“Landau levels in biased graphene structures with monolayer-bilayer interfaces”. Mirzakhani M, Zarenia M, Vasilopoulos P, Ketabi SA, Peeters FM, Physical review B 96, 125430 (2017). http://doi.org/10.1103/PHYSREVB.96.125430
Abstract: The electron energy spectrum in monolayer-bilayer-monolayer and in bilayer-monolayer-bilayer graphene structures is investigated and the effects of a perpendicular magnetic field and electric bias are studied. Different types of monolayer-bilayer interfaces are considered as zigzag (ZZ) or armchair (AC) junctions which modify considerably the bulk Landau levels (LLs) when the spectra are plotted as a function of the center coordinate of the cyclotron orbit. Far away from the two interfaces, one obtains the well-known LLs for extended monolayer or bilayer graphene. The LL structure changes significantly at the two interfaces or junctions where the valley degeneracy is lifted for both types of junctions, especially when the distance between them is approximately equal to the magnetic length. Varying the nonuniform bias and the width of this junction-to-junction region in either structure strongly influence the resulting spectra. Significant differences exist between ZZ and AC junctions in both structures. The densities of states (DOSs) for unbiased structures are symmetric in energy whereas those for biased structures are asymmetric. An external bias creates interface LLs in the gaps between the LLs of the unbiased system in which the DOS can be quite small. Such a pattern of LLs can be probed by scanning tunneling microscopy.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PHYSREVB.96.125430
|
“Landau levels in asymmetric graphene trilayer”. Sena SHR, Pereira JM, Peeters FM, Farias GA, Physical review : B : condensed matter and materials physics 84, 205448 (2011). http://doi.org/10.1103/PhysRevB.84.205448
Abstract: The electronic spectrum of three coupled graphene layers (graphene trilayers) is investigated in the presence of an external magnetic field. We obtain analytical expressions for the Landau level spectrum for both the ABA and ABC type of stacking, which exhibit very different dependence on the magnetic field. We show that layer asymmetry and an external gate voltage can strongly influence the properties of the system.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 30
DOI: 10.1103/PhysRevB.84.205448
|
“Landau levels and oscillator strength in a biased bilayer of graphene”. Milton Pereira J, Peeters FM, Vasilopoulos P, Physical review : B : condensed matter and materials physics 76, 115419 (2007). http://doi.org/10.1103/PhysRevB.76.115419
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 91
DOI: 10.1103/PhysRevB.76.115419
|
“Landau levels and magnetopolaron effect in dilute GaAs:N”. Krstajić, PM, Peeters FM, Helm M, Solid state communications 150, 1575 (2010). http://doi.org/10.1016/j.ssc.2010.05.044
Abstract: The magnetic-field dependence of the energy spectrum of GaAs doped with nitrogen impurities is investigated. Our theoretical model is based on the phenomenological band anticrossing model (BAC) which we extended in order to include the magnetic field and electronphonon interaction. Due to the highly localized nature of the nitrogen state, we find that the energy levels are very different from those of pure GaAs. The polaron correction results in a lower cyclotron resonance energy as compared to pure GaAs. The magneto-absorption spectrum exhibits series of asymmetric peaks close to the cyclotron energy ħωc.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.554
DOI: 10.1016/j.ssc.2010.05.044
|
“Land-use suitability in Northeast Iran : application of AHP-GIS hybrid model”. Memarbashi E, Azadi H, Barati AA, Mohajeri F, Van Passel S, Witlox F, Isprs International Journal Of Geo-Information 6, 396 (2017). http://doi.org/10.3390/IJGI6120396
Abstract: Land-use suitability is the ability of a given type of land to support a defined use. Analysis of land-use suitability requires the consideration of a variety of criteria, not only the natural/physical capacity of a land unit, but also its socioeconomic and environmental impact implications. As land suitability is assessed within a Geographic Information System (GIS) environment, it is formulated as a multi-criteria decision making (MCDM) problem. The study was conducted in the Sangab Plain in northeast Iran. We investigated the study areas suitability for grassland and agricultural uses. A hybrid method of the analytic hierarchy process (AHP) and GIS methodology was applied to evaluate land suitability based on a set of criteria and sub-criteria. Results showed that 20% of the study area had high (rich), 65% had medium (fair), and 15% had low (poor) suitability for agriculture. In terms of grassland use, the comparable amounts were, respectively, about 7%, 23%, and 70%. The lands of the Sangab Plain have medium potential for agricultural use and low potential for grassland use. This paper used both qualitative and quantitative techniques.
