“Cubic lead perovskite PbMoO3 with anomalous metallic behavior”. Takatsu H, Hernandez O, Yoshimune W, Prestipino C, Yamamoto T, Tassel C, Kobayashi Y, Batuk D, Shibata Y, Abakumov AM, Brown CM, Kageyama H, Physical review B 95, 155105 (2017). http://doi.org/10.1103/PHYSREVB.95.155105
Abstract: A previously unreported Pb-based perovskite PbMoO3 is obtained by high-pressure and high-temperature synthesis. This material crystallizes in the Pm3m cubic structure at room temperature, making it distinct from typical Pb-based perovskite oxides with a structural distortion. PbMoO3 exhibits a metallic behavior down to 0.1 K with an unusual T-sublinear dependence of the electrical resistivity. Moreover, a large specific heat is observed at low temperatures accompanied by a peak in C-P/T-3 around 10 K, in marked contrast to the isostructural metallic system SrMoO3. These transport and thermal properties for PbMoO3, taking into account anomalously large Pb atomic displacements detected through diffraction experiments, are attributed to a low-energy vibrational mode, associated with incoherent off-centering of lone-pair Pb2+ cations. We discuss the unusual behavior of the electrical resistivity in terms of a polaronlike conduction, mediated by the strong coupling between conduction electrons and optical phonons of the local low-energy vibrational mode.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1103/PHYSREVB.95.155105
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“Cultural heritage and the environment”. Van Grieken R, Delalieux F, Gysels K, Pure and applied chemistry 70, 2327 (1998). http://doi.org/10.1351/PAC199870122327
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1351/PAC199870122327
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“Current trends in the literature on X-ray emission spectrometry”. Van Grieken R, Markowicz A, Veny P, X-ray spectrometry 20, 271 (1991). http://doi.org/10.1002/XRS.1300200605
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300200605
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“CVD growth of monolayer MoS2: Role of growth zone configuration and precursors ratio”. Ozden A, Ay F, Sevik C, Perkgoz NK, Japanese journal of applied physics 56, 06gg05 (2017). http://doi.org/10.7567/JJAP.56.06GG05
Abstract: Single-layer, large-scale two-dimensional material growth is still a challenge for their wide-range usage. Therefore, we carried out a comprehensive study of monolayer MoS2 growth by CVD investigating the influence of growth zone configuration and precursors ratio. We first compared the two commonly used approaches regarding the relative substrate and precursor positions, namely, horizontal and face-down configurations where facedown approach is found to be more favorable to obtain larger flakes under identical growth conditions. Secondly, we used different types of substrate holders to investigate the influence of the Mo and S vapor confinement on the resulting diffusion environment. We suggest that local changes of the S to Mo vapor ratio in the growth zone is a key factor for the change of shape, size and uniformity of the resulting MoS2 formations, which is also confirmed by performing depositions under different precursor ratios. Therefore, to obtain continuous monolayer films, the S to Mo vapor ratio is needed to be kept within a certain range throughout the substrate. As a conclusion, we obtained monolayer triangles with a side length of 90 mu m and circles with a diameter of 500 mu m and continuous films with an area of 85 0 mu m x 1 cm when the S-to-Mo vapor ratio is optimized. (C) 2017 The Japan Society of Applied Physics
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.7567/JJAP.56.06GG05
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“CVD growth of monolayer WS2 through controlled seed formation and vapor density”. Yorulmaz B, Ozden A, Sar H, Ay F, Sevik C, Perkgoz NK, Materials science in semiconductor processing 93, 158 (2019). http://doi.org/10.1016/J.MSSP.2018.12.035
Abstract: Large area, single layer WS2 has a high potential for use in optoelectrical devices with its high photo-luminescence intensity and low response time. In this work, we demonstrate a systematic study of controlled tungsten disulfide (WS2) monolayer growth using chemical vapor deposition (CVD) technique. With a detailed investigation of process parameters such as H-2 gas inclusion into the main carrier gas, growth temperature and duration, we have gained insight into two-dimensional (2D) WS2 synthesis through controlling the seed formations and the radical vapor density associated with WO3. We confirm that H-2 gas, when included to the carrier gas, is directly involved in WO3 reduction due to its reductive reagent nature, which provides a more effective sulfurization and monolayer formation process. Additionally, by changing the CVD growth configuration, hence, increasing the tungsten related vapor density and confining the reactant radicals, we succeed in realizing larger WS(2 )monolayers, which is still a technological challenge in order to utilize these structures for practical applications. Further optimization of the growth procedure is demonstrated by tuning the growth duration to prevent the excess seed formations and additional layers which will possibly limit the device performance of the monolayer flakes or films when applied.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1016/J.MSSP.2018.12.035
