Search

Furthermore, the pressure-temperature diagram in the phase boundary of calcite was well established at temperature ranges from 298 K to 773 K, pressures up to 16.0 GPa, and a depth up to 480 km, and further, its potential geophysical implications were discussed in detail. At three representative pressure points (i.e., 10.5 GPa, 12.5 GPa, and 13.8 GPa), the phase transition temperatures between CaCO SB 3 sb -III and CaCO SB 3 sb -VI phases were individually determined. They found that the high-pressure hematite phase began to form at the temperature point of 653 K and, subsequently, the starting material of the pyrite phase was thoroughly transformed into the hematite phase at the temperature point of 688 K, and, finally, the hematite phase would be melted at a temperature higher than 853 K. [Extracted from the article]

[Display omitted] Shear flow applied to bicontinuous microemulsions is expected to induce a transition to lamellae via the suppression of surfactant monolayer fluctuations. Compared to the topologically analogous L 3 (sponge) phase, composed of surfactant bilayers, this transition is likely to occur at much higher shear rates. We examine the flow response of a model bicontinuous microemulsion, D 2 O/ n -octane/C 10 E 4 by coupling microfluidics with small-angle neutron scattering (SANS), attaining wall shear rates in excess of 105 s−1. The reduction of probed sample volumes down to ∼ 10 nL allows the spatial mapping of the structural and orientation changes within the microchannel, as a function of the flow field components. With increasing flow rate, we observe a gradual increase in scattering anisotropy, accompanied by a decrease of the microemulsion domain size along the main flow orientation. A consistent description of the degree of anisotropy was obtained when considering the velocity gradient along the scattering plane perpendicular to the flow. We discuss the flow dependence of the effective bending rigidity, rationalizing a strong influence of shear on thermal membrane fluctuations. Assuming a similar shear dependence for the saddle splay modulus, the bicontinuous-to-lamellar transition can be attributed to the gradual disappearance of inter-lamellar passages. [ABSTRACT FROM AUTHOR]

[Display omitted] Recent advances in protein expression protocols, sample handling, and experimental set up of small-angle scattering experiments have allowed users of the technique to structurally investigate biomolecules of growing complexity and structural disorder. Notable examples include intrinsically disordered proteins, multi-domain proteins and membrane proteins in suitable carrier systems. Here, we outline a modeling scheme for calculating the scattering profiles from such complex samples. This kind of modeling is necessary for structural information to be refined from the corresponding data. The scheme bases itself on a hybrid of classical form factor based modeling and the well-known spherical harmonics-based formulation of small-angle scattering amplitudes. Our framework can account for flexible domains alongside other structurally elaborate components of the molecular system in question. We demonstrate the utility of this modeling scheme through a recent example of a structural model of the growth hormone receptor membrane protein in a phospholipid bilayer nanodisc which is refined against experimental SAXS data. Additionally we investigate how the scattering profiles from the complex would appear under different scattering contrasts. For each contrast situation we discuss what structural information is contained and the related consequences for modeling of the data. [ABSTRACT FROM AUTHOR]

An effect of receptor‐binding domain (RBD) of SARS‐CoV‐2 S‐protein on structural parameters of model lipid membranes presented by dimyristoylphosphatidylcholine (DMPC) systems with cholesterol and melatonin impurities is studied by small angle neutron scattering (SANS). It is shown that an increase in melatonin concentration in the lipid membrane leads to a decrease in the thickness of the lipid bilayer, while an increase in the concentration of cholesterol leads to an increase in its thickness. It is suggested that increasing the concentration of melatonin in a membrane prevents the interaction of coronaviral S‐protein with a lipid membrane of a cell. In the presence of cholesterol in the system, the interaction of a lipid membrane with an active part of S‐protein occurs depending on a phase state of the lipid: in the case of a gel phase, there is no changes in structural parameters, but at higher temperatures in the case of a liquid crystal phase, an addition of RBD SARS‐CoV‐2 to the system causes a reduce in the membrane thickness. [ABSTRACT FROM AUTHOR]

Organic-inorganic composite systems for biomedical applications with zero-valent copper nanoparticles were synthesized. Hydrazine hydrate was used as a reducing agent; ionogenic water-soluble copolymers (polyelectrolytes) were used as hydrophilic polymeric stabilizers. Small-angle X-ray and neutron scattering methods were used to evaluate the size distribution of zero-valent copper nanoparticles stabilized by the copolymer. Transmission electron microscopy and atomic force microscopy were used to visualize this distribution. It was shown that using a copolymer of 2-deoxy-2-methacrylamido-D-glucose with 2-dimethylaminoethyl methacrylate or acrylic acid with N,N,N,N-trimethyl [methacryloyloxyethyl] ammonium methyl sulfate facilitated the preparation of zero-valent copper nanoparticles with the sizes of less than 5 nm. The maximum size of nanoparticles in their distribution was less than 60 nm. This effect is due to the relatively good shielding of nanoparticles in solution. [ABSTRACT FROM AUTHOR]

In this paper, we continue the adaptation of neutron-scattering methods for studying the microstructure of electrode materials of lithium-ion batteries in order to improve their specific energy storage. The effect of conductive carbon additives (graphene and graphene oxide) on the porous structure of electrodes with various bases, including LiFePO4, Li4Ti5O12, and LiNiMnCoO2, is studied via the small-angle scattering of thermal neutrons. To separate the scattering by closed and open pores, the electrodes are wetted with a typical liquid electrolyte with a deuterated liquid carrier (dimethyl carbonate), which leads to the matching of scattering by open pores. It is established that electrically conductive carbon additives change the porosity of the electrode to varying degrees and affect the wettability of materials due to both varying degrees of penetration into the pores of the initial material and the effect on the initial matrix. A universal effect on the dispersion of a polymer binder (polyvinylidene fluoride) is also found. [ABSTRACT FROM AUTHOR]

Precipitation hardening is a promising approach for strengthening of Hadfield steels. The present study examines the potential to achieve this by combining vanadium addition (up to 2 wt pct) with short-time aging (15 minutes) at 1173 K (900 °C). It was found that such a treatment is sufficient to generate a dispersion of nanoscale precipitates that provided a significant increase in hardness. Small-angle neutron scattering and transmission electron microscopy measurements were performed to quantify the particle dispersion, and Orowan precipitate hardening predictions made using the parameters thus obtained show good correspondence with the observed rates of age hardening, suggesting the precipitates are resistant to shearing. The present steels containing vanadium showed a small reduction in work-hardening capacity and this is believed to be due to carbon depletion from the matrix. It is concluded that the addition of vanadium and a short aging treatment at 1173 K (900 °C) provide a promising pathway to imparting hardness increases that provide gouge resistance during the running-in period of components made from Hadfield steel. For optimum performance, additional carbon should be added to maintain the solute carbon content of the matrix, and hence the matrix work-hardening rate. [ABSTRACT FROM AUTHOR]

