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“Selective decoration of isolated carbon nanotubes by potassium evaporation : scanning photoemission microscopy and density functional theory”. Struzzi C, Erbahar D, Scardamaglia M, Amati M, Gregoratti L, Lagos, Van Tendeloo G, Snyders R, Ewels C, Bittencourt C, Journal of materials chemistry C : materials for optical and electronic devices 3, 2518 (2015). http://doi.org/10.1039/c4tc02478h
Abstract: Site selective doping of aligned carbon nanostructures represents a promising approach for their implementation in actual devices. In the present work we report on alkali metals decoration on low density vertically aligned carbon nanotubes, disclosing the possibility of engineering site selective depositions of potassium atoms on the carbon systems. Photoemission measurements were combined with microscopy demonstrating the effective spatial control of alkali deposition. The changes of electronic structures of locally doped carbon regions were studied by exploiting the ability of the scanning photoemission microscopy technique. From the analysis of experimental data supported by theoretical calculations, we show the tuning of the charge transfer from potassium to carbon atoms belonging to neighboring nanotubes or along the same tube structure.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.256
Times cited: 6
DOI: 10.1039/c4tc02478h
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“Selective bifunctional catalytic conversion of cellulose over reshaped ni particles at the tip of carbon nanofibers”. Van de Vyver S, Geboers J, Dusselier M, Schepers H, Vosch T, Zhang L, Van Tendeloo G, Jacobs PA, Sels BF, Chemsuschem 3, 698 (2010). http://doi.org/10.1002/cssc.201000087
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 7.226
Times cited: 136
DOI: 10.1002/cssc.201000087
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“Selective anodes for seawater splitting via functionalization of manganese oxides by a plasma-assisted process”. Bigiani L, Barreca D, Gasparotto A, Andreu T, Verbeeck J, Sada C, Modin E, Lebedev OI, Morante JR, Maccato C, Applied Catalysis B-Environmental 284, 119684 (2021). http://doi.org/10.1016/J.APCATB.2020.119684
Abstract: The electrolysis of seawater, a significantly more abundant natural reservoir than freshwater, stands as a promising alternative for sustainable hydrogen production, provided that the competitive chloride electro-oxidation is minimized. Herein, we propose an original material combination to selectively trigger oxygen evolution from seawater at expenses of chlorine generation. The target systems, based on MnO2 or Mn2O3 decorated with Fe2O3 or Co3O4, are fabricated by plasma enhanced-chemical vapor deposition of manganese oxides, functionalization with Fe2O3 and Co3O4 by sputtering, and annealing in air/Ar to obtain Mn(IV)/Mn(III) oxides. Among the various options, MnO2 decorated with Co3O4 yields the best performances in alkaline seawater splitting, with an outstanding Tafel slope of approximate to 40 mV x dec(-1) and an overpotential of 450 mV, enabling to rule out chlorine evolution. These attractive performances, resulting from the synergistic contribution of catalytic and electronic effects, open the door to low-cost hydrogen generation from seawater under real-world conditions, paving the way to eventual large-scale applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.446
Times cited: 67
DOI: 10.1016/J.APCATB.2020.119684
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“Segregation in InxGa1-xAs/GaAs Stranski-Krastanow layers grown by metal-organic chemical vapour deposition”. Piscopiello E, Rosenauer A, Passaseo A, Montoya Rossi EH, Van Tendeloo G, Philosophical magazine 85, 3857 (2005). http://doi.org/10.1080/147830500269402
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.505
Times cited: 11
DOI: 10.1080/147830500269402
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“Seeing and measuring in 3D with electrons”. Bals S, Goris B, Altantzis T, Heidari H, Van Aert S, Van Tendeloo G, Comptes rendus : physique 15, 140 (2014). http://doi.org/10.1016/j.crhy.2013.09.015
