December 2018 issue
J. Appl. Cryst. (2018). 51, 1511-1524
The technical features and performance of a new instrument for time-resolved ultra-small-angle and coherent X-ray scattering are presented. The instrument enables static and kinetic investigations from ångström to micrometre size scales and time resolution down to the sub-millisecond range. Applications include elucidation of static and transient hierarchical structures in soft matter and biophysical systems.
J. Appl. Cryst. (2018). 51, 1525-1534
AstroEBSD: exploring new space in pattern indexing with methods launched from an astronomical approach
A method to automatically index electron backscatter diffraction patterns is introduced and demonstrated with dynamical diffraction simulations and experimental patterns.
J. Appl. Cryst. (2018). 51, 1535-1543
The scattering contribution of free, not chemically bound water in different water–solid mixtures as well as the changes of the scattering contribution due to the reaction progress of hydrating systems is examined. Rietveld analysis with a combination of the G factor and PONKCS (partial or no known crystal structure) method is used for quantification.
J. Appl. Cryst. (2018). 51, 1544-1550
The local atomic motif method is further refined and applied to amorphous germanium models, revealing subtle differences between two similar models.
J. Appl. Cryst. (2018). 51, 1551-1555
Inversion domain boundary structure of laterally overgrown c-GaN domains including the inversion from Ga to N polarity at a mask pattern boundary
During polarity-inverted lateral overgrowth, inversion domain boundaries (IDBs) are found to be formed on the energetically less favorable plane. A model that takes a geometrical factor into consideration can explain this preferential tendency of IDB formation. Computational simulations based on the proposed model are consistent with experimental results.
J. Appl. Cryst. (2018). 51, 1556-1563
Limitations of the kinematic approximation in neutron reflectivity measurements for the analysis of bilayers
Neutron reflectivity on metallic superlattices is used to measure the volume expansion induced by deuterium content. The differences between treating the data with simple Gaussian fits and full reflectivity fits using Parratt's recursive method are shown and an explanation is proposed.
J. Appl. Cryst. (2018). 51, 1564-1570
Quasielastic neutron scattering is applied to analyse the atomic scale hydrogen transport processes occurring within the crystal lattices of hydrous minerals. Two types of transport processes were observed in Mg(OH)2, which has a prototypical layered hydrogen lattice structure.
J. Appl. Cryst. (2018). 51, 1571-1585
Energy-dispersive X-ray diffraction implemented in a back-reflection geometry has unique characteristics, particularly its insensitivity to sample morphology. The potential to develop a handheld X-ray diffraction instrument based on this technique is explored with the help of a prototype instrument adapted from a handheld X-ray fluorescence device.
J. Appl. Cryst. (2018). 51, 1586-1596
It is shown, using kinematic theory, that the helical nature of twisted nanowires is revealed in X-ray diffraction patterns by either elastic or shape anisotropy.
J. Appl. Cryst. (2018). 51, 1597-1604
Data collection and reduction on the ECHIDNA neutron powder diffractometer are described in detail, along with achievements and highlights from over ten years of operation. This paper replaces the previous design report as the canonical reference for ECHIDNA-derived data.
J. Appl. Cryst. (2018). 51, 1605-1615
Study of a multi-pinhole collimation system based small-angle neutron scattering instrument at the Compact Pulsed Hadron Source
A small-angle neutron scattering instrument based on a multi-pinhole collimator system is used to increase neutron current at the sample compared with a single-pinhole collimator system. Disadvantages such as crosstalk and reflection noise are overcome by the described optimization.
J. Appl. Cryst. (2018). 51, 1616-1622
The results of research into the three-dimensional structure of dislocation half-loops in silicon single crystals using laboratory X-ray and synchrotron sources are presented.
J. Appl. Cryst. (2018). 51, 1623-1632
Size-exclusion chromatography small-angle X-ray scattering of water soluble proteins on a laboratory instrument
Size-exclusion chromatography coupled with a laboratory-based small-angle X-ray scattering setup is presented and its performance evaluated for studies of various proteins covering a broad range of molecular weights.
J. Appl. Cryst. (2018). 51, 1633-1640
Upgraded SSRF BL19U2 beamline for small-angle X-ray scattering of biological macromolecules in solution
The upgraded biological small-angle X-ray scattering (SAXS) station at the Shanghai Synchrotron Radiation Facility is equipped with an in-vacuum automated sample loading system, an inline Agilent high-performance liquid chromatography system and a Wyatt light scattering device. The versatile sample environments and easy-to-access remote-control platform make the high-brightness beamline BL19U2 ideally suitable for performing SAXS experiments on biological macromolecules in solution.
