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Author Gao, C.; Hofer, C.; Pennycook, T.J.
Title On central focusing for contrast optimization in direct electron ptychography of thick samples Type A1 Journal article
Year 2024 Publication Ultramicroscopy Abbreviated Journal
Volume 256 Issue Pages 113879-7
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the projected potential becomes strong for both direct and iterative inversion ptychography methods. It has recently been shown that these reversals can often be counteracted in direct ptychography methods by adapting the focus. Here we provide an explanation of why the best contrast is often found with the probe focused to the middle of the sample. The phase contribution due to defocus at each sample slice above and below the central plane in this configuration effectively cancels out, which can prevent contrast reversals when dynamical scattering effects are not overly strong. In addition we show that the convergence angle can be an important consideration for removal of contrast reversals in relatively thin samples.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001112166400001 Publication Date 2023-11-03
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 2.2 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 2.2; 2024 IF: 2.843
Call Number UA @ admin @ c:irua:202029 Serial 9066
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Author Korneychuk, S.; Partoens, B.; Guzzinati, G.; Ramaneti, R.; Derluyn, J.; Haenen, K.; Verbeeck, J.
Title Exploring possibilities of band gap measurement with off-axis EELS in TEM Type A1 Journal article
Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 189 Issue 189 Pages 76-84
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract A technique to measure the band gap of dielectric materials with high refractive index by means of energy electron loss spectroscopy (EELS) is presented. The technique relies on the use of a circular (Bessel) aperture and suppresses Cherenkov losses and surface-guided light modes by enforcing a momentum transfer selection. The technique also strongly suppresses the elastic zero loss peak, making the acquisition, interpretation and signal to noise ratio of low loss spectra considerably better, especially for excitations in the first few eV of the EELS spectrum. Simulations of the low loss inelastic electron scattering probabilities demonstrate the beneficial influence of the Bessel aperture in this setup even for high accelerating voltages. The importance of selecting the optimal experimental convergence and collection angles is highlighted. The effect of the created off-axis acquisition conditions on the selection of the transitions from valence to conduction bands is discussed in detail on a simplified isotropic two band model. This opens the opportunity for deliberately selecting certain transitions by carefully tuning the microscope parameters. The suggested approach is experimentally demonstrated and provides good signal to noise ratio and interpretable band gap signals on reference samples of diamond, GaN and AlN while offering spatial resolution in the nm range. (C) 2018 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000432868500008 Publication Date 2018-03-29
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 7 Open Access OpenAccess
Notes ; S.K., B.P. and J.V. acknowledge funding from the “Geconcentreerde Onderzoekacties” (GOA) project “Solarpaint” of the University of Antwerp. S.K. and J.V. also acknowledge the FWO-Vlaanderen for financial support under contract G.0044.13N 'Charge ordering'. Financial support via the Methusalem “NANO” network is acknowledged. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek-Vlaanderen (FWO). ; Approved Most recent IF: 2.843
Call Number UA @ lucian @ c:irua:151472UA @ admin @ c:irua:151472 Serial 5026
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Author Croitoru, M.D.; van Dyck, D.; Van Aert, S.; Bals, S.; Verbeeck, J.
Title An efficient way of including thermal diffuse scattering in simulation of scanning transmission electron microscopic images Type A1 Journal article
Year 2006 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 106 Issue 10 Pages 933-940
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Vision lab
Abstract We propose an improved image simulation procedure for atomic-resolution annular dark-field scanning transmission electron microscopy (STEM) based on the multislice formulation, which takes thermal diffuse scattering fully into account. The improvement with regard to the classical frozen phonon approach is realized by separating the lattice configuration statistics from the dynamical scattering so as to avoid repetitive calculations. As an example, the influence of phonon scattering on the image contrast is calculated and investigated. STEM image simulation of crystals can be applied with reasonable computing times to problems involving a large number of atoms and thick or large supercells.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000240397200006 Publication Date 2006-05-10
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 18 Open Access
Notes Fwo; Fwo-V Approved Most recent IF: 2.843; 2006 IF: 1.706
Call Number UA @ lucian @ c:irua:87604UA @ admin @ c:irua:87604 Serial 876
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Author Bertoni, G.; Beyers, E.; Verbeeck, J.; Mertens, M.; Cool, P.; Vansant, E.F.; Van Tendeloo, G.
Title Quantification of crystalline and amorphous content in porous TiO2 samples from electron energy loss spectroscopy Type A1 Journal article
Year 2006 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 106 Issue 7 Pages 630-635
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract We present an efficient method for the quantification of crystalline versus amorphous phase content in mesoporous materials, making use of electron energy loss spectroscopy. The method is based on fitting a superposition of core-loss edges using the maximum likelihood method with measured reference spectra. We apply the method to mesoporous TiO2 samples. We show that the absolute amount of the crystalline phase can be determined with an accuracy below 5%. This method takes also the amorphous phase into account, where standard X-ray diffraction is only quantitative for crystalline phases and not for amorphous phase. (c) 2006 Elsevier B.V.. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000238479300011 Publication Date 2006-04-28
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 83 Open Access
Notes Iap-V; Goa-2005; Fwo Approved Most recent IF: 2.843; 2006 IF: 1.706
Call Number UA @ lucian @ c:irua:58823UA @ admin @ c:irua:58823 Serial 2741
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Author Zhuge, X.; Jinnai, H.; Dunin-Borkowski, R.E.; Migunov, V.; Bals, S.; Cool, P.; Bons, A.-J.; Batenburg, K.J.
Title Automated discrete electron tomography – Towards routine high-fidelity reconstruction of nanomaterials Type A1 Journal article
Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 175 Issue 175 Pages 87-96
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract Electron tomography is an essential imaging technique for the investigation of morphology and 3D structure of nanomaterials. This method, however, suffers from well-known missing wedge artifacts due to a restricted tilt range, which limits the objectiveness, repeatability and efficiency of quantitative structural analysis. Discrete tomography represents one of the promising reconstruction techniques for materials science, potentially capable of delivering higher fidelity reconstructions by exploiting the prior knowledge of the limited number of material compositions in a specimen. However, the application of discrete tomography to practical datasets remains a difficult task due to the underlying challenging mathematical problem. In practice, it is often hard to obtain consistent reconstructions from experimental datasets. In addition, numerous parameters need to be tuned manually, which can lead to bias and non-repeatability. In this paper, we present the application of a new

