“Optical absorption window in Na₃Bi based three-dimensional Dirac electronic system”. Li QN, Xu W, Xiao YM, Ding L, Van Duppen B, Peeters FM, Journal Of Applied Physics 128, 155707 (2020). http://doi.org/10.1063/5.0022669
Abstract: We present a detailed theoretical study of the optoelectronic properties of a Na3Bi based three-dimensional Dirac electronic system (3DDES). The optical conductivity is evaluated using the energy-balance equation derived from a Boltzmann equation, where the electron Hamiltonian is taken from a simplified k . p approach. We find that for short-wavelength irradiation, the optical absorption in Na3Bi is mainly due to inter-band electronic transitions. In contrast to the universal optical conductance observed for graphene, the optical conductivity for Na3Bi based 3DDES depends on the radiation frequency but not on temperature, carrier density, and electronic relaxation time. In the radiation wavelength regime of about 5 mu m, < lambda < 200 mu m, an optical absorption window is found. This is similar to what is observed in graphene. The position and width of the absorption window depend on the direction of the light polarization and sensitively on temperature, carrier density, and electronic relaxation time. Particularly, we demonstrate that the inter-band optical absorption channel can be switched on and off by applying the gate voltage. This implies that similar to graphene, Na3Bi based 3DDES can also be applied in infrared electro-optical modulators. Our theoretical findings are helpful in gaining an in-depth understanding of the basic optoelectronic properties of recently discovered 3DDESs.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.2
Times cited: 1
DOI: 10.1063/5.0022669
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“Methane to Methanol through Heterogeneous Catalysis and Plasma Catalysis”. Li S, Ahmed R, Yi Y, Bogaerts A, Catalysts 11, 590 (2021). http://doi.org/10.3390/catal11050590
Abstract: Direct oxidation of methane to methanol (DOMTM) is attractive for the increasing industrial demand of feedstock. In this review, the latest advances in heterogeneous catalysis and plasma catalysis for DOMTM are summarized, with the aim to pinpoint the differences between both, and to provide some insights into their reaction mechanisms, as well as the implications for future development of highly selective catalysts for DOMTM.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.082
DOI: 10.3390/catal11050590
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“Editorial: Special issue on CO2 utilization with plasma technology”. Li S, Liu C, Bogaerts A, Gallucci F, Journal Of Co2 Utilization 61, 102017 (2022). http://doi.org/10.1016/j.jcou.2022.102017
Abstract: Plasma technology has advanced significantly in recent years, with application ranging from chemical conversion, to surface treatment, material development and several other fields. Special attention has been paid to the development of possible novel approaches for the conversion of chemicals in a more sustainable way. Plasma technology offers advantages over thermochemical routes such as high process versatility, mild reaction condition, one-step synthesis, fast reaction and instant control. More importantly, it can be easily combined with electricity generated from various renewable sources and is suitable for energy storage via the conversion of intermittent renewable energy into carbon-neutral fuels or other chemicals. In recent years, there has been a growing interest in the development of plasma technology for CO2 utilization. Investigation on different reactions such as CO2 splitting, dry reforming of methane (DRM) and CO2 hydrogenation with different types of plasma reactors and catalysts have been reported by researchers worldwide. Although technological maturity still needs to be increased, the potential of plasma has been well-recognized by the scientific community and industry. More research output in the future is expected as a result of intensive research activities and various kinds of investment. In this context, we present this special issue on CO2 utilization with plasma technology, which collects 22 articles, covering topics in related areas such as plasma reactor design, plasma catalysis, plasmamaterial interaction, modeling and new ideas for possible applications.
