issue contents
November 2017 issue
advances
research papers
Open access
New kinds of defects can appear in crystals where the atoms and unit cell sit on the nodes of -modules, i.e. on three-dimensional projections of N-dimensional lattices. These defects are the result of the symmetry breaking due to the projection of the structure from N to three dimensions. Examples are given that illustrate the processes. A new kind of dislocation, here called a `scalar dislocation', is expected; it generates no deformation and has no interaction with stress fields.
foundations
research papers
Properties of the phase problem for two-dimensional crystals are examined. Implications for ab initio phasing of X-ray free-electron laser data from two-dimensional crystalline specimens are described.
Extrinsic faulting is revisited under the framework of computational mechanics. Expressions for the statistical complexity, entropy density and excess entropy are derived as a function of faulting probability. The deductions follow from optimal hidden Markov model descriptions of the faulting process (∊-machine).
The most popular difference syntheses are characterized and a new difference synthesis is proposed.
Spherical wavefields in the Laue case are obtained under conditions in which the real part of the crystal structure factor is small or zero.
short communications
The vertex and edge truncations of all crystal closed simple forms are enumerated and interpreted as special combinations of crystal simple forms.
book reviews
Free
international union of crystallography
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