iterative reconstruction technique, named TVR-DART, for discrete electron tomography. The technique is capable of consistently delivering reconstructions with significantly reduced missing wedge artifacts for a variety of challenging data and imaging conditions, and can automatically estimate its key parameters. We describe the principles of the technique and apply it to datasets from three different types of samples acquired under diverse imaging modes. By further reducing the available tilt range and number of projections, we show that the

proposed technique can still produce consistent reconstructions with minimized missing wedge artifacts. This new development promises to provide the electron microscopy community with an easy-to-use and robust tool for high-fidelity 3D characterization of nanomaterials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000403342500008 Publication Date 2017-01-24
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 22 Open Access OpenAccess
Notes This work has been supported in part by the Stichting voor de Technische Wetenschappen (STW) through a personal grant (Veni,13610), and was in part by ExxonMobil Chemical Europe Inc. The authors further acknowledge financial support from the University of Antwerp through BOF GOA funding. S.B. acknowledges financial support from the European Research Council (ERC Starting Grant #335078-COLOURATOMS). R.D.B. is grateful for funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007–2013)/ ERC grant agreement number 320832. Thomas Altantzis is gratefully acknowledged for acquiring the Anatase nanosheets dataset. (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); saraecas; ECAS_Sara; Approved Most recent IF: 2.843
Call Number EMAT @ emat @ c:irua:141218UA @ admin @ c:irua:141218 Serial 4485
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Author Batenburg, K.J.; Bals, S.; Sijbers, J.; Kübel, C.; Midgley, P.A.; Hernandez, J.C.; Kaiser, U.; Encina, E.R.; Coronado, E.A.; Van Tendeloo, G.
Title 3D imaging of nanomaterials by discrete tomography Type A1 Journal article
Year 2009 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 109 Issue 6 Pages 730-740
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The field of discrete tomography focuses on the reconstruction of samples that consist of only a few different materials. Ideally, a three-dimensional (3D) reconstruction of such a sample should contain only one grey level for each of the compositions in the sample. By exploiting this property in the reconstruction algorithm, either the quality of the reconstruction can be improved significantly, or the number of required projection images can be reduced. The discrete reconstruction typically contains fewer artifacts and does not have to be segmented, as it already contains one grey level for each composition. Recently, a new algorithm, called discrete algebraic reconstruction technique (DART), has been proposed that can be used effectively on experimental electron tomography datasets. In this paper, we propose discrete tomography as a general reconstruction method for electron tomography in materials science. We describe the basic principles of DART and show that it can be applied successfully to three different types of samples, consisting of embedded ErSi2 nanocrystals, a carbon nanotube grown from a catalyst particle and a single gold nanoparticle, respectively.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000265816400005 Publication Date 2009-02-01
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 220 Open Access
Notes Fwo; Esteem 026019 Approved Most recent IF: 2.843; 2009 IF: 2.067
Call Number UA @ lucian @ c:irua:74665 c:irua:74665 Serial 12
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Author Roelandts, T.; Batenburg, K.J.; Biermans, E.; Kübel, C.; Bals, S.; Sijbers, J.
Title Accurate segmentation of dense nanoparticles by partially discrete electron tomography Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 114 Issue Pages 96-105
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Accurate segmentation of nanoparticles within various matrix materials is a difficult problem in electron tomography. Due to artifacts related to image series acquisition and reconstruction, global thresholding of reconstructions computed by established algorithms, such as weighted backprojection or SIRT, may result in unreliable and subjective segmentations. In this paper, we introduce the Partially Discrete Algebraic Reconstruction Technique (PDART) for computing accurate segmentations of dense nanoparticles of constant composition. The particles are segmented directly by the reconstruction algorithm, while the surrounding regions are reconstructed using continuously varying gray levels. As no properties are assumed for the other compositions of the sample, the technique can be applied to any sample where dense nanoparticles must be segmented, regardless of the surrounding compositions. For both experimental and simulated data, it is shown that PDART yields significantly more accurate segmentations than those obtained by optimal global thresholding of the SIRT reconstruction.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000301954300011 Publication Date 2012-01-06