Abstract: Modern TEM enables the investigation of nanostructures at the atomic scale. However, TEM images are only two-dimensional (2D) projections of a three-dimensional (3D) object. Electron tomography can overcome this limitation. The technique is increasingly focused towards quantitative measurements and reaching atomic resolution in 3D has been the ultimate goal for many years. Therefore, one needs to optimize the acquisition of the data, the 3D reconstruction techniques as well as the quantification methods. Here, we will review a broad range of methodologies and examples. Finally, we will provide an outlook and will describe future challenges in the field of electron tomography.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.048
Times cited: 15
DOI: 10.1016/j.crhy.2013.09.015
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“Seedless synthesis of single crystalline Au nanoparticles with unusual shapes and tunable LSPR in the near-IR”. Angelomé, PC, Heidari Mezerji H, Goris B, Pastoriza-Santos I, Pérez-Juste J, Bals S, Liz-Marzán LM, Chemistry of materials 24, 1393 (2012). http://doi.org/10.1021/cm3004479
Abstract: The plasmonic properties of metal nanoparticles have acquired great importance because of their potential applications in very diverse fields. Metal nanoparticles with localized surface plasmon resonances (LSPR) in the near-infrared (NIR, 7501300 nm) are of particular interest because tissues, blood, and water display low absorption in this spectral range, thus facilitating biomedical applications. Cetyltrimethylammonium chloride (CTAC) was used to induce the seedless formation of highly anisotropic, twisted single crystalline Au nanoparticles in a single step. The LSPR of the obtained particles can be tuned from 600 nm up to 1400 nm by simply changing the reaction temperature or the reagents concentrations. The tunability of the LSPR is closely associated with significant changes in the final particle morphology, which was studied by advanced electron microscopy techniques (3D Tomography and HAADF-STEM). Kinetic experiments were carried out to establish the growth mechanism, suggesting that slow kinetics together with the complexation of the gold salt precursor to CTAC are key factors favoring the formation of these anisotropic particles.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 42
DOI: 10.1021/cm3004479
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“Seeded growth combined with cation exchange for the synthesis of anisotropic Cu2-xS/ZnS, Cu2-xS, and CuInS2 nanorods”. Xia C, Pedrazo-Tardajos A, Wang D, Meeldijk JD, Gerritsen HC, Bals S, de Donega CM, Chemistry of materials 33, 102 (2021). http://doi.org/10.1021/ACS.CHEMMATER.0C02817
Abstract: Colloidal copper(I) sulfide (Cu2-xS) nanocrystals (NCs) have attracted much attention for a wide range of applications because of their unique optoelectronic properties, driving scientists to explore the potential of using Cu2-xS NCs as seeds in the synthesis of heteronanocrystals to achieve new multifunctional materials. Herein, we developed a multistep synthesis strategy toward Cu2-xS/ZnS heteronanorods. The Janus-type Cu2-xS/ZnS heteronanorods are obtained by the injection of hexagonal high-chalcocite Cu2-xS seed NCs in a hot zinc oleate solution in the presence of suitable surfactants, 20 s after the injection of sulfur precursors. The Cu2-xS seed NCs undergo rapid aggregation and coalescence in the first few seconds after the injection, forming larger NCs that act as the effective seeds for heteronucleation and growth of ZnS. The ZnS heteronucleation occurs on a single (100) facet of the Cu2-xS seed NCs and is followed by fast anisotropic growth along a direction that is perpendicular to the c-axis, thus leading to Cu2-xS/ZnS Janus-type heteronanorods with a sharp heterointerface. Interestingly, the high-chalcocite crystal structure of the injected Cu2-xS seed NCs is preserved in the Cu2-xS segments of the heteronanorods because of the highthermodynamic stability of this Cu2-xS phase. The Cu2-xS/ZnS heteronanorods are subsequently converted into single-component Cu2-xS and CuInS2 nanorods by postsynthetic topotactic cation exchange. This work expands the possibilities for the rational synthesis of colloidal multicomponent heteronanorods by allowing the design principles of postsynthetic heteroepitaxial seeded growth and nanoscale cation exchange to be combined, yielding access to a plethora of multicomponent heteronanorods with diameters in the quantum confinement regime.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 10
DOI: 10.1021/ACS.CHEMMATER.0C02817
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“Sedimentation rate of the floodplain sediments of the Yamuna river basin (tributary of the river Ganges, India) by using <tex>210Pb</tex>, and <tex>137Cs</tex>, techniques”. Saxena DP, Joos P, Van Grieken R, Subramanian V, Journal of radioanalytical and nuclear chemistry 251, 399 (2002). http://doi.org/10.1023/A:1014821906600
