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“Reconstruction of the La0.9Sr0.1MnO3-SrTiO3 interface by quantitative high-resolution electron microscopy”. Geuens P, Lebedev OI, Van Tendeloo G, Solid state communications 116, 643 (2000). http://doi.org/10.1016/S0038-1098(00)00411-7
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.554
Times cited: 2
DOI: 10.1016/S0038-1098(00)00411-7
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“Reclaiming the image of daguerreotypes: Characterization of the corroded surface before and after atmospheric plasma treatment”. Grieten E, Schalm O, Tack P, Bauters S, Storme P, Gauquelin N, Caen J, Patelli A, Vincze L, Schryvers D, Journal of cultural heritage (2017). http://doi.org/10.1016/j.culher.2017.05.008
Abstract: Technological developments such as atmospheric plasma jets for industry can be adapted for the conservation of cultural heritage. This application might offer a potential method for the removal or transformation of the corrosion on historical photographs. We focus on daguerreotypes and present an in-depth study of the induced changes by a multi-analytical approach using optical microscopy, scanning electron microscopy, different types of transmission electron microscopy and X-ray absorption fine structure. The H2-He afterglow removes S from an Ag2S or Cu2S layer which results in a nano-layer of metallic Ag or Cu on top of the deteriorated microstructure. In case the corrosion layer is composed of Cu-Ag-S compounds, our proposed setup can be used to partially remove the corrosion. These alterations of the corrosion results in an improvement in the readability of the photographic image.
Keywords: A1 Journal article; Art; History; Electron microscopy for materials research (EMAT); Antwerp Cultural Heritage Sciences (ARCHES)
Impact Factor: 1.838
Times cited: 9
DOI: 10.1016/j.culher.2017.05.008
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“Recent results on characterization of detonation nanodiamonds”. Vlasov II, Turner S, Van Tendeloo G, Shiryaev AA Elsevier, Amsterdam, page 291 (2012).
Keywords: H3 Book chapter; Electron microscopy for materials research (EMAT)
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“Recent EM investigations on nano-and micro-defect structures in SMAs”. Schryvers D, Cao S, Pourbabak, Shi H, Lu, Journal of alloys and compounds 577, S705 (2013). http://doi.org/10.1016/j.jallcom.2011.10.112
Abstract: The present contribution reviews some recent electron microscopy investigations on different shape memory systems in which a variety of nano- and micro-defect structures play an essential role in the functional behaviour of the material. (NiTi3)-Ti-4 precipitates in Ni-Ti are a well-known example for which the focus is now on the 3D configurations, in Ni-Ti-Nb Nb-rich nanoprecipitates are thought to have a large impact on the hysteresis, in Co-Ni-Al an Al-enriched zone nearby the y'-precipitates yields a small sandwiched austenite while some first signs of quasidynamical lattice deformation in non-frozen Ni-Ti strain glass are measured by Cs-aberration-corrected transmission electron microscopy. (C) 2011 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
Times cited: 7
DOI: 10.1016/j.jallcom.2011.10.112
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“Recent breakthroughs in scanning transmission electron microscopy of small species”. van den Bos KHW, Altantzis T, De Backer A, Van Aert S, Bals S, Advances in Physics: X 3, 1480420 (2018). http://doi.org/10.1080/23746149.2018.1480420
Abstract: Over the last decade, scanning transmission electron microscopy has become one of the most powerful tools to characterise nanomaterials at the atomic scale. Often, the ultimate goal is to retrieve the three-dimensional structure, which is very challenging since small species are typically sensitive to electron irradiation. Nevertheless, measuring individual atomic positions is crucial to understand the relation between the structure and physicochemical properties of these (nano)materials. In this review, we highlight the latest approaches that are available to reveal the 3D atomic structure of small species. Finally, we will provide an outlook and will describe future challenges where the limits of electron microscopy will be pushed even further.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 8
DOI: 10.1080/23746149.2018.1480420
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“Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp”. Guzzinati G, Altantzis T, Batuk M, De Backer A, Lumbeeck G, Samaee V, Batuk D, Idrissi H, Hadermann J, Van Aert S, Schryvers D, Verbeeck J, Bals S, Materials 11, 1304 (2018). http://doi.org/10.3390/ma11081304
Abstract: The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.654
Times cited: 15
DOI: 10.3390/ma11081304
