Showing papers in "Microscopy Microanalysis Microstructures in 1995"
TL;DR: In this article, the similarity in crystal symmetry between carbon and the isotructural BN system results in spectral similarities in both the low-loss features and electron energy-loss near-edge structure associated with the particular core-loss ionization edges.
Abstract: Electron energy-loss spectroscopy measurements have been made on carbon and BN polymorphs, as well as on a number of borides, carbides and nitrides present in sintered cBN based compacts. The similarity in crystal symmetry between carbon and the isotructural BN system results in spectral similarities in both the low-loss features and electron energy-loss near-edge structure associated with the particular core-loss ionization edges. ELNES features hold information on the nearest neighbour environment of the excited atom in a given phase. It is shown that the analysis of these features provides characteristic coordination fingerprints for the identification of carbon and BN allotropes. Similarly, the comparison of ELNES features associated with B-K, C-K and N-K ionization edges provides fingerprints for the identification of B in TiB 2 and B 4 C, C in TiC and B 4 C, and Nin AlN, TiN and BN, respectively. An attempt is made to quantify the fraction of sp 5 bonding in diamond-like carbon and cBN based cutting tool material from the relative intensity of the π resonance in C-K and B-K ELNES, respectively
75 citations
TL;DR: The spectral properties of metal-ceramic composites are strongly affected by the local chemistry and atomic bonding across the interface. Information on both are contained in the energy-loss near-edge structure.
Abstract: The physical properties of metal-ceramic composites are strongly affected by the local chemistry and atomic bonding across the interface. Information on both are contained in the energy-loss near-edge structure. The spectral component specific for the interface can be obtained by the spatial- difference technique. This method was applied for the investigation of two different interfaces, namely Al/Al 2 O 3 and Cu/Al 2 O 3 . The Al-L 2,3 edge at the Al/Al 2 O 3 interface shows a characteristic energy-loss near-edge structure which was compared to multiple scattering calculations for Al(O 3 Al) tetrahedra with various Al-Al bond lengths. Good agreement with the experimental data was found for a cluster with an Al-Al bond length larger than the Al-O distance which is nearly that of amorphous Al 2 O 3 . No interface-specific component could be detected at the Al-L 2,3 edge of the Cu/Al 2 O 3 interface. However, the energy-loss near-edge structure of the Cu-L 2,3 edge indicates that Cu exists at the interface in a Cu 1+ state and that the chemical bond is established at the interface between Cu and O atoms
55 citations
TL;DR: In this article, a comparison of the electron energy loss near edge structure (ELNES) on the carbon K-edges from the binary carbides with compositions close to stoichiometry is presented.
Abstract: The mono-carbides of the 3d, 4d and 5d transition metals of groups IVA (Ti, Zr, Hf) and VA (V, Nb, Ta) of the periodic table have the rock salt (B1) structure. They are-found in many technologically important systems. The binary compounds exist over a range of compositions, normally with a deficit of carbon. Since their structures are identical and their lattice parameters similar, there is considerable mutual solubility between then so that a wide range of compounds of the form MC x exist where M is a mixture of transition metals. This paper presents a comparison of the electron energy loss near edge structure (ELNES) on the carbon K-edges from the binary carbides with compositions close to stoichiometry. The spectra show systematic changes of the ELNES and the threshold energy as the metal species is changed. The threshold energy and intensity increase on going from group IVA to group VA. Equivalent features can be identified in the spectrum from each compound. The energy of each feature, relative to the threshold energy, varies systematically with the lattice parameter of the compound. The systematic change in the ELNES with composition has potential applications where mixed metal carbides, nitrides and carbo-nitrides co-exist. In such cases, it can be difficult to obtain an unambiguous interpretation of microanalytical data and ELNES offers one more channel of information
33 citations
TL;DR: In this article, a study of both phases with electron (EELS) and X-ray (XAS) spectroscopy was performed, and the results indicated that the range of existence of the cubic phase is very narrow around the binary composition.
