouters, M.; Verhulst, K. |
Title |
Unravelling the solvent flux behaviour of ceramic nanofiltration and ultrafiltration membranes |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Journal of membrane science |
Abbreviated Journal |
J Membrane Sci |
Volume |
439 |
Issue |
|
Pages |
36-47 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Applied Electrochemistry & Catalysis (ELCAT) |
Abstract |
In order to increase the understanding of the underlying processes in organic solvent nanofiltration (OSN), a study has been undertaken aimed at clarifying the solvent flux behaviour of ceramic nanofiltration and ultrafiltration membranes. Ceramic membranes were chosen for their non-swelling character. Pure water and a variation of 11 different organic solvents were measured on a series of different ceramic membranes with pore-size diameters ranging from 0.9 nm up to 100 nm. To avoid any historical effects, each flux measurement was carried out on a new membrane. The flux results were analysed in a phenomenological way, and a common very simple linear relationship was observed between the product of flux and viscosity of the solvent, and the total Hansen solubility parameter of the solvent. The linear relationship was found for all membranes, independent of the membrane pore size and the membrane material. The slope of the linear relationship was found to depend exponentially on the pore-size diameter and on the polarity of the membrane surface. This result emphasizes the importance of viscosity in the solvent transport, but also of the polarity difference between membrane surface and solvent. The very simple flux model deduced, allows a straightforward prediction of the flux of any solvent or solvent mixture, once the water flux of the membrane is known. At the high pore-size end, the phenomenological model naturally transforms into the viscous-flow or pore-flow behaviour as required. A tentative physical explanation of the model takes into account the presence and extension of a water layer adsorbed to the total pore surface of these membranes. This work also shows that the water flux of a hydrophilic membrane gives a good indication of its molecular weight cut-off (MWCO), and therefore of its separation performance in water. (C)0 2013 Elsevier B.V. All rights reserved. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000319501200005 |
Publication Date |
2013-03-30 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0376-7388; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.035 |
Times cited |
55 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 6.035; 2013 IF: 4.908 |
Call Number |
UA @ lucian @ c:irua:109568 |
Serial |
3816 |
Permanent link to this record |
|
|
|
Author |
Sels, D.; Brosens, F.; Magnus, W. |
Title |
Wigner distribution functions for complex dynamical systems : a path integral approach |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physica: A : theoretical and statistical physics |
Abbreviated Journal |
Physica A |
Volume |
392 |
Issue |
2 |
Pages |
326-335 |
Keywords |
A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT) |
Abstract |
Starting from Feynmans Lagrangian description of quantum mechanics, we propose a method to construct explicitly the propagator for the Wigner distribution function of a single system. For general quadratic Lagrangians, only the classical phase space trajectory is found to contribute to the propagator. Inspired by Feynmans and Vernons influence functional theory we extend the method to calculate the propagator for the reduced Wigner function of a system of interest coupled to an external system. Explicit expressions are obtained when the external system consists of a set of independent harmonic oscillators. As an example we calculate the propagator for the reduced Wigner function associated with the CaldeiraLegett model. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000311135200004 |
Publication Date |
2012-09-14 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0378-4371; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.243 |
Times cited |
9 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 2.243; 2013 IF: 1.722 |
Call Number |
UA @ lucian @ c:irua:101414 |
Serial |
3921 |
Permanent link to this record |
|
|
|
Author |
Filippousi, M.; Papadimitriou, S.A.; Bikiaris, D.N.; Pavlidou, E.; Angelakeris, M.; Zamboulis, D.; Tian, H.; Van Tendeloo, G. |
Title |
Novel coreshell magnetic nanoparticles for Taxol encapsulation in biodegradable and biocompatible block copolymers : preparation, characterization and release properties |
Type |
A1 Journal article |
Year |
2013 |
Publication |
International journal of pharmaceutics |
Abbreviated Journal |
Int J Pharmaceut |
Volume |
448 |
Issue |
1 |
Pages |
221-230 |
Keywords |
A1 Journal article; Pharmacology. Therapy; Electron microscopy for materials research (EMAT) |
Abstract |