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“Real‐Time Reconstruction of Arbitrary Slices for Quantitative and In Situ 3D Characterization of Nanoparticles”. Vanrompay H, Buurlage J‐W, Pelt DM, Kumar V, Zhuo X, Liz‐Marzán LM, Bals S, Batenburg KJ, Particle &, Particle Systems Characterization 37, 2000073 (2020). http://doi.org/10.1002/ppsc.202000073
Abstract: A detailed 3D investigation of nanoparticles at a local scale is of great importance to connect their structure and composition to their properties. Electron tomography has therefore become an important tool for the 3D characterization of nanomaterials. 3D investigations typically comprise multiple steps, including acquisition, reconstruction, and analysis/quantification. Usually, the latter two steps are performed offline, at a dedicated workstation. This sequential workflow prevents on-the-fly control of experimental parameters to improve the quality of the 3D reconstruction, to select a relevant nanoparticle for further characterization or to steer an in-situ tomography experiment. Here, we present an efficient approach to overcome these limitations, based on the real-time reconstruction of arbitrary 2D reconstructed slices through a 3D object. Implementation of this method may lead to generalized implementation of electron tomography for routine nanoparticle characterization in 3D.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.7
Times cited: 10
DOI: 10.1002/ppsc.202000073
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“Real-time tilt undersampling optimization during electron tomography of beam sensitive samples using golden ratio scanning and RECAST3D”. Craig TM, Kadu AA, Batenburg KJ, Bals S, Nanoscale 15, 5391 (2023). http://doi.org/10.1039/D2NR07198C
Abstract: Electron tomography is a widely used technique for 3D structural analysis of nanomaterials, but it can cause damage to samples due to high electron doses and long exposure times. To minimize such damage, researchers often reduce beam exposure by acquiring fewer projections through tilt undersampling. However, this approach can also introduce reconstruction artifacts due to insufficient sampling. Therefore, it is important to determine the optimal number of projections that minimizes both beam exposure and undersampling artifacts for accurate reconstructions of beam-sensitive samples. Current methods for determining this optimal number of projections involve acquiring and post-processing multiple reconstructions with different numbers of projections, which can be time-consuming and requires multiple samples due to sample damage. To improve this process, we propose a protocol that combines golden ratio scanning and quasi-3D reconstruction to estimate the optimal number of projections in real-time during a single acquisition. This protocol was validated using simulated and realistic nanoparticles, and was successfully applied to reconstruct two beam-sensitive metal–organic framework complexes.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.7
Times cited: 1
DOI: 10.1039/D2NR07198C
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“Real-time simulations of ADF STEM probe position-integrated scattering cross-sections for single element fcc crystals in zone axis orientation using a densely connected neural network”. Lobato I, De Backer A, Van Aert S, Ultramicroscopy 251, 113769 (2023). http://doi.org/10.1016/j.ultramic.2023.113769
Abstract: Quantification of annular dark field (ADF) scanning transmission electron microscopy (STEM) images in terms
of composition or thickness often relies on probe-position integrated scattering cross sections (PPISCS). In
order to compare experimental PPISCS with theoretically predicted ones, expensive simulations are needed for
a given specimen, zone axis orientation, and a variety of microscope settings. The computation time of such
simulations can be in the order of hours using a single GPU card. ADF STEM simulations can be efficiently
parallelized using multiple GPUs, as the calculation of each pixel is independent of other pixels. However, most
research groups do not have the necessary hardware, and, in the best-case scenario, the simulation time will
only be reduced proportionally to the number of GPUs used. In this manuscript, we use a learning approach and
present a densely connected neural network that is able to perform real-time ADF STEM PPISCS predictions as
a function of atomic column thickness for most common face-centered cubic (fcc) crystals (i.e., Al, Cu, Pd, Ag,
Pt, Au and Pb) along [100] and [111] zone axis orientations, root-mean-square displacements, and microscope
parameters. The proposed architecture is parameter efficient and yields accurate predictions for the PPISCS
values for a wide range of input parameters that are commonly used for aberration-corrected transmission