Keywords: Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2022.102017
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“Plasma-Assisted Dry Reforming of CH4: How Small Amounts of O2Addition Can Drastically Enhance the Oxygenate Production─Experiments and Insights from Plasma Chemical Kinetics Modeling”. Li S, Sun J, Gorbanev Y, van’t Veer K, Loenders B, Yi Y, Kenis T, Chen Q, Bogaerts A, ACS Sustainable Chemistry &, Engineering 11, 15373 (2023). http://doi.org/10.1021/acssuschemeng.3c04352
Abstract: Plasma-based dry reforming of methane (DRM) into
high-value-added oxygenates is an appealing approach to enable
otherwise thermodynamically unfavorable chemical reactions at
ambient pressure and near room temperature. However, it suffers
from coke deposition due to the deep decomposition of CH4. In this
work, we assess the DRM performance upon O2 addition, as well as
varying temperature, CO2/CH4 ratio, discharge power, and gas
residence time, for optimizing oxygenate production. By adding O2,
the main products can be shifted from syngas (CO + H2) toward
oxygenates. Chemical kinetics modeling shows that the improved
oxygenate production is due to the increased concentration of
oxygen-containing radicals, e.g., O, OH, and HO2, formed by electron
impact dissociation [e + O2 → e + O + O/O(1D)] and subsequent
reactions with H atoms. Our study reveals the crucial role of oxygen-coupling in DRM aimed at oxygenates, providing practical
solutions to suppress carbon deposition and at the same time enhance the oxygenates production in plasma-assisted DRM.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 8.4
DOI: 10.1021/acssuschemeng.3c04352
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“Microscale profiling of photosynthesis-related variables in a highly productive biofilm photobioreactor”. Li T, Piltz B, Podola B, Dron A, de Beer D, Melkonian M, Biotechnology and bioengineering 113, 1046 (2016). http://doi.org/10.1002/BIT.25867
Abstract: In the present study depth profiles of light, oxygen, pH and photosynthetic performance in an artificial biofilm of the green alga Halochlorella rubescens in a porous substrate photobioreactor (PSBR) were recorded with microsensors. Biofilms were exposed to different light intensities (50-1,000mol photons m(-2) s(-1)) and CO2 levels (0.04-5% v/v in air). The distribution of photosynthetically active radiation showed almost identical trends for different surface irradiances, namely: a relatively fast drop to a depth of about 250 mu m, (to 5% of the incident), followed by a slower decrease. Light penetrated into the biofilm deeper than the Lambert-Beer Law predicted, which may be attributed to forward scattering of light, thus improving the overall light availability. Oxygen concentration profiles showed maxima at a depth between 50 and 150m, depending on the incident light intensity. A very fast gas exchange was observed at the biofilm surface. The highest oxygen concentration of 3.2mM was measured with 1,000mol photons m(-2) s(-1) and 5% supplementary CO2. Photosynthetic productivity increased with light intensity and/or CO2 concentration and was always highest at the biofilm surface; the stimulating effect of elevated CO2 concentration in the gas phase on photosynthesis was enhanced by higher light intensities. The dissolved inorganic carbon concentration profiles suggest that the availability of the dissolved free CO2 has the strongest impact on photosynthetic productivity. The results suggest that dark respiration could explain previously observed decrease in growth rate over cultivation time in this type of PSBR. Our results represent a basis for understanding the complex dynamics of environmental variables and metabolic processes in artificial phototrophic biofilms exposed to a gas phase and can be used to improve the design and operational parameters of PSBRs. Biotechnol. Bioeng. 2016;113: 1046-1055. (c) 2015 Wiley Periodicals, Inc.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1002/BIT.25867
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“Nano-single crystal coalesced PtCu nanospheres as robust bifunctional catalyst for hydrogen evolution and oxygen reduction reactions”. Li W, Hu Z-Y, Zhang Z, Wei P, Zhang J, Pu Z, Zhu J, He D, Mu S, Van Tendeloo G, Journal of catalysis 375, 164 (2019). http://doi.org/10.1016/J.JCAT.2019.05.031
Abstract: Because of high electrocatalytic activity, Pt based metal nanospheres (NSs) have attracted a lot of attention. Hence, multi-particle nano-single crystal coalesced PtCu NSs are designed and successfully synthesized by a cost-effective aqueous solution method. The formed PtCu NS catalyst exhibits a superior hydrogen evolution reaction (HER) electrocatalytic activity with an ultralow onset potential of 18 mV at the current density of 2 mA/cm(2) and high mass activity of 1.08 A/mg(pt) (7.2 times higher than that of commercial Pt/C catalysts). Also, it shows an enhancement of 3.2 and 2.7 times in the mass and specific activities toward oxygen reduction reaction (ORR) compared to that of Pt/C. Moreover, it possesses an excellent catalytic durability for both ORR and HER. Even after 10,000 cycles, its ORR mass activity retains 87% of its initial value. The density functional theory (DFT) calculations demonstrate that by introducing Cu atoms into the Pt lattice, a downshift of the D-band center and favorable hydrogen adsorption free energy of approaching to zero (Delta G) occur, indicating the increased electrocatalytic activity of Pt electrocatalysts. (C) 2019 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 25