Keywords: A1 Journal article; Economics; Engineering Management (ENM); Government and Law
Impact Factor: 0.371
Times cited: 7
DOI: 10.3390/IJGI6120396
|
“LAMMA and electron-microprobe analysis of atmospheric aerosols”. Bruynseels F, Storms H, Van Grieken R, Journal de physique 45, 785 (1984). http://doi.org/10.1051/JPHYSCOL:19842180
Abstract: A laser microprobe mass analyser and a highly automated electron probe X-ray microanalysis unit have been used to study the elemental composition, inorganic speciation and morphology of atmospheric aerosols collected at various remote to polluted and marine to continental locations.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1051/JPHYSCOL:19842180
|
“Laminated altered layers in historical glass : density variations of silica nanoparticle random packings as explanation for the observed lamellae”. Schalm O, Anaf W, Journal of non-crystalline solids 442, 1 (2016). http://doi.org/10.1016/J.JNONCRYSOL.2016.03.019
Abstract: One of the most striking but unexplained phenomena in the natural degradation of glass is the transformation of an almost colorless, transparent and homogeneous glass into a colored, opaque and heterogeneous degradation layer. In many cases, the degradation layer consists of numerous lamellae with a thickness between 0.1 and 10 pm. However, both internal structure and formation proess of laminated degradation layers remain unclear. In this paper, a model is proposed where we assume that transformed (degraded) glass consists of a random packing of nano-sized silica particles while the lamellae are the result of different packing densities. The model is able to connect the texture of numerous lamellae observed by several types of microscopic techniques with the structure at molecular level determined by means of chemical analysis. In addition, the model is able to explain numerous properties such as the parameters responsible for the contrast between lamellae. This contrast can be caused by differences in color, density, elemental composition, or surface roughness. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
DOI: 10.1016/J.JNONCRYSOL.2016.03.019
|
“LaFeO3 nanofibers for high detection of sulfur-containing gases”. Queralto A, Graf D, Frohnhoven R, Fischer T, Vanrompay H, Bals S, Bartasyte A, Mathur S, ACS Sustainable Chemistry and Engineering 7, 6023 (2019). http://doi.org/10.1021/ACSSUSCHEMENG.8B06132
Abstract: Lanthanum ferrite nanofibers were electrospun from a chemical sol and calcined at 600 degrees C to obtain singlephase LaFeO3 (LFO) perovskite. High-resolution transmission electron microscopy in conjunction with 3D tomographic analysis confirmed an interwoven network of hollow and porous (surface) LFO nanofibers. Owing to their high surface area and p-type behavior, the nanofiber meshes showed high chemoselectivity toward reducing toxic gases (SO2, H2S) that could be reproducibly detected at very low concentrations (<1 ppm), well below the threshold values for occupational safety and health. An increased sensitivity was observed in the temperature range of 150-300 degrees C with maximum sensor response at 250 degrees C. The surface reaction at the heterogeneous solid (LFO)/gas (SO2) interface that confirmed the formation of La-2(SO4)(3) was investigated by X-ray photoelectron spectroscopy. Moreover, the LFO fibers showed a high selectivity in the detection of oxidizing and reducing gases. Whereas superior detection of NH3 and H2S was measured, little response was observed for CO and NO2. Finally, the integration of nanowire meshes in commercial sensor platforms was successfully demonstrated.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.951
Times cited: 41
DOI: 10.1021/ACSSUSCHEMENG.8B06132
|
“Laboratory-scale membrane up-concentration and co-anaerobic digestion for energy recovery from sewage and kitchen waste”. Nguyen Thi Tuyet, Nguyen Phuoc Dan, Nguyen Cong Vu, Nguyen Le Hoang Trung, Bui Xuan Thanh, De Wever H, Goemans M, Diels L, Water science and technology 73, 597 (2016). http://doi.org/10.2166/WST.2015.535
Abstract: This study assessed an alternative concept for co-treatment of sewage and organic kitchen waste in Vietnam. The goal was to apply direct membrane filtration for sewage treatment to generate a permeate that is suitable for discharge. The obtained chemical oxygen demand (COD) concentrations in the permeate of ultrafiltration tests were indeed under the limit value (50 mg/L) of the local municipal discharge standards. The COD of the concentrate was 5.4 times higher than that of the initial feed. These concentrated organics were then co-digested with organic kitchen wastes at an organic loading rate of 2.0 kg VS/m(3).d. The volumetric biogas production of the digester was 1.94 +/- 0.34 m(3)/m(3).d. The recovered carbon, in terms of methane gas, accounted for 50% of the total carbon input of the integrated system. Consequently, an electrical production of 64 Wh/capita/d can be obtained when applying the proposed technology with the current wastes generated in Ho Chi Minh City. Thus, it is an approach with great potential in terms of energy recovery and waste treatment.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.2166/WST.2015.535