Resorcinol-formaldehyde aerogels were synthesised using acid-catalysed polycondensation of resorcinol and formaldehyde in acetonitrile or dimethyl sulfoxide, followed by supercritical drying in CO2. The structure and mechanical properties of the aerogels were analysed using low temperature nitrogen adsorption, scanning electron microscopy, small-angle neutron scattering and stress-strain measurements in compression regime. The resorcinol-formaldehyde aerogels possessed a high specific surface area (200–510 m2/g) and porosity (41–82%), with a surface fractal dimension of 2.2–2.5. The mechanical strength of the materials reached high values (up to 31 MPa) and was well correlated with the density of aerogels (0.27–0.86 g/cm3). The results obtained demonstrate the dramatic influence of the nature of a solvent used during the gelation of resorcinol-formaldehyde aerogels on their structure and properties. [ABSTRACT FROM AUTHOR]

Due to their unique characteristics, cosmic-ray neutron sensors (CRNSs) have potential in monitoring and informing irrigation management, and thus optimising the use of water resources in agriculture. However, practical methods to monitor small, irrigated fields with CRNSs are currently not available and the challenges of targeting areas smaller than the CRNS sensing volume are mostly unaddressed. In this study, CRNSs are used to continuously monitor soil moisture (SM) dynamics in two irrigated apple orchards (Agia, Greece) of ~1.2 ha. The CRNS-derived SM was compared to a reference SM obtained by weighting a dense sensor network. In the 2021 irrigation period, CRNSs could only capture the timing of irrigation events, and an ad hoc calibration resulted in improvements only in the hours before irrigation (RMSE between 0.020 and 0.035). In 2022, a correction based on neutron transport simulations, and on SM measurements from a non-irrigated location, was tested. In the nearby irrigated field, the proposed correction improved the CRNS-derived SM (from 0.052 to 0.031 RMSE) and, most importantly, allowed for monitoring the magnitude of SM dynamics that are due to irrigation. The results are a step forward in using CRNSs as a decision support system in irrigation management. [ABSTRACT FROM AUTHOR]

This research aims to characterize the adsorption morphology of block copolymer dispersants of the styrene-block-4-vinylpyridine family (S4VP) on the surface of multi-walled carbon nanotubes (MWCNT) in a polar organic solvent, N,N-dimethyl formamide (DMF). Good, unagglomerated dispersion is important in several applications such as fabricating CNT nanocomposites in a polymer film for electronic or optical devices. Small-angle neutron scattering (SANS) measurements, using the contrast variation (CV) method, are used to evaluate the density and extension of the polymer chains adsorbed on the nanotube surface, which can yield insight into the means of successful dispersion. The results show that the block copolymers adsorb onto the MWCNT surface as a continuous coverage of low polymer concentration. Poly(styrene) (PS) blocks adsorb more tightly, forming a 20 Å layer containing about 6 wt.% PS, whereas poly(4-vinylpyridine) (P4VP) blocks emanate into the solvent, forming a thicker shell (totaling 110 Å in radius) but of very dilute (<1 wt.%) polymer concentration. This indicates strong chain extension. Increasing the PS molecular weight increases the thickness of the adsorbed layer but decreases the overall polymer concentration within it. These results are relevant for the ability of dispersed CNTs to form a strong interface with matrix polymers in composites, due to the extension of the 4VP chains allowing for entanglement with matrix chains. The sparse polymer coverage of the CNT surface may provide sufficient space to form CNT-CNT contacts in processed films and composites, which are important for electrical or thermal conductivity. [ABSTRACT FROM AUTHOR]

Malonamide derivatives, which are the most extensively investigated extractants for solvent extraction of lanthanides, actinides, and platinum group metal ions, were deuterated by using Pd/C and Rh/C catalysts in a D2O/2-propanol mixture. This method replaces 1H atoms in the malonamides with 2H atoms at a controllable deuteration rate. The maximum rate reached about 75%, determined by nuclear magnetic resonance and electrospray ionization – mass spectrometry. The extraction behavior of metal ions by the malonamides was unchanged by the deuteration. Deuterated malonamides are a powerful tool for fundamental research on solvent extraction systems and for structural analysis of organic phases. The large difference in the cross section of coherent neutron scattering between 1H and 2H leads to a large difference in neutron scattering length density of malonamide derivatives before and after the deuteration. Therefore, using deuterated malonamides in small-angle neutron scattering and neutron reflectivity studies may help to reveal the microscopic structure of the specific solute species in the bulk organic phase and at the liquid–liquid interface, respectively. In this paper, we report the advantage of the deuterated malonamides for a contrast-matching method in the SANS experiment. This deuteration method could be generalized and extended to a wide variety of extractant molecules. [ABSTRACT FROM AUTHOR]

Chromatin, consisting of a meter-long DNA strand and associated proteins, is packed into the nucleus of a biological cell tightly but without entanglement. There is a hypothesis, confirmed by experiments involving the chromatin conformation capture technology [1], that curves densely filling the space (Peano or Hilbert curves) provide a good theoretical model to describe the chromatin packing into the nucleus. However, small-angle neutron scattering (SANS) experiments show a bifractal organization of chromatin in the interphase nucleus, thus demonstrating the presence of a logarithmic fractal on larger scales and a volume fractal on smaller scales [2]. In this paper, numerical Fourier analysis in the two-dimensional space is applied to simulate neutron scattering, and a model of a unified bifractal object is presented. It is shown that, in numerical radiation scattering experiments in the two-dimensional space, the mass and logarithmic fractals are significantly different from space-filling curves and from nonfractal objects. For instance, for a logarithmic fractal with a Hausdorff dimension of 2, scattering intensity decreases with increasing Fourier coordinate q by the power law q–2. For curves filling the two-dimensional space, the intensity decreases by the power law q–3, just as for nonfractal objects with sharp boundary in the plane. Thus, first, it is demonstrated that the model of space-filling curves is inadequate to describe the chromatin packing into the nucleus of a biological cell; second, a model of a unified bifractal object is proposed that combines logarithmic and mass fractals on different scales; and, third, a model of chromatin packing is proposed that can describe the data of both small-angle neutron scattering experiments and experiments involving chromatin conformation capture technology. [ABSTRACT FROM AUTHOR]