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“Damage and molecular changes under a laser beam in SEM-EDX/MRS interface : a case study on iron-rich particles”. Worobiec A, Darchuk L, Brooker A, Potgieter H, Van Grieken R, Journal of Raman spectroscopy 42, 808 (2011). http://doi.org/10.1002/JRS.2789
Abstract: The control of damage to individual environmental particles by a laser beam during Raman spectroscopy carried out in ambient air is generally well understood. The nature and control of damage under vacuum conditions (e.g. in the scanning electron microscopy with energy X-ray detection combined with micro-Raman spectroscopyinterfaced SEM-EDX/MRS) are more complex and less well comprehended. The physical and chemical processes that affect the damage caused to small particles by lasers still remain somewhat unclear, but certainly the atmosphere (vacuum/air) and the beam intensity have very significant influences. Furthermore, it has been determined that some particles (e.g. haematite), although stable under an electron beam, are damaged by the laser beam, hampering their analysis. Additionally, when simultaneous analyses by SEM/EDX and MRS are considered, the correct choice of the collection surface plays a crucial role. As a result, the following collection substrates were tested to determine their influence on the laser beam damage process to the particle: silver and aluminium foils and silicon wafers. A test study was performed using artificial examples of haematite (Fe2O3) particles. Exposure of Fe2O3 particles in vacuum to 514- and 785-nm laser radiation often leads to their melting, transformation and evaporation. The dependence of the damage caused by the laser beam on the particle structure is reported here. Molecular and crystallographic changes have also been revealed. Formation of magnetite (as an effect of re-crystallisation) and Raman inactive structures was detected.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
DOI: 10.1002/JRS.2789
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“Damage functions and mechanism equations derived from limestone weathering in field exposure”. Delalieux F, Cardell-Fernandez C, Torfs K, Vleugels G, Van Grieken RE, Water, air and soil pollution 139, 75 (2002). http://doi.org/10.1023/A:1015827031669
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1023/A:1015827031669
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“Deammonification for digester supernatant pretreated with thermal hydrolysis : overcoming inhibition through process optimization”. Zhang Q, De Clippeleir H, Su C, Al-Omari A, Wett B, Vlaeminck SE, Murthy S, Applied microbiology and biotechnology 100, 5595 (2016). http://doi.org/10.1007/S00253-016-7368-0
Abstract: The thermal hydrolysis process (THP) has been proven to be an excellent pretreatment step for an anaerobic digester (AD), increasing biogas yield and decreasing sludge disposal. The goal of this work was to optimize deammonification for efficient nitrogen removal despite the inhibition effects caused by the organics present in the THP-AD sludge filtrate (digestate). Two sequencing batch reactors were studied treating conventional digestate and THP-AD digestate, respectively. Improved process control based on higher dissolved oxygen set-point (1 mg O-2/L) and longer aeration times could achieve successful treatment of THP-AD digestate. This increased set-point could overcome the inhibition effect on aerobic ammonium-oxidizing bacteria (AerAOB), potentially caused by particulate and colloidal organics. Moreover, based on the mass balance, anoxic ammonium-oxidizing bacteria (AnAOB) contribution to the total nitrogen removal decreased from 97 +/- A 1 % for conventional to 72 +/- A 5 % for THP-AD digestate treatment, but remained stable by selective AnAOB retention using a vibrating screen. Overall, similar total nitrogen removal rates of 520 +/- A 28 mg N/L/day at a loading rate of 600 mg N/L/day were achieved in the THP-AD reactor compared to the conventional digestate treatment operating at low dissolved oxygen (DO) (0.38 +/- A 0.10 mg O-2/L).