electron microscopes.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.2
DOI: 10.1016/j.ultramic.2023.113769
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“Real-Time Integration Center of Mass (riCOM) Reconstruction for 4D STEM”. Yu C-P, Friedrich T, Jannis D, Van Aert S, Verbeeck J, Microscopy and microanalysis , 1 (2022). http://doi.org/10.1017/S1431927622000617
Abstract: A real-time image reconstruction method for scanning transmission electron microscopy (STEM) is proposed. With an algorithm requiring only the center of mass of the diffraction pattern at one probe position at a time, it is able to update the resulting image each time a new probe position is visited without storing any intermediate diffraction patterns. The results show clear features at high spatial frequency, such as atomic column positions. It is also demonstrated that some common post-processing methods, such as band-pass filtering, can be directly integrated in the real-time processing flow. Compared with other reconstruction methods, the proposed method produces high-quality reconstructions with good noise robustness at extremely low memory and computational requirements. An efficient, interactive open source implementation of the concept is further presented, which is compatible with frame-based, as well as event-based camera/file types. This method provides the attractive feature of immediate feedback that microscope operators have become used to, for example, conventional high-angle annular dark field STEM imaging, allowing for rapid decision-making and fine-tuning to obtain the best possible images for beam-sensitive samples at the lowest possible dose.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.8
Times cited: 7
DOI: 10.1017/S1431927622000617
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“Real-time atomic scale imaging of nanostructural evolution in aluminum alloys”. Malladi SK, Xu Q, van Huis MA, Tichelaar FD, Batenburg KJ, Yucelen E, Dubiel B, Czyrska-Filemonowicz A, Zandbergen HW, Nano Letters 14, 384 (2014). http://doi.org/10.1021/nl404565j
Abstract: We present a new approach to study the three-dimensional compositional and structural evolution of metal alloys during heat treatments such as commonly used for improving overall material properties. It relies on in situ heating in a high-resolution scanning transmission electron microscope (STEM). The approach is demonstrated using a commercial Al alloy AA2024 at 100-240 degrees C, showing in unparalleled detail where and how precipitates nucleate, grow,or dissolve. The observed size evolution of individual precipitates enables a separation between nucleation and growth phenomena, necessary for the development of refined growth models. We conclude that the in situ heating STEM approach opens a route to a much faster determination of the interplay between local compositions, heat treatments, microstructure, and mechanical properties of new alloys.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 12.712
Times cited: 12
DOI: 10.1021/nl404565j
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“Real-space simulations of spin-polarized electronic transitions in iron”. Schattschneider P, Verbeeck J, Mauchamp V, Jaouen M, Hamon A-L, Physical review : B : condensed matter and materials physics 82, 144418 (2010). http://doi.org/10.1103/PhysRevB.82.144418
Abstract: After the advent of energy-loss magnetic chiral dichroism (EMCD) in 2006, rapid progress in theoretical understanding and in experimental performance was achieved, recently demonstrating a spatial resolution of better than 2 nm. Similar to the x-ray magnetic circular dichroism technique, EMCD is used to study atom specific magnetic moments. The latest generation of electron microscopes opens the road to the mapping of spin moments on the atomic scale with this method. Here the theoretical background to reach this challenging aim is elaborated. Numerical simulations of the L3 transition in an Fe specimen, based on a combination of the density-matrix approach for inelastic electron scattering with the propagation of the probe electron in the lattice potential indicate the feasibility of single spin mapping in the electron microscope.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 11
DOI: 10.1103/PhysRevB.82.144418
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“Real-space multiple scattering method for angle-resolved photoemission and valence-band photoelectron diffraction and its application to Cu(111)”. Krüger P, da Pieve F, Osterwalder J, Physical review : B : condensed matter and materials physics 83, 115437 (2011). http://doi.org/10.1103/PhysRevB.83.115437
