TERMIUM Plus^®

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To solve the problem on the microstructural characterization of metallic superlattices, taking the NiFe/Cu superlattices as example, we show that the structures of metallic superlattices can be characterized exactly by combining low-angle X-ray diffraction with high-angle X-ray diffraction. First, we determine exactly the total film thickness by a straightforward and precise method based on a modified Bragg law from the subsidiary maxima around the low-angle X-ray diffraction peak. Then, by combining with the simulation of high-angle X-ray diffraction, we obtain the structural parameters such as the superlattice period, the sublayer and buffer thickness. This characterization procedure is also applicable to other types of metallic superlattices.  2, fiche 1, Anglais, - metallic%20superlattice

Fiche 1,  Justifications,  Français

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Un super-réseau est constitué par une répétition périodique de couches de compositions différentes. À la périodicité du réseau cristallin à l'intérieur de chaque couche s'ajoute alors la périodicité de composition du matériau final, d'où l'appellation.  2, fiche 1, Français, - super%2Dr%C3%A9seau%20m%C3%A9tallique

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À partir du milieu des années 1980, les progrès de l'épitaxie par jets moléculaires ont permis à des équipes américaines (aux laboratoires Bell et à l'université de l'Illinois) de réaliser des super-réseaux métalliques [...]  3, fiche 1, Français, - super%2Dr%C3%A9seau%20m%C3%A9tallique

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[...] la technique d'épitaxie par jets moléculaires permet d'élaborer des super-réseaux métalliques de grande qualité cristalline, avec des interfaces abruptes et un contrôle de l'épaisseur des couches individuelles à l'échelle de la monocouche atomique.  3, fiche 1, Français, - super%2Dr%C3%A9seau%20m%C3%A9tallique

Fiche 1,  Justifications,  Espagnol

Fiche 2,  Justifications,  Anglais

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A method of studying crystalline structures by x-ray diffraction, in which a finely collimated beam of polychromatic x-rays falls on a single crystal whose orientation can be set as desired, and diffracted beams are recorded on a photographic film.  1, fiche 2, Anglais, - Laue%20method

Fiche 2,  Justifications,  Français

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Outre [l’] expérience classique de biocristallographie, deux techniques sont développées en parallèle et sont exclusives du rayonnement synchrotron. La première est la méthode MAD (multiple wavelength anomalous diffraction) qui consiste à exploiter la diffusion anomale d’un atome lourd inclus dans la protéine et à déterminer sa position, puis à aider au phasage, à partir de la collecte de données autour du seuil d’absorption. La seconde, méthode de Laue, consiste à travailler avec un faisceau blanc, ce qui permet des collectes de données avec des temps d’exposition excessivement courts, de la microseconde à la picoseconde.  1, fiche 2, Français, - m%C3%A9thode%20de%20Laue

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Fiche 3,  Justifications,  Anglais

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An analytical technique analogous to x-ray diffraction in which an incident beam of neutrons is scattered by the atoms of a crystal.  2, fiche 3, Anglais, - neutron%20diffraction

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Because elements that are close to each other in the Periodic Table differ considerably in their neutron-scattering ability, neutron diffraction is capable of distinguishing between them. For example, carbon nitrogen, and oxygen atoms can be readily identified by neutron diffraction, where as they appear almost identical by the x-ray method. More accurate determination of the bond lengths of light atoms and distribution of molecular bonding electrons is also possible. Details of molecular structure that can only be inferred by other techniques can often be observed directly by neutron diffraction. Investigations using this method include hydrogen bonding, so-called metal cluster compounds(C. H. M relationships) and electronic charge distributions.  2, fiche 3, Anglais, - neutron%20diffraction

Fiche 3,  Justifications,  Français

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En réalité la seule méthode capable de déceler la structure atomique de la plupart des macromolécules est la diffraction des rayons X par des cristaux. [...] La diffraction neutronique est surtout utilisée pour placer les atomes d'hydrogène, trop légers pour être normalement détectés par diffraction des rayons X, dans des modèles atomiques obtenus par cette dernière méthode.  4, fiche 3, Français, - diffraction%20neutronique

Fiche 3,  Justifications,  Espagnol

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Difracción de los neutrones térmicos que por tener una longitud de onda asociada aproximadamente igual a la distancia entre los átomos de los cristales, son difractados por éstos.  1, fiche 3, Espagnol, - difracci%C3%B3n%20de%20neutrones

Fiche 4,  Justifications,  Anglais

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X-ray powder diffraction is used in the identification of crystalline phases in unknown samples, finding the lattice parameter and other lattice related information, quantitative determination of phases in multiphase samples, finding the orientation in single crystals, and stereographic projections. The samples must be crystalline solids such as metals, ceramics, rocks etc. These samples are usually about 1 mg in size. If the sample fits in the sample holder then there is no preparation necessary otherwise the sample may have to be crushed in order to fit. The sample takes less than one hour to be analyzed for qualitative analysis in major phases and up to 16 hours for trace phases. The quantitative analysis can take several minutes to several hours after set up. There are several detectors used in XRPD varying from films to cameras to diffractometers.  1, fiche 4, Anglais, - x%2Dray%20powder%20diffraction

