Journal articles: 'Ewald construction'

1

Maiwald, Lukas, Slawa Lang, Dirk Jalas, Hagen Renner, Alexander Yu Petrov, and Manfred Eich. "Ewald sphere construction for structural colors." Optics Express 26, no. 9 (April 18, 2018): 11352. http://dx.doi.org/10.1364/oe.26.011352.

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Daniilidis, Nikolaos, Ivo Dimitrov, and Xinsheng Sean Ling. "Ewald construction and resolution function for rocking-curve small-angle neutron scattering experiments." Journal of Applied Crystallography 40, no. 5 (September 5, 2007): 959–63. http://dx.doi.org/10.1107/s0021889807033377.

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A geometrical Ewald construction for small-angle neutron scattering experiments from line-like objects with a preferential orientation of the lines, such as flux-line lattices in type-II superconductors, is described. The Ewald construction offers a straightforward way to interpret rocking-curve experiments. It allows calculation of the resolution function in rocking-curve measurements. The resolution function for a given instrumental geometry can be readily computed by performing two numerical integrations.

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Skeel, Robert D. "An alternative construction of the Ewald sum." Molecular Physics 114, no. 21 (August 24, 2016): 3166–70. http://dx.doi.org/10.1080/00268976.2016.1222455.

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4

Barbour, Leonard J. "EwaldSphere: an interactive approach to teaching the Ewald sphere construction." Journal of Applied Crystallography 51, no. 6 (October 11, 2018): 1734–38. http://dx.doi.org/10.1107/s1600576718012876.

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EwaldSphere is a Microsoft Windows computer program that superimposes the Ewald sphere construction onto a small-molecule single-crystal X-ray diffractometer. The main objective of the software is to facilitate teaching of the Ewald sphere construction by depicting our classical description of the X-ray diffraction process as a three-dimensional model that can be explored interactively. Several features of the program are also useful for introducing students to the operation of a diffractometer. EwaldSphere creates a virtual reciprocal lattice based on user-defined unit-cell parameters. The Ewald sphere construction is then rendered visible, and the user can explore the effects of changing various diffractometer parameters (e.g. X-ray wavelength and intensity, goniometer angles, and detector distance) on the resulting diffraction pattern as captured by a virtual area detector. Additional digital resources are provided, including a simple but comprehensive program manual, a PowerPoint presentation that introduces the essential concepts, and an Excel file to facilitate calculation of lattice dhk spacings (required for the presentation). The program and accompanying resources are provided free of charge, and there are no restrictions on their use.

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Kokosza, Łukasz, Jakub Pawlak, Zbigniew Mitura, and Marek Przybylski. "Simplified Determination of RHEED Patterns and Its Explanation Shown with the Use of 3D Computer Graphics." Materials 14, no. 11 (June 3, 2021): 3056. http://dx.doi.org/10.3390/ma14113056.

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The process of preparation of nanostructured thin films in high vacuum can be monitored with the help of reflection high energy diffraction (RHEED). However, RHEED patterns, both observed or recorded, need to be interpreted. The simplest approaches are based on carrying out the Ewald construction for a set of rods perpendicular to the crystal surface. This article describes how the utilization of computer graphics may be useful for realistic reproduction of experimental conditions, and then for carrying out the Ewald construction in a reciprocal 3D space. The computer software was prepared in the Java programing language. The software can be used to interpret real diffractions patterns for relatively flat surfaces, and thus it may be helpful in broad research practice.

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Liboff, Richard L. "Display of real‐space scattering in the Ewald construction." American Journal of Physics 60, no. 12 (December 1992): 1152. http://dx.doi.org/10.1119/1.16967.

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Loh, Yen Lee. "The Ewald sphere construction for radiation, scattering, and diffraction." American Journal of Physics 85, no. 4 (April 2017): 277–88. http://dx.doi.org/10.1119/1.4973369.

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Fewster, Paul F. "Response to Fraser & Wark's comments on A new theory for X-ray diffraction." Acta Crystallographica Section A Foundations and Advances 74, no. 5 (July 18, 2018): 457–65. http://dx.doi.org/10.1107/s2053273318007489.