The applications of surfactants in various fields are gaining more attention, which makes full characterization of surfactants of growing interest. It is fundamental to measure the critical micelle concentration (CMC) as a parameter for characterizing surfactants. Spectroscopic methods for determination of CMC are more common, easier to perform, and in certain applications more accurate. In this review, different spectroscopic techniques and methods used for determination of CMC are discussed. These methods include direct UV/VIS Spectroscopy, which studies liquid surface curvature in thin wells using vertical detecting light beam with the wavelength set at 900 nm. The indirect UV/VIS Spectroscopic methods include using surface plasmon resonance or surface-enhanced Raman scattering of metal nanoparticles. Direct spectrofluorometric methods measure CMC based on the intrinsic fluorescence of the tested surfactants, and it was reserved for surfactants with intrinsic fluorescence such as Triton-X100. Indirect spectrofluorometric methods include measuring the change in fluorescence intensity, spectral shape, lifetime, polarization, or the solvatochromic shift of surfactant-dye solution. Other spectroscopic methods have been reported such as X-ray diffraction, nuclear magnetic resonance spectroscopy and small-angle neutron scattering. This review article discusses the spectroscopic methods developed for CMC determination with emphasis on the principle, applications, advantages, and limitations of each method. [ABSTRACT FROM AUTHOR]

The interaction of many peptides with lipid bilayer membranes strongly depends on the lipid composition. Here, a study of the impact of unsaturated lipid acyl chains on the interaction of a derivative of the HIV-1 fusion peptide with lipid bilayer vesicles is presented. Lipid bilayer vesicles composed of mixtures of lipids with two saturated acyl chains and lipids and one saturated and one unsaturated acyl chain, but identical head groups, were studied. The dependence of the peptide conformation on the unsaturated lipid content was probed by circular dichroism spectroscopy, while the impact of the peptide on the bilayer structure was determined by small-angle neutron scattering. The impact of the peptide on the lipid bilayer vesicle dynamics was investigated using neutron spin echo spectroscopy. Molecular dynamics simulations were used to characterize the behavior of the systems studied to determine if there were clear differences in their physical properties. The results reveal that the peptide–bilayer interaction is not a simple function of the unsaturated lipid acyl chain content of the bilayer. Instead, the peptide behavior is more consistent with that seen for the bilayer containing only unsaturated lipids, which is supported by lipid-specific interactions revealed by the simulations. [ABSTRACT FROM AUTHOR]

Interactions between molecules in the synovial fluid and the cartilage surface may play a vital role in the formation of adsorbed films that contribute to the low friction of cartilage boundary lubrication. Osteoarthritis (OA) is the most common degenerative joint disease. Previous studies have shown that in OA-diseased joints, hyaluronan (HA) not only breaks down resulting in a much lower molecular weight (MW), but also its concentration is reduced ten times. Here, we have investigated the structural changes of lipid-HA complexes as a function of HA concentration and MW to simulate the physiologically relevant conditions that exist in healthy and diseased joints. Small angle neutron scattering and dynamic light scattering were used to determine the structure of HA-lipid vesicles in bulk solution, while a combination of atomic force microscopy and quartz crystal microbalance was applied to study their assembly on a gold surface. We infer a significant influence of both MW and HA concentrations on the structure of HA-lipid complexes in bulk and assembled on a gold surface. Our results suggest that low MW HA cannot form an amorphous layer on the gold surface, which is expected to negatively impact the mechanical integrity and longevity of the boundary layer and could contribute to the increased wear of the cartilage that has been reported in joints diseased with OA. [ABSTRACT FROM AUTHOR]

Immobilization of biomolecules into porous materials could lead to significantly enhanced performance in terms of stability towards harsh reaction conditions and easier separation for their reuse. Metal-Organic Frameworks (MOFs), offering unique structural features, have emerged as a promising platform for immobilizing large biomolecules. Although many indirect methods have been used to investigate the immobilized biomolecules for diverse applications, understanding their spatial arrangement in the pores of MOFs is still preliminary due to the difficulties in directly monitoring their conformations. To gain insights into the spatial arrangement of biomolecules within the nanopores. We used in situ small-angle neutron scattering (SANS) to probe deuterated green fluorescent protein (d-GFP) entrapped in a mesoporous MOF. Our work revealed that GFP molecules are spatially arranged in adjacent nanosized cavities of MOF-919 to form "assembly" through adsorbate-adsorbate interactions across pore apertures. Our findings, therefore, lay a crucial foundation for the identification of proteins structural basics under confinement environment of MOFs. Immobilization of biomolecules into porous materials could lead to enhanced performance in terms of stability and easier separation for their reuse. Here authors gain insights into the spatial arrangement of green fluorescent protein entrapped in a mesoporous MOF by situ small-angle neutron scattering. [ABSTRACT FROM AUTHOR]

The structure and interaction parameters of the water-soluble cholesterol-based surfactant, Chobimalt, are investigated by small-angle neutron and X-ray scattering techniques. The obtained data are analyzed by a model-independent approach applying the inverse Fourier transformation procedure as well as considering a model fitting procedure, using a core-shell form factor and hard-sphere structure factor. The analysis reveals the formation of the polydisperse spherical or moderately elongated ellipsoidal shapes of the Chobimalt micelles with the hard sphere interaction in the studied concentration range 0.17–6.88 mM. The aggregation numbers are estimated from the micelle geometry observed by small-angle scattering and are found to be in the range of 200–300. The low pH of the solution does not have a noticeable effect on the structure of the Chobimalt micelles. The critical micelle concentrations of the synthetic surfactant Chobimalt in water and in H2O-HCl solutions were obtained according to fluorescence measurements as ~3 μM and ~2.5 μM, respectively. In-depth knowledge of the basic structural properties of the detergent micelles is necessary for further applications in bioscience and biotechnology. [ABSTRACT FROM AUTHOR]

Nanoscale thin film coatings and surface treatments are ubiquitous across industry, science, and engineering; imbuing specific functional or mechanical properties (such as corrosion resistance, lubricity, catalytic activity and electronic behaviour). Non-destructive nanoscale imaging of thin film coatings across large (ca. centimetre) lateral length scales, crucial to a wide range of modern industry, remains a significant technical challenge. By harnessing the unique nature of the helium atom–surface interaction, neutral helium microscopy images these surfaces without altering the sample under investigation. Since the helium atom scatters exclusively from the outermost electronic corrugation of the sample, the technique is completely surface sensitive. Furthermore, with a cross-section that is orders of magnitude larger than that of electrons, neutrons and photons, the probe particle routinely interacts with features down to the scale of surface defects and small adsorbates (including hydrogen). Here, we highlight the capacity of neutral helium microscopy for sub-resolution contrast using an advanced facet scattering model based on nanoscale features. By replicating the observed scattered helium intensities, we demonstrate that sub-resolution contrast arises from the unique surface scattering of the incident probe. Consequently, it is now possible to extract quantitative information from the helium atom image, including localised ångström-scale variations in topography. Neutral helium microscopy is a completely nondestructive, surface-sensitive imaging technique. Here, the authors demonstrate sub-resolution contrast using an advanced facet scattering model to reconstruct the topography of technological thin films in the ångström range. [ABSTRACT FROM AUTHOR]