Abstract: Cubic Boron Nitride (c-BN) single-crystals have been synthesized under high pressure and high temperature conditions (HP - HT) using hexagonal Boron Nitride (h-BN) precursors. We have performed a study of both phases with electron (EELS) and X-ray (XAS) spectroscopy that are compared. The c-BN ELNES spectra at B-K and N-K edges are found to be consistent with the XANES (XAS) data, although the energy resolution achieved with X-rays is better than that obtained by EELS with a LaB 6 filament. However, XAS is at a disadvantage by comparison with EELS owing to the presence of the N-K edge second order. Attempts were made to dope c-BN with carbon atoms. The examination of the EELS spectra reveals that the incorporation of carbon species in the BN material is always accompanied by the addition of oxygen. Several samples were analyzed both with selected area electron diffraction and energy loss spectroscopy. Most probed crystals containing C (and therefore O) were found to be hexagonal. These results emphasized that the range of existence of the cubic phase is very narrow around the binary composition
31 citations
TL;DR: In this paper, the contribution of CCC, CCV and CVV Auger transitions can make to the study of electronic structure is reviewed and appropriate theoretical context for the interpretation of the spectra produced by each process is discussed.
Abstract: This review is concerned with the development of Auger spectroscopy as a probe of local electronic structure. The contribution that CCC, CCV and CVV Auger transitions can make to the study of electronic structure is reviewed and the appropriate theoretical context for the interpretation of the spectra produced by each process is discussed. It is shown how Auger spectroscopy can yield insight into on-site electron correlation, charge transfer and electron screening in a variety of systems and can be used to develop potential models that give rise to a new scale of electronegativity. Studies of particular transitions reveal the local electron configuration and the shape of the local density of states in the vicinity of a core-ionised site. Auger profiles are sensitive to the hybridisation between d bands and sp bands and to the localisation of screening charge. The recent development of high performance instruments and of sophisticated theoretical techniques is allowing Auger spectroscopy
31 citations
TL;DR: In this paper, the electron energy-loss spectra reveal an excess of Mg along with Cr segregated to the interfacial zone at the spinel/sapphire interface, probably interstitial O anions which are also present in excess quantity relative to stoichiometric spinel and sapphire.
Abstract: Spatially resolved chemical composition and spectroscopic line profiles have been gathered from the space charge region across a spinel/sapphire interface using a dedicated scanning transmission electron microscope. The electron energy-loss spectra reveal an excess of Mg (relative to stoichiometric spinel) along with Cr segregated to the interfacial zone. A quantitative least squares decomposition of a spectrum-line profile of the Al L2, 3 absorption edge fine structures into two standard components clearly highlights the transition from sapphire into spinel; further analysis indicates that the degree of site inversion, which is the fractional occupancy of tetrahedral sites by trivalent Al, increases within 5 nm of the boundary. The overall charge neutrality at the interface is maintained by the increased concentration of negative charge, probably interstitial O anions which are also present in excess quantity relative to stoichiometric spinel and sapphire.
28 citations
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TL;DR: A brief history of the discovery of the Auger effect is given in this article, followed by a short description of some of the fields in which this discovery has had a major impact.
Abstract: A brief history of the discovery of the Auger effect is given, which is followed by a short description of some of the fields in which this discovery has had a major impact.
24 citations
TL;DR: In this article, the ionization damage associated with electron and X-ray irradiation of insulating specimens during their investigation by various techniques (EM, AES, XPS, etc) is considered from the point of view of the Auger mechanism.