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The criticisms of my theory, as given by Fraser & Wark [(2018), Acta Cryst. A74, 447–456], are built on a misunderstanding of the concept and the methodology I have used. The assumption they have made rules out my description from which they conclude that my theory is proved to be wrong. They assume that I have misunderstood the diffraction associated with the shape of a crystal and my calculation is only relevant to a parallelepiped and even that I have got wrong. It only appears wrong to Fraser & Wark because the effect I predict has nothing to do with the crystal shape. The effect though can be measured as well as the crystal shape effects. This response describes my reasoning behind the theory, how it can be related to the Ewald sphere construction, and the build-up of the full diffraction pattern from all the scatterers in a stack of planes. It is the latter point that makes the Fraser & Wark analysis incomplete. The description given in this article describes my approach much more precisely with reference to the Ewald sphere construction. Several experiments are described that directly measure the predictions of the new theory, which are explained with reference to the Ewald sphere description. In its simplest terms the new theory can be considered as giving a thickness to the Ewald sphere surface, whereas in the conventional theory it has no thickness. Any thickness immediately informs us that the scattering from a peak at the Bragg angle does not have to be in the Bragg condition to be observed. I believe the conventional theory is a very good approximation, but as soon as it is tested with careful experiments it is shown to be incomplete. The new theory puts forward the idea that there is persistent intensity at the Bragg scattering angle outside the Bragg condition. This intensity is weak (∼10−5) but can be observed in careful laboratory experiments, despite being on the limit of observation, yet it has a profound impact on how we should interpret diffraction patterns.

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Ling, P., and R. Gronsky. "On the geometrical relationship between Kikuchi line position and excitation error in electron diffraction." Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 870–71. http://dx.doi.org/10.1017/s0424820100145698.

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All of the main features of the geometry of Kikuchi lines can be thoroughly explained using the treatment first proposed by Kikuchi in which the observed diffraction lines are considered to arise from the elastic iBraggi scattering of electrons that had been previously scattered inelastically by the specimen. The positions of the lines occur at the intersection of Kikuchi cones or Kossel cones with the Ewald sphere, giving an accurate indication of the orientation of the specimen relative to the incident beam direction, and providing a rapid means (inspection) of deducing the sign of the deviation parameter, s. Less obvious from these traditional presentations however is the actual magnitude of s. This paper presents an alternative geometrical construction employing multiple Ewald spheres to illustrate the phenomenon of multiple scattering which is responsible for the formation of Kikuchi lines, and to provide a straightforward derivation of the excitation error from the relative positions of the Kikuchi lines and their corresponding diffraction spots.

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10

Gévay, Gábor. "A Class of Cellulated Spheres with Non-Polytopal Symmetries." Canadian Mathematical Bulletin 52, no. 3 (September 1, 2009): 366–79. http://dx.doi.org/10.4153/cmb-2009-040-7.

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AbstractWe construct, for all d ≥ 4, a cellulation of . We prove that these cellulations cannot be polytopal with maximal combinatorial symmetry. Such non-realizability phenomenon was first described in dimension 4 by Bokowski, Ewald and Kleinschmidt, and, to the knowledge of the author, until now there have not been any known examples in higher dimensions. As a starting point for the construction, we introduce a new class of (Wythoffian) uniform polytopes, which we call duplexes. In proving our main result, we use some tools that we developed earlier while studying perfect polytopes. In particular, we prove perfectness of the duplexes; furthermore, we prove and make use of the perfectness of another new class of polytopes which we obtain by a variant of the so-called E-construction introduced by Eppstein, Kuperberg and Ziegler.

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11

Han, Karen F., John W. Sedat, and David A. Agard. "Image restoration of thick biological specimens using a through focus series as applied to electron tomography." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 338–39. http://dx.doi.org/10.1017/s0424820100169420.

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The main focus of our laboratory is the study of higher order chromatin structure using three dimensional electron microscope tomography. Three dimensional tomography involves the reconstruction of an object by combining multiple projection views of the object at different tilt angles. It is thus imperative to obtain an accurate representation of the projected object mass density to reconstruct the object correctly in three dimensions. Due to the effects of electron-specimen interactions and microscope lens aberrations, image intensities are not always related to the projected mass density in a simple fashion. We are using a variety of techniques to interpret collected images. In previous work, we have analyzed image formation for thick (0.3-0.7um) biological specimens by electron energy loss spectroscopy and imaging, as well as Ewald sphere construction analysis. In this work, we have modified existing techniques to restore images with only three focus levels using the exit surface wave reconstruction as a reference for comparison.

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12

Spence, J. C. H., and W. Qian. "Interpretation of low-voltage field-emission projection interferograms." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 938–39. http://dx.doi.org/10.1017/s0424820100129322.