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1023/A:1014821906600
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“Secondary-Phase-Assisted Grain Boundary Migration in CuInSe2”. Li C, Sanli ES, Barragan-Yani D, Stange H, Heinemann M-D, Greiner D, Sigle W, Mainz R, Albe K, Abou-Ras D, van Aken P A, Physical Review Letters 124, 095702 (2020). http://doi.org/10.1103/PhysRevLett.124.095702
Abstract: Significant structural evolution occurs during the deposition of CuInSe2 solar materials when the Cu content increases. We use in situ heating in a scanning transmission electron microscope to directly observe how grain boundaries migrate during heating, causing nondefected grains to consume highly defected grains. Cu substitutes for In in the near grain boundary regions, turning them into a Cu-Se phase topotactic with the CuInSe2 grain interiors. Together with density functional theory and molecular dynamics calculations, we reveal how this Cu-Se phase makes the grain boundaries highly mobile.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.6
DOI: 10.1103/PhysRevLett.124.095702
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“Secondary ion formation of low molecular weight organic dyes in time-of-flight static secondary ion mass spectrometry”. Lenaerts J, van Vaeck L, Gijbels R, Rapid communications in mass spectrometry 17, 2115 (2003). http://doi.org/10.1002/rcm.1160
Abstract: Time-of-flight static secondary ion mass spectrometry (TOF-S-SIMS) was used to characterize thin layers of oxy- and thiocarbocyanine dyes on Ag and Si. Apart from adduct ions a variety of structural fragment ions were detected for which a fragmentation pattern is proposed. Peak assignments were confirmed by comparing spectra of dyes with very similar structures. All secondary ions were assigned with a mass accuracy better than 50 ppm. The intensity of molecular ions as well as fragment ions has been studied as a function of the type of organic dye, the substrate, the layer thickness and the type of primary ion. A large yield difference of two orders of magnitude was observed between the precursor ions of cationic carbocyanine dyes and the protonated molecules of the anionic dyes. Fragment ions, on the other hand, yielded similar intensities for both types of dye. As the dye layers deposited on an Ag substrate yielded higher secondary ion intensities than those deposited on a Si substrate, the Ag metal clearly acts as a promoting agent for secondary ion formation. The effect was more pronounced for precursor signals than for fragment ions. The promoting effect decreased as the deposited layer thickness of the organic dye layer was increased. Copyright (C) 2003 John Wiley Sons, Ltd.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.998
Times cited: 10
DOI: 10.1002/rcm.1160
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“Secondary electron induced current in scanning transmission electron microscopy: an alternative way to visualize the morphology of nanoparticles”. Vlasov E, Skorikov A, Sánchez-Iglesias A, Liz-Marzán LM, Verbeeck J, Bals S, ACS materials letters , 1916 (2023). http://doi.org/10.1021/acsmaterialslett.3c00323
Abstract: Electron tomography (ET) is a powerful tool to determine the three-dimensional (3D) structure of nanomaterials in a transmission electron microscope. However, the acquisition of a conventional tilt series for ET is a time-consuming process and can therefore not provide 3D structural information in a time-efficient manner. Here, we propose surface-sensitive secondary electron (SE) imaging as an alternative to ET for the investigation of the morphology of nanomaterials. We use the SE electron beam induced current (SEEBIC) technique that maps the electrical current arising from holes generated by the emission of SEs from the sample. SEEBIC imaging can provide valuable information on the sample morphology with high spatial resolution and significantly shorter throughput times compared with ET. In addition, we discuss the contrast formation mechanisms that aid in the interpretation of SEEBIC data.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1021/acsmaterialslett.3c00323
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“Second-order multiple-quanta flux entry into a perforated spherical mesoscopic superconductor”. Xu B, Milošević, MV, Peeters FM, Physical review : B : condensed matter and materials physics 82, 214501 (2010). http://doi.org/10.1103/PhysRevB.82.214501