Abstract: The ionization damage associated with electron and X-ray irradiation of insulating specimens during their investigation by various techniques (EM, AES, XPS, etc) is considered from the point of view of the Auger mechanism. This damage results from the Auger electron transport through the specimen and more specifically from the Auger cascade in the excited atom. After electronic rearrangements, this cascade finally leaves electron vacancies in the uppermost allowed states of the valence band. It is shown that these vacancies may explain various experimental results such as the stimulated desorption of ionic species in halides and oxides as well as the atomic displacements in covalent crystals. A possible way to quantify these effects is shown for the case of X-ray irradiation and for the case of electron irradiation. In the two cases, the correlation between the microscopic mechanisms and their macroscopic consequences, from the point of view of charging effects, is pointed out for the first time. Finally various positive aspects of these effects are outlined. They concern some new methods of characterization and of elaboration in materials science.
24 citations
TL;DR: In this paper, a method based on alternating embeddings in vacuum with epoxy resin and grindings with final polishing down to 0.25 μm alumina grain size, prevents the breaking of the glassy interconnections and fills with resin the majority of the bubbles and voids.
Abstract: A method is reported for the preparation of flat specimens (30 μm thick) of porous, brittle and low permeability materials and rocks for both optical microscopy (OM), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The method, based on alternating embeddings in vacuum with epoxy resin and grindings with final polishing down to 0.25 μm alumina grain size, prevents the breaking of the glassy interconnections and fills with resin the majority of the bubbles and voids. It has been applied to the analysis of pumices sampled at Linosa, Sicily, which are glassy materials with inhomogeneities on a micro-scale and with a vesicular texture often not interconnected. The method has been successfully applied also to the preparation of various sedimentary rocks, synthetics, bones and biomaterials.
19 citations
TL;DR: In this article, an analytical model for the electric field associated to a periodic array of alternating p and n stripes lying in a halfplane is presented and discussed, which allows the interpretation of the main features of the observed holograms and the quantitative evaluation of the effect of the fringing field on the holograms.
Abstract: Reverse-biased p-n junctions have been observed by means of electron holography using a transmission electron microscope equipped with an electron biprism and a field emission gun. Aim of this work is to present and discuss an analytical model for the electric field associated to a periodic array of alternating p and n stripes lying in a half-plane which simulates the experimental setup and allows the interpretation of the main features of the observed holograms and the quantitative evaluation of the effect of the fringing field on the holograms and on the reconstructed images.
13 citations
TL;DR: The methode image-spectre EELS (EELS) as mentioned in this paper is an image filtree en energie, which consists in the acquisition of a serie of images filtrees en energy.
Abstract: La methode image-spectre EELS consiste a faire l'acquisition d'une serie d'images filtrees en energie. Nous avons developpe un logiciel pour cette application qui permet d'obtenir, apres acquisition et de maniere interactive, soit une image filtree en energie, soit un spectre EELS. L'avantage de cette technique, comparee a la methode traditionnelle spectre-image en mode STEM, reside dans la detection parallele de l'image au lieu de celle du spectre. Ceci conduit a une reduction tres importante du temps d'acquisition, (plusieurs centaines de fois plus courte). Le temps total d'acquisition dans une experience pour 256 images ne depasse pas cinq minutes. Pour illustrer le potentiel de cette technique, nous avons applique la methode image-spectre a la cartographie elementaire a haute resolution spatiale (Calcium, Bore et Oxygene) de particules colloidales dont la taille est de l'ordre du nanometre. Les resultats montrent l'existence d'une structure interne a deux phases. Les limitations de notre equipement sont dues a une faible tension d'acceleration, un filtre non corrige en aberrations du second ordre et une faible gamme dynamique de la camera (numerisation sur 8 bits). Malgre ces limitations, nous montrons que les performances atteintes sont proches de celles prevues par les theories de la diffusion inelastique dans le M.E.T
TL;DR: In this article, an ensemble of methodes for morphologique de milieux pulverulents are proposed. But they do not require the segmentation of images, and do not need to be segmented.
