October 2015 issue
J. Appl. Cryst. (2015). 48, 1346-1354
In situ monitoring of phase transformation microstructures at Earth's mantle pressure and temperature using multi-grain XRD
A new approach is presented for an in situ investigation of the microstructures of polycrystalline samples undergoing phase transitions at Earth's mantle pressure and temperature. Diffraction experiments are carried out using synchrotron radiation combined with a resistively heated diamond anvil cell up to 25 GPa and 1000 K. Multi-grain analysis is used to follow phase proportions and grain size distributions, and to track individually hundreds of grains in the transforming sample. As an illustration, results are presented of the evolution of microstructure during the α–γ transition in hydrous Mg2SiO4·H2O up to 22 GPa and 940 K.
J. Appl. Cryst. (2015). 48, 1355-1363
Small-angle X-ray scattering is used to determine the shape and periodicity of nanostructures patterned with industrially relevant fabrication techniques.
J. Appl. Cryst. (2015). 48, 1364-1380
Thermal expansion tensors and their temperature dependence are derived for a set of 13 energetic materials.
J. Appl. Cryst. (2015). 48, 1381-1390
The mosaic crystal highly annealed pyrolytic graphite (HAPG) has been characterized with respect to its diffraction properties using monochromated synchrotron radiation.
J. Appl. Cryst. (2015). 48, 1391-1404
A general theory for elastic scattering from laterally heterogeneous vesicles is presented. The analytical form factor for static round domains provides a new and important tool for the quantitative analysis of neutron scattering data from phase-separated vesicles.
J. Appl. Cryst. (2015). 48, 1405-1419
The influence of noncentrosymmetric crystal structures on electron backscatter diffraction (EBSD) patterns is analysed using the example of zincblende-structure-type semiconductors. EBSD measurements combined with dynamical theory Kikuchi pattern simulations enable the polarity of lattice planes to be assigned.
J. Appl. Cryst. (2015). 48, 1420-1428
On the use of molecular dynamics simulation to calculate X-ray thermal diffuse scattering from molecular crystals
A procedure is investigated for calculating single-crystal X-ray thermal diffuse scattering features using a molecular dynamics simulation. The results are compared with experimental observations and the results from previous Monte Carlo simulations.
J. Appl. Cryst. (2015). 48, 1429-1436
A study of the atomic structure of multi-layered graphene obtained by chemical exfoliation is described. Wide-angle neutron and X-ray scattering along with computer simulations were used, which yielded a good agreement between the experimental data and the theoretical models.
J. Appl. Cryst. (2015). 48, 1437-1450
On the basis of the continuum theory of micromagnetics, the correlation function of the spin-misalignment small-angle neutron scattering cross section of bulk ferromagnets is computed and discussed.
J. Appl. Cryst. (2015). 48, 1451-1461
Diffraction analysis of strongly inhomogeneous residual stress depth distributions by modification of the stress scanning method. I. Theoretical concept
On the basis of simulations, a theoretical concept for the evaluation of strongly inhomogeneous residual stress depth gradients by means of the stress scanning method is presented. Simulations for very small gauge volumes are presented for the energy-dispersive case of diffraction.
J. Appl. Cryst. (2015). 48, 1462-1475
Diffraction analysis of strongly inhomogeneous residual stress depth distributions by modification of the stress scanning method. II. Experimental implementation
The modified stress scanning concept, which was introduced in the first part of this study, is implemented for the analysis of the strongly inhomogeneous residual stress depth distributions present within a bulk material and an alternately stacked multilayer coating system.
J. Appl. Cryst. (2015). 48, 1476-1484
Reliably distinguishing protein nanocrystals from amorphous precipitate by means of depolarized dynamic light scattering
Depolarized dynamic light scattering is applied to distinguish between nucleation and amorphous cluster formation in protein solutions during crystallization.
J. Appl. Cryst. (2015). 48, 1485-1497
Empirical correction for resolution- and temperature-dependent errors caused by factors such as thermal diffuse scattering
Resolution- and temperature-dependent factors such as thermal diffuse scattering can lead to significant errors in charge density studies. The influence on the model of the crystal structure is shown and a simple empirical correction is proposed.
J. Appl. Cryst. (2015). 48, 1498-1506
Phase densities and lamellar morphologies of semicrystalline polyethylenes via absolute small-angle X-ray scattering measurements
The analysis of absolute small-angle X-ray scattering measurements reveals that the temperature-dependent density of the liquid-like amorphous phase enclosed between crystalline layers in semicrystalline polyethylene is crystallinity independent and lower than melt-extrapolated values.