DOI: 10.1016/J.JCAT.2019.05.031
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“Shape control beyond the seeds in gold nanoparticles”. Li W, Tong W, Yadav A, Bladt E, Bals S, Funston AM, Etheridge J, Chemistry Of Materials 33, 9152 (2021). http://doi.org/10.1021/ACS.CHEMMATER.1C02459
Abstract: In typical seed-mediated syntheses of metal nanocrystals, the shape of the nanocrystal is determined largely by the seed nucleation environment and subsequent growth environment (where “environment” refers to the chemical environment, including the surfactant and additives). In this approach, crystallinity is typically determined by the seeds, and surfaces are controlled by the environment(s). However, surface energies, and crystallinity, are both influenced by the choice of environment(s). This limits the permutations of crystallinity and surface facets that can be mixed and matched to generate new nanocrystal morphologies. Here, we control post-seed growth to deliberately incorporate twin planes during the growth stage to deliver new final morphologies, including twinned cubes and bipyramids from single-crystal seeds. The nature and number of twin planes, together with surfactant control of facet growth, define the final nanoparticle morphology. Moreover, by breaking symmetry, the twin planes introduce new facet orientations. This additional mechanism opens new routes for the synthesis of different morphologies and facet orientations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 3
DOI: 10.1021/ACS.CHEMMATER.1C02459
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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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“The Hall effect of an inhomogeneous magnetic field in mesoscopic structures”. Li XQ, Peeters FM, Geim AK, Journal of physics : condensed matter 9, 8065 (1997)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 8
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“An elliptical blade is not a true ellipse, but a superellipse : evidence from two Michelia species”. Li Y, Niklas KJ, Gielis J, Niinemets Ü, Schrader J, Wang R, Shi P, Journal of forestry research 33, 1341 (2022). http://doi.org/10.1007/S11676-021-01385-X
Abstract: The shape of leaf laminae exhibits considerable diversity and complexity that reflects adaptations to environmental factors such as ambient light and precipitation as well as phyletic legacy. Many leaves appear to be elliptical which may represent a ‘default’ developmental condition. However, whether their geometry truly conforms to the ellipse equation (EE), i.e., (x/a)2 + (y/b)2 = 1, remains conjectural. One alternative is described by the superellipse equation (SE), a generalized version of EE, i.e., |x/a|n +|y/b|n = 1. To test the efficacy of EE versus SE to describe leaf geometry, the leaf shapes of two Michelia species (i.e., M. cavaleriei var. platypetala, and M. maudiae), were investigated using 60 leaves from each species. Analysis shows that the majority of leaves (118 out of 120) had adjusted root-mean-square errors of < 0.05 for the nonlinear fitting of SE to leaf geometry, i.e., the mean absolute deviation from the polar point to leaf marginal points was smaller than 5% of the radius of a hypothesized circle with its area equaling leaf area. The estimates of n for the two species were ˂ 2, indicating that all sampled leaves conformed to SE and not to EE. This study confirms the existence of SE in leaves, linking this to its potential functional advantages, particularly the possible influence of leaf shape on hydraulic conductance.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3
DOI: 10.1007/S11676-021-01385-X
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“Evidence that supertriangles exist in nature from the vertical projections of Koelreuteria paniculata fruit”. Li Y, Quinn BK, Gielis J, Li Y, Shi P, Symmetry 14, 23 (2022). http://doi.org/10.3390/SYM14010023
Abstract: Many natural radial symmetrical shapes (e.g., sea stars) follow the Gielis equation (GE) or its twin equation (TGE). A supertriangle (three triangles arranged around a central polygon) represents such a shape, but no study has tested whether natural shapes can be represented as/are supertriangles or whether the GE or TGE can describe their shape. We collected 100 pieces of Koelreuteria paniculata fruit, which have a supertriangular shape, extracted the boundary coordinates for their vertical projections, and then fitted them with the GE and TGE. The adjusted root mean square errors (RMSEadj) of the two equations were always less than 0.08, and >70% were less than 0.05. For 57/100 fruit projections, the GE had a lower RMSEadj than the TGE, although overall differences in the goodness of fit were non-significant. However, the TGE produces more symmetrical shapes than the GE as the two parameters controlling the extent of symmetry in it are approximately equal. This work demonstrates that natural supertriangles exist, validates the use of the GE and TGE to model their shapes, and suggests that different complex radially symmetrical shapes can be generated by the same equation, implying that different types of biological symmetry may result from the same biophysical mechanisms.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.7