Abstract: Flux entry in type-II superconductors without prominent symmetry is a first-order phase transition, where flux enters conventionally gradual in units of a flux quantum. Here we show that neither is necessarily the case in a mesoscopic superconducting sphere with a perforation. In axially applied magnetic field, vortices initially occupy the hole, and can oppose further flux entry in the sample. As a result, multiple-quanta flux entry is found at significantly higher field, and it can manifest as a second-order transition due to suppressed geometric barrier at the equatorial belt of the sample. At high fields a new state is found, with gradually destroyed condensate from the equator inwards, the exact opposite of surface superconductivity.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 2
DOI: 10.1103/PhysRevB.82.214501
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“Second generation of vortex-antivortex states in mesoscopic superconductors: stabilization by artificial pinning”. Geurts R, Milošević, MV, Peeters FM, Physical review : B : solid state 79, 174508 (2009). http://doi.org/10.1103/PhysRevB.79.174508
Abstract: Antagonistic symmetries of superconducting polygons and their induced multivortex states in a homogeneous magnetic field may lead to the appearance of antivortices in the vicinity of the superconducting/normal-state boundary (where mesoscopic confinement is particularly strong). Resulting vortex-antivortex (V-Av) molecules match the sample symmetry but are extremely sensitive to defects and fluctuations and remain undetected experimentally. Here we show that V-Av states can reappear deep in the superconducting state due to an array of perforations in a polygonal setting, surrounding a central hole. Such states are no longer caused by the symmetry of the sample but rather by pinning itself, which prevents the vortex-antivortex annihilation. As a result, even micron size, clearly spaced V-Av molecules can be stabilized in large mesoscopic samples.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 17
DOI: 10.1103/PhysRevB.79.174508
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“Seasonality of ship emission related atmospheric pollution over coastal and open waters of the North Sea”. Bencs L, Horemans B, Buczyńska AJ, Deutsch F, Degraeuwe B, Van Poppel M, Van Grieken R, Atmospheric Environment: X 7, 100077 (2020). http://doi.org/10.1016/J.AEAOA.2020.100077
Abstract: The seasonal changes of a large set of atmospheric pollutants (i.e., gases, water-soluble aerosols, metallic/elemental components and black carbon (BC) content) have been studied over the southern bight of the North Sea (the Belgian Continental Shelf) and the English Channel during several marine sampling campaigns, carried out in 2010-2011. A coastal research station at De Haan, Belgium was concurrently used as a background air monitoring site. Size-segregated aerosols (PM1, PM2.5-1, PM10-2.5) were analyzed for particulate mass, elemental content and water-soluble (ionic) compounds, while the equivalent BC content in PM10 was monitored with an Aethalometer. The results clearly demonstrated that the aerosols originating from ship exhaust emissions contributed mostly to fine fraction (PM1), and to a lesser extent to medium-sized fraction (PM2.5-1), whereas components of sea spray and of mineral/soil origin were dominating in the medium-size and coarse aerosol fractions. Looking at seasonal differences, more ship emission related components occurred in the fine and medium-sized PM during winter. Mineral aerosol components were more apparent in coarse PM and especially during the cold season, increased levels were noted. Similarly, higher concentrations of marine fine PM were found during winter, likely due to more extensive ship emissions and/or calm weather conditions. Gaseous pollutants (e.g., HNO2, HNO3, HCl, SO2, NH3) originating from exhaust fumes of ocean-going ships mostly reached the maximum levels in the cold season as well, thus supporting the more intense formation of secondary aerosols. The seasonal trends of total (inorganic) ionic species sampled on the open sea and at the coastal station were usually similar to those of the corresponding PM masses, peaking in the cold season. Sea salt bound fine sulfate and nitrate peaked in spring or the cold season for marine areas, whereas for the coastal site they clearly reached the maximum in the cold season. Ammonium-bound nitrates and sulfates in each PM fraction reached their peak air levels in the cold season over marine sites. Similar seasonal trends could be observed for the coastal station. The general tendency of aerosol distribution over the study areas was independent of the sampling site: the higher the aerosol mass on the open sea with ship traffic, the higher the suspended particulate mass sampled at the coast.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.AEAOA.2020.100077