J. Appl. Cryst. (2015). 48, 1507-1513
A large amount of local strain is found to be accumulated in tetragonal hen egg white lysozyme crystals grown under an applied field at 20 kHz through analysis of the X-ray rocking-curve profile full width at half-maximum. Comparison with previous results obtained for crystals grown with an applied field at 1 MHz suggests that there is an optimum frequency to achieve an improved quality of protein crystals.
J. Appl. Cryst. (2015). 48, 1514-1521
Polarization analysis in neutron small-angle scattering with a novel triplet dynamic nuclear polarization spin filter
A novel neutron spin filter based on the strong spin dependence of the neutron scattering on protons has been developed. Its application as a polarization analyzer is demonstrated in a magnetic SANS experiment with the measurement of the spin-dependent scattering signals of a CuFeNi alloy.
J. Appl. Cryst. (2015). 48, 1522-1533
Complementary use of monochromatic and white-beam X-ray micro-diffraction for the investigation of ancient materials
Laue single-crystal and monochromatic powder micro-diffraction mappings are combined to describe the organization of the crystalline phases in archaeological artefacts at the micrometre scale, in relation with the physical properties of these heterogeneous materials.
J. Appl. Cryst. (2015). 48, 1534-1542
Information on the shape and size distribution of Pd nanocrystals as well as their surface structure and defects is obtained by combining X-ray diffraction line profile analysis with transmission electron microscopy and surface electrochemistry.
J. Appl. Cryst. (2015). 48, 1543-1550
Topology and temperature dependence of the diffuse X-ray scattering in Na0.5Bi0.5TiO3 ferroelectric single crystals
The high-resolution temperature-dependent diffuse X-ray scattering from an Na0.5Bi0.5TiO3 perovskite-based single crystal is measured on the approach to the polymorphic phase transition. The previously unseen topological features of the diffuse scattering and their temperature evolution are reported.
J. Appl. Cryst. (2015). 48, 1551-1559
SdsA polymorph isolation and improvement of their crystal quality using nonconventional crystallization techniques
Different crystallization techniques such as vapour diffusion in hanging drops and counterdiffusion in gels allowed the selective isolation of different crystal polymorphs of the SdsA protein from Pseudomonas aeruginosa PAO1 and improved their diffraction quality. Analysis of the three-dimensional structures obtained from the different polymorphs provided insights into the relevance of crystal packing for the interpretation of biological information.
J. Appl. Cryst. (2015). 48, 1560-1572
Representational analysis of extended disorder in atomistic ensembles derived from total scattering data
Representational analysis is used to characterize correlated short-range order in large atomistic ensembles. This method, analogous to tight-binding methods, enables the extraction of relevant structural parameters in an orthogonal and local basis that permits robust statistical analysis of crystalline disorder.
J. Appl. Cryst. (2015). 48, 1573-1580
Profex is a platform-independent open-source graphical user interface for the Rietveld refinement program BGMN.
J. Appl. Cryst. (2015). 48, 1581-1586
AutoFP: a GUI for highly automated Rietveld refinement using an expert system algorithm based on FullProf
AutoFP is distributed freely as a highly automated software toolkit for the widely used Rietveld refinement program FullProf.
J. Appl. Cryst. (2015). 48, 1587-1598
A computer program to perform small-angle X-ray and neutron scattering data evaluation is presented.
J. Appl. Cryst. (2015). 48, 1599-1603
Effect of using polyimide capillaries during thermal experiments on the particle size distribution of supported Pt nanoparticles
Evidence is presented that water outgassing from polyimide (Kapton HN-type) capillaries at temperatures as low as 438 K causes the overgrowth of supported Pt catalysts.
J. Appl. Cryst. (2015). 48, 1604-1606
Molecular weight–gyration radius relation of globular proteins: a comparison of light scattering, small-angle X-ray scattering and structure-based data
Light scattering and small-angle scattering data indicate that for globular proteins the relation between molecular weight and radius of gyration follows a power law which can be related to the fractal dimension of the proteins.
J. Appl. Cryst. (2015). 48, 1607-1608
J. Appl. Cryst. (2015). 48, 1609
J. Appl. Cryst. (2015). 48, 1610