DOI: 10.3390/SYM14010023
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“Ellipticalness index : a simple measure of the complexity of oval leaf shape”. Li Y, Quinn BK, Niinemets Ü, Schrader J, Gielis J, Liu M, Shi P, Pakistan journal of botany : An official publication of pakistan botanical society 54, 1 (2022). http://doi.org/10.30848/PJB2022-6(44)
Abstract: Plants have diverse leaf shapes that have evolved to adapt to the environments they have experienced over their evolutionary history. Leaf shape and leaf size can greatly influence the growth rate, competitive ability, and productivity of plants. However, researchers have long struggled to decide how to properly quantify the complexity of leaf shape. Prior studies recommended the leaf roundness index (RI = 4πA/P2) or dissection index (DI = ), where P is leaf perimeter and A is leaf area. However, these two indices merely measure the extent of the deviation of leaf shape from a circle, which is usually invalid as leaves are seldom circular. In this study, we proposed a simple measure, named the ellipticalness index (EI), for quantifying the complexity of leaf shape based on the hypothesis that the shape of any oval leaf can be regarded as a variation from a standard ellipse. 2220 leaves from nine species of Magnoliaceae were sampled to check the validity of the EI. We also tested the validity of the Montgomery equation (ME), which assumes a proportional relationship between leaf area and the product of leaf length and width, because the EI actually comes from the proportionality coefficient of the ME. We also compared the ME with five other models of leaf area. The ME was found to be the best model for calculating leaf area based on consideration of the trade-off between model fit vs. complexity, which strongly supported the robustness of the EI for describing oval leaf shape. The new index can account for both leaf shape and size, and we conclude that it is a promising method for quantifying and comparing oval leaf shapes across species in future studies.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.2
DOI: 10.30848/PJB2022-6(44)
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“Insight into the growth of multiple branched MnOOH nanorods”. Li Y, Tan H, Lebedev O, Verbeeck J, Biermans E, Van Tendeloo G, Su B-L, Crystal growth &, design 10, 2969 (2010). http://doi.org/10.1021/cg100009k
Abstract: Multiple branched manganese oxide hydroxide (MnOOH) nanorods prepared by a hydrothermal process were extensively studied by transmission electron microscopy (TEM). A model of the branch formation is proposed together with a study of the interface structure. The sword-like tip plays a crucial role for the nanorods to form different shapes. Importantly, the branching occurs at an angle of around either 57 degrees or 123 degrees. Specifically, a (111) twin plane can only be formed at the interface with a 123 degrees angle. The interfaces formed with a 57 degrees angle usually contain edge dislocations. Electron energy loss spectroscopy (EELS) demonstrates that the whole crystal has a uniform chemical composition. Interestingly, an epitaxial growth of Mn3O4 at the radial surface was also observed under electron beam irradiation; this is because of the rough purification of the products. The proposed mechanism is expected to shed light on the branched/dendrite nanostructure growth and to provide opportunities for further novel nanomaterial structure growth and design.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 41
DOI: 10.1021/cg100009k
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“Well shaped Mn3O4 nano-octahedra with anomalous magnetic behavior and enhanced photodecomposition properties”. Li Y, Tan H, Yang X-Y, Goris B, Verbeeck J, Bals S, Colson P, Cloots R, Van Tendeloo G, Su B-L, Small 7, 475 (2011). http://doi.org/10.1002/smll.201001403
Abstract: Very uniform and well shaped Mn3O4 nano-octahedra are synthesized using a simple hydrothermal method under the help of polyethylene glycol (PEG200) as a reductant and shape-directing agent. The nano-octahedra formation mechanism is monitored. The shape and crystal orientation of the nanoparticles is reconstructed by scanning electron microscopy and electron tomography, which reveals that the nano-octahedra only selectively expose {101} facets at the external surfaces. The magnetic testing demonstrates that the Mn3O4 nano-octahedra exhibit anomalous magnetic properties: the Mn3O4 nano-octahedra around 150 nm show a similar Curie temperature and blocking temperature to Mn3O4 nanoparticles with 10 nm size because of the vertical axis of [001] plane and the exposed {101} facets. With these Mn3O4 nano-octahedra as a catalyst, the photodecomposition of rhodamine B is evaluated and it is found that the photodecomposition activity of Mn3O4 nano-octahedra is much superior to that of commercial Mn3O4 powders. The anomalous magnetic properties and high superior photodecomposition activity of well shaped Mn3O4 nano-octahedra should be related to the special shape of the nanoparticles and the abundantly exposed {101} facets at the external surfaces. Therefore, the shape preference can largely broaden the application of the Mn3O4 nano-octahedra.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.643
