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This article describes a correction procedure for the removal of indirect background contributions to measured small‐angle X‐ray scattering patterns. The high scattering power of a sample in the ultra‐small‐angle region may serve as a secondary source for a window placed in front of the detector. The resulting secondary scattering appears as a sample‐dependent background in the measured pattern that cannot be directly subtracted. This is an intricate problem in measurements at ultra‐low angles, which can significantly reduce the useful dynamic range of detection. Two different procedures are presented to retrieve the real scattering profile of the sample. [ABSTRACT FROM AUTHOR]

This study characterizes the microstructure and mineralogy of 132 (ODP sample), 1000 and 1880 million‐year‐old chert samples. By using ultra‐small‐angle X‐ray scattering (USAXS), wide‐angle X‐ray scattering and other techniques, the preservation of organic matter (OM) in these samples is studied. The scarce microstructural data reported on chert contrast with many studies addressing porosity evolution in other sedimentary rocks. The aim of this work is to solve the distribution of OM and silica in chert by characterizing samples before and after combustion to pinpoint the OM distribution inside the porous silica matrix. The samples are predominantly composed of alpha quartz and show increasing crystallite sizes up to 33 ± 5 nm (1σ standard deviation or SD). In older samples, low water abundances (∼0.03%) suggest progressive dehydration. (U)SAXS data reveal a porous matrix that evolves over geological time, including, from younger to older samples, (1) a decreasing pore volume down to 1%, (2) greater pore sizes hosting OM, (3) decreasing specific surface area values from younger (9.3 ± 0.1 m2 g−1) to older samples (0.63 ± 0.07 m2 g−1, 1σ SD) and (4) a lower background intensity correlated to decreasing hydrogen abundances. The pore‐volume distributions (PVDs) show that pores ranging from 4 to 100 nm accumulate the greater volume fraction of OM. Raman data show aromatic organic clusters up to 20 nm in older samples. Raman and PVD data suggest that OM is located mostly in mesopores. Observed structural changes, silica–OM interactions and the hydrophobicity of the OM could explain the OM preservation in chert. [ABSTRACT FROM AUTHOR]

Recently, fourth‐generation synchrotron sources with several orders of magnitude higher brightness and higher degree of coherence compared with third‐generation sources have come into operation. These new X‐ray sources offer exciting opportunities for the investigation of soft matter and biological specimens by small‐angle X‐ray scattering (SAXS) and related scattering methods. The improved beam properties together with the advanced pixel array detectors readily enhance the angular resolution of SAXS and ultra‐small‐angle X‐ray scattering in the pinhole collimation. The high degree of coherence is a major boost for the X‐ray photon correlation spectroscopy (XPCS) technique, enabling the equilibrium dynamics to be probed over broader time and length scales. This article presents some representative examples illustrating the performance of SAXS and XPCS with the Extremely Brilliant Source at the European Synchrotron Radiation Facility. The rapid onset of radiation damage is a significant challenge with the vast majority of samples, and appropriate protocols need to be adopted for circumventing this problem. [ABSTRACT FROM AUTHOR]

Reflective display devices, especially for electrochromic photonic crystals (ECPCs), are of great interest to researchers due to their convenient control approach, wide color regulation range, fast response, and low power consumption. Herein, liquid colloidal crystals (LCCs) of SiO2 nanospheres were prepared through an evaporation-induced self-assembly method and used as a reflective unit for fabricating dynamic ECPC devices. The ECPC device exhibited brilliant controllable structural color across the visible spectrum under low voltages (<3.5 V). Based on the in situ ultra-small-angle X-ray scattering results and reflective spectra, regulatory rules of the dynamic ECPC device concerning a color tunable range, reflectance intensity, response speed, and cyclic performance were set up, and the relationship between slurry concentration, electrode spacing, and viewing angle was established. Furthermore, a dynamic mechanism was revealed for explaining the responsive behaviors of reflection spectra during the electrical modulation, which is significant for the development of ECPC devices in the future. Based on the parameter optimization and structure design of the dynamic ECPC device, a pressure-responsive electrochromic prototype device was constructed with rapid response, dynamic structural color, and good reversibility, which demonstrated its great potential in reflective display units and multifunctional sensors. [ABSTRACT FROM AUTHOR]

Purpose: Multiple-image radiography (MIR) is an analyzer-based synchrotron X-ray imaging approach capable of dissociating absorption, refraction, and scattering components of X-ray interaction with the material. It generates additional image contrast mechanisms (besides absorption), especially in the case of soft tissues, while minimizing absorbed radiation dose. Our goal is to develop a contrast agent for MIR using ultrasound microbubbles by carrying out a systematic assessment of size, shell material, and concentration. Procedures: Microbubbles were synthesized with two different shell materials: phospholipid and polyvinyl-alcohol. Polydisperse perfluorobutane-filled lipid microbubbles were divided into five size groups using centrifugation. Two distributions of air-filled polymer microbubbles were generated: 2–3 µm and 3–4 µm. A subset of polymer microbubbles 3–4 µm had iron oxide nanoparticles incorporated into their shell or coated on their surface. Microbubbles were immobilized in agar with different concentrations: 5 × 107, 5 × 106, and 5 × 105 MBs/ml. MIR was conducted on the BioMedical Imaging and Therapy beamline at the Canadian Light Source. Three images were generated: Gaussian amplitude, refraction, and ultra-small-angle X-ray scattering (USAXS). The contrast signal was quantified by measuring mean pixel values and comparing them with agar. Results: No difference was detected in absorption or refraction images of all tested microbubbles. Using USAXS, a significant signal increase was observed with lipid microbubbles 6–10 µm at the highest concentration (p = 0.02), but no signal was observed at lower concentrations. Conclusions: These data indicate that lipid microbubbles 6–10 µm are candidates as contrast agents for MIR, specifically for USAXS. A minimum concentration of 5 × 107 microbubbles (lipid-shell 6–10 µm) per milliliter was needed to generate a detectable signal. [ABSTRACT FROM AUTHOR]