|
“Label-free impedance aptasensor for major peanut allergen Ara h 1”. Trashin S, De Jong M, Breugelmans T, Pilehvar S, De Wael K, Electroanalysis 27, 32 (2015). http://doi.org/10.1002/ELAN.201400365
Abstract: The peanut allergen Ara h 1 belonging to the vicilin family of seed storage proteins is known to be a suitable marker for peanut detection in foods. In the present work, we suggest an electrochemical detection of Ara h 1 using a recently selected 80-base DNA aptamer. The detection strategy relies on insulation effect of a bulky protein captured by an immobilized aptamer. The electrodes were modified by the aptamer and characterized using electrochemical impedance spectroscopy (EIS). The aptamer surface density and analytical parameters of the calibration curves for Ara h 1 were compared with the system prepared with thrombin binding aptamer (TBA) and operated in the same conditions.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Applied Electrochemistry & Catalysis (ELCAT)
Times cited: 10
DOI: 10.1002/ELAN.201400365
|
“LA-ICP-MS labels early medieval Tuscan finds from Siena and Donoratico as late natron glass”. Hellemans K, Cagno S, Bogana L, Janssens K, Mendera M, Journal of Archaeological Science: Reports 23, 844 (2019). http://doi.org/10.1016/J.JASREP.2018.12.002
Abstract: The late antique/early medieval age in Central Italy is a well-suited context to verify the implications of the end of the natron glass supplies, and to explore the beginnings of the new plant-ash glass technology. We present the results of a LA-ICP-MS analysis campaign conducted on archaeological glass finds excavated at the Santa Maria della Scala hospital site in Siena and in Donoratico. This provided us with major, minor and trace element quantitative data for 49 glass samples belonging to drinking vessels and lamps, dated mainly between the 5th and the 8th century. On the basis of these data, we have sought to identify the working processes and possible glassware trade that are reflected in the glass composition. Major and minor element contents revealed that most samples, also at the later boundary of the explored timeframe, fit well within known late Roman glass classifications (e.g. HIMT, Levantine). Trace element analysis provided further information on the raw materials that were used in the glassmaking process, indicating the use of coastal sands as a silica source and allowing us to formulate different hypotheses on the materials used for the colouring process.
Keywords: A1 Journal article; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 3
DOI: 10.1016/J.JASREP.2018.12.002
|
“LA-ICP-MS for Pu source identification at Mayak PA, the Urals, Russia”. Cagno S, Hellemans K, Lind OC, Skipperud L, Janssens K, Salbu B, Environmental science : processes &, impacts 16, 306 (2014). http://doi.org/10.1039/C3EM00531C
Abstract: Information on Pu in environmental samples is traditionally based on the determination of the 240+239PU activity via Alpha Spectrometry (AS). A large number of alpha spectrometry sources (planchettes) containing radiochemically separated Pu are therefore stored worldwide and are available for further analyses. These archive samples represent a resource from which valuable information on isotopic composition of alpha emitters including Pu can be obtained. The relative abundances of Pu isotopes can be used to trace specific Pu sources and characterize the relative contributions of different Pu sources in a sample. Thus, in addition to the total 239+240PU activity, determination of the Pu-240/Pu-239 ratio can provide valuable information on the nature of the Pu emitting sources. The Pu isotopic ratios can be determined by mass spectrometry techniques such as Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICPMS) or Accelerator Mass Spectrometry (AMS) that require dissolution and complete destruction of the material deposited on the planchettes. In this study Laser Ablation (LA)-quadrupole-ICP-MS has been employed for the analysis of Pu-239/Pu-240 ratios from alpha-planchettes prepared from samples originating from the Mayak PA nuclear facility, Russia. The results are compared with data from AMS and show that the Pu-240/Pu-239 ratios obtained by LA-ICP-MS can be utilized to distinguish weapons-grade Pu from civil reprocessing sources. Moreover, isotope ratio mapping can also be performed across the planchettes, allowing e.g. the visualization of possible inhomogeneities in the Pu-isotope distribution on their surface. Thus, this solid sample technique can be applied to extract additional information from existing archives of samples.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.592
Times cited: 10
DOI: 10.1039/C3EM00531C
|