Times cited: 131
DOI: 10.1002/smll.201001403
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“Ultralong Cu(OH)(2) and CuO nanowire bundles: PEG200-directed crystal growth for enhanced photocatalytic performance”. Li Y, Yang X-Y, Rooke J, Van Tendeloo G, Su B-L, Journal of colloid and interface science 348, 303 (2010). http://doi.org/10.1016/j.jcis.2010.04.052
Abstract: Ultralong Cu(OH)(2) and CuO nanowire bundles with lengths ranging from tens to hundreds of micrometers have been selectively synthesized on a large scale by a facile solution-phase method, using PEG200 as growth-directing agent. The growth mechanisms were investigated by monitoring the nanowire evolution process. The results showed that under the action of PEG200 molecules, the Cu(OH)(2) and CuO nanowires were first formed through oriented attachment of colloidal particles, then through side self-assembly leading to nanowire bundles, and finally to CuO nanoleaves. PEG200 plays a critical role in the synthesis of nanowires as it not only prevents the random aggregation of colloidal particles toward CuO nanoleaves but also helps to orientate nanowire growth by the coalescence and alignment in one direction of the colloidal particles. The concentration of OH(-) in the reaction system is also important for nanowire growth. In the absence of PEG200, nanoleaves are formed by an Ostwald ripening process. The band-gap value estimated from a UV-Vis absorption spectrum of CuO nanowire bundles is 2.32 eV. The photodegradation of a model pollutant, rhodamine B, by CuO nanowires and nanoleaves was compared with commercial nanopowders, showing that the as-synthesized ultralong CuO polycrystalline nanowire bundles have an enhanced photocatalytic activity with 87% decomposition of rhodamine B after an 8-h reaction, which was much higher than that of single-crystal nanoleaves (61%) and commercial nanopowders (32%). The origin of the high photocatalytic activity of these new polycrystalline CuO nanowire bundles has been discussed. This present work reveals that the (0 0 2) crystallographic surface is more favorable for photocatalytic decomposition of organic compounds and that these ultralong CuO nanowire bundles are potential candidates for photocatalysts in wastewater treatment. (C) 2010 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.233
Times cited: 70
DOI: 10.1016/j.jcis.2010.04.052
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“Chemistry of trimethyl aluminum: a spontaneous route to thermally stable 3D crystalline macroporous alumina foams with a hierarchy of pore sizes”. Li Y, Yang X-Y, Tian G, Vantomme A, Yu J, Van Tendeloo G, Su B-L, Chemistry of materials 22, 3251 (2010). http://doi.org/10.1021/cm100491r
Abstract: A simple and spontaneous one-pot self-formation procedure that is easy to scale up has been developed based on the chemistry of trimethylaluminum (TMA), leading to thermally stable macroporous crystalline alumina with a very unique and unprecedented three-dimensional (3D) hierarchical pore structure consisting of well-defined wormlike mesopores. TMA is the precursor of both product and porogene (viz, two working functions within the same molecule (2 in 1)). The materials obtained have been intensively characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), N2 adsorption−desorption, and mercury porosimetry. The open cagelike macrocavities are self-constructed by mesoporous nanorods (diameter of ca. 40−70 nm), which are themselves formed by a random assembly of fibrous nanoparticles 5−6 nm in size. Optical microscopy (OM) has been used in situ to follow the synthesis procedure, which led to the proposal of the formation mechanism. Methane molecules as porogens, which were instantaneously released because of the fast hydrolysis of the chemical precursor, were the key factor in producing these 3D structures with uniform co-continuous macropores that interconnected directly with the wormlike mesopores. The important characteristic of this procedure is the concurrent formation of a multiscaled porous network. The material exhibits great thermal stability. The hierarchically mesoporous−macroporous Al2O3 obtained is quite attractive for a myriad of applications, from catalysis to biomedicine. The present work illustrates that the one-pot self-formation concept, based on the chemistry of alkyl metals, is a versatile method to design industrially valuable hierarchically porous materials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 38
DOI: 10.1021/cm100491r
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“Behavior of Ni-doped MgMoO4 single-phase catalysts for synthesis of multiwalled carbon nanotube bundles”. Li Y, Zhang X, Geise HJ, Van Tendeloo G, Chemical vapor deposition 13, 30 (2007). http://doi.org/10.1002/cvde.200606531
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.333
Times cited: 4
DOI: 10.1002/cvde.200606531
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“Controlling the diameters in large-scale synthesis of single-walled carbon nanotubes by catalytic decomposition of CH4”. Li Y, Zhang X, Shen L, Luo J, Tao X, Liu F, Xu G, Wang Y, Geise HJ, Van Tendeloo G, Chemical physics letters 398, 276 (2004). http://doi.org/10.1016/j.cplett.2004.09.068