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 34 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:97710 Serial 52
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Author van den Broek, W.; Verbeeck, J.; de Backer, S.; Scheunders, P.; Schryvers, D.
Title Acquisition of the EELS data cube by tomographic reconstruction Type A1 Journal article
Year 2006 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 106 Issue 4/5 Pages 269-276
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Energy filtered TEM, EFTEM, provides three-dimensional data, two spatial and one spectral dimension. We propose to acquire these data by measuring a series of images with a defocused energy filter. It will be shown that each image is a projection of the data on the detector and that reconstruction of the data out of a sufficient number of such projections using a tomographic reconstruction algorithm is possible. This technique uses only a fraction of the electron dose an energy filtered series (EFS) needs for the same spectral and spatial resolution and the same mean signal-to-noise ratio. (c) 2005 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000236042300003 Publication Date 2005-11-30
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 Approved Most recent IF: 2.843; 2006 IF: 1.706
Call Number UA @ lucian @ c:irua:56910UA @ admin @ c:irua:56910 Serial 55
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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 (up) 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
Corporate Author 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
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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 (up) 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
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
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Author Xu, Q.; Zandbergen, H.W.; van Dyck, D.
Title Applying an information transmission approach to extract valence electron information from reconstructed exit waves Type A1 Journal article
Year 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 7 Pages 912-919
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The knowledge of the valence electron distribution is essential for understanding the properties of materials. However this information is difficult to obtain from HREM images because it is easily obscured by the large scattering contribution of core electrons and by the strong dynamical scattering process. In order to develop a sensitive method to extract the information of valence electrons, we have used an information transmission approach to describe the electron interaction with the object. The scattered electron wave is decomposed in a set of basic functions, which are the eigen functions of the Hamiltonian of the projected electrostatic object potential. Each basic function behaves as a communication channel that transfers the information of the object with its own transmission characteristic. By properly combining the components of the different channels, it is possible to design a scheme to extract the information of valence electron distribution from a series of exit waves. The method is described theoretically and demonstrated by means of computer simulations.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461000024 Publication Date 2011-02-02
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 1 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:93623 Serial 146
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Author Chen, J.H.; van Dyck, D.; op de Beeck, M.; van Landuyt, J.
Title Computational comparisons between the conventional multislice method and the third-order multislice method for calculating high-energy electron diffraction and imaging Type A1 Journal article
Year 1997 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 69 Issue Pages 219-240
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1997YG59500001 Publication Date 0000-00-00
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 11 Open Access
Notes Approved Most recent IF: 2.843; 1997 IF: 1.600
Call Number UA @ lucian @ c:irua:21416 Serial 455
Permanent link to this record
 