Abstract: Dans cette etude, nous proposons un ensemble de methodes pour l'analyse morphologique de milieux pulverulents. Ces methodes sont evaluees a partir d'applications a des poudres d'UO 2 . Elles sont basees sur le modele des feuilles mortes, qui simule un processus de masquage, et ne necessitent pas de segmentation d'images. Nous avons constate qu'il est preferable d'eliminer l'approche de type segmentation pour les structures complexes, et d'operer directement sur les images a niveaux de gris. Ces nouveaux algorithmes sont compares aux methodes traditionnelles pour mesurer une granulometrie par ouvertures.
TL;DR: In this paper, the reduction of TiO 2 (anatase) subjected to high flux electron irradiation (∼ 10 8 A/m 2 ) to titanium monoxide is followed using the evolution of fine structure in the electron energy loss spectrum.
Abstract: The reduction of TiO 2 (anatase) subjected to high flux electron irradiation (∼ 10 8 A/m 2 ) to titanium monoxide is followed using the evolution of fine structure in the electron energy loss spectrum. Changes in extended fine structure are consistent with changes in interatomic distance and the shift in d band onset clearly shows the transition from insulator to metal.
TL;DR: In this article, structural change of boron carbide during hydrogen and helium ion bombardments at room temperature was reported, and the amorphization process was presented as a function of the shift of plasmon-loss peak energy and the change of core-loss profiles in addition to electron diffraction patterns.
Abstract: Increasing attention has been paid recently to boron carbide (B 4 C) from a viewpoint of plasma-facing materials in a fusion device. This paper reports structural change of B 4 C observed in situ by EELS and TEM during hydrogen- and helium-ion bombardments at room temperature. The B 4 C became amorphous by the ion bombardments. This amorphization process was presented as a function of the shift of plasmon-loss peak energy and the change of core-loss profiles in addition to electron diffraction patterns. Analysis of core-loss peaks for boron as well as for carbon in B 4 C during amorphization process revealed the formation of sp 2 type bonding between constituent carbon atoms by the ion bombardments
TL;DR: The detection of Auger electrons in a scanning electron microscope in order to form chemically specific images of the surfaces of solids is reviewed in this article, where the limits to sensitivity and spatial resolution are described and the current'state of the art' is summarised.
Abstract: The detection of Auger electrons in a scanning electron microscope in order to form chemically specific images of the surfaces of solids is reviewed. The limits to sensitivity and spatial resolution are described and the current 'state of the art' is summarised. Some of the useful image processing tools are reviewed and then a small set of applications of the technique when used for the study of surface segregation, semiconducting devices and archaeology are described.
TL;DR: In this article, 3-D Pd particles epitaxially oriented on the ZnO faces were observed by HRTEM, both in top view and in profile view on the lateral (10.0) faces of the znO prisms.
Abstract: Pd particles (1-6 nm) were grown under UHV conditions from a Knudsen cell, on small ZnO prisms in situ prepared in a controlled atmosphere. 3-D Pd particles epitaxially oriented on the ZnO faces were observed by HRTEM, both in top view and in profile view on the lateral (10.0) faces of the ZnO prisms. The epitaxial relations were determined: (211) Pd ∥(10.0) ZnO and [011] Pd ∥[001] ZnO . From the HRTEM observations of the single ZnO prisms and the tetrapods twins, the precise structure of the central ZnO nucleus was also evidenced
TL;DR: In this paper, a TEM-EELS-ESI procedure was used to identify mineral microparticles in individual model suspensions of iron oxides, aluminum oxides and clays in the presence of polysaccharides, at concentrations typical of natural levels.
Abstract: Submicron mineral particles in freshwaters represent an important proportion of the total particle number. These microparticles are frequently associated to macromolecular organic matter and have a high specific surface area; they might thus be strong heavy metal and nutrient scavengers in aquatic systems. Their non-artefacted characterization at the level of individual particles represents a promising challenge, while preservation of the undisturbed state of natural fragile specimens is a prerequisite. We have used a TEM-EELS-ESI procedure which allows the identification of mineral microparticles in individual model suspensions of iron oxides, aluminum oxides and clays in the presence of polysaccharides, at concentrations typical of natural levels. As expected, core-loss ionization edge intensities measured by this method are limited by the thickness of particles. Heterogeneous mixtures of the former microparticles/macromolecules were prepared in order to mimic natural specimens. Under optimum analytical conditions, it was possible to extract the very nature of these entities, to reveal low electron-density polysaccharides and even to identify microparticles masked within complex aggregates.
