Die Discriminante der Form 7. Gradesf=a x 7

First-principles studies of hydrogenated Si(111)-7 x 7.

The relaxed geometries and electronic properties of the hydrogenated phases of the Si~111!-737 surface are studied using first-principles molecular dynamics. A monohydride phase, with one H per dangling bond adsorbed on the bare surface, is found to be energetically favorable. Another phase where 43 hydrogens saturate the dangling bonds created by the removal of the adatoms from the clean surfa...

Direct solutions of the Si ( 111 ) 7 x 7 structure

We show that it is possible to use direct methods to solve surface structures as complicated as that of the Si( 111 ) 7 x 7. The first of these methods is maximum entropy combined with likelihood estimation, the second a combination of symbolic phasing methods and weakly interpolating modifications of the Sayre equation. These techniques are applied to two different elements of the structure de...

Wendelstein 7-X and fusion

Spin(7)-manifolds with Parallel Torsion Form

Any Spin (7)-manifold admits a metric connection ∇ with totally skewsymmetric torsion T preserving the underlying structure. We classify those with ∇-parallel T 6= 0 and non-Abelian isotropy algebra iso (T) 6 spin (7). These are isometric to either Riemannian products or homogeneous naturally reductive spaces, each admitting two ∇-parallel spinor fields.

Die Bedeutung der Empirie fuer die Softwaretechnik

Empirische Untersuchungen sind aus der Softwareforschung nicht mehr wegzudenken. Explorative empirische Studien einschließlich kontrollierter Experimente vergleichen verschiedene Techniken, um festzustellen, ob bei Verwendung der Techniken Unterschiede in der Qualität von Software, der Bearbeitungszeit oder anderen Eigenschaften tatsächlich zu beobachten sind. Diese Studien bestätigen oder verw...