Three mesogenic compounds: n-cyano-3-fluorophenyl 4-butylbenzoates (n = 4,6,8), abbreviated 4CFPB, 6CFPB, and 8CFPB contained in mesoporous Anodic Aluminium Oxide (AAO) membranes were subjected to Small Angle Neutron Scattering measurements with the aim to test the feasibility of SANS experiment as a means of detecting a boundary layer and estimating its thickness. This proved successful for 4CFB and 6CFPB in 18 nm pores, and indicative in 35 nm pores. The thickness of the boundary layer was estimated by core-shell SANS models at ca. 23–26 Å (2.3–2.6 nm). [ABSTRACT FROM AUTHOR]

With the increasing importance of light‐responsive materials, it is vital to analyze the relationship between function and structural changes induced by light irradiation. Small‐angle scattering (SAS) is effective for such structural analysis. However, quantitatively capturing local molecular structure formation and molecular reactions at a scale of less than 1 nm via SAS is difficult. In this study, to analyze the structure of non‐equilibrium phenomena in light‐responsive materials, a new sample environment has been developed for a time‐of‐flight small‐ and wide‐angle neutron scattering instrument (TAIKAN), comprising a UV–Vis irradiation system, UV–Vis absorption measurement equipment and photodetector. Simultaneous measurement of small‐angle neutron scattering and UV–Vis absorption was achieved. This system was used to demonstrate the in situ observation of UV–Vis irradiation‐induced structural change of micelles formed by 4‐butylazobenzene‐4′‐(oxyethyl)trimethylammonium bromide, which is a light‐responsive surfactant, in an aqueous solution. The results showed that the present measuring system provides direct information on the interplay between changes in micelle structure and changes in molecular configuration. [ABSTRACT FROM AUTHOR]

Magnetic small‐angle neutron scattering (SANS) is ideally suited to providing direct reciprocal‐space information on long‐wavelength magnetic modulations, such as helicoids, solitons, merons or skyrmions. SANS of such structures in thin films or micro‐structured bulk materials is strongly limited by the tiny scattering volume vis a vis the prohibitively high background scattering by the substrate and support structures. Considering near‐surface scattering just above the critical angle of reflection, where unwanted signal contributions due to substrate or support structures become very small, it is established that the scattering patterns of the helical, conical, skyrmion lattice and fluctuation‐disordered phases in a polished bulk sample of MnSi are equivalent for conventional transmission and near‐surface SANS geometries. This motivates the prediction of a complete repository of scattering patterns expected for thin films in the near‐surface SANS geometry for each orientation of the magnetic order with respect to the scattering plane. [ABSTRACT FROM AUTHOR]

This work studies the magnetic excitations of amorphous ferromagnetic alloys (Fe40Ni40P1411B6 and Fe48Ni34P18) by small‐angle polarized neutron scattering in the geometry when the magnetic field is inclined towards the neutron beam direction. Polarized neutrons are used in order to extract the scattering arising from the spin waves only. In this case, the energy‐integrated neutron cross section contains a component which depends on neutron polarization and has a left–right asymmetry in the plane determined by the directions of the field and the neutron beam. Small‐angle polarized neutron scattering measurements on spin waves in amorphous iron–nickel alloys were performed at different values of the external magnetic field H and neutron wavelength λ. The spin‐wave spectrum is quadratic in terms of the momentum transfer and contains both a field gap and an inherent gap Δ of a non‐field nature: Eq = Aq2 + gμBH + Δ. Only by measuring simultaneously two dependencies of the cut‐off angle θc – on the applied magnetic field and on the neutron wavelength – is it possible to obtain reliable information about the spin‐wave stiffness and the spin‐wave gap in these amorphous ferromagnetic systems. [ABSTRACT FROM AUTHOR]

The characterization of Zr-containing dispersoids in aluminum alloys is challenging due to their broad size distribution, low volume fraction, and heterogeneous distribution within the grains. In this work, small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) were compared to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) regarding their capability to characterize Zr-containing dispersoids in aluminum alloys. It was demonstrated that both scattering techniques are suitable tools to characterize dispersoids in a multi-phase industrial 7xxx series aluminum alloy. While SAXS is more sensitive than SANS due to the high electron density of Zr-containing dispersoids, SANS has the advantage of being able to probe a much larger sample volume. The combination of both scattering techniques allows for the verification that the contribution from dispersoids can be separated from that of other precipitate phases such as the S-phase or GP-zones. The size distributions obtained from SAXS, SANS and TEM showed good agreement. The SEM-derived size distributions were, however, found to significantly deviate from those of the other techniques, which can be explained by considering the resolution-limited restrictions of the different techniques. [ABSTRACT FROM AUTHOR]

The translocator protein (TSPO) is a ubiquitous transmembrane protein of great pharmacological interest thanks to its high affinity to many drug ligands. The only high-resolution 3D-structure known for mammalian TSPO was obtained by NMR for the mouse mTSPO in DPC detergent only in presence of the high-affinity PK 11195 ligand. An atomic structure of free-ligand mTSPO is still missing to better understand the interaction of ligands with mTSPO and their effects on the protein conformation. Here, we decipher the solution structures of the recombinant mTSPO without ligand both in (i) SDS, the detergent used to extract and purify the protein from E. coli inclusion bodies, and (ii) DPC, the detergent used to solve the PK 11195-binding mTSPO NMR structure. We report partially refolded and less flexible mTSPO helices in DPC compared to SDS. Besides, DPC stabilizes the tertiary structure of mTSPO, as shown by a higher intrinsic Trp fluorescence and changes in indole environment. We evaluate by SEC-MALLS that ∼135 SDS and ∼100 DPC molecules are bound to mTSPO. SEC-small-angle X-ray (SAXS) and neutron (SANS) scattering confirm a larger mTSPO-detergent complex in SDS than in DPC. Using the contrast-matching technique in SEC-SANS, we demonstrate that mTSPO conformation is more compact and less flexible in DPC than in SDS. Combining ab initio modeling with SANS, we confirm that mTSPO conformation is less elongated in DPC than in SDS. However, the free-ligand mTSPO envelope in DPC is not as compact as the PK 11195-binding protein NMR structure, the ligand stiffening the protein. [Display omitted] • mTSPO 3D-structure is partially unfolded in SDS environment. • mTSPO can refold progressively to a more native state from SDS to DPC. • mTSPO helicity and coiled coil increase from SDS to DPC environment. • Intrinsic fluorescence from mTSPO 12 Trp increases in DPC compared to SDS. • mTSPO is more compact in DPC but not as much as in presence of a stabilizing ligand. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of phase separation (PS) on the super duplex stainless steel SAF 2507, the evolution of the nanostructure, mechanical properties, and corrosion resistance of the alloy was studied after aging at 500 °C for 1, 10, 100, and 1000 h. The nanostructure of PS was quantitatively characterized by small-angle neutron scattering. The hardness, impact toughness, and pitting corrosion resistance were measured for different conditions. The results show that the early stage of PS had a more significant impact on the nanostructure and properties of SAF 2507. The fracture behavior of the alloy was likely determined by the mechanical properties of ferrite for aged conditions. The pitting corrosion resistance of SAF 2507 aged at 500 °C was closely related to the Cr depletion caused by PS, and the resistance became weaker with the progression of PS. The evolution of the passivation region with aging time correlated well with that of mechanical properties and characteristic parameters of PS, indicating that it is possible to develop a new nondestructive electrochemical method to quantify the evolution of PS in SAF 2507. [ABSTRACT FROM AUTHOR]