“K₅Eu(MoO₄)₄, red phosphor for solid state lighting applications, prepared by different techniques”. Posokhova SMM, Morozov VA, Deyneko DVV, Redkin BSS, Spassky DAA, Nagirnyi V, Belik AAA, Hadermann J, Pavlova ETT, Lazoryak BII, CrystEngComm 25, 835 (2023). http://doi.org/10.1039/D2CE01107G
Abstract: The influence of preparation techniques on the structure and luminescent properties of K5Eu(MoO4)(4) (KEMO) was investigated. KEMO phosphors were synthesized by three different techniques: solid state and sol-gel (sg) methods as well as the Czochralski (CZ) crystal growth technique. Laboratory powder X-ray diffraction (PXRD) studies revealed that all KEMO samples had a structure analogous to that of other high temperature alpha-K5R(MoO4)(4) palmierite-type phases (space group (SG) R3m). Contrary to laboratory PXRD data, electron diffraction revealed that the KEMO crystal grown by the CZ technique had a (3 + 1)D incommensurately modulated structure (super space group (SSG) C2/m(0 beta 0)00) with the modulation vector q = 0.689b*. A detailed analysis of electron diffraction patterns has shown formation of three twin domains rotated along the c axis of the R-subcell at 60 degrees with respect to each other. Synchrotron XRD patterns showed additional ultra-wide reflexes in addition to reflections of the R-subcell of the palmierite. However, the insufficient number of reflections, their low intensity and large width in the synchrotron X-ray diffraction patterns made it impossible to refine the structure as incommensurately modulated C2/m(0 beta 0)00. An average structure was refined in the C2/m space group with random distribution of K1 and Eu1 in [M1A(2)O(8)]-layers of the palmierite-type structure. The dependence of luminescent properties on utilized synthesis techniques was studied. The emission spectra of all samples exhibit intense red emission originating from the D-5(0) -> F-7(2) Eu3+ transition. The integrated intensity of the emission from the Eu3+ 5D0 term was found to be the highest in the crystal grown by the CZ technique. The quantum yield measured for KEMO crystals demonstrates a very high value of 66.5%. This fact confirms that KEMO crystals are exceptionally attractive for applications as a near-UV converting red phosphor for LEDs.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.1
DOI: 10.1039/D2CE01107G
|
“K2CaV2O7 : a pyrovanadate with a new layered type of structure in the A2BV2O7 family”. Tyutyunnik AP, Slobodin BV, Samigullina RF, Verberck B, Tarakina NV, Journal of the Chemical Society : Dalton transactions 42, 1057 (2013). http://doi.org/10.1039/c2dt31246h
Abstract: The crystal structure of K2CaV2O7 prepared by a conventional solid-state reaction has been solved by a direct method and refined using Rietveld full profile fitting based on X-ray powder diffraction data. This compound crystallises in the triclinic space group (P (1) over bar, Z = 2) with unit cell constants a = 7.1577(1) angstrom, b = 10.5104(2) angstrom, c = 5.8187(1) angstrom, alpha = 106.3368(9)degrees, beta = 106.235(1)degrees, gamma = 71.1375(9)degrees. The structure can be described as infinite undulating CaV2O72- layers parallel to the ac plane, which consist of pairs of edge-sharing CaO6 octahedra connected to each other through V2O7 pyrogroups. The potassium atoms are positioned in two sites between the layers, with a distorted IX-fold coordination of oxygen atoms. The chemical composition obtained from the structural solution was confirmed by energy-dispersive X-ray analysis. The stability of compounds in the family of alkali metal calcium pyrovanadates is discussed based on an analysis of the correlation between anion and cation sizes and theoretical first-principles calculations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.029
Times cited: 3
DOI: 10.1039/c2dt31246h
|
“KSm(MoO4)2, an incommensurately modulated and partially disordered scheelite-like structure”. Arakcheeva A, Pattison P, Chapuis G, Rossell M, Filaretov A, Morozov V, Van Tendeloo G, Acta crystallographica: section B: structural science 64, 160 (2008). http://doi.org/10.1107/S0108768108001870
Abstract: The incommensurately modulated scheelite-like KSm( MoO4)(2) structure has been refined in the monoclinic superspace group I2/b(alpha beta 0)00 by the Rietveld method on the basis of synchrotron radiation powder diffraction data. The systematic broadening of satellite reflections has been accounted for by applying anisotropic microstrain line-broadening. The microstructure has been studied by transmission electron microscopy (TEM). The partial disorder of the K and Sm cations in the A position is best approximated by a combination of harmonic and complex crenel functions with (0.952Sm + 0.048K) and (0.952K + 0.048Sm) atomic domains. This combination yields a compositional wave distribution from {KMoO4} to {SmMoO4} observed in the ab structure projection along q. The specific features of KSm(MoO4)(2) and degree of the A-cation ordering are discussed in comparison with the previously reported structure of KNd(MoO4)(2).