Abstract: A computational method is presented for angle-resolved photoemission spectra (ARPES) and photoelectron diffraction (PED) in the ultraviolet regime. The one-step model is employed and both initial valence and final continuum states are calculated using the finite-cluster, real-space multiple scattering method. Thereby the approach is versatile and provides a natural link to core-level PED. The method is applied to the Cu(111) valence band and good agreement with experiment is found for both ARPES spectra and PED patterns. When the PED patterns are integrated over a filled band of a single-orbital symmetry, such as Cu-3d, we show, both numerically and analytically, that the exact theory with delocalized initial states can be replaced by the much simpler, core-level-type theory where the initial states are taken as localized.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 17
DOI: 10.1103/PhysRevB.83.115437
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“Real-space mapping of electronic orbitals”. Stefan Löffler, Matthieu Bugnet, Nicolas Gauquelin, Sorin Lazar, Elias Assmann, Karsten Held, Gianluigi A Botton, Peter Schattschneider, Ultramicroscopy 177, 26 (2017). http://doi.org/10.1016/j.ultramic.2017.01.018
Abstract: Electronic states are responsible for most material properties, including chemical bonds, electrical and thermal conductivity, as well as optical and magnetic properties. Experimentally, however, they remain mostly elusive. Here, we report the real-space mapping of selected transitions between p and d states on the Ångström scale in bulk rutile (TiO2) using electron energy-loss spectrometry (EELS), revealing information on individual bonds between atoms. On the one hand, this enables the experimental verification of theoretical predictions about electronic states. On the other hand, it paves the way for directly investigating electronic states under conditions that are at the limit of the current capabilities of numerical simulations such as, e.g., the electronic states at defects, interfaces, and quantum dots.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
DOI: 10.1016/j.ultramic.2017.01.018
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“Real-space characterization of short-range order in Cu-Pd alloys”. Rodewald M, Rodewald K, De Meulenaere P, Van Tendeloo G, Physical review : B : condensed matter and materials physics 55, 14173 (1997). http://doi.org/10.1103/PhysRevB.55.14173
Abstract: Cu-Pd alloys containing 10, 20, 30, 40, and 50 at. % Pd and quenched from a temperature just above the ordering temperature T-c are investigated by electron diffraction and high-resolution electron microscopy (HREM). The results show diffuse electron diffraction intensities at {100} and {110} positions for the alloy with 10 at. % Pd, but with a characteristic twofold and fourfold splitting for the alloys with more than 10 at. % Pd. High-resolution images show the formation of microdomains best developed between 20 and 30 at. % Pd. A real-space characterization has been performed by applying videographic real-structure simulations revealing that the splitting of the diffuse maxima depends on the average distance between microdomains of Cu3Au type in antiphase with each other. By applying image processing routines on the HREM images, correlation vectors are identified which correspond to correlations between microdomains.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 15
DOI: 10.1103/PhysRevB.55.14173
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“Real space maps of magnetic moments on the atomic scale: theory and feasibility”. Schattschneider P, Ennen I, Stoger-Pollach M, Verbeeck J, Mauchamp V, Jaouen M, Ultramicroscopy 110, 1038 (2010). http://doi.org/10.1016/j.ultramic.2009.11.020
Abstract: The recently discovered EMCD technique (energy loss magnetic chiral dichroism) can detect atom specific magnetic moments with nanometer resolution, exploiting the spin selectivity of electronic transitions in energy loss spectroscopy. Yet, direct imaging of magnetic moments on the atomic scale is not possible. In this paper we present an extension of EMCD that can overcome this limit. As a model system we chose bcc Fe. We present image simulations of the L3 white line signal, based on the kinetic equation for the density matrix of the 200 kV probe electron. With actual progress in instrumentation (high brightness sources, aberration corrected lenses) this technique should allow direct imaging of spin moments on the atomic scale.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 10
DOI: 10.1016/j.ultramic.2009.11.020
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“Real space maps of atomic transitions”. Schattschneider P, Verbeeck J, Hamon AL, Ultramicroscopy 109, 781 (2009). http://doi.org/10.1016/j.ultramic.2009.01.016