The small-angle neutron-scattering spectra of polydisperse populations of unilamellar vesicles are analyzed as functions of the concentration of maltose in a heavy-water solution. The spectra are recorded using a YuMO small-angle spectrometer at the Dzhelepov Laboratory of Neutron Physics, Joint Institute for Nuclear Research (Dubna, Russia). Two types of nanosystems developed at the Orekhovich Institute of Biomedical Chemistry are studied. These are a phospholipid-transport nanosystem and the Indolip nanodrug based on a phospholipid-transport nanosystem. The possibilities of obtaining data on the vesicular structure of nanodrugs based on a phospholipid-transport nanosystem from small-angle neutron scattering data are discussed. The computer analysis of small-angle scattering spectra is based on application of the method of separated form factors. The obtained values of the basic structural parameters of these vesicular systems (the average radius of vesicles in the population, the thickness of the bilayer across the membrane, the polydispersity coefficient, etc.) are generally consistent with the corresponding results of the similar processing of small-angle X-ray scattering data. However, the method of small-angle neutron scattering in comparison with small-angle X-ray scattering turns out to be less sensitive to the detailed analysis of structural features of the bilayer of the vesicle shell. [ABSTRACT FROM AUTHOR]

This study investigates the nanostructural properties of pseudo-binary Al–1.0Mg2Si (mass%) alloys with and without 0.5Cu using transmission electron microscopy (TEM) and small-angle neutron scattering (SANS). The TEM results show that both alloys exhibit extra electron diffraction spots related to MgSiMg second clusters at peak-aged conditions. High-resolution TEM images have revealed that the second cluster exists as a needle-shaped precipitate that is shorter and thicker than the β″ phase. We found that the second cluster, which we referred to as the R phase in this paper, is more likely to form partially along the longitudinal axis of a random-type precipitate. Thus, the atomic arrangement in the random-type precipitate is not completely random. SANS is used to quantify the size and volume fraction of the observed needle-shaped precipitates since the R phase is difficult to observe with TEM. The R phase forms even in the Cu-free alloy, but the volume fraction is low, and the growth and formation are retarded near the peak-aged conditions. Undoubtedly, the Cu addition has the effect of stabilizing the growth of the R phase and also promoting its formation. Therefore, the R phase also contributes to the increase in hardness at both under- and peak-aged conditions in the Cu-containing alloy in addition to the strengthening β″ phases.

Utilized for gaining structural insights, small-angle neutron and X-ray scattering techniques (SANS and SAXS, respectively) enable an examination of biomolecules, including photosynthetic pigment-protein complexes, in solution at physiological temperatures. These methods can be seen as instrumental bridges between the high-resolution structural information achieved by crystallography or cryo-electron microscopy and functional explorations conducted in a solution state. The review starts with a comprehensive overview about the fundamental principles and applications of SANS and SAXS, with a particular focus on the recent advancements permitting to enhance the efficiency of these techniques in photosynthesis research. Among the recent developments discussed are: (i) the advent of novel modeling tools whereby a direct connection between SANS and SAXS data and high-resolution structures is created; (ii) the employment of selective deuteration, which is utilized to enhance spatial selectivity and contrast matching; (iii) the potential symbioses with molecular dynamics simulations; and (iv) the amalgamations with functional studies that are conducted to unearth structure-function relationships. Finally, reference is made to time-resolved SANS/SAXS experiments, which enable the monitoring of large-scale structural transformations of proteins in a real-time framework.

Complete structural characterization of colloidal nanocrystals is challenging due to rapid variation in the electronic, vibrational, and elemental properties across the nanocrystal surface. While electron microscopy and X-ray scattering techniques can provide detailed information about the inorganic nanocrystal core, these techniques provide little information about the molecular ligands coating the nanocrystal surface. Moreover, because most models for scattering data are parametrically nonlinear, uncertainty estimates for parameters are challenging to formulate robustly. Here, using oleate-capped PbS quantum dots as a model system, we demonstrate the capability of small angle neutron scattering (SANS) in resolving core, ligand-shell, and solvent structure for well-dispersed nanocrystals using a single technique. SANS scattering data collected at eight separate solvent deuteration fractions were used to characterize the structure of the nanocrystals in reciprocal space. Molecular dynamics simulations were used to develop a coarse-grained form factor describing the scattering length density profile of ligand-stabilized nanocrystals in solution. We introduce an affine invariant Markov chain Monte Carlo method to efficiently perform nonlinear parameter estimation for the form factor describing such dilute solutions. This technique yields robust uncertainty estimates. This experimental design is broadly applicable across colloidal nanocrystal material systems including emergent perovskite nanocrystals, and the parameter estimation protocol significantly accelerates characterization and provides new insights into the atomic and molecular structure of colloidal nanomaterials. [ABSTRACT FROM AUTHOR]

Post-irradiation annealing of neutron-irradiated reactor pressure vessel steels is a matter of both technical and scientific interest. Small-angle neutron scattering (SANS), while being sensitive to nm-sized irradiation-induced solute-atom clusters, provides macroscopically representative and statistically reliable measures of cluster volume fraction, number density and size. In the present study, SANS was applied to uncover the size distribution of clusters in as-irradiated samples of a VVER-1000 weld and their gradual dissolution as function of the post-irradiation annealing temperature. The same samples were used to measure Vickers hardness. The results are consistent with Mn-Ni-Si-rich clusters of less than 2 nm radius to be the dominant source of both scattering and hardening. Annealing gave rise to small but significant partial recovery at 350°C and almost complete recovery at 475°C. The dispersed-barrier hardening model was applied to bridge the gap between the characteristics of nano-features and macro-hardness.