TL;DR: In this article, the SIMS MCs + method, consisting of detecting the molecular ions formed by the element of interest M and Cs + ion, emitted under Cs+ bombardment is discussed.
Abstract: The SIMS MCs + method, consisting of detecting the molecular ions formed by the element of interest M and Cs + ion, emitted under Cs + bombardment is discussed in this work. A strong reduction of matrix effects has been observed in all the investigated samples. Moreover linear calibration curves can been obtained with good accuracies by plotting the relative matrix concentrations against the corresponding signal intensity ratios. A comparison with XPS results obtained from the analysis of a Fe on Zr on SiO 2 structure has been also reported. In addition good depth resolution and near surface pre-equilibrium region reduction have been observed on MCs + profiles.
TL;DR: In this article, the LACBED technique has been applied to the determination of the tetragonal distortion in Si 1-x Ge x /Si heterostructures, which are of great interest in the device technology.
Abstract: The LACBED technique has been applied to the determination of the tetragonal distortion in Si 1-x Ge x /Si heterostructures, which are of great interest in the device technology The strain determination has been performed on plan sections in an analytical electron microscope The agreement between this strain value and the tetragonal distortion is influenced mainly by the local sample flatness and the acceleration voltage
TL;DR: In this article, electron energy-loss spectroscopy and zero-loss electron spectroscopic imaging (ZLESI) in conjunction with spot energy-dispersive X-ray microanalysis (EDX) were applied to the structural and chemical characterization of practical emulsion core (AgBr)-shell (Agbr1-x Ix) tabular microcrystals.
Abstract: Electron energy-loss spectroscopy (EELS) and zero-loss electron spectroscopic imaging (ZLESI) in conjunction with spot energy-dispersive X-ray microanalysis (EDX) were applied to the structural and chemical characterization of practical emulsion core (AgBr)-shell (AgBr1-x Ix) tabular microcrystals. The samples were cryocooled to minimize damage under the electron beam. Recorded energy-loss spectra of the crystals in the initial state and after a 2-minute development contained several low intensity bands, which were tentatively assigned to silver and halides, as well as bulk, surface and defect plasmons and interband transitions. Spatially resolved energy-loss spectra of silver specks on extractive carbon replicas of silver halide grains showed the presence of the delayed Ag M4, 5edge at 400 eV Results of EELS-microanalysis have been confirmed by EDX spot analysis of the same emulsion samples. The improved contrast in the ZLESI mode enabled the detection of dislocation grid and stacking faults on the tabular grains as well as the visualization of the morphology and defect structure of silver filaments formed during development of microcrystals. Zero-loss filtering was also used to obtain high-resolution point diffraction patterns of the crystals with low background, containing extra reflections at commensurate positions in between the Bragg reflections probably due to a number of defects in the shell region.
TL;DR: TEM/STEM-EDS methods for the quantitative assessment of geometrical parameters, chemical composition and crystal structure of second phase particles are reviewed in this paper, where significant applications are discussed with regard to different ferritic steels : Interstitial Free (IF) steel for deep drawing, electrical 1%Si steel and enameling steel.