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“Seasonal trends of atmospheric nitrogen dioxide and sulfur dioxide over North Santa Clara, Cuba”. Alejo D, Morales MC, de la Torre JB, Grau R, Bencs L, Van Grieken R, van Espen P, Sosa D, Nuñez V, Environmental monitoring and assessment 185, 6023 (2013). http://doi.org/10.1007/S10661-012-3003-4
Abstract: Atmospheric nitrogen dioxide (NO2) and sulfur dioxide (SO2) levels were monitored simultaneously by means of Radiello passive samplers at six sites of Santa Clara city, Cuba, in the cold and the warm seasons in 2010. The dissolved ionic forms of NO2 and SO2 as nitrate and sulfite plus sulfate, respectively, were determined by means of ion chromatography. Analysis of NO2 as nitrite was also performed by UVVis spectrophotometry. For NO2, significant t tests show good agreement between the results of IC and UVVis methods. The NO2 and SO2 concentrations peaked in the cold season, while their minimum levels were experienced in the warm season. The pollutant levels do not exceed the maximum allowable limit of the Cuban Standard 39:1999, i.e., 40 μg/m3 and 50 μg/m3 for NO2 and SO2, respectively. The lowest pollutant concentrations obtained in the warm season can be attributed to an increase in their removal via precipitation (scavenging) while to the decreased traffic density and industrial emission during the summer holidays (e.g., July and August).
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S10661-012-3003-4
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“Seasonal and site-specific variation in vapour and aerosol phase PAHs over Flanders (Belgium) and their relation with anthropogenic activities”. Ravindra K, Bencs L, Wauters E, de Hoog J, Deutsch F, Roekens E, Bleux N, Berghmans P, Van Grieken R, Atmospheric environment : an international journal 40, 771 (2006). http://doi.org/10.1016/J.ATMOSENV.2005.10.011
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.ATMOSENV.2005.10.011
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“Screening of the electron-phonon interaction in quasi-one-dimensional semiconductor structures”. Hai GQ, Peeters FM, Devreese JT, Wendler L, Physical review : B : condensed matter and materials physics 48, 12016 (1993). http://doi.org/10.1103/PhysRevB.48.12016
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 3.736
Times cited: 41
DOI: 10.1103/PhysRevB.48.12016
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“Screening of novel MBR fouling reducers : benchmarking with known fouling reducers and evaluation of their mechanism of action”. Huyskens C, De Wever H, Fovet Y, Wegmann U, Diels L, Lenaerts S, Separation and purification technology 95, 49 (2012). http://doi.org/10.1016/J.SEPPUR.2012.04.024
Abstract: A novel fouling characterization method was applied for a first screening of two novel synthetic flocculants developed by BASF (BASF-1 and BASF-2) and benchmarking with six well-known products. Results showed that this MBR-VITO Fouling Measurement (VFM) was able to identify beneficial and adverse effects of different additives on the mixed liquor's reversible and irreversible fouling and, in combination with supporting mixed liquor analyses, allowed to identify the additive's main working mechanism. The first screening tests indicated that BASF-1 and BASF-2 reduced reversible and irreversible fouling to a similar extent as the known synthetic flocculants due to a charge neutralization mechanism, resulting in enhanced flocculation and SMP removal. Further testing at different additive concentrations provided a first indication of the optimal dosage and revealed a considerable risk of overdosing for BASF-2, rendering it less suited for fouling control. In contrast, such adverse effects were not observed for BASF-1. BASF-1 induced similar beneficial effects as the known MPE50 polymer at lower dosage and was therefore considered promising for application in MBRs. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.359
Times cited: 24
DOI: 10.1016/J.SEPPUR.2012.04.024
