It has been recently pointed out that atomic nuclei with tetrahedral symmetry could be encountered all over the nuclear chart. The predictions are based on a very general analysis of symmetries of the nuclear mean-field and are inspired by the group-theory considerations. The implied unique 4-fold degeneracies of the single-particle levels characteristic of tetrahedral (and/or octahedral) symme...

The interactive deformation and visualization of volumetric objects is still a challenging problem for many application areas. We present a novel integrated system which implements physically-based deformation and volume visualization of tetrahedral meshes on modern graphics hardware by exploiting the last features of vertex and fragment shaders. We achieve fast and stable deformation of tetrah...

On an automatically parallel generation technique for tetrahedral meshes Summary : In order to prepare modern nite element analysis a program for the eecient parallel generation of tetrahedral meshes in a wide class of three dimensional domains having a generalized cylindric shape is presented. The applied mesh generation strategy is based on the decomposition of some 2D-reference domain into s...

Two non-interpenetrated zirconium metal-organic frameworks (Zr-MOFs), NPF-200 and NPF-201, were synthesized via the assembly of elongated tetrahedral linkers with Zr6 and Zr8 clusters. They represent the first examples of MOFs to have the β-UH3-like, 4,12,12T1 topology. Upon activation, NPF-200 exhibits the largest BET surface area (5463 m(2) g(-1)) and void volume (81.6%) among all MOFs formed...

This paper deals with topological analysis of sets of tetrahedra (‘‘tetrahedral meshes’’ of three-dimensional objects). We introduce a definition of simple elements for any normal tetrahedral representation. Then we prove a local characterization of simple tetrahedra in the case of a scene composed of one object and its background, based on homology groups and on relative homology. This allows ...

S U M MARY. Comparison of the infrared spectra (4oo0-50 cm -1) of natural and synthetic samples of margarite, beryllian margaritc, ephesite, and clintonite indicates that the tetrahedral layers of margarite and ephcsite, containing Si and AI in equal atomic proportions, are ordered as the spectra are sharp and show no A1--O-AI vibrations. Clintonite of this tctrahedral composition is disordered...

Using electron microscopy and diffraction techniques, as well as first-principles calculations, we demonstrate that as much as 35% of the total Ge atoms in the cubic phase of Ge2Sb2Te5 locate in tetrahedral environments. The Ge-vacancy interactions play a crucial stabilizing role, leading to Ge-vacancy pairs and the sharing of vacancies that clusters tetrahedral Ge into domains. The Ge2Sb2Te5 s...

Structures and energetics of various types of silicon nanowires have been investigated using both quantum and classical molecular dynamics simulations to determine the most stable forms. The tetrahedral type nanowires have been found to be the most stable and, surprisingly, the polycrystalline forms of nanowires, while having the smallest surface to bulk ratio, are found to be the least stable....

It is known that piecewise linear continuous finite element (FE) approximations on nonobtuse tetrahedral FE meshes guarantee the validity of discrete analogues of various maximum principles for a wide class of elliptic problems of the second order. Such analogues are often called discrete maximum principles (or DMPs in short). In this work we present several global and local refinement techniqu...