Theranostic polymeric nanocarriers loaded with anticancer drug Taxol and superparamagnetic iron oxide nanocrystals have been developed for possible magnetic resonance imaging (MRI) use and cancer therapy. Multifunctional nanocarriers with a coreshell structure have been prepared by coating superparamagnetic Fe3O4 nanoparticles with block copolymer of poly(ethylene glycol)-b-poly(propylene succinate) with variable molecular weights of the hydrophobic block poly(prolylene succinate). The multifunctional polymer nano-vehicles were prepared using a nanoprecipitation method. Scanning transmission electron microscopy revealed the encapsulation of magnetic nanoparticles inside the polymeric matrix. Energy dispersive X-ray spectroscopy and electron energy loss spectroscopy mapping allowed us to determine the presence of the different material ingredients in a quantitative way. The diameter of the nanoparticles is below 250 nm yielding satisfactory encapsulation efficiency. The nanoparticles exhibit a biphasic drug release pattern in vitro over 15 days depending on the molecular weight of the hydrophobic part of the polymer matrix. These new systems where anti-cancer therapeutics like Taxol and iron oxide nanoparticles (IOs) are co-encapsulated into new facile polymeric nanoparticles, could be addressed as potential multifunctional vehicles for simultaneous drug delivery and targeting imaging as well as real time monitoring of therapeutic effects. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000319052000026 |
Publication Date |
2013-03-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0378-5173; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.649 |
Times cited |
29 |
Open Access |
|
Notes |
Countatoms |
Approved |
Most recent IF: 3.649; 2013 IF: 3.785 |
Call Number |
UA @ lucian @ c:irua:107348 |
Serial |
2374 |
Permanent link to this record |
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|
|
Author |
Alfeld, M.; Broekaert, J.A.C. |
Title |
Mobile depth profiling and sub-surface imaging techniques for historical paintings : a review |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Spectrochimica acta: part B : atomic spectroscopy |
Abbreviated Journal |
|
Volume |
88 |
Issue |
|
Pages |
211-230 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
Hidden, sub-surface paint layers and features contain valuable information for the art-historical investigation of a painting's past and for its conservation for coming generations. The number of techniques available for the study of these features has been considerably extended in the last decades and established techniques have been refined. This review focuses on mobile non-destructive subsurface imaging and depth profiling techniques, which allow for the in-situ investigation of easel paintings, i.e. paintings on a portable support. Among the techniques discussed are: X-ray radiography and infrared reflectography, which are long established methods and are in use for several decades. Their capabilities of element/species specific imaging have been extended by the introduction of energy/wavelength resolved measurements. Scanning macro-X-ray fluorescence analysis made it for the first time possible to acquire elemental distribution images in-situ and optical coherence tomography allows for the non-destructive study the surface paint layers in virtual cross-sections. These techniques and their variants are presented next to other techniques, such as Terahertz imaging, Nuclear Magnetic Resonance depth profiling and established techniques for non destructive testing (thermography, ultrasonic imaging and laser based interference methods) applied in the conservation of historical paintings. Next to selected case studies the capabilities and limitations of the techniques are discussed. (C) 2013 Elsevier B.V. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000325838900028 |
Publication Date |
2013-07-19 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0584-8547; 1873-3565 |
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:112232 |
Serial |
8256 |
Permanent link to this record |
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|
|
Author |
Clima, S.; Kaczer, B.; Govoreanu, B.; Popovici, M.; Swerts, J.; Verhulst, A.S.; Jurczak, M.; De Gendt, S.; Pourtois, G. |
Title |
Determination of ultimate leakage through rutile TiO2 and tetragonal ZrO2 from ab initio complex band calculations |
Type |
A1 Journal article |
Year |
2013 |
Publication |
IEEE electron device letters |
Abbreviated Journal |
Ieee Electr Device L |
Volume |
34 |
Issue |
3 |
Pages |
402-404 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
First-principle complex band structures have been computed for rutile TiO2 and tetragonal ZrO2 insulating materials that are of current technological relevance to dynamic random accessmemorymetal-insulator-metal (MIM) capacitors. From the magnitude of the complex wave vectors in different orientations, the most penetrating orientations have been identified. Tunneling effective masses m(tunnel) have been extracted, are shown to be a crucial parameter for the intrinsic leakage, and are identified to be an important parameter in further scaling of MIM capacitors. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
|
Language |
|
Wos |
000315723000024 |
Publication Date |
2013-01-31 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0741-3106;1558-0563; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.048 |
Times cited |
3 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.048; 2013 IF: 3.023 |