Abstract: TEM/STEM-EDS methods for the quantitative assessment of geometrical parameters, chemical composition and crystal structure of second phase particles are reviewed. Significant applications are discussed with regard to different ferritic steels : Interstitial Free (IF) steel for deep drawing, electrical 1%Si steel and enameling steel. After short term isothermal annealing, a Ti-containing IF steel exhibited Ti(C,N) precipitates that were finer and more frequent than Ti 4 C 2 S 2 . Ti(C,N) was a preferential site for Ti 4 C 2 S 2 nucleation. The experimental results were compared with calculations by a mathematical model of precipitation. Analysis of second phase particles in an electrical 1% Si steel after isothermal annealing allowed evaluation of the inhibition factor for grain growth. The abnormal grain growth in this steel was mainly due to dissolution of Cu 1.92 S and Ostwald ripening of (Mn,Cu)S and Ti(C,N) with AIN. Quantitative investigation of precipitates in an enameling steel, together with hydrogen permeation measurements, showed that interstitial sites at the surface of coherent e-Ti(C,N) precipitates act as efficient traps for hydrogen atoms.
TL;DR: In this paper, the trend of the reconstructed phase across the fluxon core or the intensity distribution of its out-of-focus image have a strong similarity with those calculated by means of previous one-dimensional models, where the fluxons was considered lying perpendicular to the electron beam.
Abstract: In order to extract quantitative information from the two-dimensional images of superconducting fluxons observed in thin tilted specimens by means of holographic or out-of-focus methods, one-dimensional line scans are taken and compared with the theoretical predictions. In particular, the trend of the reconstructed phase across the fluxon core, or the intensity distribution of its out-of-focus image have a strong similarity with those calculated by means of previous one-dimensional models, where the fluxon was considered lying perpendicular to the electron beam. This work exploits this analogy showing that, in spite of the different geometry, suitably modified one-dimensional models can be usefully applied for the interpretation of the experimental results and the analysis of the experimental conditions as well as for the assessment of new methods, like f.i. the one proposed for discriminating between London and Clem models.
TL;DR: The extremely demanding materials specifications of the electronics industry provides an interesting example of how Auger Electron Spectroscopy is now being put to work to provide valuable input into materials processing and device technology.
Abstract: The extremely demanding materials specifications of the electronics industry provides an interesting example of how Auger Electron Spectroscopy is now being put to work to provide valuable input into materials processing and device technology.
TL;DR: The aspects of this algebra of particular interest in electron optics are presented and the advantages of adopting it as a lingua franca are described.
Abstract: An ever-increasing proportion of the algorithms employed in image processing are being translated into the language of image algebra. The aspects of this algebra of particular interest in electron optics are presented and the advantages of adopting it as a lingua franca are described.
TL;DR: In this paper, the role of the relaxation has to be taken into account if the structural properties of the bulk heterostructures are deduced from those of the thinned specimens, and the theoretical evaluation of strain fields in ultra-thinned HRTEM samples shows a bending of the lattice and the local lattice spacings are representative of neither the bulk tetragonally distorted material nor the unstressed material.
Abstract: HRTEM observations require ultra-thinned specimens and, due to the very small thickness (1 to 30 nm), an elastic stress relaxation may occur near the free surfaces of strained heterostructures. These relaxation phenomena can modify the structural features of the thinned specimens with respect to the bulk materials. Thus, the role of the relaxation has to be taken into account if the structural properties of the bulk heterostructures are deduced from those of the thinned specimens. In this work we investigate the case of lattice-mismatched semiconductor superlattices, thinned along the [011]-crystallographic direction. The theoretical evaluation of strain fields in ultra-thinned HRTEM samples shows a bending of the lattice, and the local lattice spacings are representative of neither the bulk tetragonally distorted material nor the unstressed material. Our results show that these distortions can be large and must be taken into account whenever HRTEM is used to deduce the local chemical composition or the unit cell dimensions in strained semiconductor materials.
TL;DR: In this paper, a Monte-Carlo simulation model was developed to reconstruct surface near depth profiles by a multiple thin film model, which is able to determine depth profiles quantitatively with regard to both composition and the real depth coordinate in terms of mass coverage.