 
Author van den Broek, W.; Rosenauer, A.; Goris, B.; Martinez, G.T.; Bals, S.; Van Aert, S.; van Dyck, D.
Title Correction of non-linear thickness effects in HAADF STEM electron tomography Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 116 Issue Pages 8-12
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In materials science, high angle annular dark field scanning transmission electron microscopy is often used for tomography at the nanometer scale. In this work, it is shown that a thickness dependent, non-linear damping of the recorded intensities occurs. This results in an underestimated intensity in the interior of reconstructions of homogeneous particles, which is known as the cupping artifact. In this paper, this non-linear effect is demonstrated in experimental images taken under common conditions and is reproduced with a numerical simulation. Furthermore, an analytical derivation shows that these non-linearities can be inverted if the imaging is done quantitatively, thus preventing cupping in the reconstruction.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000304473700002 Publication Date 2012-03-09
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 67 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:96558 Serial 518
Permanent link to this record
 

 
Author Wang, A.; Chen, F.R.; Van Aert, S.; van Dyck, D.
Title Direct structure inversion from exit waves: part 1: theory and simulations Type A1 Journal article
Year 2010 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 110 Issue 5 Pages 527-534
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In order to interpret the amplitude and phase of the exit wave in terms of mass and position of the atoms, one has to invert the dynamic scattering of the electrons in the object so as to obtain a starting structure which can then be used as a seed for further quantitative structure refinement. This is especially challenging in case of a zone axis condition when the interaction of the electrons with the atom column is very strong. Based on the channelling theory we will show that the channelling map not only yields a circle on the Argand plot but also a circular defocus curve for every column. The former gives the number of atoms in each column, while the latter provides the defocus value for each column, which reveals the surface roughness at the exit plane with single atom sensitivity.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000279065700019 Publication Date 2009-12-12
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 25 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:83691 Serial 723
Permanent link to this record
 

 
Author Wang, A.; Chen, F.R.; Van Aert, S.; van Dyck, D.
Title Direct structure inversion from exit waves : part 2 : a practical example Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 116 Issue Pages 77-85
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract This paper is the second part of a two-part paper on direct structure inversion from exit waves. In the first part, a method has been proposed to quantitatively determine structure parameters with atomic resolution such as atom column positions, surface profile and the number of atoms in the atom columns. In this part, the theory will be demonstrated by means of a Au[110] exit wave reconstructed from a set of focal-series images. The procedures to analyze the experimentally reconstructed exit wave in terms of quantitative structure information are described in detail.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000304473700011 Publication Date 2012-03-28
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 8 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:96660 Serial 724
Permanent link to this record
 

 
Author den Dekker, A.J.; Van Aert, S.; van Dyck, D.; van den Bos, A.; Geuens, P.
Title Does a monochromator improve the precision in quantitative HRTEM? Type A1 Journal article
Year 2001 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 89 Issue Pages 275-290
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000172667000004 Publication Date 2002-07-25
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 22 Open Access
Notes Approved Most recent IF: 2.843; 2001 IF: 1.890
Call Number UA @ lucian @ c:irua:47518 Serial 746
Permanent link to this record
 

 
Author De Meulenaere, P.; van Dyck, D.; Van Tendeloo, G.; van Landuyt, J.
Title Dynamical electron diffraction in substitutionally disordered column structures Type A1 Journal article
Year 1995 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 60 Issue 1 Pages 171-185
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract For column structures, such as fee-based alloys viewed along the cube direction, the concept of electron channelling through the atom columns is more and more used to interpret the corresponding HREM images. In the case of(partially) disordered columns, the projected potential approach which is used in the channelling description must be questioned since the arrangement of the atoms along the beam direction might affect the exit wave of the electrons. In this paper, we critically inspect this top-bottom effect using multi-slice calculations. A modified channelling theory is introduced which turns out to be very appropriate for the interpretation of these results. For substitutionally disordered column structures, it is also discussed how to link the chemical composition of the material to statistical data of the HREM image. This results in a convenient tool to discern images taken at different thicknesses and focus values.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1995TG59500017 Publication Date 2002-07-25
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 2.436 Times cited 14 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:13013 Serial 770
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Author Van Aert, S.; Geuens, P.; van Dyck, D.; Kisielowski, C.; Jinschek, J.R.
Title Electron channelling based crystallography Type A1 Journal article
Year 2007 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 107 Issue 6/7 Pages 551-558
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000245341300015 Publication Date 2006-12-13
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 32 Open Access
Notes Approved Most recent IF: 2.843; 2007 IF: 1.996
Call Number UA @ lucian @ c:irua:64286 Serial 913
Permanent link to this record
 