Call Number |
UA @ lucian @ c:irua:108295 |
Serial |
680 |
Permanent link to this record |
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|
|
Author |
Baken, S.; Sjostedt, C.; Gustafsson, J.P.; Seuntjens, P.; Desmet, N.; De Schutter, J.; Smolders, E. |
Title |
Characterisation of hydrous ferric oxides derived from iron-rich groundwaters and their contribution to the suspended sediment of streams |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Applied geochemistry |
Abbreviated Journal |
|
Volume |
39 |
Issue |
|
Pages |
59-68 |
Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract |
When Fe(II) bearing groundwaters surface in streams, particulate authigenic Fe-rich material is produced by oxidation. Such freshly precipitated Fe minerals may be transported as suspended sediment and have a profound impact on the fate of trace metals and nutrients in rivers. The objective of this study was to monitor changes in mineralogy and composition of authigenic material from its source to streams of increasing order. Groundwaters, surface waters, and suspended sediment in streams of different order were sampled in the Kleine Nete catchment (Belgium), a lowland with Fe-rich groundwaters (3.5-53.8 mg Fe/L; pH 6.3-6.9). Fresh authigenic material (>0.45 mu m) was produced by oxidising filtered (<0.45 mu m) groundwater and surface water. This material contained, on average, 44% Fe, and smaller concentrations of C, P, and Ca. Iron EXAFS (Extended X-ray Absorption Fine Structure) spectroscopy showed that the Fe was present as poorly crystalline hydrous ferric oxides with a structure similar to that of ferrihydrite. The Fe concentration in the suspended sediment samples decreased to 36-40% (stream order 2), and further to 18-26% (stream order 4 and 5). Conversely, the concentrations of organic C, Ca, Si, and trace metals increased with increasing stream order, suggesting mixing of authigenic material with suspended sediment from a different source. The Fe speciation in the suspended sediment was similar to that in fresh authigenic material, but more Fe-Fe interactions were observed, i.e. it was increasingly hydrolysed, suggesting ageing reactions. The suspended sediment in the streams of order 4 and 5 is estimated to contain between 31% and 59% of authigenic material, but more data are needed to refine this estimate. The authigenic material is an important sink for P in these streams which may alleviate the eutrophication risk in this catchment. (C) 2013 Elsevier Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
|
Wos |
000327488700007 |
Publication Date |
2013-10-05 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0883-2927 |
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:112769 |
Serial |
7595 |
Permanent link to this record |
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|
|
Author |
Celebi, S.; Sezgin, M.E.; Çakir, D.; Baytan, B.; Demirkaya, M.; Sevinir, B.; Bozdemir, S.E.; Gunes, A.M.; Hacimustafaoglu, M. |
Title |
Catheter-associated bloodstream infections in pediatric hematology-oncology patients |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Pediatric Hematology And Oncology |
Abbreviated Journal |
Pediatr Hemat Oncol |
Volume |
30 |
Issue |
3 |
Pages |
187-194 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Catheter-associated bloodstream infections (CABSIs) are common complications encountered with cancer treatment. The aims of this study were to analyze the factors associated with recurrent infection and catheter removal in pediatric hematology-oncology patients. All cases of CABSIs in patients attending the Department of Pediatric Hematology-Oncology between January 2008 and December 2010 were reviewed. A total of 44 episodes of CABSIs, including multiple episodes involving the same catheter, were identified in 31 children with cancer. The overall CABSIs rate was 7.4 infections per 1000 central venous catheter (CVC) days. The most frequent organism isolated was coagulase-negative Staphylococcus (CONS). The CVC was removed in nine (20.4%) episodes. We found that hypotension, persistent bacteremia, Candida infection, exit-side infection, neutropenia, and prolonged duration of neutropenia were the factors for catheter removal. There were 23 (52.2%) episodes of recurrence or reinfection. Mortality rate was found to be 9.6% in children with CABSIs. In this study, we found that CABSIs rate was 7.4 infections per 1000 catheter-days. CABSIs rates in our hematology-oncology patients are comparable to prior reports. Because CONS is the most common isolated microorganism in CABSIs, vancomycin can be considered part of the initial empirical regimen. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
New York |
Editor |
|
Language |
|
Wos |
|
Publication Date |
2013-04-25 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0888-0018 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.12 |
Times cited |
|
Open Access |
|
Notes |
|
Approved |
Most recent IF: 1.12; 2013 IF: 0.963 |
Call Number |
UA @ lucian @ c:irua:128324 |
Serial |
4589 |
Permanent link to this record |
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|
|
Author |
Abakumov, A.M.; Erni, R.; Tsirlin, A.A.; Rossell, M.D.; Batuk, D.; Nénert, G.; Van Tendeloo, G. |