Abstract: The remarkable features of modern EPMA techniques are high sensitivity for very small coverages of thin films on substrates (10 14 cm -2 ) and a reliable quantitative determination of elemental compositions. The present work makes use of these features and combines them with ion sputtering of the sample surface to extend the capability of EPMA to real in-depth analysis in the submicron range. The general theoretical background of this EPMA-sputter-depth profiling is worked out and on the basis of a Monte-Carlo simulation model a technique was developed to reconstruct surface near depth profiles by a multiple thin film model. As a result, this new approach is able to determine depth profiles quantitatively with regard to both composition and the real depth coordinate in terms of mass coverage. After having been verified at an artificial layer system of different Ti-Al-N-O-compounds the new technique was used to study oxide scales which were grown on technical hardcoatings of the type Ti 1 - x Al x N with different fractions x. Despite the roughness of the oxide scales and although the structure of different oxide types was interlocked the variation of the elemental composition with depth could be worked out quantitatively with a relative accuracy of 10%. Additionally a reasonable evaluation of the depth coordinate in mass coverage could be attained, the results of which could be assessed by SEM imaging of the scales in fractured samples.
ENEA1
TL;DR: In this article, the first steps of the solid state reaction between Cu and Fe induced by plastic deformation at low temperature have been studied by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC).
Abstract: The first steps of the solid state reaction between Cu and Fe induced by plastic deformation at low temperature have been studied by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). Despite the positive enthalpy of mixing, plastic deformation induces interdiffusion in this system as evidenced by XRD and DSC analysis. TEM observations of samples prepared in different ways show the presence of some Fe into the Cu matrix, a relatively low density of dislocations, a large concentration of small agglomerates of point defects and a well-defined grain shape, suggesting that some dynamic recrystallization occurs during deformation. Considering the low processing temperature we advance the hypothesis that the excess concentration of point defects induced by the high strain rate plastic deformation can provide the necessary atomic mobility. Moreover the role played by these defects on the thermodynamic driving force of the alloying process is considered.
TL;DR: In this article, the authors utilise the microscopie electronique en haute resolution for mettre en evidence des boucles de dislocations partielles provenant de l'amincissement par bombardement ionique d'un echantillon de ZnO.
Abstract: On utilise la microscopie electronique en haute resolution pour mettre en evidence des boucles de dislocations partielles provenant de l'amincissement par bombardement ionique d'un echantillon de ZnO. Les defauts d'empilement crees par insertion d'une double couche de Zn-O dans le plan basal sont du type 1Δ
TL;DR: In this article, a weighted average mass absorption coefficient is proposed for use in analysis with L series radiation when the energy separation of the component lines is less than the spectrometer resolution, which improves agreement between experimental data and the theoretically calculated X-ray intensities.
Abstract: Recent advances in the mathematical description of the depth distribution of X-ray generation, o(03C1z), have permitted the quantitative analysis of multilayer structures with a precision approaching ±1 nm. A weighted average mass absorption coefficient is proposed for use in analysis with L series radiation when the energy separation of the component lines is less than the spectrometer resolution. This is shown to improve agreement between experimental data and the theoretically calculated X-ray intensities. An example of the application of the O(03C1z) method to the analysis of a titanium-boron nitride bilayer is described with special reference to the problem of detection of interfacial diffusion and oxidation phenomena.
TL;DR: In this paper, the combined application of Extended Energy Loss Fine Structure (EXELFS) analysis, a "short-range" probe, and Selected Area Electron Diffraction (SAED), a ''long-range'' probe, allowed to investigate the atomic arrangement of proteins constituting the siderosomes.
Abstract: Electron energy loss spectroscopy imaging (EELSI) was used to obtain Fe maps, with molecular resolution, in human alveolar macrophages. Fe concentrations were found in particular structures named siderosomes. The combined application of Extended energy loss fine structure (EXELFS) analysis, a «short-range» probe, and Selected area electron diffraction (SAED), a «long-range» probe, allowed us to investigate the atomic arrangement of proteins constituting the siderosomes. Results are compared with structural data obtained on purified proteins. It is found that the siderosomes seem to be constituted mainly by normal hemosiderins