716 research outputs found
High-frequency dynamics in the near-surface region studied by inelastic x-ray scattering: The case of liquid indium
No full textInelastic x-ray scattering in grazing angle geometry provides a novel tool for studying the surface and bulk lattice dynamics in a single experiment by varying the incidence angle around the critical angle of total reflection. At very small incidence angles (below the critical angle), it is possible to study the collective dynamics in a subsurface region of a few nanometres at interatomic length and time scales. An experimental study on liquid indium in the near-surface region is presented here and the results are analysed within a theoretical framework, based on classical hydrodynamics for the height-height fluctuations (capillary waves and non-propagating fluctuations) and generalized hydrodynamics for the bulk density fluctuations. The investigation reveals the presence of capillary waves in the inelastic x-ray spectra as an additional contribution at zero-energy transfer and a modification of the bulk density fluctuation contribution. A longer structural relaxation time and a larger longitudinal viscosity with respect to bulk indium are observed, similarly to related studies in confined liquids. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
Full Elasticity Tensor from Thermal Diffuse Scattering
No full textWe present a method for the precise determination of the full elasticity tensor from a single crystal diffraction experiment using monochromatic x rays. For the two benchmark systems calcite and magnesium oxide, we show that the measurement of thermal diffuse scattering in the proximity of Bragg reflections provides accurate values of the complete set of elastic constants. This approach allows for a reliable and model-free determination of the elastic properties and can be performed together with crystal structure investigation in the same experiment
Dynamics of glasses and glass-forming liquids studied by inelastic x-ray scattering
No full textThe development of inelastic x-ray scattering with millielectron volt energy resolution a
Kommentare zur Neubearbeitung der Exkursionsflora von Deutschland, Band 4 (Kritischer Band) 6.: Zur Taxonomie und Nomenklatur einiger Elytrigia-Sippen
No full textKRISCH, H. 2007: Kommentare zur Neubearbeitung der Exkursionsflora von Deutschland, Band 4 (Kritischer Band). 6. Zur Taxonomie und Nomenklatur einiger Elytrigia-Sippen. Schlechtendalia 16: 9–17.
Behandelt werden zwei infraspezifische Taxa (sogenannte „Küstensippen“) und die Namen zweier Hybriden. Die diskutierten Probleme stehen vor allem im Zusammenhang mit Triticum littoreum, Agropyron campestre und Elytrigia maritima – (1) Aufgrund neuer Erkenntnisse von Stace wurde das Binom für Elytrigia atherica × E. repens geändert in E. ×drucei. (2) Mehrere Quellen belegen, dass der Name Triticum littoreum ein völlig unklarer Name ist. Deshalb wird für Elytrigia junceiformis × E. repens der Name E. ×laxa beibehalten. (3) Die sogenannte Küstensippe der Elytrigia repens wird wegen gleitender Übergänge zur typischen Sippe nur als Varietät betrachtet und folglich var. littoralis genannt, obwohl das Triticum littoreum inzwischen von Conert ebenfalls als „Küstensippe“(Elymus repens subsp. littoreus) lectotypisiert wurde. (4) Noch unzureichend erforscht sind Elytrigia campestris und ihre Hybriden. Die Abgrenzung von E. atherica ist unklar, und deshalb ist auch das Vorkommen einer Küstensippe der E. campestris auf deutschem Boden noch unklar. – Die AbkürzungE. bedeutet in diesem Beitrag immer Elytrigia, niemals Elymus. Die Autorzitate der häufig genannten Elytrigia-Sippen wurden weggelassen, weil deren Namen verwendet werden wie in der 10. Auflage des 4. Bandes der „Exkursionsflora“.KRISCH, H. 2007: Comments to the revised edition of „Exkursionsflora von Deutschland, Band 4 (Kritischer Band)“. 6. To the taxonomy and nomenclature of some Elytrigia-taxa. Schlechtendalia 16: 9–17
Two infraspecific taxa (so-called „coastal taxa“) and the names of two hybrids are treated. The discussed problems are mainly connected with Triticum littoreum, Agropyron campestre and Elytrigia maritima – (1) The binomial name for Elytrigia atherica × E. repens was changed into E. ×drucei from the ninth to the tenth edition because of new knowledges by Stace. (2) Several sources verify that Triticum littoreum is an entirely obscure name and, therefore, Elytrigia ×laxa is preserved to E. junceiformis × E. repens. (3) The so-called coastal taxon of Elytrigia repens is regarded as variety by reason of transitional forms towards the typical taxon and in consequence designated as var. littoralis,although Conert has meanwhile lecto-typified Triticum littoreum as „coastal taxon“ Elymus repens subsp. littoreus. (4) Elytrigia campestris and their hybrids are still inadequatly investigated. The separation from E. atherica is not clarified and, therefore, also the occurence of a coastal taxon of the E. campestris in Germany is uncertain. – The abbreviation E. means in this article always Elytrigia, never Elymus. The author citations of the frequently mentioned Elytrigia-taxa are omitted becausewhose names are used as in the tenth edition of vol. 4 of the „Exkursionsflora“.Die Schlechtendalia publiziert Originalbeiträge mit Schwerpunkt Spezielle Botanik und Biodiversität, Floristik, Mykologie/Lichenologie, Wissenschaftsgeschichte und andere Themen mit Bezug zu Botanischen Gärten und Herbarien
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