Title |
Frustrated octahedral tilting distortion in the incommensurately modulated Li3xNd2/3-xTiO3 perovskites |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
25 |
Issue |
13 |
Pages |
2670-2683 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Perovskite-structured titanates with layered A-site ordering form remarkably complex superstructures. Using transmission electron microscopy, synchrotron X-ray and neutron powder diffraction, and ab initio structure relaxation, we present the structural solution of the incommensurately modulated Li3xNd2/3xTiO3 perovskites (x = 0.05, superspace group Pmmm(α1,1/2,0)000(1/2,β2 0)000, a = 3.831048(5) Å, b = 3.827977(4) Å, c = 7.724356(8) Å, q1 = 0.45131(8)a* + 1/2b*, q2 = 1/2a* + 0.41923(4)b*). In contrast to earlier conjectures on the nanoscale compositional phase separation in these materials, all peculiarities of the superstructure can be understood in terms of displacive modulations related to an intricate octahedral tilting pattern. It involves fragmenting the pattern of the out-of-phase tilted TiO6 octahedra around the a- and b-axes into antiphase domains, superimposed on the pattern of domains with either pronounced or suppressed in-phase tilt component around the c-axis. The octahedral tilting competes with the second order JahnTeller distortion of the TiO6 octahedra. This competition is considered as the primary driving force for the modulated structure. The A cations are suspected to play a role in this modulation affecting it mainly through the tolerance factor and the size variance. The reported crystal structure calls for a revision of the structure models proposed for the family of layered A-site ordered perovskites exhibiting a similar type of modulated structure. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
Language |
|
Wos |
000321809700015 |
Publication Date |
2013-06-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
23 |
Open Access |
|
Notes |
Countatoms |
Approved |
Most recent IF: 9.466; 2013 IF: 8.535 |
Call Number |
UA @ lucian @ c:irua:109216 |
Serial |
1292 |
Permanent link to this record |
|
|
|
Author |
Morozov, V.A.; Bertha, A.; Meert, K.W.; Van Rompaey, S.; Batuk, D.; Martinez, G.T.; Van Aert, S.; Smet, P.F.; Raskina, M.V.; Poelman, D.; Abakumov, A.M.; Hadermann, J.; |
Title |
Incommensurate modulation and luminescence in the CaGd2(1-x)Eu2x(MoO4)4(1-y)(WO)4y (0\leq x\leq1, 0\leq y\leq1) red phosphors |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
25 |
Issue |
21 |
Pages |
4387-4395 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Scheelite related compounds (A',A '') [(B',B '')O-4], with B', B '' = W and/or Mo are promising new light-emitting materials for photonic applications, including phosphor converted LEDs (light-emitting diodes). In this paper, the creation and ordering of A-cation vacancies and the effect of cation substitutions in the scheelite-type framework are investigated as a factor for controlling the scheelite-type structure and luminescent properties. CaGd2(1-x)Eu2x(MoO4)(4(1-y))(WO4)(4y) (0 <= x <= 1, 0 <= y <= 1) solid solutions with scheelite-type structure were synthesized by a solid state method, and their structures were investigated using a combination of transmission electron microscopy techniques and powder X-ray diffraction. Within this series all complex molybdenum oxides have (3 + 2)D incommensurately modulated structures with superspace group I4(1)/a(alpha,beta,0)00(-beta,alpha,0)00, while the structures of all tungstates are (3 + 1)D incommensurately modulated with superspace group I2/b(alpha beta 0)00. In both cases the modulation arises because of cation-vacancy ordering at the A site. The prominent structural motif is formed by columns of A-site vacancies running along the c-axis. These vacant columns occur in rows of two or three aligned along the [110] direction of the scheelite subcell. The replacement of the smaller Gd3+ by the larger Eu3+ at the A-sublattice does not affect the nature of the incommensurate modulation, but an increasing replacement of Mo6+ by W6+ switches the modulation from (3 + 2)D to (3 + 1)D regime. Thus, these solid solutions can be considered as a model system where the incommensurate modulation can be monitored as a function of cation nature while the number of cation vacancies at the A sites remain constant upon the isovalent cation replacement. All compounds' luminescent properties were measured, and the optical properties were related to the structural properties of the materials. CaGd2(1-x)(MoO4)(4(1-y))(WO4)(4y) phosphors emit intense red light dominated by the D-5(0)-F-7(2) transition at 612 nm, along with other transitions from the D-5(1) and D-5(0) excited states. The intensity of the 5D0-7F2 transition reaches a maximum at x = 0.5 for y = 0 and 1. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000327045000030 |
Publication Date |
2013-09-24 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
63 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 9.466; 2013 IF: 8.535 |
Call Number |
UA @ lucian @ c:irua:112776 |
Serial |
1594 |
Permanent link to this record |
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Author |