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1007/S00253-016-7368-0
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“A decision support system for preventive conservation : from measurements towards decision making”. Schalm O, Cabal A, Anaf W, Leyva Pernia D, Callier J, Ortega N, The European Physical Journal Plus 134, 74 (2019). http://doi.org/10.1140/EPJP/I2019-12441-5
Abstract: We present a decision-support system that guides heritage guardians in selecting mitigation actions to improve the indoor air quality and thus the preservation conditions of indoor collections in heritage buildings. This contribution shows that it is feasible to build a decision support system dedicated to preventive conservation when the following barriers are overcome: 1) simultaneous measurement of a wide range of environmental parameters in order to detect a larger number of undesired situations; 2) development of an algorithm to perform reproducible indoor air quality assessments; and 3) transformation of the air quality assessment into a graph that can be read intuitively without causing a wide variation of interpretations among stakeholders. An important aspect of the decision support system is that it reduces several sources of uncertainty that hamper reliable indoor air quality assessments. The possibilities of such a system are illustrated with a measurement campaign in a church where a heating system has been installed and used for the first time.
Keywords: A1 Journal article; Engineering sciences. Technology; Antwerp Systems and software Modelling (AnSyMo); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
DOI: 10.1140/EPJP/I2019-12441-5
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“Degradation of galvanised iron roofing material in Tanzania by atmospheric corrosion”. Potgieter-Vermaak SS, Mmari A, Van Grieken R, McCrindle RI, Potgieter JH, Corrosion engineering science and technology 46, 642 (2011). http://doi.org/10.1179/147842210X12695149033972
Abstract: Galvanised iron is popular in many applications, particular as a roofing material. However, just like other materials, especially metallic ones, it is prone to degradation by corrosion. In this particular study, the degradation of galvanised roof sheets was investigated at a coastal, urban and rural site in Tanzania, Africa. Samples were exposed to various outdoor environments over a period of 3 years. In addition, some accelerated laboratory investigations were conducted in different simulated air pollution environments in an artificial corrosion chamber constructed for this purpose to supplement the outdoor exposure tests. It was found that the combination of the tropical climate and increasing air pollution due to industrial development in the capital Dar-es-Salaam resulted in substantial atmospheric corrosion of the roof sheets, which eventually leads to failure and the necessity for replacement. The rural site had the lowest degree of atmospheric corrosion as expected. A combination of different corrosion products was identified as a result of the atmospheric corrosion by Raman and EDX analyses. The information gained from this investigation could be utilised to construct more durable structures requiring less frequent replacement and maintenance in future.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1179/147842210X12695149033972
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“Degradation potential of airborne particulate matter at the Alhambra monument : a Raman spectroscopic and electron probe X-ray microanalysis study”. Potgieter-Vermaak S, Horemans B, Anaf W, Cardell C, Van Grieken R, Journal of Raman spectroscopy 43, 1570 (2012). http://doi.org/10.1002/JRS.4052
Abstract: It is well known that airborne particulate matter (APM) has an impact on our cultural heritage. A limited number of articles have been published on the sequential application of elemental and molecular techniques to estimate the degradation potential of APM in environments of cultural heritage importance, and most of these were concerned with indoor environments. The Alhambra monument (Granada, Spain) represents one of the grandest and finest examples of Islamic art and architecture from the Middle Ages. As part of an air quality investigation, two sets of APM were collected at the Hall of the Ambassadors and characterised to determine its potential degradation profile. These were analysed by means of micro-Raman spectroscopy (MRS) and electron probe microanalysis with X-ray detection (EPXMA). The Raman data indicated the presence of various mixed salts of acidic and/or hygroscopic nature, such as sodium and ammonium nitrates and sulfates, especially in the finer fraction. Automated EPXMA estimated this fraction to be as high as 50%. Apart from the potential chemical attack, the soiling due to carbonaceous matter deposition is a real concern. Soot was identified by MRS and EPXMA in all size fractions, reaching values of up to 55%, and was often intertwined with soluble inorganic salts. Ongoing degradation of the pigments is implicated by the presence of brightly coloured particles. MRS and molar abundance ternary diagrams elicited the chemical structure of individual APM so that the degradation potential could be established.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/JRS.4052
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“Deposition of atmospheric trace elements into the North Sea: coastal, ship, platform measurements and model predictions”. Injuk J, Van Grieken R, de Leeuw G, Atmospheric environment : an international journal 32, 3011 (1998). http://doi.org/10.1016/S1352-2310(97)00497-4
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/S1352-2310(97)00497-4
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“Design and simulation of plasmonic interference-based majority gate”. Doevenspeck J, Zografos O, Gurunarayanan S, Lauwereins R, Raghavan P, Sorée B, AIP advances 7, 065116 (2017). http://doi.org/10.1063/1.4989817
Abstract: Major obstacles in current CMOS technology, such as the interconnect bottleneck and thermal heat management, can be overcome by employing subwavelength-scaled light in plasmonic waveguides and devices. In this work, a plasmonic structure that implements the majority (MAJ) gate function is designed and thoroughly studied through simulations. The structure consists of three merging waveguides, serving as the MAJ gate inputs. The information of the logic signals is encoded in the phase of transmitted surface plasmon polaritons (SPP). SPPs are excited at all three inputs and the phase of the output SPP is determined by theMAJof the input phases. The operating dimensions are identified and the functionality is verified for all input combinations. This is the first reported simulation of a plasmonic MAJ gate and thus contributes to the field of optical computing at the nanoscale. (C) 2017 Author(s).