Left: In the binary system glycyrrhizic acid monoammonium salt (AGA)/H 2 O, 'infinite' rigid helical fibrils are coexisting with shorter fibrils. Middle: Ethanol (EtOH, red) as a co-solvent facilitates the formation of end caps, thus reducing the length of short fibrils; the 'infinite' ones stay initially intact as they do not have unstable ends. Right: As EtOH reaches a threshold concentration (∼30 wt%), only end caps remain, meaning that all fibrils have been transformed into micelle-like aggregates pervaded by a EtOH-enriched solvent. [Display omitted] The monoammonium salt of glycyrrhizic acid (AGA) is known to form fibrillar hydrogels and few studies regarding self-assembly of AGA have been published. Yet, the understanding of the fibrillar microstructures and the gelation remains vague. Thus, we attempt to achieve a deeper understanding of the microstructures and the gelation process of binary solutions of AGA in water. Further, we examine the effect of ethanol on the microstructures to pave the way for potential enhancement of drug loading in AGA hydrogels. A partial room temperature phase map of the ternary system AGA/ethanol/water was recorded. Small-angle X-ray and neutron scattering experiments were performed over wide ranges of compositions in both binary AGA/water and ternary AGA/ethanol/water mixtures to get access to the micro-structuring. Binary aqueous solutions of AGA form birefringent gels consisting of a network of long helical fibrils. 'Infinitely' long negatively charged fibrils are in equilibrium with shorter fibrils (≈25 nm), both of which have a diameter of about 3 nm and are made of around 30 stacks of AGA per helical period (≈9 nm), with each stack consisting of two AGA molecules. The interaxial distance (order of magnitude ≈20 nm) varies with an almost two-dimensional swelling law. Addition of ethanol reduces electrostatic repulsion and favors the formation of fibrillar end caps, reducing the average length of shorter fibrils, as well as the formation of small, swollen aggregates. While the gel network built by the long fibrils is resilient to a significant amount of ethanol, all fibrils are finally dissolved into small aggregates above a certain threshold concentration of ethanol (≈30 wt%). [ABSTRACT FROM AUTHOR]

Time modulation methods are routinely used on neutron scattering time-of-flight instruments, which exploit the time structure of neutron pulses for energy determination. In the past, complex time modulation methods were proposed, either to maximize the neutron flux which can be used, or to increase the energy resolution of the measurements. In this article, we explore the possibilities offered by such methods and in particular random modulation using statistical choppers to improve the performances of the DIoGENE scattering instrument installed around the IPHI-neutron CANS source at Saclay. We conclude that when the source is operated in continuous mode, the implementation of a statistical chopper is very efficient to perform either metallurgical studies such as strain scanning or phase transition studies. Random modulation techniques may be easily and efficiently implemented because the high capacity of modern computers enables high-speed data processing from large surface pixelated detectors. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of 6 wt.% Mn-doped martensitic steel have been investigated through a combination of electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and small-angle neutron scattering (SANS). The 6 wt.% Mn-doped steel exhibits a yield strength of ~1.83 GPa and an elongation-to-failure of ~7% under peak aging, and the ~853 MPa of precipitation strengthening is much higher than that observed in the 1.5 wt.% and 3 wt.% Mn-doped steels. The steel is composed of α'-martensite and slightly equiaxed α-ferrite together with a high proportion (~62.3%) of low-angle grain boundaries, and 6 wt.% Mn doping and the aging treatment have an effect on the matrix's microstructure. However, 6 wt.% Mn doping can obviously increase the mean size of the Cu/NiAl nanoparticles by enhancing the chemical driving force of the Mn partitioning on the NiAl nanoparticles, which differs from the refining effect on the nanoparticles in 3 wt.% Mn-doped steels. Furthermore, larger Cu/NiAl nanoparticles can significantly improve the yield strength of martensitic steel through precipitation-strengthening mechanisms. [ABSTRACT FROM AUTHOR]

Protein structural changes during freezing and subsequent thawing are of great importance to a variety of biopharmaceutical applications. In this work, we studied the influence of non-ionic surfactants (polysorbate 20 and poloxamer 188) on protein structural changes during freeze and thaw using lysozyme as a model protein. Small-angle neutron scattering was employed to characterize protein structures in both liquid and frozen solution states. The results show minimal impact of polysorbate 20 on lysozyme structures during freeze and thaw using practically relevant concentrations. Polysorbate 20 used at 0.04% (w/w) completely prevents freeze-induced aggregation of lysozyme. Poloxamer 188 seems to interact with lysozyme; when applied at high concentrations (10% w/w), such interaction prevents protein crowding or close packing typically associated with freeze concentration. Despite such interactions, lysozyme aggregation is observed with 10% (w/w) of poloxamer 188 during freezing, although the aggregation is reversed upon thawing. [ABSTRACT FROM AUTHOR]

We present an in situ uniaxial pressure device optimized for small angle x-ray and neutron scattering experiments at low-temperatures and high magnetic fields. A stepper motor generates force, which is transmitted to the sample via a rod with an integrated transducer that continuously monitors the force. The device has been designed to generate forces up to 200 N in both compressive and tensile configurations, and a feedback control allows operating the system in a continuous-pressure mode as the temperature is changed. The uniaxial pressure device can be used for various instruments and multiple cryostats through simple and exchangeable adapters. It is compatible with multiple sample holders, which can be easily changed depending on the sample properties and the desired experiment and allow rapid sample changes. [ABSTRACT FROM AUTHOR]

It is proposed that nanosized graphene aggregation could facilitate coherent neutron scattering under particle size conditions similar to nanodiamonds to enhance neutron intensity below cold neutrons. Using the RIKEN accelerator-driven compact neutron source and iMATERIA at J-PARC, we performed neutron measurement experiments, total neutron cross-section and small-angle neutron scattering on nanosized graphene aggregation. For the first time, the measured data revealed that nanosized graphene aggregation increased the total neutron cross-sections and small-angle scattering in the cold neutron energy region. This is most likely due to coherent scattering, resulting in higher neutron intensities, similar to nanodiamonds. [ABSTRACT FROM AUTHOR]