Abstract: Considering the rapid technical development of transmission electron microscopes, we investigate the possibility to map electronic transitions in real space on the atomic scale. To this purpose, we analyse the information carried by the scatterer's initial and final state wave functions and the role of the different atomic transition channels for the inelastic scattering cross section. It is shown that the change in the magnetic quantum number in the transition can be mapped. Two experimental set-ups are proposed, one blocking half the diffraction plane, the other one using a cylinder lens for imaging. Both methods break the conventional circular symmetry in the electron microscope making it possible to detect the handedness of electronic transitions as an asymmetry in the image intensity. This finding is of important for atomic resolution energy-loss magnetic chiral dichroism (EMCD), allowing to obtain the magnetic moments of single atoms.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 10
DOI: 10.1016/j.ultramic.2009.01.016
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“Rationalizing the influence of the Mn(IV)/Mn(III) red-Ox transition on the electrocatalytic activity of manganese oxides in the oxygen reduction reaction”. Ryabova AS, Napolskiy FS, Poux T, Istomin SY, Bonnefont A, Antipin DM, Baranchikov AY, Levin EE, Abakumov AM, Kéranguéven G, Antipov EV, Tsirlina GA, Savinova ER;, Electrochimica acta 187, 161 (2016). http://doi.org/10.1016/j.electacta.2015.11.012
Abstract: Knowledge on the mechanisms of oxygen reduction reaction (ORR) and descriptors linking the catalytic activity to the structural and electronic properties of transition metal oxides enable rational design of more efficient catalysts. In this work ORR electrocatalysis was studied on a set of single and complex Mn (III) oxides with a rotating disc electrode method and cyclic voltammetry. We discovered an exponential increase of the specific electrocatalytic activity with the potential of the surface Mn(IV)/Mn(III) red-ox couple, suggesting the latter as a new descriptor for the ORR electrocatalysis. The observed dependence is rationalized using a simple mean-field kinetic model considering availability of the Mn( III) centers and adsorbate-adsorbate interactions. We demonstrate an unprecedented activity of Mn2O3, ca. 40 times exceeding that of MnOOH and correlate the catalytic activity of Mn oxides to their crystal structure. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.798
Times cited: 51
DOI: 10.1016/j.electacta.2015.11.012
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“Rational synthesis of F-doped iron oxides on Al2O3(0001) single crystals”. Carraro G, Gasparotto A, Maccato C, Bontempi E, Lebedev OI, Sada C, Turner S, Van Tendeloo G, Barreca D, Rsc Advances , 52140 (2014). http://doi.org/10.1039/C4RA09021G
Abstract: A plasma enhanced-chemical vapor deposition (PE-CVD) route to Fe2O3-based materials on Al2O3(0001) single crystals at moderate growth temperatures (200400 °C) is reported. The use of the fluorinated Fe(hfa)2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N′,N′-tetramethylethylenediamine) molecular precursor in Ar/O2 plasmas enabled an in situ F-doping of iron oxide matrices, with a fluorine content tunable as a function of the adopted preparative conditions. Variations of the thermal energy supply enabled control of the system phase composition, resulting in γ-Fe2O3 at 200 °C and α-Fe2O3 nanostructures at higher deposition temperatures. Notably, at 400 °C the formation of highly oriented α-Fe2O3 nanocolumns characterized by an epitaxial relation with the Al2O3(0001) substrate was observed. Beside fluorine content, phase composition and nano-organization, even the system optical properties and, in particular, energy gap values, could be tailored by proper modifications of processing parameters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 4
DOI: 10.1039/C4RA09021G
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“Rational synthesis of F-doped iron oxides on Al2O3(0001) single crystals”. Carraro G, Gasparotto A, Maccato C, Bontempi E, Lebedev OI, Sada C, Turner S, Van Tendeloo G, Barreca D, RSC advances 4, 52140 (2014). http://doi.org/10.1039/c4ra09021g
Abstract: A plasma enhanced-chemical vapor deposition (PE-CVD) route to Fe2O3-based materials on Al2O3(0001) single crystals at moderate growth temperatures (200-400 degrees C) is reported. The use of the fluorinated Fe(hfa)(2)TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N',N'-tetramethylethylenediamine) molecular precursor in Ar/O-2 plasmas enabled an in situ F-doping of iron oxide matrices, with a fluorine content tunable as a function of the adopted preparative conditions. Variations of the thermal energy supply enabled control of the system phase composition, resulting in gamma-Fe2O3 at 200 degrees C and alpha-Fe2O3 nanostructures at higher deposition temperatures. Notably, at 400 degrees C the formation of highly oriented alpha-Fe2O3 nanocolumns characterized by an epitaxial relation with the Al2O3(0001) substrate was observed. Beside fluorine content, phase composition and nano-organization, even the system optical properties and, in particular, energy gap values, could be tailored by proper modifications of processing parameters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 4