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Remarkable transmission electron interference patterns have been reported from very thin crystals at energies Eo < 400 volts using a field emission tip, distance z1 ≈ 200 nm from a semi-transparent crystal sample, which acts as the grounded anode. As predicted, “atomic resolution” Fourier images ar observed on a screen distance z2 from the sample, with magnification z2/z1 ≈ 106 at interior sample regions, confused by Fresnel fringes at edges. The same geometry is used to observe lattice images without scanning in coherent CBED patterns with overlapping orders. The interpretation of these patterns must be based on the theory of transmission LEED (TLEED), including multiple scattering. Figure 1 shows the Ewald sphere construction for 250 volt electrons along [110] gold. Image resolutio is limited to the inner reflections by the small sphere (large wavelength). TLEED computations using the Bloch-wave method of Collela are compared with the single scattering approximation in figure 2 Convergence tests show that 58 forward and backscattered beams are sufficient (Backscattered beams hop along the surface under the repulsive influence of the tip field).

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13

Bittner, Dagmar, Wolfgang U. Dressler, and Marianne Kilani-Schoch. "First verbs: on the way to mini-paradigms." ZAS Papers in Linguistics 18 (January 1, 2000): 173. http://dx.doi.org/10.21248/zaspil.18.2000.53.

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This 18th issue of ZAS-Papers in Linguistics consists of papers on the development of verb acquisition in 9 languages from the very early stages up to the onset of paradigm construction. Each of the 10 papers deals with first-Ianguage developmental processes in one or two children studied via longitudinal data. The languages involved are French, Spanish, Russian, Croatian, Lithuanien, Finnish, English and German. For German two different varieties are examined, one from Berlin and one from Vienna. All papers are based on presentations at the workshop 'Early verbs: On the way to mini-paradigms' held at the ZAS (Berlin) on the 30./31. of September 2000. This workshop brought to a close the first phase of cooperation between two projects on language acquisition which has started in October 1999: a) the project on "Syntaktische Konsequenzen des Morphologieerwerbs" at the ZAS (Berlin) headed by Juergen Weissenborn and Ewald Lang, and financially supported by the Deutsche Forschungsgemeinschaft, and b) the international "Crosslinguistic Project on Pre- and Protomorphology in Language Acquisition" coordinated by Wolfgang U. Dressler in behalf of the Austrian Academy of Sciences.

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14

Han, Karen F. "Image formation analysis of thick biological specimens using three-dimensional power-spectra of through focus series." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 124–25. http://dx.doi.org/10.1017/s0424820100168359.

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The primary focus in our laboratory is the study of higher order chromatin structure using three dimensional electron microscope tomography. Three dimensional tomography involves the deconstruction of an object by combining multiple projection views of the object at different tilt angles, image intensities are not always accurate representations of the projected object mass density, due to the effects of electron-specimen interactions and microscope lens aberrations. Therefore, an understanding of the mechanism of image formation is important for interpreting the images. The image formation for thick biological specimens has been analyzed by using both energy filtering and Ewald sphere constructions. Surprisingly, there is a significant amount of coherent transfer for our thick specimens. The relative amount of coherent transfer is correlated with the relative proportion of elastically scattered electrons using electron energy loss spectoscopy and imaging techniques.Electron-specimen interactions include single and multiple, elastic and inelastic scattering. Multiple and inelastic scattering events give rise to nonlinear imaging effects which complicates the interpretation of collected images.

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15

Astutiningsih, Irana. "The Construction of Racism in Edward P Jones’s The Known World: A Genetic Structuralism Analysis." Metahumaniora 7, no. 1 (April 29, 2017): 32. http://dx.doi.org/10.24198/metahumaniora.v7i1.23322.

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Wacana diskriminasi rasial telah menjadi perbincangan yang tak henti baik dalam konteks akademik maupun non-akademik. Sebagai hasil penelitian, artikel ini membincang wacana rasisme yang mewujud dalam konteks perbudakan dengan objek materi novel The Known World, sebuah novel karya Eward P Jones yang diterbitkan tahun 2003 dan berlatar fenomena perbudakan di abad ke-19. Dengan merujuk pada teori Strukturalisme Genetik yang digagas Lucien Goldman, riset ini berupaya untuk mengetahui bagaimana wacana rasis dalam perbudakan dikonstruksi dalam novel terkait dengan latar kontekstualnya di Amerika pada abad ke-19. Lebih jauh lagi, riset ini juga berupaya menemukan pandangan dunia terkait persoalan rasis sebagaimana terkonstruksi dalam novel. Melalui metode dialektik Goldman, hasil analisis menunjukkan bahwa diskriminasi rasial tidak hanya dilakukan oleh orang-orang kulit putih terhadap kulit hitam sebagai budak mereka, namun juga dilakukan oleh orangorang kulit hitam terhadap sesama kulit hitam. Dengan kata lain, ada wacana rasisme internal dimana orang kulit hitam yang telah dibebaskan dari perbudakan kembali mereproduksi wacana perbudakan dan rasisme dengan cara memiliki budak kulit hitam.