Abstract: High-quality single-walled carbon nanotubes (SWNTs) are synthesized in gram amount on Fe-Mo/MgO catalysts by catalytic decomposition of CH4 in H-2 or N-2. Raman data reveal that the as-prepared SATNTs have a diameter of about 0.74-1.29 nm. It is found that the diameter of the as-prepared SWNTs can be controlled mainly by adjusting the molar ratio of Fe-Mo versus the MgO support. Several other factors that potentially influence the growth of SWNTs have been studied in detail. The experimental results show that the nature of the catalyst determines the diameter of the as-prepared SWNTs. (C) 2004 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.815
Times cited: 45
DOI: 10.1016/j.cplett.2004.09.068
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Li Y, Zhang XB, Tao XY, Xu JM, Chen F, Shen LH, Yang XF, Liu F, Van Tendeloo G, Geise HJ (2005) Single phase MgMoO4 as catalyst for the synthesis of bundled multi-wall carbon nanotubes by CVD. Oxford, 1325–1328
Keywords: L1 Letter to the editor; Electron microscopy for materials research (EMAT)
Impact Factor: 6.337
Times cited: 23
DOI: 10.1016/j.carbon.2004.12.022
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“Impact of spin-orbit coupling on the Holstein polaron”. Li Z, Covaci L, Berciu M, Baillie D, Marsiglio F, Physical review : B : condensed matter and materials physics 83, 195104 (2011). http://doi.org/10.1103/PhysRevB.83.195104
Abstract: We utilize an exact variational numerical procedure to calculate the ground state properties of a polaron in the presence of a Rashba-like spin-orbit interaction. Our results corroborate previous work performed with the momentum average approximation and with weak-coupling perturbation theory. We find that spin-orbit coupling increases the effective mass in the regime with weak electron-phonon coupling, and decreases the effective mass in the regimes of intermediate and strong electron-phonon coupling. Analytical strong-coupling perturbation theory results confirm our numerical results in the small-polaron regime. A large amount of spin-orbit coupling can lead to a significant lowering of the polaron effective mass.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 9
DOI: 10.1103/PhysRevB.83.195104
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“Impact of Dresselhaus versus Rashba spin-orbit coupling on the Holstein polaron”. Li Z, Covaci L, Marsiglio F, Physical review : B : condensed matter and materials physics 85, 205112 (2012). http://doi.org/10.1103/PhysRevB.85.205112
Abstract: We utilize an exact variational numerical procedure to calculate the ground-state properties of a polaron in the presence of Rashba and linear Dresselhaus spin-orbit coupling. We find that when the linear Dresselhaus spin-orbit coupling approaches the Rashba spin-orbit coupling, the Van Hove singularity in the density of states will be shifted away from the bottom of the band and finally disappear when the two spin-orbit couplings are tuned to be equal. The effective mass will be suppressed; the trend will become more significant for low phonon frequency. The presence of two dominant spin-orbit couplings will make it possible to tune the effective mass with more varied observables.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PhysRevB.85.205112
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“Interplay of doping and structural modulation in superconducting Bi2Sr2-xLaxCuO6+\delta thin films”. Li ZZ, Raffy H, Bals S, Van Tendeloo G, Megtert S, Physical review : B : condensed matter and materials physics 71, 174503 (2005). http://doi.org/10.1103/PhysRevB.71.174503
Abstract: We have studied the evolution of the structural modulation in epitaxial, c-axis-oriented, Bi2Sr2-xLaCuO6+delta thin films when varying the La content x and for a given x as a function of oxygen content. A series of thin films with 0 <= x <= 0.8 has been prepared in situ by rf-magnetron sputtering and characterized by R(T) measurements, Rutherford backscattering spectroscopy, transmission electron microscopy, and x-ray diffraction techniques. The oxygen content of each individual film was varied by thermal annealing across the phase diagram. The evolution of the structural modulation has been thoroughly studied by x-ray diffraction in determining the variation of the amplitude of satellite reflections in special two axes 2 theta/theta-theta scans (reciprocal space scans). It is shown that the amplitude of the modulation along the c axis decreases strongly when x increases from 0 to 0.2. It is demonstrated that this variation is essentially governed by La content x and that changing the oxygen content by thermal treatments has a much lower influence, even becoming negligible for x > 0.2. Such study is important to understand the electronical properties of Bi2Sr2-xLaxCuO6+gamma thin films.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 11
DOI: 10.1103/PhysRevB.71.174503
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“CoFe nanodumbbells : synthesis, structure, and magnetic properties”. Liakakos N, Gatel C, Blon T, Altantzis T, Lentijo-Mozo S, Garcia-Marcelot C, Lacroix LM, Respaud M, Bals S, Van Tendeloo G, Soulantica K, Nano letters 14, 2747 (2014). http://doi.org/10.1021/nl500734k