Retuerto, M.; Emge, T.; Hadermann, J.; Stephens, P.W.; Li, M.R.; Yin, Z.P.; Croft, M.; Ignatov, A.; Zhang, S.J.; Yuan, Z.; Jin, C.; Simonson, J.W.; Aronson, M.C.; Pan, A.; Basov, D.N.; Kotliar, G.; Greenblatt, M.; |
Title |
Synthesis and properties of charge-ordered thallium halide perovskites, CsTl0.5+Tl0.53+X3 (X = F or Cl) : theoretical precursors for superconductivity? |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
25 |
Issue |
20 |
Pages |
4071-4079 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Recently, CsTlCl3 and CsTlF3 perovskites were theoretically predicted to be potential superconductors if they were optimally doped. The syntheses of these two compounds together with a complete characterization of the samples are reported. CsTlCl3 was obtained as orange crystals in two different polymorphs: a tetragonal phase (I4/m) and a cubic phase (Fm (3) over barm). CsTlF3 was formed as a light brown powder, and also as a double cubic perovskite (Fm (3) over barm). In all three CsTlX3 phases, Tl+ and Tl3+ were located in two different crystallographic positions that accommodate their different bond lengths. In CsTlCl3, some Tl vacancies were found in the Tl+ position. The charge ordering between Tl+ and Tl3+ was confirmed by X-ray absorption and Raman spectroscopy. The Raman spectroscopy of CsTlCl3 at high pressure (58 GPa) did not indicate any phase transition to a possible single Tl2+ state. However, the highly insulating material became less resistive with an increasing high pressure, while it underwent a change in its optical properties, from transparent to deeply opaque red, indicative of a decrease in the magnitude of the band gap. The theoretical design and experimental validation of the existence of CsTlF3 and CsTlCl3 cubic perovskites are the necessary first steps in confirming the theoretical prediction of superconductivity in these materials. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000326209200017 |
Publication Date |
2013-09-18 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
28 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 9.466; 2013 IF: 8.535 |
Call Number |
UA @ lucian @ c:irua:112248 |
Serial |
3434 |
Permanent link to this record |
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Author |
Pietra, F.; van Dijk-Moes, R.J.A.; Ke, X.; Bals, S.; Van Tendeloo, G.; de Mello Donega, C.; Vanmaekelbergh, D. |
Title |
Synthesis of highly luminescent silica-coated CdSe/CdS nanorods |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
25 |
Issue |
17 |
Pages |
3427-3434 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
CdSe(core)/CdS(shell) nanorods (NRs) have been extensively investigated for their unique optical properties, such as high photoluminescence (PL) quantum efficiency (QE) and polarized light emission. The incorporation of these NRs in silica (SiO2) is of high interest, since this renders them processable in polar solvents while increasing their photochemical stability, which would be beneficial for their application in LEDs and as biolabels. We report the synthesis of highly luminescent silica-coated CdSe/CdS NRs, by using the reverse micelle method. The mechanism for the encapsulation of the NRs in silica is unravelled and shown to be strongly influenced by the NR shape and its asymmetry. This is attributed to both the different morphology and the different crystallographic nature of the facets terminating the opposite tips of the NRs. These results lead to the formation of a novel class of NR architectures, whose symmetry can be controlled by tuning the degree of coverage of the silica shell. Interestingly, the encapsulation of the NRs in silica leads to a remarkable increase in their photostability, while preserving their optical properties. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000330097900004 |
Publication Date |
2013-08-13 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
46 |
Open Access |
|
Notes |
262348 ESMI; 246791 COUNTATOMS; Hercules |
Approved |
Most recent IF: 9.466; 2013 IF: 8.535 |
Call Number |
UA @ lucian @ c:irua:110037 |
Serial |
3456 |
Permanent link to this record |
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Author |
Verbruggen, S.W.; Dirckx, J.J.J.; Martens, J.A.; Lenaerts, S. |
Title |
Surface photovoltage measurements : a quick assessment of the photocatalytic activity? |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Catalysis today |
Abbreviated Journal |
Catal Today |
Volume |
209 |
Issue |
|
Pages |
215-220 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract |
Surface photovoltage (SPV) measurements can contribute to a better understanding of electronic properties of photocatalysts under illumination. Direct linking of SPV data to the actual photocatalytic activity remains troublesome. This work aims to discuss SPV measurements from a photocatalytic point of view. By means of several application-based scenarios we illustrate that the trend between SPV and photocatalysis strongly depends on parameters such as the crystal structure, surface modifications, morphology and humidity. This makes the interpretation far from straightforward. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000319498800035 |
Publication Date |