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“Screen versus cyclone for improved capacity and robustness for sidestream and mainstream deammonification”. Van Winckel T, Vlaeminck SE, Al-Omari A, Bachmann B, Sturm B, Wett B, Takács I, Bott C, Murthy SN, De Clippeleir H, Environmental Science: Water Research &, Technology 5, 1769 (2019). http://doi.org/10.1039/C9EW00384C
Abstract: Deammonification systems are being implemented as cost- and resource-efficient nitrogen removal processes. However, their complexity is a major hurdle towards successful transposition from side- to mainstream application. Merely out-selecting nitrite oxidizing bacteria (NOB) or retaining anammox bacteria (AnAOB) does not guarantee efficient mainstream deammonification. This paper presents for the first time the interactions and synergies between kinetic selection, through management of residual substrates, and physical selection, through separation of solid retention times (SRTs). This allowed the formulation of tangible operational recommendations for successful deammonification. Activity measurements were used to establish retention efficiencies (η) for AnAOB for full-scale cyclones and rotating drum screens installed at a sidestream and mainstream deammonification reactor (Strass, Austria). In the sidestream reactor, using a screen (η = 91%) instead of a cyclone (η = 88%) may increase the capacity by up to 29%. For the mainstream reactor, higher AnAOB retention efficiencies achieved by the screen (η = 72%) compared to the cyclone (η = 42%) induced a prospective increase in capacity by 80–90%. In addition, the switch in combination with bioaugmentation from the sidestream made the process less dependent on nitrite availability, thus aiding in the outselection of NOB. This allowed for a more flexible (intermittent) aeration strategy and a reduced need for tight SRT control for NOB washout. A sensitivity analysis explored expected trends to provide possible operational windows for further calibration. In essence, characterization of the physical selectors at full scale allowed a deeper understanding of operational windows of the process and quantification of capacity, ultimately leading to a more space and energy conservation process.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1039/C9EW00384C
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“Scheme for the generation of entangled atomic state in cavity QED”. Duan ZL, Chen ZY, Zhang JT, Feng XL, Xu ZZ, European physical journal : D : atomic, molecular and optical physics 30, 275 (2004). http://doi.org/10.1140/epjd/e2004-00086-2
Abstract: We propose a scheme to generate the entangled state of two Lambda-type three-level atoms trapped in a cavity. The atoms are initially prepared in their excited state and the cavity in vacuum state. Each atom has two possibilities to deexcite to one of the ground states. If two different polarized photons are detected subsequently, it is sure that both atoms are in different ground states. But which atom is in which ground state cannot be determined, the atoms are thus prepared in a superposition of two ground states, i.e., an entangled state. In comparison with the proposal of Hong and Lee [Phys. Rev. Lett. 89, 237901 (2002)], the requirement of a single polarized photon source can be avoided in our scheme.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.288
Times cited: 4
DOI: 10.1140/epjd/e2004-00086-2
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“Scheme for coherently quenching resonant current in a three-level quantum dot energy level mixer”. Austing DG, Payette C, Nair SV, Yu G, Gupta JA, Partoens B, Amaha S, Tarucha S, Physica status solidi: C: conferences and critical reviews 6, 940 (2009). http://doi.org/10.1002/pssc.200880584
Abstract: We outline a scheme to create a dark state by three-level mixing that is potentially a useful tool for quantum coherent transport. Magnetic-field-induced intra-dot level mixing can lead to rich quantum superposition phenomena between three approaching single-particle states in a quantum dot when probed by the ground state of an adjacent weakly coupled quantum dot in the single-electron resonant tunnelling regime. The mixing relies on non-negligible anharmonicity and anisotropy in confining potentials of realistic quantum dots. Anti-crossing and transfer of strengths between resonances can be understood with a simple coherent level mixing model. Superposition can lead to the formation of a dark state by complete cancellation of an otherwise strong resonance. This is an all-electrical analogue of coherent population trapping seen in three-level-systems from quantum and atom optics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1002/pssc.200880584