The Monday morning session started with the awarding of the Clifford G. Shull Prize in Neutron Scattering to Dan A. Neumann (NIST) "for outstanding contributions, leadership, and vision to the neutron scattering community as scientist, mentor, instrument developer, and facility steward" (Figure 1). The meeting, organized by the Neutron Scattering Society of America (NSSA), was led by Conference Chair and NSSA Vice President Peter Gehring (National Institute of Standards and Technology [NIST]) and NSSA President Young Lee (Stanford University) together with the Local Committee Co-chairs Steven DeCaluwe (Colorado School of Mines) and Dmitry Reznik (University of Colorado). The recipients were Paul Butler "for service to the neutron scattering community through his leadership and development of scientific software for small-angle scattering", Simon Billinge "for service to the neutron scattering community through his leadership and development of scientific software for total scattering experiments", Brent Fultz "for service to the neutron scattering community through his leadership and development of scientific software and instrumentation for inelastic scattering", and William D. Ratcliff "for service to the neutron community by founding and organizing a national school on solving magnetic structures with neutron diffraction and developing new AI data collection and analysis methods." The main scientific program began on Monday, and many special events were held throughout the week, including the NCNR User Group (NUG) and SNS/HFIR User Group (SHUG) meetings, an exhibitor hall, the ACNS Banquet, a Diversity, Equity, and Inclusion (DEI) discussion focused on barriers to access for neutron science, a breakout discussion on how to improve the user experience with Oak Ridge National Laboratory (ORNL) neutron data systems, and the Women in Neutron Science Mixer. [Extracted from the article]

A specialized irradiation instrument "created instrument" was designed and created from various kinds and sizes of available plastic household-waste materials. In addition, a neutron beam collimator with a lid was designed and implemented. The collimator is with dimensions of 25 cm in height and 10 cm in inner diameter, while the lid dimensions are 11.5 cm height and outer diameter of 9.9 cm to perfectly match the inner diameter of the collimator with the possibility of movement (opening and closing), and also the shielding of the radioactive 241Am/Be neutron source with a recent activity of 37.5 mCi. To investigate the efficiency of the "created instrument", ten hydrogenous material samples (ordinary paraffin of chemical structure CnH2n+2) with the same cylindrical dimensions (Ø = 8.5 cm, 0.5 cm thickness) and with the same weight of 20 g ± 0.005 for each, were used with and without the "created instrument". The neutron measurements were slowed (4.7 – 1.58 n/s) when the paraffin sample thickness was progressively increased (0 – 5 cm). Most importantly, the "created instrument" was effectively contributed to reducing the user’s radiation exposure time from approximately 90 seconds to a few seconds no longer than 30 seconds for each measurement with considerable reduction ratio of 66.67% by making the samples of thicknesses ranging from 0.5 cm to 5 cm easier to position on the neutron beam collimator compared without using the "created instrument". It may also be utilized to evaluate the moderation on-site for different materials in neutron source shielding thickness based on the measuring procedures and data gathered. It is predicted that this study will help future improvements to use additional techniques to satisfy more protection related to the radiation field. [ABSTRACT FROM AUTHOR]

Post‐loading of polymersomes with different bio(macro)molecules has been successfully demonstrated, thus mimicking the diffusion processes through biological membranes. However, it is still an open issue the extent to which this diffusion process leads to transmembrane transportation, or rather encapsulation of cargo within the membrane. In this study, well‐established pH‐responsive and cross‐linked polymeric vesicles are studied. A pH‐controllable and stable membrane, as well as a hollow particle shape and membrane uniformity are confirmed using dynamic light scattering (DLS) and cryogenic‐transmission electron microscopy (Cryo‐TEM). Post‐loading with myoglobin (Mb) as a model enzyme is analyzed using multidetector asymmetrical flow field‐flow fractionation (AF4). Advanced analysis of conformational parameters allowed for the estimation of enzyme localization and the pH‐dependent loading efficiency thereof. Static light scattering coupled to AF4 is employed to successfully deliver information on the global size of the polymersomes (>50 nm). Furthermore, membrane structure and thickness, which are in the few nanometer range, can be successfully analyzed using small‐angle neutron scattering (SANS). Deuterated solvent as well as Mb deuteration for tuning the contrast are considered. Two different vesicle model fits, as well as Kratky–Porod interpretation confirm effective determination of vesicle core and membrane thickness and for evaluation of the membrane changes after post‐loading. [ABSTRACT FROM AUTHOR]

By combining oppositely charged polydiallyldimethylammonium chloride (PDADMAC) and sodium polyacrylate (NaPA), interpolyelectrolyte complexes (IPECs) can be formed in aqueous solution. Such IPECs are studied for rather short NaPA and under variation of the Mw of PDADMAC. The focus is on elucidating the effect of having a hydrophobic modification of the NaPA, which is introduced by having 10 mol% of the monomeric units substituted by ones carrying a dodecyl alkyl chain. This modification renders the complexes more hydrophobic, which is seen in the fact that precipitation of the complexes occurs at a lower mixing ratio and the biphasic region is also wider. The structures of the soluble IPECs are studied by a combination of light and neutron scattering (SANS). It is observed that the complexes formed possess typical radii of gyration of ≈30–40 nm, which become somewhat smaller with increasing length of the PDADMAC chain. The SANS data can be described well with the Beaucage model for complexes, where locally small hydrophobic domains of cylindrical shape are formed, whose persistence length decreases with increasing content of NaPA in the complexes. In contrast no such structures are seen for NaPA without the hydrophobic modification. The cylindrical domains are then arranged within larger‐sized clusters of 30–40 nm, which become more compact with reduced length of the PDAMAC chains. The structure of the IPECs is largely determined by the presence of the hydrophobic modification of the NaPA and is further controlled by the length of the hydrophobic modification. Such IPECs of controlled structure, relatively small size, and containing hydrophobic domains are potentially interesting as delivery systems due to having domains of variable polarity. [ABSTRACT FROM AUTHOR]

The backsheet layer of a solar module provides a safety and environmental barrier to the high voltages running through the photovoltaic (PV) cells and electrical contacts within the core of the module. However, in the past decade, backsheet cracking has become one of the most observed failure modes in PV module field surveys. In this work, the degradation of polyvinylidene fluoride (PVDF)‐based backsheets is explored. Backsheet samples are either exposed to accelerated laboratory aging (UV light, heat, and moisture) or collected from the field. Fourier transform infrared and Raman spectroscopy, fragmentation testing, atomic force and scanning electron microscopy, and small‐angle neutron scattering are combined to develop an understanding of how chemistry and microstructure evolve during aging. Chemical degradation, surface pitting, polymer phase changes, and anisotropic polymer domains are all observed in aged backsheet samples. The results provide insight into the degradation mechanisms that lead to cracking and field failure of PVDF‐based backsheets. The comparison of aged PVDF‐based backsheets helps to lay the groundwork for limiting polymer‐based failure modes in PV modules. [ABSTRACT FROM AUTHOR]

The article presents a study which provides insights and fresh perspectives for understanding the interactions and structural dynamics of intrinsically disordered proteins (IDPs). It mentions about the robust extension-contraction model has been postulated to capture the fundamental phenomena governing the observed behavior of IDPs.

