Multidimensional paperfolding systems

A general multidimensional recursion rule for the regular paperfolding structure is put forward. The two-dimensional structure is explicitly constructed and its symbolic complexity computed. The structures yield multidimensional tilings as well.

Calculation of absorption and secondary scattering of X-rays by spherical amorphous materials in an asymmetric transmission geometry

Expressions for absorption and the secondary scattering intensity ratio are presented for a small beam impinging off-center of a spherical amorphous sample.

Structural constraints on the three-dimensional geometry of simple viruses: case studies of a new predictive tool

A new concept in virology provides insights into structural constraints on virus structure, extending Caspar–Klug theory to include predictions across all radial levels of the virus particle including genome organization. The predictive power of the new tool is demonstrated for a range of viruses, revealing a previously unrecognized structural interdependence of shapes and sizes of different viral components.

From an affine extended icosahedral group towards a toolkit for viral architecture

Affine extensions of the icosahedral group, applied to the investigation of icosahedral viruses, are considered in the framework of molecular crystallography.

A tunable multicolour `rainbow' filter for improved stress and dislocation density field mapping in polycrystals using X-ray Laue microdiffraction

A technique to measure the energy profiles of Laue spots in X-ray Laue microdiffraction is presented. It uses a single-crystal diamond filter that attenuates several well defined energies in the incident white-beam spectrum. A first application to lattice-parameter measurements is demonstrated.

Structure refinement from precession electron diffraction data

It is demonstrated that crystal structures can be successfully refined against precession electron diffraction data using full dynamical calculations of diffracted intensities.

Propagation of neutron spherical waves through a thick, vibrating Ge single crystal

The results of experimental and theoretical studies of the influence of ultrasound on neutron wave propagation in a thick Ge crystal are presented. At low amplitudes of ultrasonic waves interference effects (diffraction intensity beatings near the center of a Bormann fan) were observed for the first time.

∊-Machine spectral reconstruction theory: a direct method for inferring planar disorder and structure from X-ray diffraction studies

A direct method for inferring and describing planar disorder in close-packed structures is presented.

Fifty years of aperiodic crystals. Corrigendum

Corrigendum to the article by Janssen [Acta Cryst. (2012). A68, 667–674].

Understanding Single-Crystal X-ray Crystallography

Report of the Executive Committee for 2011