 
Author Luyten, W.; Krekels, T.; Amelinckx, S.; Van Tendeloo, G.; van Dyck, D.; van Landuyt, J.
Title Electron diffraction effects of conical, helically wound, graphite whiskers Type A1 Journal article
Year 1993 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 49 Issue Pages 123-131
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1993KV56700014 Publication Date 2002-10-18
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 2.436 Times cited 14 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:6784 Serial 917
Permanent link to this record
 

 
Author Goris, B.; van den Broek, W.; Batenburg, K.J.; Heidari Mezerji, H.; Bals, S.
Title Electron tomography based on a total variation minimization reconstruction technique Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 113 Issue Pages 120-130
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The 3D reconstruction of a tilt series for electron tomography is mostly carried out using the weighted backprojection (WBP) algorithm or using one of the iterative algorithms such as the simultaneous iterative reconstruction technique (SIRT). However, it is known that these reconstruction algorithms cannot compensate for the missing wedge. Here, we apply a new reconstruction algorithm for electron tomography, which is based on compressive sensing. This is a field in image processing specialized in finding a sparse solution or a solution with a sparse gradient to a set of ill-posed linear equations. Therefore, it can be applied to electron tomography where the reconstructed objects often have a sparse gradient at the nanoscale. Using a combination of different simulated and experimental datasets, it is shown that missing wedge artefacts are reduced in the final reconstruction. Moreover, it seems that the reconstructed datasets have a higher fidelity and are easier to segment in comparison to reconstructions obtained by more conventional iterative algorithms.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300554400006 Publication Date 2011-11-14
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 171 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:93637 Serial 987
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Author Bladt, E.; Pelt, D.M.; Bals, S.; Batenburg, K.J.
Title Electron tomography based on highly limited data using a neural network reconstruction technique Type A1 Journal article
Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 158 Issue 158 Pages 81-88
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Gold nanoparticles are studied extensively due to their unique optical and catalytical properties. Their exact shape determines the properties and thereby the possible applications. Electron tomography is therefore often used to examine the three-dimensional (3D) shape of nanoparticles. However, since the acquisition of the experimental tilt series and the 3D reconstructions are very time consuming, it is difficult to obtain statistical results concerning the 3D shape of nanoparticles. Here, we propose a new approach for electron tomography that is based on artificial neural networks. The use of a new reconstruction approach enables us to reduce the number of projection images with a factor of 5 or more. The decrease in acquisition time of the tilt series and use of an efficient reconstruction algorithm allows us to examine a large amount of nanoparticles in order to retrieve statistical results concerning the 3D shape.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000361574800011 Publication Date 2015-07-10
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 25 Open Access OpenAccess
Notes 335078 COLOURATOM; FWO; COST Action MP1207; 312483 ESTEEM2; esteem2jra4; ECASSara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); Approved Most recent IF: 2.843; 2015 IF: 2.436
Call Number c:irua:126675 c:irua:126675 Serial 988
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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 (up) 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
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Author Potapov, P.; Lichte, H.; Verbeeck, J.; van Dyck, D.
Title Experiments on inelastic electron holography Type A1 Journal article
Year 2006 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 106 Issue 11-12 Pages 1012-1018
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Using the combination of an electron biprism and an energy filter, the coherence distribution in an inelastically scattered wave-field is measured. It is found that the degree of coherence decreases rapidly with increasing distance between two superimposed points in the object, and with increasing energy-loss. In a Si sample, coherence of plasmon scattering increases in vacuum with the distance from the edge of the sample. (c) 2006 Published by Elsevier B.V.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000241592900009 Publication Date 2006-07-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 28 Open Access
Notes Approved Most recent IF: 2.843; 2006 IF: 1.706
Call Number UA @ lucian @ c:irua:61380UA @ admin @ c:irua:61380 Serial 1147
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Author Goris, B.; Bals, S.; van den Broek, W.; Verbeeck, J.; Van Tendeloo, G.
Title Exploring different inelastic projection mechanisms for electron tomography Type A1 Journal article
Year 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 8 Pages 1262-1267
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Several different projection mechanisms that all make use of inelastically scattered electrons are used for electron tomography. The advantages and the disadvantages of these methods are compared to HAADFSTEM tomography, which is considered as the standard electron tomography technique in materials science. The different inelastic setups used are energy filtered transmission electron microscopy (EFTEM), thickness mapping based on the log-ratio method and bulk plasmon mapping. We present a comparison that can be used to select the best inelastic signal for tomography, depending on different parameters such as the beam stability and nature of the sample. The appropriate signal will obviously also depend on the exact information which is requested.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461100039 Publication Date 2011-03-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 21 Open Access
Notes Fwo; Iap; Esteem 026019 Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:91260UA @ admin @ c:irua:91260 Serial 1151
Permanent link to this record
 