This structural study exploits the possibility to use modular protein deuteration to facilitate the study of ubiquitin signalling, transfer, and modification. A protein conjugation reaction is used to combine protonated E2 enzyme with deuterated ubiquitin for small angle X-ray and neutron scattering with neutron contrast variation. The combined biomolecules stay as a monodisperse system during data collection in both protonated and deuterated buffers indicating long stability of the E2–Ub conjugate. With multiphase ab initio shape restoration and rigid body modelling, we reconstructed the shape of a E2–Ub-conjugated complex of UBE2D1 linked to ubiquitin via an isopeptide bond. Solution X-ray and neutron scattering data for this E2–Ub conjugate in the absence of E3 jointly indicate an ensemble of open and backbent states, with a preference for the latter in solution. The approach of combining protonated and labelled proteins can be used for solution studies to assess localization and movement of ubiquitin and could be widely applied to modular Ub systems in general. [ABSTRACT FROM AUTHOR]

The field‐induced ordering of concentrated ferrofluids based on spherical and cuboidal maghemite nanoparticles is studied using small‐angle neutron scattering, revealing a qualitative effect of the faceted shape on the interparticle interactions as shown in the structure factor and correlation lengths. Whereas a spatially disordered hard‐sphere interaction potential with a short correlation length is found for ∼9 nm spherical nanoparticles, nanocubes of a comparable particle size exhibit a more pronounced interparticle interaction and the formation of linear arrangements. Analysis of the anisotropic two‐dimensional pair distance correlation function gives insight into the real‐space arrangement of the nanoparticles. On the basis of the short interparticle distances found here, oriented attachment, i.e. a face‐to‐face arrangement of the nanocubes, is likely. The unusual field dependence of the interparticle correlations suggests a field‐induced structural rearrangement. [ABSTRACT FROM AUTHOR]

The magnetization of cobalt ferrite nanocubes of similar size, but with varying Co/Fe ratio, is extensively characterized on atomistic and nanoscopic length scales. Combination of X‐ray diffraction, Mössbauer spectroscopy, magnetization measurements and polarized small‐angle neutron scattering (SANS) reveals that a lower amount of cobalt leads to an enhanced magnetization. At the same time, magnetic SANS confirms no or negligible near‐surface spin disorder in these highly crystalline, homogeneously magnetized nanoparticles, resulting in an exceptionally hard magnetic material with high coercivity. [ABSTRACT FROM AUTHOR]

The magnetization profile and the related magnetic small‐angle neutron scattering cross section of a single spherical nanoparticle with Néel surface anisotropy are analytically investigated. A Hamiltonian is employed that comprises the isotropic exchange interaction, an external magnetic field, a uniaxial magnetocrystalline anisotropy in the core of the particle and the Néel anisotropy at the surface. Using a perturbation approach, the determination of the magnetization profile can be reduced to a Helmholtz equation with Neumann boundary condition, whose solution is represented by an infinite series in terms of spherical harmonics and spherical Bessel functions. From the resulting infinite series expansion, the Fourier transform, which is algebraically related to the magnetic small‐angle neutron scattering cross section, is analytically calculated. The approximate analytical solution for the spin structure is compared with the numerical solution using the Landau–Lifshitz equation, which accounts for the full nonlinearity of the problem. The signature of the Néel surface anisotropy can be identified in the magnetic neutron scattering observables, but its effect is relatively small, even for large values of the surface anisotropy constant. [ABSTRACT FROM AUTHOR]

Kinetic small‐angle neutron scattering provides access to the microscopic properties of mesoscale systems under slow, periodic perturbations. By interlocking the phases of neutron pulse, sample modulation and detector signal, time‐involved small‐angle neutron scattering experiments (TISANE) allow one to exploit the neutron velocity spread and record data without major sacrifice in intensity at timescales down to microseconds. This article reviews the optimization strategies of TISANE that arise from specific aspects of the process of data acquisition and data analysis starting from the basic principles of operation. Typical artifacts of data recorded in TISANE due to the choice of time binning and neutron chopper pulse width are illustrated by virtue of the response of the skyrmion lattice in MnSi under periodic changes of the direction of the stabilizing magnetic field. [ABSTRACT FROM AUTHOR]

Small‐angle scattering (SAS) experiments are a powerful method for studying self‐assembly phenomena in nanoscopic materials because of the sensitivity of the technique to structures formed by interactions on the nanoscale. Numerous out‐of‐the‐box options exist for analysing structures measured by SAS but many of these are underpinned by assumptions about the underlying interactions that are not always relevant for a given system. Here, a numerical algorithm based on reverse Monte Carlo simulations is described to model the intensity observed on a SAS detector as a function of the scattering vector. The model simulates a two‐dimensional detector image, accounting for magnetic scattering, instrument resolution, particle polydispersity and particle collisions, while making no further assumptions about the underlying particle interactions. By simulating a two‐dimensional image that can be potentially anisotropic, the algorithm is particularly useful for studying systems driven by anisotropic interactions. The final output of the algorithm is a relative particle distribution, allowing visualization of particle structures that form over long‐range length scales (i.e. several hundred nanometres), along with an orientational distribution of magnetic moments. The effectiveness of the algorithm is shown by modelling a SAS experimental data set studying finite‐length chains consisting of magnetic nanoparticles, which assembled in the presence of a strong magnetic field due to dipole interactions. [ABSTRACT FROM AUTHOR]

Intermetallic Pd‐doped (Fe,Ni)3P, which crystallizes in a non‐centrosymmetric tetragonal structure with S4 symmetry, has recently been discovered to host magnetic antiskyrmions, antivortex‐like topological spin textures. In this material, uniaxial magnetic anisotropy and dipolar interactions play a significant role, giving rise to finely branched magnetic domain patterns near the surface of bulk crystals, as revealed by a previous magnetic force microscopy (MFM) measurement. However, small‐angle neutron scattering (SANS) is a more suitable method for characterizing bulk properties and fractal structures on the mesoscopic length scale. In this study, using SANS and MFM, the magnetic domain structure in bulk single crystals of (Fe0.63Ni0.30Pd0.07)3P is quantitatively investigated. The SANS results demonstrate that the magnetic domain structure exhibits anisotropic fractal character on length scales down to the width of the magnetic domain walls. The fractal features are gradually lost in magnetic fields, and different field dependencies are observed at 300 and 2 K due to a temperature‐dependent anisotropy. This study quantifies the fractality of the highly anisotropic magnetic domain structures in an antiskyrmion material, and highlights the versatility of SANS for the study of fractal structures in magnetic systems. [ABSTRACT FROM AUTHOR]