Determination of the orientation of microfibrils within ultra-high molecular weight polyethylene (UHMWPE) fibers is considered to be an important method in evaluating the mechanical properties of the fibers. Four commonly used orientation evaluation methods are summarized and used to evaluate UHMWPE fibers at different drawing stages in the industrial line, and the results exhibit certain limitations. To overcome these limitations, a new evaluation method for quantitive characterization of UHMWPE fiber properties is proposed. Meanwhile, in situ small-angle X-ray scattering data of an UHMWPE fiber drawn at 100 °C were used to perform a Pearson correlation coefficient test, and the results show a very strong correlation between the strain ratio and the evaluated coefficient. [ABSTRACT FROM AUTHOR]

Developing an earlier suggestion by Spalla, Lyonnard & Testard [J. Appl. Cryst. (2003), 36, 338–347], it is shown that the porosity and the specific surface of a porous material can be determined by the small‐ and ultra‐small‐angle X‐ray scattering (SAXS and USAXS, respectively) intensity of a sample made up of loosely packed and rather large grains of the material, provided the Porod plot of the intensity shows two plateaux within the range of the explored scattering vectors. To this end, it is necessary to consider the system geometrically as formed by three phases: the bulk matter, the macropores and the micropores. [ABSTRACT FROM AUTHOR]

The new technical features and enhanced performance of the ID02 beamline with the Extremely Brilliant Source (EBS) at the ESRF are described. The beamline enables static and kinetic investigations of a broad range of systems from ångström to micrometre size scales and down to the sub‐millisecond time range by combining different small‐angle X‐ray scattering techniques in a single instrument. In addition, a nearly coherent beam obtained in the high‐resolution mode allows multispeckle X‐ray photon correlation spectroscopy measurements down to the microsecond range over the ultra‐small‐ and small‐angle regions. While the scattering vector (of magnitude q) range covered is the same as before, 0.001 ≤ q ≤ 50 nm−1 for an X‐ray wavelength of 1 Å, the EBS permits relaxation of the collimation conditions, thereby obtaining a higher flux throughput and lower background. In particular, a coherent photon flux in excess of 1012 photons s−1 can be routinely obtained, allowing dynamic studies of relatively dilute samples. The enhanced beam properties are complemented by advanced pixel‐array detectors and high‐throughput data reduction pipelines. All these developments together open new opportunities for structural, dynamic and kinetic investigations of out‐of‐equilibrium soft matter and biophysical systems. [ABSTRACT FROM AUTHOR]

Breakup (dispersion) and distribution of nanoparticles are the chief hurdles towards taking advantage of nanoparticles in polymer nanocomposites for reinforcement, flame retardancy, conductivity, chromaticity, and other properties. Microscopy is often used to quantify mixing, but it has a limited field of view, does not average over bulk samples, and fails to address nano-particle hierarchical structures. Ultra-small-angle X-ray scattering (USAXS) can provide a macroscopic statistical average of nanoscale dispersion (breakup) and emergent hierarchical structure, as well as the distribution on the nanoscale. This work compares several common mixer geometries for carbon black-polystyrene nanocomposites. Two twin-screw extruder geometries, typical for industrial processing of melt blends, are compared with a laboratory-scale single screw extruder and a Banbury mixer. It is found that for a given mixer, nanoscale distribution increases following a van der Waals function using accumulated strain as an analogue for temperature while macroscopic distribution/dispersion, using microscopy, does not follow this dependency. Breakup and aggregation in dispersive mixing follow expected behavior on the nanoscale. Across these drastically different mixing geometries an unexpected dependency is observed for nanoscale distributive mixing (both nano and macroscopic) as a function of accumulated strain that may reflect a transition from distributive turbulent to dispersive laminar mixing as the mixing gap is reduced. [Display omitted] • Nanoparticle dispersion/distribution is controlled by mixing geometry and accumulated strain. • Nanocomposites of carbon black in polystyrene studied using twin and single screw extruders and a Banbury mixer. • Small-angle X-ray scattering (virial/Van der Waals model) and SEM characterized mixing. • Dispersive/breakup may arise in narrow gap/laminar flow; distributive mixing in wider gap/turbulent flow. • Mixing changes in carbon black hierarchical structure are described. [ABSTRACT FROM AUTHOR]