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“Scattering on circular inhomogeneous magnetic field profiles in an electron waveguide junction”. Li XQ, Peeters FM, Superlattices and microstructures 22, 243 (1997)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.123
Times cited: 9
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“Scattering of Dirac electrons by circular mass barriers : valley filter and resonant scattering”. Masir MR, Matulis A, Peeters FM, Physical review : B : condensed matter and materials physics 84, 245413 (2011). http://doi.org/10.1103/PhysRevB.84.245413
Abstract: The scattering of two-dimensional (2D) massless Dirac electrons is investigated in the presence of a random array of circular mass barriers. The inverse momentum relaxation time and the Hall factor are calculated and used to obtain parallel and perpendicular resistivity components within linear transport theory. We found a nonzero perpendicular resistivity component which has opposite sign for electrons in the different K and K′ valleys. This property can be used for valley filter purposes. The total cross section for scattering on penetrable barriers exhibits resonances due to the presence of quasibound states in the barriers that show up as sharp gaps in the cross section while for Schrödinger electrons they appear as peaks.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 32
DOI: 10.1103/PhysRevB.84.245413
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“Scattering of Dirac electrons by a random array of magnetic flux tubes”. Masir MR, Peeters FM, Journal of computational electronics 12, 115 (2013). http://doi.org/10.1007/s10825-013-0440-4
Abstract: The scattering of two-dimensional (2D) massless electrons as presented in graphene in the presence of a random array of circular magnetic flux tubes is investigated. The momentum relaxation time and the Hall factor are obtained using optical theorem techniques for scattering. Electrons with energy close to those of the Landau levels of the flux tubes exhibit resonant scattering and have a long life-time to reside inside the magnetic flux tube. These resonances appear as sharp structures in the Hall factor and the magneto-resistance.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.526
Times cited: 2
DOI: 10.1007/s10825-013-0440-4
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“Scattering of ballistic electrons at a mesoscopic spot of strong magnetic field”. Novoselov KS, Geim AK, Dubonos SV, Cornelissens YG, Peeters FM, Maan JC, Physical review : B : condensed matter and materials physics 65, 233312 (2002). http://doi.org/10.1103/PhysRevB.65.233312
Abstract: We report quenching of the Hall effect with increasing magnetic field confined in a micron-sized spot. Such fields were created by placing tall ferromagnetic pillars on top of a two-dimensional electron gas, which allowed us to achieve the field strength up to 0.4 T under the pillars in the absence of external field. The quenching is accompanied by an anomalous increase in resistance and occurs when the cyclotron diameter matches the size of the magnetic spot. The results are explained by a rapid increase in the number of electrons that are scattered or quasilocalized by the magnetic region.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 38
DOI: 10.1103/PhysRevB.65.233312
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“Scattering of a Dirac electron on a mass barrier”. Matulis A, Masir MR, Peeters FM, Physical review : A : atomic, molecular and optical physics 86, 022101 (2012). http://doi.org/10.1103/PhysRevA.86.022101
Abstract: The interaction of a wave packet (and in particular the wave front) with a mass barrier is investigated in one dimension. We discuss the main features of the wave packet that are inherent to two-dimensional wave packets, such as compression during reflection, penetration in the case when the energy is lower than the height of the barrier, waving tails, precursors, and the retardation of the reflected and penetrated wave packets. These features depend on the wave-packet envelope function which we demonstrate by considering the case of a rectangular wave packet with sharp front and trailing edges and a smooth Gaussian wave packet. The method of Fourier integral for obtaining the nonstationary solutions is used.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.925
