Search results for " sphere"

Structural and vibrational study ofZn(IO3)2combining high-pressure experiments and density-functional theory

2021

We report a characterization of the high-pressure behavior of zinc iodate, $\mathrm{Zn}{(\mathrm{I}{\mathrm{O}}_{3})}_{2}$. By the combination of x-ray diffraction, Raman spectroscopy, and first-principles calculations we have found evidence of two subtle isosymmetric structural phase transitions. We present arguments relating these transitions to a nonlinear behavior of phonons and changes induced by pressure on the coordination sphere of the iodine atoms. This fact is explained as a consequence of the formation of metavalent bonding at high pressure which is favored by the lone-electron pairs of iodine. In addition, the pressure dependence of unit-cell parameters, volume, and bond distanc…

Crossing the boundary between face-centred cubic and hexagonal close packed: the structure of nanosized cobalt is unraveled by a model accounting for…

2014

The properties of nanostructured cobalt in the fields of magnetic, catalytic and biomaterials depend critically on Co close packing. This paper reports a structural analysis of nanosized cobalt based on the whole X-ray diffraction (XRD) pattern simulation allowed by the Debye equation. The underlying structural model involves statistical sequences of cobalt layers and produces simulated XRD powder patterns bearing the concurrent signatures of hexagonal and cubic close packing (h.c.p. and f.c.c.). Shape, size distribution and distance distribution between pairs of atoms are also modelled. The simulation algorithm allows straightforward fitting to experimental data and hence the quantitative …

The β-relaxation amplitudes for a dipolar hard sphere glass

1998

Abstract The β-relaxation amplitudes h m l , l ′ ( q ) for a dipolar hard sphere model are calculated in the diagonalization approximation up to l =1. The relevance to experimental difficulties to detect the characteristic β-relaxation minimum in dielectric loss measurements is discussed. Additionally, the microscopic nature of the β-relaxation of the rotational components is investigated by discussing the amplitudes in real space at different temperatures and densities.

On Weakly Locally Uniformly Rotund Banach Spaces

1999

Abstract We show that every normed space E with a weakly locally uniformly rotund norm has an equivalent locally uniformly rotund norm. After obtaining a σ -discrete network of the unit sphere S E for the weak topology we deduce that the space E must have a countable cover by sets of small local diameter, which in turn implies the renorming conclusion. This solves a question posed by Deville, Godefroy, Haydon, and Zizler. For a weakly uniformly rotund norm we prove that the unit sphere is always metrizable for the weak topology despite the fact that it may not have the Kadec property. Moreover, Banach spaces having a countable cover by sets of small local diameter coincide with the descript…

Proper 1-ball contractive retractions in Banach spaces of measurable functions

2005

In this paper we consider the Wosko problem of evaluating, in an infinite-dimensional Banach space X, the infimum of all k > 1 for which there exists a k-ball contractive retraction of the unit ball onto its boundary. We prove that in some classical Banach spaces the best possible value 1 is attained. Moreover we give estimates of the lower H-measure of noncompactness of the retractions we construct. 1. Introduction Let X be an infinite-dimensional Banach space with unit closed ball B(X) and unit sphere S(X). It is well known that, in this setting, there is a retraction of B(X) onto S(X), that is, a continuous mapping R : B(X) ! S(X) with Rx = x for all x 2 S(X). In (4) Benyamini and Sternf…

Interpolating sequences on uniform algebras

2009

Abstract We consider the problem of whether a given interpolating sequence for a uniform algebra yields linear interpolation. A positive answer is obtained when we deal with dual uniform algebras. Further we prove that if the Carleson generalized condition is sufficient for a sequence to be interpolating on the algebra of bounded analytic functions on the unit ball of c 0 , then it is sufficient for any dual uniform algebra.

An optimal extension of Marstrand?s plane-packing theorem

2003

We prove that if F is a subset of the 2-dimensional unit sphere in $\mathbb{R}^3$, with Hausdorff dimension strictly greater than 1, and E is a subset of $\mathbb{R}^3$ such that for each $e \in F$, E contains a plane perpendicular to the vector e, then E must have positive 3-dimensional Lebesgue measure.

Beginning Becoming: The First 1000 Days

2019

Thomas Balmes’ (Babies. Studio Canal documentaries, 2010) ‘Babies’ (Baby(ies) or Bebes) provides a glimpse into the earliest experiences of four infants from four different localities in the world. Although this movie offers no interpretation of what takes place, the discerning viewer is left in no doubt of the significance of these powerful images about infants and their ways of being, doing and knowing in the earliest phases of life. The provocations of ‘Babies’ offer a useful beginning orienting place for a book – almost 10 years later – that promises to focus on becoming in the first 1000 days across a different set of five countries – this time Australia, Finland, New Zealand, Norway a…

The European Public Sphere and the Media: Europe in Crisis - Edited by A. Triandafyllidou, R. Wodak and M. Krzyżanowski

2010

CONTROVERSIAS EN TORNO AL SOFTWARE LIBRE: PRÁCTICAS Y DISCURSOS EN LA DOCENCIA UNIVERSITARIA VALENCIANA

2008

Resumen basado en el de la publicación La progresiva implantación del software libre en los ámbitos universitarios, se acompaña de un discurso construido sobre las controversias que rodean a esta tecnología. Para el análisis de este problema se utiliza el modelo de 'espacios controversiales' propuesto por Nudler, definiendo uno de estos espacios en torno a la aplicación de las tecnologías informáticas en las enseñanzas universitarias. El supuesto es que el debate sobre el copyleft está alcanzando también al discurso pedagógico que acompaña a las aplicaciones de estas tecnologías. Este modelo es el que se trata de aplicar al estudio de cómo se formulan tales controversias en la difusión del …