DOI: 10.1039/c4ra09021g
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“Rational synthesis of a nanocrystalline calcium phosphate cement exhibiting rapid conversion to hydroxyapatite”. Neira IS, Kolen'ko YV, Lebedev OI, Van Tendeloo G, Gupta HS, Matsushita N, Yoshimura M, Guitian F, Materials science and engineering: part C: biomimetic materials 29, 2124 (2009). http://doi.org/10.1016/j.msec.2009.04.011
Abstract: The rational synthesis, comprehensive characterization, and mechanical and micromechanical properties of a calcium phosphate cement are presented. Hydroxyapatite cement biomaterial was synthesized from reactive sub-micrometer-sized dicalcium phosphate dihydrate and tetracalcium phosphate via a dissolution-precipitation reaction using water as the liquid phase. As a result nanostructured, Ca-deficient and carbonated B-type hydroxyapatite is formed. The cement shows good processibility, sets in 22 ± 2 min and entirely transforms to the end product after 6 h of setting reaction, one of the highest conversion rates among previously reported for calcium phosphate cements based on dicalcium and tetracalcium phosphates. The combination of all elucidated physical-chemical traits leads to an essential bioactivity and biocompatibility of the cement, as revealed by in vitro acellular simulated body fluid and cell culture studies. The compressive strength of the produced cement biomaterial was established to be 25 ± 3 MPa. Furthermore, nanoindentation tests were performed directly on the cement to probe its local elasticity and plasticity at sub-micrometer/micrometer level. The measured elastic modulus and hardness were established to be Es = 23 ± 3.5 and H = 0.7 ± 0.2 GPa, respectively. These values are in close agreement with those reported in literature for trabecular and cortical bones, reflecting good elastic and plastic coherence between synthesized cement biomaterial and human bones.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.164
Times cited: 18
DOI: 10.1016/j.msec.2009.04.011
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“Rational design of Ag/TiO2 nanosystems by a combined RF-sputtering/sol-gel approach”. Armelao L, Barreca D, Bottaro G, Gasparotto A, Maccato C, Tondello E, Lebedev OI, Turner S, Van Tendeloo G, Štangar UL, ChemPhysChem : a European journal of chemical physics and physical chemistry 10, 3249 (2009). http://doi.org/10.1002/cphc.200900571
Abstract: The present work is devoted to the preparation of Ag/TiO2 nanosystems by an original synthetic strategy, based on the radio-frequency (RF) sputtering of silver particles on titania-based xerogels prepared by the sol-gel (SG) route. This approach takes advantage of the synergy between the microporous xerogel structure and the infiltration power characterizing RF-sputtering, whose combination enables the obtainment of a tailored dispersion of Ag-containing particles into the titania matrix. In addition, the systems chemico-physical features can be tuned further through proper ex situ thermal treatments in air at 400 and 600 °C. The synthesized composites are extensively characterized by the joint use of complementary techniques, that is, X-ray photoelectron and X-ray excited Auger electron spectroscopies (XPS, XE-AES), secondary ion mass spectrometry (SIMS), glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), electron diffraction (ED), high-angle annular dark field scanning TEM (HAADF-STEM), energy-filtered TEM (EF-TEM) and optical absorption spectroscopy. Finally, the photocatalytic performances of selected samples in the decomposition of the azo-dye Plasmocorinth B are preliminarily investigated. The obtained results highlight the possibility of tailoring the system characteristics over a broad range, directly influencing their eventual functional properties.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.075
Times cited: 56
DOI: 10.1002/cphc.200900571
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“Rapid microwave-assisted synthesis of benzene bridged periodic mesoporous organosilicas”. Smeulders G, Meynen V, van Baelen G, Mertens M, Lebedev OI, Van Tendeloo G, Maes BUW, Cool P, Journal of materials chemistry 19, 3042 (2009). http://doi.org/10.1039/b820792e