 
Author de Backer, A.; Van Aert, S.; van Dyck, D.
Title High precision measurements of atom column positions using model-based exit wave reconstruction Type A1 Journal article
Year 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 9/10 Pages 1475-1482
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In this paper, it has been investigated how to measure atom column positions as accurately and precisely as possible using a focal series of images. In theory, it is expected that the precision would considerably improve using a maximum likelihood estimator based on the full series of focal images. As such, the theoretical lower bound on the variances of the unknown atom column positions can be attained. However, this approach is numerically demanding. Therefore, maximum likelihood estimation has been compared with the results obtained by fitting a model to a reconstructed exit wave rather than to the full series of focal images. Hence, a real space model-based exit wave reconstruction technique based on the channelling theory is introduced. Simulations show that the reconstructed complex exit wave contains the same amount of information concerning the atom column positions as the full series of focal images. Only for thin samples, which act as weak phase objects, this information can be retrieved from the phase of the reconstructed complex exit wave.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461200004 Publication Date 2011-07-28
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 8 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:91879 Serial 1438
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Author Lobato, I.; van Dyck, D.
Title Improved multislice calculations for including higher-order Laue zones effects Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 119 Issue Pages 63-71
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract A new method for including higher-order Laue zones (HOLZs) effects in an efficient way in electron scattering simulations has been developed and tested by detail calculations. The calculated results by the conventional multislice (CMS) method and the improved conventional multislice (ICMS) method using a large dynamical aperture to avoid numerical errors are compared with accurate results. We have found that the zero-order Laue zones (ZOLZs) reflection cannot be properly described only using the projected potential in the whole unit cell; in general, we need to subslice the electrostatic potential inside the unit cell. It is shown that the ICMS method has higher accuracy than the CMS method for the calculation of the ZOLZ, HOLZ and Pseudo-HOLZ reflections. Hence, ICMS method allows to use a larger slice thickness than the CMS method and reduces the calculation time. (C) 2012 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000308079200011 Publication Date 2012-01-14
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 Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:101902 Serial 1567
Permanent link to this record
 

 
Author Potapov, P.L.; Verbeeck, J.; Schattschneider, P.; Lichte, H.; van Dyck, D.
Title Inelastic electron holography as a variant of the Feynman thought experiment Type A1 Journal article
Year 2007 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 107 Issue 8 Pages 559-567
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Using a combination of electron holography and energy filtering, interference fringes produced after inelastic interaction of electrons with hydrogen molecules are examined. Surprisingly, the coherence of inelastic scattering increases when moving from the surface of a hydrogen-containing bubble to the vacuum. This phenomenon can be understood in terms of the Feynman two-slit thought experiment with a variable ambiguity of the which-way registration. (C) 2006 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000246937000001 Publication Date 2006-12-16
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 13 Open Access
Notes Fwo G.0147.06 Approved Most recent IF: 2.843; 2007 IF: 1.996
Call Number UA @ lucian @ c:irua:103588UA @ admin @ c:irua:103588 Serial 1605
Permanent link to this record
 

 
Author Fanidis, C.; van Dyck, D.; van Landuyt, J.
Title Inelastic scattering of high-energy electrons in a crystal in thermal equilibrium with the environment: 1: theoretical framework Type A1 Journal article
Year 1992 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 41 Issue Pages 55-64
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1992HX68100005 Publication Date 2002-10-18
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 2.436 Times cited 17 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:4092 Serial 1608
Permanent link to this record
 

 
Author Fanidis, C.; van Dyck, D.; van Landuyt, J.
Title Inelastic scattering of high-energy electrons in a crystal in thermal equilibrium with the environment: part 2: solution of the equations and applications to concrete cases Type A1 Journal article
Year 1993 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 48 Issue Pages 133-164
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1993KM78800013 Publication Date 0000-00-00
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 2.436 Times cited 6 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:6782 Serial 1609
Permanent link to this record
 

 
Author van Dyck, D.; Van Aert, S.; den Dekker, A.J.; van den Bos, A.
Title Is atomic resolution transmission electron microscopy able to resolve and refine amorphous structures? Type A1 Journal article
Year 2003 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 98 Issue Pages 27-42
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000186831500003 Publication Date 2003-04-25
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 26 Open Access
Notes Approved Most recent IF: 2.843; 2003 IF: 1.665
Call Number UA @ lucian @ c:irua:47516 Serial 1749
Permanent link to this record