Levels of residual stresses in partially crystallized Li2O±2SiO2 glass-ceramics were calculated for several crystallographic planes. The stresses were also determined by an X-ray di€raction method (XRD) using synchrotron radiation. The linear thermal expansion coecient (ahkl) of a fully crystallized, stress-free, powdered sample, was measured in situ using a hot-stage XRD technique. The therma...

The linear thermal expansivities of polycrystalline samples of mixtures of L i 2 S 0 4 with K 2 S 0 4 and with N a 2 S 0 4 have been measured with a "Fused-Quarz T u b e " apparatus Phase transitions are accompanied by changes in the expansion coeff icient and also by volume changes. The observed expansion coeff icient is constant over wide temperature intervals. Simple crystal structures show ...

I n t r o d u c t i o n THE structures of the cancrinite-group minerals are character ized by parallel s ix-membered rings consisting of alternating A104 and SiO4 tetrahedra. The hexagonal symmetry is the result of the stacking of such six-membered rings in an AB... sequence. This stacking leads to large continuous channels that are formed by twelve-membered rings of alternating A1Oa and SiO4 t...

Introduction Conclusions References

Introduction Many materials which we encounter in everyday life expand on heating. This fact of life is easily highlighted with a simple experiment that we are all familiar with and involves a metallic sphere passing through a metal ring. At room temperature, the sphere is of such a size that it can easily pass through the ring, but after the sphere is heated, it will have expanded with the res...

We report evidence of the absence of zero thermal expansion in well-characterized high-quality polycrystalline samples of YbGaGe. High-quality samples of YbGaGe were produced from high-purity starting elements and were extensively characterized using x-ray powder diffraction, differential thermal analysis, atomic emission spectroscopy, magnetization, and neutron powder diffraction at various te...

The creation of a surface breaks the translational symmetry of the bulk with the electrons redistributing to lower their energy, resulting in a new lattice structure. Surface relaxation and reconstruction have been studied for years, and it is generally assumed that theory and experiment are in fairly good agreement for the ground state properties at a metal surface. There is a conceptual pictu...

Thermal expansion is an important property of substances. Its theoretical prediction has been challenging, particularly in cases the volume decreases with temperature, i.e., thermal contraction or negative thermal expansion at high temperatures. In this paper, a new theory recently developed by the authors has been reviewed and further examined in the framework of fundamental thermodynamics and...