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Powder X-Ray Diffraction. Powders of crystalline materials diffract X-Rays. A beam of X-rays passing through a sample of randomly-oriented micro-crystals produces a pattern of rings on a distant screen. Powder X-Ray diffraction provides less information than single-crystal diffraction, however, it is much simpler and faster. Powder X-Ray diffraction is useful for confirming the identity of a solid material and determining crystallinity and phase purity. Modern powder X-Ray diffractometers consist of an X-Ray source, a movable sample platform, an X-Ray detector, and associated computer-controlled electronics. The sample is either packed into a shallow cup-shaped holder or deposited as a slurry onto a quartz substrate, and the sample holder spins slowly during the experiment to reduce sample heating. The X-Ray source is usually the same as used in single-crystal diffractometers, Mo or Cu. The X-Ray beam is fixed and the sample platform rotates with respect to the beam by an angle theta. The detector rotates at twice the rate of the sample and is at an angle of 2 theta with respect to the incoming X-Ray beam.  4, fiche 4, Anglais, - x%2Dray%20powder%20diffraction

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Fine particles such as clays must be separated from larger particles and measured separately if they are to be detected properly. To reduce errors associated with preferred orientation of minerals, samples are most commonly ground to a powder before analysis, a technique known as powder X-ray diffraction.  4, fiche 4, Anglais, - x%2Dray%20powder%20diffraction

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X-ray powder diffraction(XRD) is a direct method for qualitative and quantitative characterization of fine-grained materials such as clinker and cement, and may also be used for analysis of raw materials. Each phase produces a unique diffraction pattern independent of others, with the intensity of each pattern proportional to that phases concentration in a mixture.  5, fiche 4, Anglais, - x%2Dray%20powder%20diffraction

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Diffraction de rayons sur poudres : analyse quantitative de composés modèles du ciment anhydre. [...] Ce stage sera consacré à la caractérisation par diffraction des rayons X de mélanges d'alites de synthèse M1 et M3. La méthode expérimentale utilisée sera la diffraction des rayons X sur poudres jointe aux autres méthodes de laboratoire associées.  1, fiche 4, Français, - diffraction%20de%20rayons%20X%20sur%20poudres

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À l'aide de la diffraction de rayons X de poudres, différentes formes polymorphiques peuvent être détectées pour des molécules à activité pharmacologique.  2, fiche 4, Français, - diffraction%20de%20rayons%20X%20sur%20poudres

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Fiche 5,  Justifications,  Anglais

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X-ray powder diffraction analysis(XRPD) was proven to be a very powerful tool for the study of "green stone" Neolithic axes and other artifacts. The amount of material to be sampled can be reduced to a few milligrams, thus making it a quasi-non destructive method.... If the dimension of an object is adequate(up to 60 cm in bulk, depending upon the shape) it can be directly analyzed, by XRPD, without sampling. Even a rough, irregular surface, both on flat and bent objects, is suitable for the analysis. The XRPD analysis is, therefore, totally non-destructive and is obviously very adapt to analyze many different materials, such as pigments, stones, ceramics, metals, patinas, salts efflorescences etc.  1, fiche 5, Anglais, - x%2Dray%20powder%20diffraction%20analysis

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Scintag X'TRA est un nouveau système d'analyse des poudres par diffraction de rayons X (XRD).  1, fiche 5, Français, - analyse%20des%20poudres%20par%20diffraction%20de%20rayons%20X

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Les techniques analytiques : [...] Diffraction des rayons X sur poudres et sur cristaux.  3, fiche 5, Français, - analyse%20des%20poudres%20par%20diffraction%20de%20rayons%20X

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En français, rayons X ne prend pas de trait d'union.  2, fiche 5, Français, - analyse%20des%20poudres%20par%20diffraction%20de%20rayons%20X

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Fiche 6,  Justifications,  Anglais

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X-ray Diffraction Method is an accurate, reliable and time proven tool for residual stress analysis. Using Bragg's law of diffraction the value of surface residual stress can be found by measuring the angle at which an X-ray beam diffracts from the surface of an analyzed component. This measurement method is absolute : i. e. it does not require calibration on samples of known stress levels.  2, fiche 6, Anglais, - X%2Dray%20diffraction%20method

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Qualitative and quantitative phase analysis, grain size and micro-stresses determination, macro-stresses measurement using X-ray diffraction method.  3, fiche 6, Anglais, - X%2Dray%20diffraction%20method

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Deux méthodes de diffraction sont les plus utilisées pour déterminer les contraintes résiduelles à la surface des matériaux cristallins : la méthode par diffraction de neutrons et la méthode par diffraction des rayons X, qui fut la première proposée par Lester et Abon au siècle dernier (1925) [...] Le principe est fondé sur la mesure des variations des distances inter-atomiques liées directement à la présence de contraintes résiduelles. L'introduction d'un champ de contraintes résiduelles va se traduire par une déformation du réseau cristallin. En utilisant les plans cristallins comme jauges de déformation, la diffractométrie permet de déterminer de manière non destructive les contraintes en surface dans les matériaux cristallins uniquement [...]  2, fiche 6, Français, - m%C3%A9thode%20par%20diffraction%20des%20rayons%20X

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Fiche 7,  Justifications,  Anglais

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In the technique of X-ray diffraction the X-rays are allowed to strike a protein crystal; the X-rays, diffracted(bent) by the crystal, impinge on a photographic plate, forming a pattern of spots. This method reveals that peptide chains can assume very complicated, apparently irregular shapes. Two extremes in shape include the closely folded structure of the globular proteins and the elongated, unidimensional structure of the threadlike fibours proteins; both were recognized many years before the technique of X-ray diffraction was developed.  2, fiche 7, Anglais, - protein%20crystal

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Un cristal est formé par la répétition dans l'espace d'un objet qu'on appelle le motif cristallin. Dans le cas le plus simple, cet objet est un atome ou une molécule. On sait depuis le dix-neuvième siècle produire des cristaux de protéines, et on a réussi à cristalliser des virus, des ARN de transfert, des nucléosomes, etc.  2, fiche 7, Français, - cristal%20de%20prot%C3%A9ine

Fiche 7,  Justifications,  Espagnol