Quasiperiodicity and the nanoscopic morphology of some polyurethanes

Small-angle X-ray scattering monitoring of tensile tests of polyurethanes from uniform components shows semi-rigid quasiperiodic sequences of hard domains which are related to the synthesis by polyaddition.

Mode-crystallography analysis of the crystal structures and the low- and high-temperature phase transitions in Na_0.5K_0.5NbO₃

Structural investigations under temperature variation were carried out on Na_0.5K_0.5NbO₃, using diffraction techniques and the symmetry mode analysis approach. The material underwent a series of three phase transitions: R3c → Amm2 → P4mm → Pm3m. A step forward in the use of the symmetry-adapted modes as degrees of freedom in the refinement process is reported

An accurate projection model for diffraction image formation and inversion using a polychromatic cone beam

An accurate projection model is introduced for X-ray diffraction contrast tomography (CT) on conventional laboratory source µCT systems.

Measurement of strain in InGaN/GaN nanowires and nanopyramids

Measurements are made of strain and composition in InGaN/GaN heterogeneous nanowires and nanopyramids using reciprocal space mapping.

Influence of multiple small-angle neutron scattering on diffraction peak broadening in ferritic steel

A sufficiently strong magnetic field can enhance the deep penetration capability of neutron diffraction by reducing the peak broadening.

X-ray micro Laue diffraction tomography analysis of a solid oxide fuel cell

Through micro Laue tomography analysis, the depth-resolved cartographies (i) of NiO grains in a solid oxide fuel cell sample and (ii) of the full tensor of the deviatoric strain into a slice of a Ge sample are obtained.

Development of a laboratory-based transmission diffraction technique for in situ deformation studies of Mg alloys

A laboratory-based transmission X-ray diffraction technique was developed to measure elastic lattice strains parallel to the loading direction during in situ tensile deformation.

Antisite defect elimination through Mg doping in stoichiometric lithium tantalate powder synthesized via a wet-chemical spray-drying method

A wet-chemical spray-drying method was developed to synthesize homogeneous MgO:SLT powder to eliminate its antisite defects for high-quality MgO:SLT crystal growth.

Dynamic strain propagation in nanoparticulate zirconia refractory

Dynamic strain propagation in granular ceramics presents a cause of failure in industrial materials that undergo rapid thermal cycling. A mechanism based on degradation of grain contacts is proposed to explain the oscillatory nature of microstrain.

Crystallization dynamics and interface stability of strontium titanate thin films on silicon

Nonstoichiometric SrTiO₃ thin films were fabricated by different thin-film deposition methods. The impact on the oxide/silcon interface stability as well as the crystallization onset temperature is investigated.

Effect of stress on NiO reduction in solid oxide fuel cells: a new application of energy-resolved neutron imaging

In this work the authors demonstrate the great potential of energy-resolved neutron imaging for studies of two important phenomena taking place in solid oxide fuel cell anode supports: accelerated creep and reduction of nucleation due to applied stress.

Dislocation structure in different texture components determined by neutron diffraction line profile analysis in a highly textured Zircaloy-2 rolled plate

The dislocation densities and major slip-system populations in the different texture components of a rolled Zircaloy-2 plate are determined by neutron diffraction line profile analysis. Fourteen diffraction patterns were recorded in seven different orientations of the specimen, and diffraction patterns were composed by selecting texture-specific diffraction profiles.

A common theory of line broadening and rocking curves

A unified theory is developed to describe radial line broadening and rocking-curve broadening of diffraction peaks of dislocated crystals. It is shown that polar decomposition of the nonlocal strain tensor is more appropriate to describe the intensity distribution around fundamental Bragg reflections than separation into symmetrical and antisymmetric tensor components.

Versatile sample environments and automation for biological solution X-ray scattering experiments at the P12 beamline (PETRA III, DESY)

An integrated environment for biological small-angle X-ray scattering (BioSAXS) at the high-brilliance P12 synchrotron beamline of the EMBL (DESY, Hamburg) allows for a broad range of solution scattering experiments. Automated hardware and software systems have been designed to ensure that data collection and processing are efficient, streamlined and user friendly.

GISAXS and TOF-GISANS studies on surface and depth morphology of self-organized TiO₂ nanotube arrays: model anode material in Li-ion batteries

Self-organized TiO₂ nanotubular arrays with/without an Si coating are model anode materials in Li-ion batteries. Morphological parameters of such nanotubular arrays like nanotube radius, intertubular distance and porosity are determined with high statistical relevance using time-of-flight grazing-incidence small-angle neutron scattering (TOF-GISANS) and small-angle X-ray scattering (GISAXS).

In situ characterization of β′′ precipitation in an Al–Mg–Si alloy by anisotropic small-angle neutron scattering on a single crystal

The growth of β′′ precipitates during ageing of an Al–Mg–Si alloy is characterized in situ by small-angle neutron scattering on a single crystal. The length, diameter and number density of precipitates are measured.

Qu­antitative X-ray phase contrast waveguide imaging of bacterial endospores

Quantitative X-ray phase contrast imaging uniquely offers quantitative imaging information in terms of electron density maps allowing for mass and mass density determinations of soft biological samples (`weighing with light'). Here, it was carried out using coherent X-ray waveguide illumination, yielding values of the mass and mass density of freeze-dried bacterial endospores (Bacillus spp.).