Abstract: We report the solution phase synthesis, the structural analysis, and the magnetic properties of hybrid nanostructures combining two magnetic metals. These nano-objects are characterized by a remarkable shape, combining Fe nanocubes on Co nanorods. The topological composition, the orientation relationship, and the growth steps have been studied by advanced electron microscopy techniques, such as HRTEM, electron tomography, and state-of-the-art 3-dimensional elemental mapping by EDX tomography. The soft iron nanocubes behave as easy nucleation centers that induce the magnetization reversal of the entire nanohybrid, leading to a drastic modification of the overall effective magnetic anisotropy.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.712
Times cited: 27
DOI: 10.1021/nl500734k
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“A generalized performance equation and its application in measuring the Gini index of leaf size inequality”. Lian M, Shi P, Zhang L, Yao W, Gielis J, Niklas KJ, Trees: structure and function 37, 1555 (2023). http://doi.org/10.1007/S00468-023-02448-8
Abstract: The goal of this study is to provide a rigorous tool to quantify the inequality of the leaf size distribution of an individual plant, thereby serving as a reference trait for quantifying plant adaptations to local environmental conditions. The tool to be presented and tested employs three components: (1) a performance equation (PE), which can produce flexible asymmetrical and symmetrical bell-shaped curves, (2) the Lorenz curve (i.e., the cumulative proportion of leaf size vs. the cumulative proportion of number of leaves), which is the basis for calculating, and (3) the Gini index, which measures the inequality of leaf size distribution. We sampled 12 individual plants of a dwarf bamboo and measured the area and dry mass of each leaf of each plant. We then developed a generalized performance equation (GPE) of which the PE is a special case and fitted the Lorenz curve to leaf size distribution using the GPE and PE. The GPE performed better than the PE in fitting the Lorenz curve. We compared the Gini index of leaf area distribution with that of leaf dry mass distribution and found that there was a significant difference between the two indices that might emerge from the scaling relationship between leaf dry mass and area. Nevertheless, there was a strong correlation between the two Gini indices (r2 = 0.9846). This study provides a promising tool based on the GPE for quantifying the inequality of leaf size distributions across individual plants and can be used to quantify plant adaptations to local environmental conditions.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.3
DOI: 10.1007/S00468-023-02448-8
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“TEM observation of aggregation steps in room-temperature silicalite-1 zeolite formation”. Liang D, Follens LRA, Aerts A, Martens JA, Van Tendeloo G, Kirschhock CEA, Journal of physical chemistry C 111, 14283 (2007). http://doi.org/10.1021/jp074960k
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
Times cited: 41
DOI: 10.1021/jp074960k
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“Phase-transformation-induced giant deformation in thermoelectric Ag₂Se semiconductor”. Liang Q, Yang D, Xia F, Bai H, Peng H, Yu R, Yan Y, He D, Cao S, Van Tendeloo G, Li G, Zhang Q, Tang X, Wu J, Advanced Functional Materials , 2106938 (2021). http://doi.org/10.1002/ADFM.202106938
Abstract: In most semiconducting metal chalcogenides, a large deformation is usually accompanied by a phase transformation, while the deformation mechanism remains largely unexplored. Herein, a phase-transformation-induced deformation in Ag2Se is investigated by in situ transmission electron microscopy, and a new ordered high-temperature phase (named as alpha '-Ag2Se) is identified. The Se-Se bonds are folded when the Ag+-ion vacancies are ordered and become stretched when these vacancies are disordered. Such a stretch/fold of the Se-Se bonds enables a fast and large deformation occurring during the phase transition. Meanwhile, the different Se-Se bonding states in alpha-, alpha '-, beta-Ag2Se phases lead to the formation of a large number of nanoslabs and the high concentration of dislocations at the interface, which flexibly accommodate the strain caused by the phase transformation. This study reveals the atomic mechanism of the deformation in Ag2Se inorganic semiconductors during the phase transition, which also provides inspiration for understanding the phase transition process in other functional materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.124
DOI: 10.1002/ADFM.202106938
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“Investigation of voltage effect on reaction mechanisms in capacitively coupled N-2 discharges”. Liang Y-S, Liu Y-X, Zhang Y-R, Wang Y-N, Journal Of Applied Physics 127, 133301 (2020). http://doi.org/10.1063/1.5143821