Abstract: Following extended use in organic chemistry, microwave-assisted synthesis is gaining more importance in the field of inorganic chemistry, especially for the synthesis of nanoporous materials. It offers some major advantages such as a significant shortening of the synthesis time and an improved promotion of nucleation. In the research here reported, microwave technology is applied for the synthesis of benzene bridged PMOs (periodic mesoporous organosilicas). PMOs are one of the latest innovations in the field of hybrid ordered mesoporous materials and have attracted much attention because of their feasibility in electronics, catalysis, separation and sorption applications. The different synthesis steps (stirring, aging and extraction) of the classical PMO synthesis are replaced by microwave-assisted synthesis steps. The characteristics of the as-synthesized materials are evaluated by X-ray diffraction, N2-sorption, thermogravimetric analysis, scanning- and transmission electron microscopy. The microwave-assisted synthesis drastically reduces the synthesis time by more than 40 hours without any loss in structural properties, such as mesoscale and molecular ordering. The porosity of the PMO materials has even been improved by more than 25%. Moreover, the number of handling/transfer steps and amounts of chemicals and waste are drastically reduced. The study also shows that there is a clear time (1 to 3 hours) and temperature frame (373 K to 403 K) wherein synthesis of benzene bridged PMO is optimal. In conclusion, the microwave-assisted synthesis pathway allows an improved material to be obtained in a more economical way i.e. a much shorter time with fewer chemicals and less waste.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY)
Times cited: 20
DOI: 10.1039/b820792e
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“RAMS and WRF sensitivity to grid spacing in large-eddy simulations of the dry convective boundary layer”. Ercolani G, Gorle C, Garcia Sánchez C, Corbari C, Mancini M, Computers and fluids 123, 54 (2015). http://doi.org/10.1016/j.compfluid.2015.09.009
Abstract: Large-eddy simulations (LESS) are frequently used to model the planetary boundary layer, and the choice of the grid cell size, numerical schemes and sub grid model can significantly influence the simulation results. In the present paper the impact of grid spacing on LES of an idealized atmospheric convective boundary layer (CBL), for which the statistics and flow structures are well understood, is assessed for two mesoscale models: the Regional Atmospheric Modeling System (RAMS) and the Weather Research and Forecasting model (WRF). Nine simulations are performed on a fixed computational domain (6 x 6 x 2 km), combining three different horizontal (120, 60, 30 m) and vertical (20, 10, 5 m) spacings. The impact of the cell size on the CBL is investigated by comparing turbulence statistics and velocity spectra. The results demonstrate that both WRF and RAMS can perform LES of the CBL under consideration without requiring extremely high computational loads, but they also indicate the importance of adopting a computational grid that is adequate for the numerical schemes and subgrid models used. In both RAMS and WRF a horizontal cell size of 30 m is required to obtain a suitable turbulence reproduction throughout the CBL height. Considering the vertical grid spacing, WRF produced similar results for all the three tested values, while in RAMS it should be ensured that the aspect ratio of the cells does not exceed a value of 3. The two models were found to behave differently in function of the grid resolution, and they have different shortcomings in their prediction of CBL turbulence. WRF exhibits enhanced damping at the smallest scales, while RAMS is prone to the appearance of spurious fluctuations in the flow when the grid aspect ratio is too high. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.313
Times cited: 3
DOI: 10.1016/j.compfluid.2015.09.009
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“Radiative and nonradiative recombination in CuInS2 nanocrystals and CuInS2-based core/shell nanocrystals”. Berends AC, Rabouw FT, Spoor FCM, Bladt E, Grozema FC, Houtepen AJ, Siebbeles LDA, de Donega CM, The journal of physical chemistry letters 7, 3503 (2016). http://doi.org/10.1021/acs.jpclett.6b01668