Simulation of X-ray diffraction profiles for bent anisotropic crystals

The equations for simulating diffraction profiles and their implementation in computer code are presented for the cases of meridionally and sagittally bent crystals using the multilamellar and Penning–Polder theories and including crystal anisotropy.

Problem of elastic anisotropy and stacking faults in stress analysis using multireflection grazing-incidence X-ray diffraction

Multireflection grazing-incidence X-ray diffraction (MGIXD) was used to determine the stress- and strain-free lattice parameter in the surface layer of mechanically treated tungsten and austenitic steel. A new interpretation of the MGIXD results was proposed and applied for the first time to measure the probability of stacking faults as a function of penetration depth.

The fast azimuthal integration Python library: pyFAI

This article details the geometry, peak-picking, calibration and integration procedures on multi- and many-core devices implemented in the Python library for high-performance azimuthal integration.

Determination of the melting and freezing temperatures of Pb nanoparticles embedded in a PbO–B₂O₃–SnO₂ glass by using only the SAXS method

It is shown that the melting and freezing temperatures of dilute sets of nanoparticles embedded in homogeneous matrices can be determined experimentally using only the small-angle X-ray scattering (SAXS) technique. From the analysis of the temperature dependence of SAXS intensity, the melting and freezing temperatures of a dilute set of Pb nanoparticles with an average radius 〈R〉 = 16.1 nm, embedded in a lead–borate glass, were determined to be 580 and 433 K, respectively.

High-resolution characterization of the forbidden Si 200 and Si 222 reflections

The basis-forbidden Si 200 and Si 222 reflections are investigated in detail as a function of the in-plane sample orientation Φ and the divergence perpendicular to the diffraction plane of the used diffractometer. The results have important consequences for the detection of layer peaks near these reflections.

Enhancement of thermoelectric figure of merit in Bi₂Se₃ crystals through a necking process

Bulk single crystals of bismuth selenide with good crystalline perfection were grown successfully by introducing a necking process in the vertical Bridgman technique (VBT) through a specially designed VBT ampoule. The structure, crystalline perfection and layered nature were assessed, thermoelectric parameters were measured, and a significantly enhanced figure of merit compared to that reported in the literature was found. Nanoindentation analysis was carried out for the first time.

Matrix effects in white-beam X-ray fluorescence holography

A procedure that allows one to correct for matrix effects in white-beam X-ray fluorescence holography is proposed.

Structural investigation of N,N′-methylenebisacryl­amide via X-ray diffraction assisted by crystal structure prediction

The crystal structure of N,N′-methylenebisacrylamide was solved by combining molecular geometry optimization and crystal structure prediction analysis with standard diffraction techniques. The best structure was selected among thousands of predicted arrangements, comparing all calculated patterns with laboratory powder X-ray diffraction data, and was then refined with the Rietveld method. This approach allowed the twinning problems affecting the single-crystal data to be overcome, which eventually confirmed the predicted model.

Nested Kirkpatrick–Baez (Montel) optics for hard X-rays

A comprehensive description and ray-tracing simulations of symmetric nested Kirkpatrick–Baez mirrors are given. The correct alignment procedure, shape and multilayer coatings of the mirrors are simulated.

Scattering functions of polyhedra

Scattering functions of polyhedra are presented, including regular, semi-regular, truncated, concave and stellated.

A versatile environmental control cell for in situ guest exchange single-crystal diffraction

A new environmental control cell has been developed for use with current single-crystal diffractometer equipment, which provides the opportunity for in situ experiments on single crystals under non-ambient atmospheres and pressures. The design and fabrication of the cell as well as the results of a case study using this device are presented.

Determination and mitigation of the uncertainty of neutron diffraction measurements of residual strain in large-grained polycrystalline material

For large-grained samples it is advantageous to perform pairs of neutron diffraction measurements at the same spatial location but rotated 180° around the geometric centre of the gauge volume as a means of minimizing the scatter coming from the random positioning of grains within the gauge volume.

An efficient algorithm for computing the primitive bases of a general lattice plane

A simple algorithm for computing the two-dimensional primitive basis vectors in an arbitrary crystallographic plane of an underlying three-dimensional lattice is proposed.

EFRESOL: effective resolution of a diffraction data set

The program EFRESOL calculates the effective resolution of a diffraction data set of an arbitrary completeness.

QUALX2.0: a qualitative phase analysis software using the freely available database POW_COD

QUALX2.0 is the new version of QUALX. The main novelty of QUALX2.0 is the possibility of querying also a freely available database, POW_COD, built up by starting from the structural information contained in the Crystallography Open Database.

Nebula: reconstruction and visualization of scattering data in reciprocal space

A software to reconstruct and visualize diffuse scattering in three-dimensional reciprocal space using data from X-ray area detectors is presented.

Achieving grazing-incidence ultra-small-angle X-ray scattering in a laboratory setup

High reciprocal spatial resolution grazing-incidence ultra-small-angle X-ray scattering measurements have been realized in a laboratory small-angle X-ray scattering setup via lengthening the distance between the collimation slit systems and the sample-to-detector distance.

Powder diffraction in Bragg–Brentano geometry with straight linear detectors

The influence of a straight linear detector on the powder diffraction signal in the Bragg–Brentano focusing geometry is presented. Recipes for how to limit resolution-degrading effects are developed.

Strain and dislocation gradients from diffraction