J. Appl. Cryst. (2018). 51, 1641-1651
Microscopic behavior and metallic iron morphology from reduction of iron oxide by CO/H2 in a fluidized bed
FeO reduced by CO/H2 was investigated by density functional theory, and the conditions for iron whisker growth in CO/H2 were calculated.
J. Appl. Cryst. (2018). 51, 1652-1661
A semi-automated routine for continuous rotation electron diffraction has been developed, enabling high-throughput data collection. Serial electron crystallography combined with a deep convolutional network are used to screen for suitable crystals.
J. Appl. Cryst. (2018). 51, 1662-1670
Calibration of the Suanni small-angle neutron scattering instrument at the China Mianyang Research Reactor
The wavelength, the scattering vector magnitude and the absolute intensity for the Suanni small-angle neutron scattering spectrometer have been calibrated by using standard samples, providing an informative reference for users and diagnostic tools for instrument scientists.
J. Appl. Cryst. (2018). 51, 1671-1683
In situ detection of a novel lysozyme monoclinic crystal form upon controlled relative humidity variation
Effects of relative humidity on a novel monoclinic crystal form of hen egg-white lysozyme are assessed via in situ laboratory X-ray powder diffraction.
J. Appl. Cryst. (2018). 51, 1684-1690
Misfit dislocations between boron-doped homoepitaxial films and diamond substrates studied by X-ray diffraction topography
Limited X-ray and section topography have been used to characterize defects in both boron-doped homoepitaxial films and high-pressure high-temperature 1b (001) diamond substrates. Lattice mismatch generates, at the interface, two orthogonal systems of misfit dislocations in the form of half-loops propagating from the interface defects, particularly threading dislocations and growth sector boundaries.
J. Appl. Cryst. (2018). 51, 1691-1705
Crystallization of Ge2Sb2Te5 and nitrogren-doped Ge2Sb2Te5 phase-change-materials thin films studied by in situ combined X-ray scattering techniques
In situ combined X-scattering techniques (XRR and XRD) on a laboratory tool provide details insight into the mechanical behaviour and volume shrinkage upon crystallization of phase-change Ge2Sb2Te5 films. The effect of nitrogen incorporation into Ge2Sb2Te5 is studied.
J. Appl. Cryst. (2018). 51, 1706-1714
Characterization of anisotropic pores and spatially oriented precipitates in sintered Mo-base alloys using small-angle neutron scattering
The present work reports a method for treating the anisotropic small-angle scattering from sintered Mo-base materials. The method yields the morphology and quantity of uniaxially deformed sinter pores and of aligned anisotropic precipitates.
J. Appl. Cryst. (2018). 51, 1715-1720
Crystallographic anisotropy in surface properties of brass and its dependence on the electron work function
This study demonstrates a novel probing parameter, the electron work function, for surface analysis and its correlation with the dependence of surface properties on crystallographic orientation.
J. Appl. Cryst. (2018). 51, 1721-1733
Combining a nine-crystal multi-analyser stage with a two-dimensional detector for high-resolution powder X-ray diffraction
The high-resolution powder diffraction setup of the ESRF ID22 beamline has been combined with a two-dimensional Pilatus3 X CdTe 300 K-W detector, offering new possibilities in terms of data handling and improving the overall performance of high-resolution powder diffraction.
teaching and education
J. Appl. Cryst. (2018). 51, 1734-1738
EwaldSphere is a Microsoft Windows program that simulates a small-molecule X-ray diffractometer and the normally invisible components of the diffraction process. The program is designed mainly for teaching the basic concepts of diffraction by allowing the user to explore a three-dimensional model of the Ewald sphere construction.
J. Appl. Cryst. (2018). 51, 1739-1744
Powder diffraction data sharing is coming. A discussion about which raw data should be shared is triggered.
J. Appl. Cryst. (2018). 51, 1745-1751
InteractiveXRDFit: a new tool to simulate and fit X-ray diffractograms of oxide thin films and heterostructures
InteractiveXRDFit is a custom-made MATLAB program that calculates the X-ray diffracted intensity for heterostructures.
J. Appl. Cryst. (2018). 51, 1752-1765
Macros implementing the main concepts of the whole powder pattern modelling approach have been written for TOPAS, taking into account the size and strain broadening components of the diffraction line profiles.
J. Appl. Cryst. (2018). 51, 1766-1772
Which glue to choose? A neutron scattering study of various adhesive materials and their effect on background scattering
This study investigates the neutron scattering signals from different adhesives that are commonly used to mount samples. The pros and cons of each glue are discussed, including when to use (or not use) each.
J. Appl. Cryst. (2018). 51, 1773-1776