Abstract: Luminescent copper indium sulfide (CIS) nanocrystals are a potential solution to the toxicity issues associated with Cd- and Pb-based nanocrystals. However, the development of high-quality CIS nanocrystals has been complicated by insufficient knowledge of the electronic structure and of the factors that lead to luminescence quenching. Here we investigate the exciton decay pathways in CIS nanocrystals using time resolved photoluminescence and transient absorption spectroscopy. Core-only CIS nanocrystals with low quantum yield are compared to core/shell nanocrystals (CIS/ZnS and CIS/CdS) with higher quantum yield. Our measurements support the model of photoluminescence by radiative recombination of a conduction band electron with a localized hole. Moreover, we find that photoluminescence quenching in low-quantum-yield nanocrystals involves initially uncoupled decay pathways for the electron and hole. The electron decay pathway determines whether the exciton recombines radiatively or nonradiatively. The development of high-quality CIS nanocrystals should therefore focus on the elimination of electron traps.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 9.353
Times cited: 67
DOI: 10.1021/acs.jpclett.6b01668
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“Radiation defects and ordered radiation patterns in Ni and Ni4Mo: a study by electron microscopy”. De Meulenaere P, Van Tendeloo G, van Landuyt J, Mommaert C, Severne G, Philosophical magazine: A: physics of condensed matter: defects and mechanical properties 67, 745 (1993). http://doi.org/10.1080/01418619308207187
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1080/01418619308207187
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“R-phase transition and related mechanical properties controlled by low-temperature aging treatment in a Ti50.8 at.% Ni thin wire”. Wang X, Li K, Schryvers D, Verlinden B, Van Humbeeck J, Scripta materialia 72-73, 21 (2014). http://doi.org/10.1016/j.scriptamat.2013.10.006
Abstract: A cold-drawn Ti50.8 at.% Ni wire was annealed at 600 °C for 30 min, followed by aging at 250 °C for different times. A microstructure with small grains and nanoscaled precipitates was obtained. The thermally induced martensite transformation is suppressed in the samples aged for 4 h or longer, leaving a one-stage R-phase transition between −150 and +150 °C. The transformation behavior, work output and recovery stress associated with the R-phase transition are presented.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.747
Times cited: 27
DOI: 10.1016/j.scriptamat.2013.10.006
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“R-phase structure refinement using electron diffraction data”. Schryvers D, Potapov PL, Materials transactions 43, 774 (2002). http://doi.org/10.2320/matertrans.43.774
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.713
Times cited: 25
DOI: 10.2320/matertrans.43.774
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“Quasiparticle energies and uniaxial pressure effects on the properties of SnO2”. Saniz R, Dixit H, Lamoen D, Partoens B, Applied physics letters 97, 261901 (2010). http://doi.org/10.1063/1.3532109
Abstract: We calculate the quasiparticle energy spectrum of SnO2 within the GW approximation, properly taking into account the contribution of core levels to the energy corrections. The calculated fundamental gap is of 3.85 eV. We propose that the difference with respect to the experimental optical gap (3.6 eV) is due to excitonic effects in the latter. We further consider the effect applied on uniaxial pressure along the c-axis. Compared to GW, the effect of pressure on the quasiparticle energies and band gap is underestimated by the local-density approximation. The quasiparticle effective masses, however, appear to be well described by the latter.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 23
DOI: 10.1063/1.3532109
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“Quasiparticle band structure of rocksalt-CdO determined using maximally localized Wannier functions”. Dixit H, Lamoen D, Partoens B, Journal of physics : condensed matter 25, 035501 (2013). http://doi.org/10.1088/0953-8984/25/3/035501
Abstract: CdO in the rocksalt structure is an indirect band gap semiconductor. Thus, in order to determine its band gap one needs to calculate the complete band structure. However, in practice, the exact evaluation of the quasiparticle band structure for the large number of k-points which constitute the different symmetry lines in the Brillouin zone can be an extremely demanding task compared to the standard density functional theory (DFT) calculation. In this paper we report the full quasiparticle band structure of CdO using a plane-wave pseudopotential approach. In order to reduce the computational effort and time, we make use of maximally localized Wannier functions (MLWFs). The MLWFs offer a highly accurate method for interpolation of the DFT or GW band structure from a coarse k-point mesh in the irreducible Brillouin zone, resulting in a much reduced computational effort. The present paper discusses the technical details of the scheme along with the results obtained for the quasiparticle band gap and the electron effective mass.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 7
DOI: 10.1088/0953-8984/25/3/035501
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