Abstract: A systematic investigation of voltage effect on the plasma parameters, especially the species densities and chemical reaction mechanisms, in the capacitive N-2 discharges is performed by employing a two-dimensional self-consistent fluid model. The validity of the numerical model is first demonstrated by the qualitative agreement of the calculated and experimental results. Then, the densities, production mechanisms, and loss mechanisms of species from simulation are examined at various voltages. It is found that all the species densities increase monotonically with the voltage, whereas their spatial profiles at lower voltages are quite different from those at higher voltages. The electrons and Nthorn 2 ions are mainly generated by the electron impact ionization of N-2 gas, while the Nthorn ions, whose density is one or two orders of magnitude lower, are mostly formed by the ionization of N atoms. The electron impact dissociation of N-2 gas dominates the generation of N atoms, which are mostly destroyed for the Nthorn ion production. As for the excited N-2 levels, the level conversion processes play a very important role in their production and depletion mechanisms, except for the electron impact excitation of the ground state N-2 molecules. Published under license by AIP Publishing.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.2
DOI: 10.1063/1.5143821
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“Investigation of active species in low-pressure capacitively coupled N-2/Ar plasmas”. Liang Y-S, Xue C, Zhang Y-R, Wang Y-N, Physics Of Plasmas 28, 013510 (2021). http://doi.org/10.1063/5.0031120
Abstract: In this paper, a self-consistent fluid model is developed focusing on the plasma parameters in capacitively coupled 20% N 2-80% Ar discharges. Measurements of ion density are performed with the help of a floating double probe, and the emission intensities from Ar(4p) and N 2 ( B ) transitions are detected by an optical emission spectroscopy to estimate their relative densities. The consistency between the numerical and experimental results confirms the reliability of the simulation. Then the plasma characteristics, specifically the reaction mechanisms of active species, are analyzed under various voltages. The increasing voltage leads to a monotonous increase in species density, whereas a less homogeneous radial distribution is observed at a higher voltage. Due to the high concentration of Ar gas, Ar + becomes the main ion, followed by the N 2 +</mml:msubsup> ion. Besides the electron impact ionization of neutrals, the charge transfer processes of Ar +/ N 2 and N 2 +</mml:msubsup>/Ar are found to have an impact on the ionic species. The results indicate that adopting the lower charge transfer reaction rate coefficients weakens the Ar + ion density and yields a higher N 2 +</mml:msubsup> ion density. However, the effect on the species spatial distributions and other species densities is limited. As for the excited-state species, the electron impact excitation of background gases remains overwhelming in the formation of Ar(4p), N 2 ( B ), and N 2 ( a ' ), whereas the <mml:msub> N 2 ( A ) molecules are mainly formed by the decay of <mml:msub> N 2 ( B ). In addition, the dissociation of <mml:msub> N 2 collided by excited-state Ar atoms dominates the N generation, which are mostly depleted to produce N + ions.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.115
DOI: 10.1063/5.0031120
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“Disproportionation of Co2+ in the topochemically reduced oxide LaSrCoRuO₅”. Liang Z, Batuk M, Orlandi F, Manuel P, Hadermann J, Hayward MA, Angewandte Chemie: international edition in English 63, e202313067 (2024). http://doi.org/10.1002/ANIE.202313067
Abstract: Complex transition-metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition-metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO6, using Zr, yields LaSrCoRuO5. This reduced phase contains an ordered array of apex-linked square-based pyramidal Ru3+O5, square-planar Co1+O4 and octahedral Co3+O6 units, consistent with the coordination-geometry driven disproportionation of Co2+. Coordination-geometry driven disproportionation of d(7) transition-metal cations (e.g. Rh2+, Pd3+, Pt3+) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition-metal such as cobalt leads to the expectation that d(7+) Co2+ should be stable to disproportionation in oxide environments, so the presence of Co1+O4 and Co3+O6 units in LaSrCoRuO5 is surprising. Low-temperature measurements indicate LaSrCoRuO5 adopts a ferromagnetically ordered state below 120 K due to couplings between S=(1)/(2) Ru3+ and S=1 Co1+.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 16.6
DOI: 10.1002/ANIE.202313067
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“Photocatalysis assisted simultaneous carbon oxidation and NOx reduction”. Liao L, Heylen S, Sree SP, Vallaey B, Keulemans M, Lenaerts S, Roeffaers MBJ, Martens JA, Applied catalysis : B : environmental 202, 381 (2017). http://doi.org/10.1016/J.APCATB.2016.09.042
Abstract: Photocatalysis assisted oxidation of carbon black was performed using TiO2 photocatalyst under UV illumination in an atmosphere with NO, O-2 and water vapor at 150 degrees C. Carbon is oxidized mainly to CO2 while NO is selectively converted to N-2. Enhanced O-2 and NO concentrations have a positive effect on the carbon oxidation rate. At a concentration of 3000 ppm NO and 13.3% O-2 in the gas phase the carbon oxidation rate reaches 2.3 mu g(carbon)/mg(TiO2) h, at a formal electron/photon quantum efficiency of 0.019. HR SEM images reveal uniform gradual reduction of the carbon particle size irrespective of the distance to TiO2 photocatalyst particles in the presence of NO, O-2 and H2O. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 11
DOI: 10.1016/J.APCATB.2016.09.042
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