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 23
DOI: 10.1107/S0108768108001870
|
“Kronig-Penney model on bilayer graphene : spectrum and transmission periodic in the strength of the barriers”. Barbier M, Vasilopoulos P, Peeters FM, Physical review : B : condensed matter and materials physics 82, 235408 (2010). http://doi.org/10.1103/PhysRevB.82.235408
Abstract: We show that the transmission through single and double δ-function potential barriers of strength P=VWb/ℏvF in bilayer graphene is periodic in P with period π. For a certain range of P values we find states that are bound to the potential barrier and that run along the potential barrier. Similar periodic behavior is found for the conductance. The spectrum of a periodic succession of δ-function barriers (Kronig-Penney model) in bilayer graphene is periodic in P with period 2π. For P smaller than a critical value Pc, the spectrum exhibits two Dirac points while for P larger than Pc an energy gap opens. These results are extended to the case of a superlattice of δ-function barriers with P alternating in sign between successive barriers; the corresponding spectrum is periodic in P with period π.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 34
DOI: 10.1103/PhysRevB.82.235408
|
“Kronig-Penney model of scalar and vector potentials in graphene”. Masir MR, Vasilopoulos P, Peeters FM, Journal of physics : condensed matter 22, 465302 (2010). http://doi.org/10.1088/0953-8984/22/46/465302
Abstract: We consider a one-dimensional (1D) superlattice (SL) on graphene consisting of very high and very thin (δ-function) magnetic and potential barriers with zero average potential and zero magnetic field. We calculate the energy spectrum analytically, study it in different limiting cases, and determine the condition under which an electron beam incident on an SL is highly collimated along its direction. In the absence of the magnetic SL the collimation is very sensitive to the value of W/Ws and is optimal for W/Ws = 1, where W is the distance between the positive and negative barriers and L = W + Ws is the size of the unit cell. In the presence of only the magnetic SL the collimation decreases and the symmetry of the spectrum around ky is broken for W/Ws\neq 1 . In addition, a gap opens which depends on the strength of the magnetic field. We also investigate the effect of spatially separated potential and magnetic δ-function barriers and predict a better collimation in specific cases.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 41
DOI: 10.1088/0953-8984/22/46/465302
|
“Knitting the catalytic pattern of artificial photosynthesis to a hybrid graphene nanotexture”. Quintana M, López AM, Rapino S, Toma FM, Iurlo M, Carraro M, Sartorel A, Maccato C, Ke X, Bittencourt C, Da Ros T, Van Tendeloo G, Marcaccio M, Paolucci F, Prato M, Bonchio M;, ACS nano 7, 811 (2013). http://doi.org/10.1021/nn305313q
Abstract: The artificial leaf project calls for new materials enabling multielectron catalysis with minimal overpotential, high turnover frequency, and long-term stability. Is graphene a better material than carbon nanotubes to enhance water oxidation catalysis for energy applications? Here we show that functionalized graphene with a tailored distribution of polycationic, quaternized, ammonium pendants provides an sp(2) carbon nanoplatform to anchor a totally inorganic tetraruthenate catalyst, mimicking the oxygen evolving center of natural PSII. The resulting hybrid material displays oxygen evolution at overpotential as low as 300 mV at neutral pH with negligible loss of performance after 4 h testing. This multilayer electroactive asset enhances the turnover frequency by 1 order of magnitude with respect to the isolated catalyst, and provides a definite up-grade of the carbon nanotube material, with a similar surface functionalization. Our innovation is based on a noninvasive, synthetic protocol for graphene functionalization that goes beyond the ill-defined oxidation-reduction methods, allowing a definite control of the surface properties.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 69
DOI: 10.1021/nn305313q
|
“KNd(MoO4)2: a new incommensurate modulated structure in the scheelite family”. Morozov VA, Arakcheeva AV, Chapuis G, Guiblin N, Rossell MD, Van Tendeloo G, Chemistry of materials 18, 4075 (2006). http://doi.org/10.1021/cm0605668
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 46
DOI: 10.1021/cm0605668
|
“Klein tunneling in single and multiple barriers in graphene”. Pereira JM, Peeters FM, Chaves A, Farias GA, Semiconductor science and technology 25, 033002 (2010). http://doi.org/10.1088/0268-1242/25/3/033002