2013-01-16 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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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 |
8 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 4.636; 2013 IF: 3.309 |
Call Number |
UA @ admin @ c:irua:106520 |
Serial |
5995 |
Permanent link to this record |
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Author |
Somers, W.; Bogaerts, A.; van Duin, A.C.T.; Huygh, S.; Bal, K.M.; Neyts, E.C. |
Title |
Temperature influence on the reactivity of plasma species on a nickel catalyst surface : an atomic scale study |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Catalysis today |
Abbreviated Journal |
Catal Today |
Volume |
211 |
Issue |
|
Pages |
131-136 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
In recent years, the potential use of hydrogen as a clean energy source has gained considerable attention. Especially H2 formation by Ni-catalyzed reforming of methane at elevated temperatures is an attractive process. However, a more fundamental knowledge at the atomic level is needed for a full comprehension of the reactions at the catalyst surface. In this contribution, we therefore investigate the H2 formation after CHx impacts on a Ni(1 1 1) surface in the temperature range 4001600 K, by means of reactive molecular dynamics (MD) simulations using the ReaxFF potential. While some H2 formation is already observed at the lower temperatures, substantial H2 formation is only obtained at elevated temperatures of 1400 K and above. At 1600 K, the H2 molecules are even the most frequently formed species. In direct correlation with the increasing dehydrogenation at elevated temperatures, an increased surface-to-subsurface C-diffusivity is observed as well. This study highlights the major importance of the temperature on the H2 formation. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000320697800020 |
Publication Date |
2013-03-25 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
0920-5861; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.636 |
Times cited |
27 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 4.636; 2013 IF: 3.309 |
Call Number |
UA @ lucian @ c:irua:108675 |
Serial |
3500 |
Permanent link to this record |
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Author |
Barba-Ortega, J.; Sardella, E.; Aguiar, J.A.; Peeters, F.M. |
Title |
Non-conventional vortex configurations in a mesoscopic flat disk |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
Volume |
487 |
Issue |
|
Pages |
47-55 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The influence of superficial defects on the vortex configurations of a thin superconducting disk is investigated within the time dependent Ginzburg-Landau formalism. The free energy, magnetization, vorticity, and the Cooper pair density are calculated for both metastable and stable vortex configurations and different number of defects on its surface in the presence of an external magnetic field applied perpendicular to the disk area. We show that the competition between the confinement geometry and the geometric position of the defects leads to non-conventional vortex configurations which are not compatible with the symmetry of the sample geometry. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000317743300009 |
Publication Date |
2013-02-27 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0921-4534; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.404 |
Times cited |
17 |
Open Access |
|
Notes |
; This work was partially supported by the Brazilian agencies CNPq, CAPES, FACEPE (APQ 0589-105/08), FAPESP, CNPq-FWO bilateral project, and Colombian Agencies Colciencias and DIB. ; |
Approved |
Most recent IF: 1.404; 2013 IF: 1.110 |
Call Number |
UA @ lucian @ c:irua:108486 |
Serial |
2344 |
Permanent link to this record |
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Author |
Zelaya, E.; Esquivel, M.R.; Schryvers, D. |
Title |
Evolution of the phase stability of NiAl under low energy ball milling |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Advanced powder technology |
Abbreviated Journal |
Adv Powder Technol |
Volume |
24 |
Issue |
6 |
Pages |
1063-1069 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Low energy mechanical alloying of Ni35 at.%Al and Ni40 at.%Al material was performed and the resulting structures were investigated by XRD and TEM. The final intermetallics observed consist of two phases, NiAl(B2) and Ni3Al while 7R and 3R martensite was observed in post-annealed samples. Different integrated milling times were associated to the intermetallic consolidation and initial blend dissociation. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Zeist |
Editor |
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Language |
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Wos |
000339175000024 |
Publication Date |
2013-03-30 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
0921-8831; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.659 |
Times cited |
10 |
Open Access |
|
Notes |
Fwo |
Approved |
Most recent IF: 2.659; 2013 IF: 1.642 |
Call Number |
UA @ lucian @ c:irua:107345 |
Serial |
1102 |
Permanent link to this record |