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1063/1.4989817
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“Design of electroporation process in irregularly shaped multicellular systems”. Mescia L, Chiapperino MA, Bia P, Lamacchia CM, Gielis J, Caratelli D, Electronics (Basel) 8, 37 (2019). http://doi.org/10.3390/ELECTRONICS8010037
Abstract: Electroporation technique is widely used in biotechnology and medicine for the transport of various molecules through the membranes of biological cells. Different mathematical models of electroporation have been proposed in the literature to study pore formation in plasma and nuclear membranes. These studies are mainly based on models using a single isolated cell with a canonical shape. In this work, a spacetime (x,y,t) multiphysics model based on quasi-static Maxwells equations and nonlinear Smoluchowskis equation has been developed to investigate the electroporation phenomenon induced by pulsed electric field in multicellular systems having irregularly shape. The dielectric dispersion of the cell compartments such as nuclear and plasmatic membranes, cytoplasm, nucleoplasm and external medium have been incorporated into the numerical algorithm, too. Moreover, the irregular cell shapes have been modeled by using the Gielis transformations.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.3390/ELECTRONICS8010037
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“Desorption-ionization of inorganic compounds in Fourier transform laser microprobe mass spectrometry with external ion source”. Struyf H, Van Vaeck L, Van Grieken R, Rapid communications in mass spectrometry 10, 551 (1996). http://doi.org/10.1002/(SICI)1097-0231(19960331)10:5<551::AID-RCM414>3.0.CO;2-S
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/(SICI)1097-0231(19960331)10:5<551::AID-RCM414>3.0.CO;2-S
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“Detailed analysis of petroleum hydrocarbon attenuation in biopiles by high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography”. Mao D, Lookman R, van de Weghe H, Vanermen G, de Brucker N, Diels L, Journal of chromatography : A 1216, 1524 (2009). http://doi.org/10.1016/J.CHROMA.2008.12.087
Abstract: Enhanced bioremediation of petroleum hydrocarbons in two biopiles was quantified by high-performance liquid chromatography (HPLC) followed by comprehensive two-dimensional gas chromatography (GCXGC). The attenuation of 34 defined hydrocarbon classes was calculated by HPLCGCXGC analysis of representative biopile samples at start-up and after 18 weeks of biopile operation. In general, a-cyclic alkanes were most efficiently removed from the biopiles, followed by monoaromatic hydrocarbons. Cycloalkanes and polycyclic aromatic hydrocarbons (PAHs) were more resistant to degradation. A-cyclic biomarkers farnesane, trimethyl-C13, norpristane, pristane and phytane dropped to only about 10% of their initial concentrations. On the other hand, C29C31 hopane concentrations remained almost unaltered after 18 weeks of biopile operation, confirming their resistance to biodegradation. They are thus reliable indicators to estimate attenuation potential of petroleum hydrocarbons in biopile processed soils.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CHROMA.2008.12.087
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“Detection limits of grazing-exit EPMA for particle analysis”. Tsuji K, Spolnik Z, Wagatsuma K, Nullens R, Van Grieken RE, Microchimica acta 132, 357 (2000). http://doi.org/10.1007/S006040050080
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S006040050080
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“Detection of a Ca-rich lithology in the Earth's deep (>, 300 km) convecting mantle”. Brenker FE, Vincze L, Vekemans B, Nasdala L, Stachel T, Vollmer C, Kersten M, Somogyi A, Adams F, Joswig W, Harris JW, Earth and planetary science letters 236, 579 (2005). http://doi.org/10.1016/J.EPSL.2005.05.021
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.EPSL.2005.05.021
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“Determination of barium, lanthanum, cerium and neodymium in lateritic materials by various energy-dispersive X-ray fluorescence techniques and neutron activation analysis”. Labrecque JJ, Beusen JM, Van Grieken RE, X-ray spectrometry 15, 13 (1986). http://doi.org/10.1002/XRS.1300150105