Abstract: We review the transmission properties of carriers interacting with potential barriers in graphene. The tunneling of electrons and holes in quantum structures in graphene is found to display features that are in marked contrast with those of other systems. In particular, the interaction between the carriers with electrostatic potential barriers can be related to the propagation of electromagnetic waves in media with negative refraction indices, also known as metamaterials. This behavior becomes evident as one calculates the time evolution of wavepackets propagating across the barrier interface. In addition, we discuss the effect of trigonal warping on the tunneling through potential barriers.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.305
Times cited: 83
DOI: 10.1088/0268-1242/25/3/033002
|
“Klein paradox for a pn junction in multilayer graphene”. Van Duppen B, Peeters FM, Europhysics letters 102, 27001 (2013). http://doi.org/10.1209/0295-5075/102/27001
Abstract: Charge carriers in single and multilayered graphene systems behave as chiral particles due to the particular lattice symmetry of the crystal. We show that the interplay between the meta-material properties of graphene multilayers and the pseudospinorial properties of the charge carriers result in the occurrence of Klein and anti-Klein tunneling for rhombohedral stacked multilayers. We derive an algebraic formula predicting the angles at which these phenomena occur and support this with numerical calculations for systems up to four layers. We present a decomposition of an arbitrarily stacked multilayer into pseudospin doublets that have the same properties as rhombohedral systems with a lower number of layers. Copyright (C) EPLA, 2013
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.957
Times cited: 17
DOI: 10.1209/0295-5075/102/27001
|
“KITE : high-performance accurate modelling of electronic structure and response functions of large molecules, disordered crystals and heterostructures”. Joao SM, Andelkovic M, Covaci L, Rappoport TG, Lopes JMVP, Ferreira A, Royal Society Open Science 7, 191809 (2020). http://doi.org/10.1098/RSOS.191809
Abstract: We present KITE, a general purpose open-source tight-binding software for accurate real-space simulations of electronic structure and quantum transport properties of large-scale molecular and condensed systems with tens of billions of atomic orbitals (N similar to 10(10)). KITE's core is written in C++, with a versatile Python-based interface, and is fully optimized for shared memory multi-node CPU architectures, thus scalable, efficient and fast. At the core of KITE is a seamless spectral expansion of lattice Green's functions, which enables large-scale calculations of generic target functions with uniform convergence and fine control over energy resolution. Several functionalities are demonstrated, ranging from simulations of local density of states and photo-emission spectroscopy of disordered materials to large-scale computations of optical conductivity tensors and real-space wave-packet propagation in the presence of magneto-static fields and spin-orbit coupling. On-the-fly calculations of real-space Green's functions are carried out with an efficient domain decomposition technique, allowing KITE to achieve nearly ideal linear scaling in its multi-threading performance. Crystalline defects and disorder, including vacancies, adsorbates and charged impurity centres, can be easily set up with KITE's intuitive interface, paving the way to user-friendly large-scale quantum simulations of equilibrium and non-equilibrium properties of molecules, disordered crystals and heterostructures subject to a variety of perturbations and external conditions.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.5
Times cited: 19
DOI: 10.1098/RSOS.191809
|
“Kink-antikink vortex transfer in periodic-plus-random pinning potential : theoretical analysis and numerical experiments”. Pogosov WV, Zhao HJ, Misko VR, Peeters FM, Physical review : B : condensed matter and materials physics 81 (2010). http://doi.org/10.1103/PhysRevB.81.024513
Abstract: The influence of random pinning on the vortex dynamics in a periodic square potential under an external drive is investigated. Using numerical experiments and theoretical approach, we found several dynamical regimes of vortex motion that are different from the ones for a regular pinning potential. Vortex transfer is controlled by kinks and antikinks, which either pre-exist in the system or appear spontaneously in pairs and then propagate. When kinks and antikinks collide, they annihilate. We provide clear physical interpretations of the observed features.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 10