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16

Astutiningsih, Irana. "The Construction of Racism in Edward P Jones’s The Known World: A Genetic Structuralism Analysis." Metahumaniora 7, no. 1 (April 29, 2017): 32. http://dx.doi.org/10.24198/mh.v7i1.23322.

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Wacana diskriminasi rasial telah menjadi perbincangan yang tak henti baik dalam konteks akademik maupun non-akademik. Sebagai hasil penelitian, artikel ini membincang wacana rasisme yang mewujud dalam konteks perbudakan dengan objek materi novel The Known World, sebuah novel karya Eward P Jones yang diterbitkan tahun 2003 dan berlatar fenomena perbudakan di abad ke-19. Dengan merujuk pada teori Strukturalisme Genetik yang digagas Lucien Goldman, riset ini berupaya untuk mengetahui bagaimana wacana rasis dalam perbudakan dikonstruksi dalam novel terkait dengan latar kontekstualnya di Amerika pada abad ke-19. Lebih jauh lagi, riset ini juga berupaya menemukan pandangan dunia terkait persoalan rasis sebagaimana terkonstruksi dalam novel. Melalui metode dialektik Goldman, hasil analisis menunjukkan bahwa diskriminasi rasial tidak hanya dilakukan oleh orang-orang kulit putih terhadap kulit hitam sebagai budak mereka, namun juga dilakukan oleh orangorang kulit hitam terhadap sesama kulit hitam. Dengan kata lain, ada wacana rasisme internal dimana orang kulit hitam yang telah dibebaskan dari perbudakan kembali mereproduksi wacana perbudakan dan rasisme dengan cara memiliki budak kulit hitam.

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17

Feuerschütte, Simone Ghisi, Dannyela da Cunha Lemos, Micheline Gaia Hoffmann, and Roberto Fabiano Fernandes. "Desenvolvimento de uma ferramenta para identificação de padrões culturais para a inovação: relato da trajetória de um projeto de cooperação técnico-científica." RACE - Revista de Administração, Contabilidade e Economia 16, no. 1 (March 23, 2017): 327–52. http://dx.doi.org/10.18593/race.v16i1.10650.

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Neste artigo, de natureza tecnológica, teve-se como objetivo descrever o processo de desenvolvimento de uma ferramenta para identificação de padrões culturais para a inovação. A demanda teve origem em um projeto de cooperação técnico-científica, firmado entre o Instituto Ewaldo Lodi de Santa Catarina (IEL-SC) e a Universidade do Estado de Santa Catarina (UDESC). Coube a esta a meta de realizar a pesquisa e o desenvolvimento para a concepção de ferramentas a serem incorporadas na Metodologia Integrada de Gestão da Inovação (Nugin), para a criação de ambientes de inovação nas empresas. Para isso, buscou-se primeiramente caracterizar o estado da arte e identificar as lacunas da metodologia Nugin. Após, realizou-se a busca por ferramentas que dessem apoio ao gap encontrado. Por fim, procedeu-se a estruturação e construção do conteúdo da metodologia para identificar os padrões culturais favoráveis à criação de ambientes de inovação, por meio da definição das dimensões de análise, assertivas e escala, da validação semântica e do design e desenvolvimento do artefato computacional.Palavras-chave: Ambiente de inovação. Padrões culturais de inovação. Cooperação técnico-científica. NAGI. NUGIN.Abstract This technological article aimed to describe the process of developing a tool for identifying cultural standards for innovation. The demand was originated on a project of technical and scientific cooperation, signed between Instituto Ewaldo Lodi de Santa Catarina (IEL-SC), and Universidade do Estado de Santa Catarina (UDESC). It was left to UDESC the goal to perform the research and the development for the design of tools to be incorporated into the Methodology Innovation Management Integrated (Nugin), for the creation of innovation environments in enterprises. To do so, it first sought to characterize the state of art and identify the gaps in Nugin methodology. After, there was the search for tools that supported the gap found. Finally, we proceeded to the structure and construction of the content of the methodology to identify cultural patterns favorable to the creation of innovation environments, by defining the dimensions of analysis, assertive and scale, the semantic validation and design and development of computational device.Keywords: Innovation environment. Cultural patterns of innovation. Technical and scientific cooperation. NAGI. Nugin.

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Journal articles on the topic 'Ewald construction'

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