Abstract: A comparison of four methods for the determination of barium, lanthanum, cerium and neodymium in lateritic materials from Brazil is presented. Three of the methods were based on x-ray fluorescence (XRF) spectroscopy: two by radioisotope excitation (Co-57 and Am-241) and one by secondary target XRF (a molybdenum target with a tungsten anode). The other method was based on neutron activation analysis employing both a Ge(Li) coaxial detector and a high-purity germanium detector. The results from these four methods were similar for lanthanum, cerium and neodymium, but for barium at low concentrations (<500 ppm) the neutron activation and the secondary target XRF methods were not suitable. Data on the precision and accuracy of these methods using a series of standard reference rocks are given. The advantages and limitations of each of these methods with respect to the analysis of lateritic materials are discussed.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300150105
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“Determination of chemical composition of individual airborne particles by SEM/EDX and micro-Raman spectrometry : a review”. Stefaniak EA, Buczyńska A, Novakovic V, Kuduk R, Van Grieken R, Journal of physics : conference series 162, 012019 (2009). http://doi.org/10.1088/1742-6596/162/1/012019
Abstract: The strategies for sampling and analysis by SEM/EDX and micro-Raman spectrometry for individual airborne particles analysis as applied at the University of Antwerp (Belgium) by the MITAC group have been reviewed. Microbeam techniques provide detailed information concerning the origin, formation, transport, reactivity, transformation reactions and environmental impact of particulate matter. Moreover, some particles of certain chemical properties have been recognized as a threat for human health and cultural heritage objects. However, the small sizes of particles result in specific problems with respect to single particle analysis. Development of equipment and software for improvement of analysis and quantification are reported.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1088/1742-6596/162/1/012019
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“Determination of chemical species in individual aerosol particles using ultrathin window EPMA”. Ro C-U, Osán J, Szalóki I, Oh K-Y, Kim H, Van Grieken R, Environmental science and technology 34, 3023 (2000). http://doi.org/10.1021/ES9910661
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ES9910661
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“The determination of copper in iron and steel by 14-Mev neutron activation analysis”. Van Grieken R, Speecke A, Hoste J, Analytica chimica acta 51, 151 (1970). http://doi.org/10.1016/S0003-2670(01)95703-4
Abstract: A fast (10 min) non-destructive determination of copper in. steel and cast iron by 14-MeV neutron activation analysis is described. The 0.511-MeV annihilation radiation of62Cu (T1/2=9.8 min), induced by the reaction63Cu(n,2n)62Cu, is counted by two opposing NaI(Tl) detectors operating in coincidence. An oxygen flux monitor is used to normalise the irradiations. For high phosphorus contents, two measurements are made and the 9-min activity contribution is calculated. As the iron content of the samples is known, the use of pure iron samples allows correction for53Fe activity from the reaction54Fe(n,2n)53Fe(T1/2= 8.9 min). When the phosphorus and silicon activities are low, the procedure of counting and computing can be greatly simplified. Nuclear interferences of most common alloying and impurity elements were investigated.The precision is 23% for steels containing above 1% Cu, andCa. 10% for 0.1%Cu.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/S0003-2670(01)95703-4
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“Determination of Dynamically Stable Electrenes toward Ultrafast Charging Battery Applications”. Kocabas T, Ozden A, Demiroglu I, Cakir D, Sevik C, The journal of physical chemistry letters 9, 4267 (2018). http://doi.org/10.1021/ACS.JPCLETT.8B01468
Abstract: Electrenes, an atomically thin form of layered electrides, are very recent members of the 2D materials family. In this work, we employed first principle calculations to determine stable, exfoliatable, and application-promising 2D electrene materials among possible M2X compounds, where M is a group II-A metal and X is a nonmetal element (C, N, P, As, and Sb). The promise of stable electrene compounds for battery applications is assessed via their exfoliation energy, adsorption properties, and migration energy barriers toward relevant Li, Na, K, and Ca atoms. Our calculations revealed five new stable electrene candidates in addition to previously known Ca2N and Sr2N. Among these seven dynamically stable electrenes, Ba2As, Ba2P, Ba2Sb, Ca2N, Sr2N, and Sr2P are found to be very promising for either K or Na ion batteries due to their extremely low migration energy barriers (5-16 meV), which roughly demonstrates 105 times higher mobility than graphene and two to four times higher mobility than other promising 2D materials such as MXene (Mo2C).