DOI: 10.1103/PhysRevB.81.024513
|
“Kinetics of lifetime changes in bimetallic nanocatalysts revealed by quick X-ray absorption spectroscopy”. Filez M, Poelman H, Redekop EA, Galvita VV, Alexopoulos K, Meledina M, Ramachandran RK, Dendooven J, Detavernier C, Van Tendeloo G, Safonova OV, Nachtegaal M, Weckhuysen BM, Marin GB, Angewandte Chemie: international edition in English 57, 12430 (2018). http://doi.org/10.1002/ANIE.201806447
Abstract: Alloyed metal nanocatalysts are of environmental and economic importance in a plethora of chemical technologies. During the catalyst lifetime, supported alloy nanoparticles undergo dynamic changes which are well-recognized but still poorly understood. High-temperature O-2-H-2 redox cycling was applied to mimic the lifetime changes in model Pt13In9 nanocatalysts, while monitoring the induced changes by insitu quick X-ray absorption spectroscopy with one-second resolution. The different reaction steps involved in repeated Pt13In9 segregation-alloying are identified and kinetically characterized at the single-cycle level. Over longer time scales, sintering phenomena are substantiated and the intraparticle structure is revealed throughout the catalyst lifetime. The insitu time-resolved observation of the dynamic habits of alloyed nanoparticles and their kinetic description can impact catalysis and other fields involving (bi)metallic nanoalloys.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 11.994
Times cited: 4
DOI: 10.1002/ANIE.201806447
|
“Kinetics of iron(II) oxidation in seawater of various pH : reply”. Roekens EJ, Van Grieken RE, Marine chemistry 15, 281 (1984). http://doi.org/10.1016/0304-4203(84)90025-2
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0304-4203(84)90025-2
|
“Kinetics of iron(II) oxidation in seawater of various pH”. Roekens EJ, Van Grieken RE, Marine chemistry 13, 195 (1983). http://doi.org/10.1016/0304-4203(83)90014-2
Abstract: The rate of iron(II) oxidation in North Sea water of pH 5.510 in the range 1025°C has been studied. The oxygenation rate depends linearly on the iron(II) and dissolved oxygen concentrations. The second-order dependence on [OH−], found by several investigators for synthetic solutions, was confirmed in seawater, but only for pOH > 6.9. For pOH < 5.9 the rate appeared to be independent of the pOH. In the intermediate range, pOH 5.96.9, corresponding to the natural pH of seawater, a first-order dependence on the pOH is obeyed. The important discrepancy in the literature between the second-order rate constant for NaCHO3 solutions and for seawater can be attributed predominantly to the incorrect assumption of a second-order pOH dependence in natural seawater. The results can be useful, for example, in predicting the effect of dumping acidic iron waste from the titanium-dioxide industry into the ocean.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0304-4203(83)90014-2
|
“Kinetics of growth and lipids accumulation in Chlorella vulgaris during batch heterotrophic cultivation : effect of different nutrient limitation strategies”. Sakarika M, Kornaros M, Bioresource technology 243, 356 (2017). http://doi.org/10.1016/J.BIORTECH.2017.06.110
Abstract: The present study aimed at: (1) determining the effect of sulfur addition on biomass growth and (2) assessing the effect of sulfur, phosphorus and nitrogen limitation on lipid accumulation by C. vulgaris SAG 211-11b. The sulfur cellular content was more than two-fold higher under nitrogen and phosphorus limitation (0.52% and 0.54% w w(-1), respectively) compared to sulfur requirements (0.20% w w(-1)) under sulfur limiting conditions. The nitrogen needs are significantly lower (2.81-3.35% w w(-1)) when compared to other microalgae and become 23% lower under nitrogen or phosphorus limitation. The microalga exhibited substrate inhibition above 30 g L-1 initial glucose concentration. Sulfur limitation had the most significant effect on lipid accumulation, resulting in maximum total lipid content of 53.43 +/- 3.93% g g(DW)(1). In addition to enhancing lipid productivity, adopting the optimal nutrient limitation strategy can result in cost savings by avoiding unnecessary nutrient additions and eliminate the environmental burden due to wasted resources. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2017.06.110
|
“Kinetics of energy selective Cs encapsulation in single-walled carbon nanotubes for damage-free and position-selective doping”. Kato T, Neyts EC, Abiko Y, Akama T, Hatakeyama R, Kaneko T, The journal of physical chemistry: C : nanomaterials and interfaces 119, 11903 (2015). http://doi.org/10.1021/acs.jpcc.5b00300