Times cited: 9
DOI: 10.1103/PhysRevA.86.022101
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“Scanning XRF investigation of a Flower Still Life and its underlying composition from the collection of the Kröller-Muller Museum”. Alfeld M, van der Snickt G, Vanmeert F, Janssens K, Dik J, Appel K, van der Loeff L, Chavannes M, Meedendorp T, Hendriks E, Applied physics A : materials science &, processing 111, 165 (2013). http://doi.org/10.1007/S00339-012-7526-X
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 35
DOI: 10.1007/S00339-012-7526-X
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“Scanning tunneling microscopy and density functional theory study on zinc(II)-phthalocyanine tetrasulfonic acid on bilayer epitaxial graphene on silicon carbide(0001)”. Nicholls D, Li RR, Ware B, Pansegrau C, Çakir D, Hoffmann MR, Oncel N, The journal of physical chemistry: C : nanomaterials and interfaces 119, 9845 (2015). http://doi.org/10.1021/acs.jpcc.5b00864
Abstract: Zinc(II)-phthalocyanine tetrasulfonic acid (Zn-PcS) molecules physisorbed on bilayer epitaxial graphene on silicon carbide (SiC(0001)) were studied by using scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT). Two different methods were used to deposit Zn-PcS molecules and regardless of the method being used, the surface coverage stayed very low indicating the weakness of surface-molecule interaction. STS measurements revealed that derivative of tunneling current with respect to voltage (dI/dV) measured on Zn-PcS molecules did not exhibit the characteristic dip observed on dI/dV curves of pristine bilayer epitaxial graphene. DFT calculations show that the energy of the lowest unoccupied molecular orbital (LUMO) of the Zn-PcS molecule is below the Dirac point of graphene which enhances local density of states (LDOS). We attribute the disappearance of the dip in the dI/dV curves measured on the Zn-PcS/bilayer system to the LUMO of Zn-PcS. Charge density calculations along Zn-PcS/graphene interface reveal that there is a small charge transfer from graphene to the molecule. Calculated adsorption energy (3.13 eV) of the molecule is notably low and is consistent with the observed low surface coverage at room temperature.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.536
Times cited: 3
DOI: 10.1021/acs.jpcc.5b00864
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“Scanning transmission electron microscopy under controlled low-pressure atmospheres”. Leuthner GT, Hummel S, Mangler C, Pennycook TJ, Susi T, Meyer JC, Kotakoski J, Ultramicroscopy 203, 76 (2019). http://doi.org/10.1016/J.ULTRAMIC.2019.02.002
Abstract: Transmission electron microscopy (TEM) is carried out in vacuum to minimize the interaction of the imaging electrons with gas molecules while passing through the microscope column. Nevertheless, in typical devices, the pressure remains at 10(-7) mbar or above, providing a large number of gas molecules for the electron beam to crack, which can lead to structural changes in the sample. Here, we describe experiments carried out in a modified scanning TEM (STEM) instrument, based on the Nion UltraSTEM 100. In this instrument, the base pressure at the sample is around 2 x 10(-10 )mbar, and can be varied up to 10(-6) mbar through introduction of gases directly into the objective area while maintaining atomic resolution imaging conditions. We show that air leaked into the microscope column during the experiment is efficient in cleaning graphene samples from contamination, but ineffective in damaging the pristine lattice. Our experiments also show that exposure to O(2 )and H2O lead to a similar result, oxygen providing an etching effect nearly twice as efficient as water, presumably due to the two 0 atoms per molecule. H(2 )and N-2 environments have no influence on etching. These results show that the residual gas environment in typical TEM instruments can have a large influence on the observations, and show that chemical etching of carbon-based structures can be effectively carried out with oxygen.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 4
DOI: 10.1016/J.ULTRAMIC.2019.02.002
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“Scanning microanalysis”. Gijbels R, Oleshko V s.l., page 427 (1998).
Keywords: H3 Book chapter; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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