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1021/ACS.JPCLETT.8B01468
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“Determination of fluorine in uranium oxyfluoride particles as an indicator of particle age”. Kips R, Pidduck AJ, Houlton MR, Leenaers A, Mace JD, Marie O, Pointurier F, Stefaniak EA, Taylor PDP, van den Berghe S, van Espen P, Van Grieken R, Wellum R, Spectrochimica acta: part B : atomic spectroscopy 64, 199 (2009). http://doi.org/10.1016/J.SAB.2008.12.001
Abstract: As swipe samples from enrichment activities typically contain uranium particles with a detectable amount of fluorine, the question was raised whether the analysis of fluorine in particles could complement the information on the uranium isotope ratios. For this, uranium oxyfluoride particles were prepared from the controlled hydrolysis of uranium hexafluoride (UF6). The relative amount of fluorine was characterized by scanning electron microscopy combined with energy-dispersive X-ray spectrometry (SEM-EDX), as well as ion-microprobe secondary ion mass spectrometry (IM-SIMS). Of particular interest was the assessment of the reduction of the amount of fluorine over time, and after exposure to UV-light and high temperatures. Micro-Raman spectrometry (MRS) was applied to look for differences in molecular structure between these various sample types. Both SEM-EDX and IM-SIMS showed a general reduction of the fluorine-to-uranium ratio after 12 years of storage. The exposure to UV-light and high temperatures was found to have accelerated the loss of fluorine. A distinct peak at 865 cm− 1 Raman shift was detected for the majority of particles analyzed by MRS. For the particles that were heat-treated, the Raman spectra were similar to the spectrum of U3O8. Although often large variations were observed between particles from the same sample, the three particle measurement techniques (IM-SIMS, SEM-EDX and MRS) showed some consistent trends. They therefore appear promising in terms of the ability to place bounds on particle age, as well as shedding light on the complex processes involved in UO2F2 particle ageing.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Chemometrics (Mitac 3)
DOI: 10.1016/J.SAB.2008.12.001
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“Determination of low-Z elements in individual environmental particles using windowless EPMA”. Ro C-U, Osán J, Van Grieken R, Analytical chemistry 71, 1521 (1999). http://doi.org/10.1021/AC981070F
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC981070F
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“Determination of methanesulfonic acid and non-sea-salt sulfate in single marine aerosol particles”. Kolaitis LN, Bruynseels FJ, Van Grieken RE, Andreae MO, Environmental science and technology 23, 236 (1989). http://doi.org/10.1021/ES00179A018
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ES00179A018
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“Determination of platinum, palladium, and rhodium in automotive catalysts using high-energy secondary target X-ray fluorescence spectrometry”. van Meel K, Smekens A, Behets M, Kazandjian P, Van Grieken R, Analytical chemistry 79, 6383 (2007). http://doi.org/10.1021/AC070815R
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC070815R
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“Determination of protein-bound copper and zinc in some organs of the cuttlefish Sepia officinalis L”. Decleir W, Vlaeminck A, Geladi P, Van Grieken R, Comparative biochemistry and physiology : B : biochemistry and molecular biology 60, 347 (1978). http://doi.org/10.1016/0305-0491(78)90057-3
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0305-0491(78)90057-3
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“Determination of rare earth elements in geological materials by total reflection X-ray fluorescence”. Muia LM, Van Grieken R, Analytica chimica acta 251, 177 (1991)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Determination of sample thickness via scattered radiation in X-ray fluorescence spectrometry with filtered continuum excitation”. Araujo MF, van Espen P, Van Grieken R, X-ray spectrometry 19, 29 (1990). http://doi.org/10.1002/XRS.1300190107
Abstract: A semi-empirical approach is described for determining the mass per unit area of a sample being analysed. The method can be used to estimate the concentration of minor and trace elements in matrices containing a substantial amount of light elements. The procedure utilizes the coherently and incoherently scattered radiation induced in the sample by the filtered continuum radiation of a rhodium x-ray tube. The relationship between the intensity of the scattered radiation per unit mass and the average atomic number of the sample is established via calibration graphs, which can be applied for different x-ray tube voltages and for different primary beam filters. The overall procedure was validated by the analysis of several geological standards, deposited as thin slurries of unknown thickness either on Mylar foil or on Nuclepore filters.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Chemometrics (Mitac 3)
DOI: 10.1002/XRS.1300190107
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