Abstract: A method has been developed for damage-free cesium (Cs) encapsulation within single-walled carbon nanotubes (SWNTs) with fine position selectivity. Precise energy tuning of Cs-ion irradiation revealed that there is a clear energy window (2060 eV) for the efficient encapsulation of Cs through the hexagonal network of SWNT sidewalls without causing significant damage. This minimum energy threshold of Cs-ion encapsulation (∼20 eV) matches well with the value obtained by ab initio simulation (∼22 eV). Furthermore, position-selective Cs encapsulation was carried out, resulting in the successful formation of pn-junction SWNT thin films with excellent environmental stability.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 3
DOI: 10.1021/acs.jpcc.5b00300
|
“Kinetics of dechlorination by Dehalococcoides mccartyi using different carbon sources”. Schneidewind U, Haest PJ, Atashgahi S, Seuntjens P, et al, Journal of contaminant hydrology 157, 25 (2014). http://doi.org/10.1016/J.JCONHYD.2013.10.006
Abstract: Stimulated anaerobic dechlorination is generally considered a valuable step for the remediation of aquifers polluted with chlorinated ethenes (CEs). Correct simulation and prediction of this process in situ, however, require good knowledge of the associated biological reactions. The aim of this study was to evaluate the dechlorination reaction in an aquifer contaminated with trichloroethene (TCE) and its daughter products, discharging into the Zenne River. Different carbon sources were used in batch cultures and these were related to the dechlorination reaction, together with the monitored biomarkers. Appropriate kinetic formulations were assessed. Reductive dechlorination of TCE took place only when external carbon sources were added to microcosms, and occurred concomitant with a pronounced increase in the Dehalococcoides mccartyi cell count as determined by 16S rRNA gene-targeted qPCR. This indicates that native dechlorinating bacteria are present in the aquifer of the Zenne site and that the oligotrophic nature of the aquifer prevents a complete degradation to ethene. The type of carbon source, the cell number of D. mccartyi or the reductive dehalogenase genes, however, did not unequivocally explain the observed differences in degradation rates or the extent of dechlorination. Neither first-order, Michaelis-Menten nor Monod kinetics could perfectly simulate the dechlorination reactions in TCE spiked microcosms. A sensitivity analysis indicated that the inclusion of donor limitation would not significantly enhance the simulations without a clear process understanding. Results point to the role of the supporting microbial community but it remains to be verified how the complexity of the microbial (inter)actions should be represented in a model framework. (C) 2013 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.JCONHYD.2013.10.006
|
“Kinetic simulation of direct-current driven microdischarges in argon at atmospheric pressure”. Zhang Y, Jiang W, Bogaerts A, Journal of physics: D: applied physics 47, 435201 (2014). http://doi.org/10.1088/0022-3727/47/43/435201
Abstract: A one-dimensional, implicit particle-in-cell Monte Carlo collision model is used to simulate the plasma kinetic properties at a steady state in a parallel-plate direct current argon glow microdischarge under various operating conditions, such as driving voltage (301000 V) and gap size (101000 µm) at atmospheric pressure. First, a comparison between rf and dc modes is shown for the same pressure, driving voltage and gap spacing. Furthermore, the effect of gap size scaling (in the range of 101000 µm) on the breakdown voltage, peak electron density and peak electron current density at the breakdown voltage is examined. The breakdown voltage is lower than 150 V in all gaps considered. The microdischarge is found to have a neutral bulk plasma region and a cathode sheath region with size varying with the applied voltage and the discharge gap. In our calculations, the electron and ion densities are of the order of 10181023 m−3, which is in the glow discharge limit, as the ionization degree is lower than 1% . The electron energy distribution function shows a two-energy group distribution at a gap of 10 µm and a three-energy group distribution at larger gaps such as 200 µm and 1000 µm, emphasizing the importance of the gap spacing in dc microdischarges.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 10
DOI: 10.1088/0022-3727/47/43/435201
|