Produce Diffraction Patterns Research Articles

Nanoscale speckle patterning for combined high‐resolution strain and orientation mapping of environmentally sensitive materials

AbstractScanning electron microscopy‐based high‐resolution digital image correlation (HRDIC) is now an established technique, providing full‐field strain and displacement measurement at the microscale. Techniques for generating speckle patterns for sub‐micron strain mapping can often be either substrate dependent or rely on applying aggressive conditions which may alter the microstructure of interest or damage the substrate in highly sensitive materials. We detail a modification of a methodology successfully applied in the literature to allow its use with metallic materials that are particularly sensitive to the corrosive media, such as copper‐base alloys. Nanometre‐thick silver films, applied with physical vapour deposition, are remodelled using NaBr in non‐aqueous isopropanol, replacing the aqueous solution of NaCl in the original method, forming a uniform dispersion of silver islands highly suitable for digital image correlation (DIC) measurement. The entire procedure is performed at ambient temperature. We find that the DIC pattern is suitably electron transparent to allow electron backscatter diffraction (EBSD) measurements without pattern removal, producing diffraction patterns of sufficient quality for cross‐correlation based high‐angular resolution EBSD. This property facilitates simultaneous EBSD and DIC mapping experiments, providing deeper insights into the kinematics of plastic deformation in crystalline materials. Sub‐100 nm islands are achieved through control of the sputter coating parameters, resulting in DIC cross‐correlation subwindows of 140 nm with a 50% overlap. This resolution is sufficient to capture the fine detail of strain localisation phenomena during plastic deformation, demonstrated here with a case study in CuCrZr, a precipitation‐hardened heat sink material for application in nuclear fusion components. Here, we extract full‐field displacement data with DIC and corresponding orientation information using EBSD without the need for pattern removal.

Characterization of Biological Samples Using Ultra-Short and Ultra-Bright XFEL Pulses.

The advent of X-ray Free Electron Lasers (XFELs) has ushered in a transformative era in the field of structural biology, materials science, and ultrafast physics. These state-of-the-art facilities generate ultra-bright, femtosecond-long X-ray pulses, allowing researchers to delve into the structure and dynamics of molecular systems with unprecedented temporal and spatial resolutions. The unique properties of XFEL pulses have opened new avenues for scientific exploration that were previously considered unattainable. One of the most notable applications of XFELs is in structural biology. Traditional X-ray crystallography, while instrumental in determining the structures of countless biomolecules, often requires large, high-quality crystals and may not capture highly transient states of proteins. XFELs, with their ability to produce diffraction patterns from nanocrystals or even single particles, have provided solutions to these challenges. XFEL has expanded the toolbox of structural biologists by enabling structural determination approaches such as Single Particle Imaging (SPI) and Serial X-ray Crystallography (SFX). Despite their remarkable capabilities, the journey of XFELs is still in its nascent stages, with ongoing advancements aimed at improving their coherence, pulse duration, and wavelength tunability.

Inferring the probability distribution over strain tensors in polycrystals from diffraction based measurements

Polycrystals illuminated by high-energy X-rays or neutrons produce diffraction patterns in which the measured diffraction peaks encode the individual single crystal strain states. While state of the art X-ray and neutron diffraction approaches can be used to routinely recover per grain mean strain tensors, less work has been produced on the recovery of higher order statistics of the strain distributions across the individual grains. In the setting of small deformations, we consider the problem of estimating the crystal elastic strain tensor probability distribution from diffraction data. For the special case of multivariate Gaussian strain tensor probability distributions, we show that while the mean of the distribution is well defined from measurements, the covariance of strain has a null-space. We show that there exist exactly 6 orthogonal perturbations to this covariance matrix under which the measured strain signal is invariant. In particular, we provide analytical parametrisations of these perturbations together with the set of possible maximum-likelihood estimates for a multivariate Gaussian fit to data. The parametric description of the null-space provides insights into the strain PDF modes that cannot be accurately estimated from the diffraction data. Understanding these modes prevents erroneous conclusions from being drawn based on the data. Beyond Gaussian strain tensor probability densities, we derive an iterative radial basis regression scheme in which the strain tensor probability density is estimated by a sparse finite basis expansion. This is made possible by showing that the operator mapping the strain tensor probability density onto the measured histograms of directional strain is linear, without approximation. The utility of the proposed algorithm is demonstrated by numerical simulations in the setting of single crystal monochromatic X-ray scattering. The proposed regression methods were found to robustly reject outliers and accurately predict the strain tensor probability distributions in the presence of Gaussian measurement noise.

Quantitative analysis of diffuse electron scattering in the lithium-ion battery cathode material Li1.2Ni0.13Mn0.54Co0.13O2

In contrast to perfectly periodic crystals, materials with short-range order produce diffraction patterns that contain both Bragg reflections and diffuse scattering. To understand the influence of short-range order on material properties, current research focuses increasingly on the analysis of diffuse scattering. This article verifies the possibility to refine the short-range order parameters in submicrometre-sized crystals from diffuse scattering in single-crystal electron diffraction data. The approach was demonstrated on Li1.2Ni0.13Mn0.54Co0.13O2, which is a state-of-the-art cathode material for lithium-ion batteries. The intensity distribution of the 1D diffuse scattering in the electron diffraction patterns of Li1.2Ni0.13Mn0.54Co0.13O2 depends on the number of stacking faults and twins in the crystal. A model of the disorder in Li1.2Ni0.13Mn0.54Co0.13O2 was developed and both the stacking fault probability and the percentage of the different twins in the crystal were refined using an evolutionary algorithm in DISCUS. The approach was applied on reciprocal space sections reconstructed from 3D electron diffraction data since they exhibit less dynamical effects compared with in-zone electron diffraction patterns. A good agreement was achieved between the calculated and the experimental intensity distribution of the diffuse scattering. The short-range order parameters in submicrometre-sized crystals can thus successfully be refined from the diffuse scattering in single-crystal electron diffraction data using an evolutionary algorithm in DISCUS.

Application of machine learning to reflection high-energy electron diffraction images for automated structural phase mapping

We have developed a phase mapping method based on machine learning analysis of reflection high-energy electron diffraction (RHEED) images. RHEED produces diffraction patterns containing a wealth of static and dynamic information and is commonly used to determine the growth rate, the growth mode, and the surface morphology of epitaxial thin films. However, the ability to extract quantitative structural information from the RHEED patterns that appear during film growth is limited by the lack of versatile and automated analysis techniques. We have created a deep learning-based analysis method for automating the identification of different RHEED pattern types that occur during the growth of a material. Our approach combines several supervised and unsupervised machine learning techniques and permits the extraction of quantitative phase composition information. We applied this method to the mapping of the structural phase diagram of ${\mathrm{Fe}}_{\mathrm{x}}{\mathrm{O}}_{\mathrm{y}}$ thin films grown by pulsed laser deposition as a function of growth temperature and oxygen pressure close to the hematite-magnetite phase boundary. The in situ RHEED-based mapping method produces results that are qualitatively similar to postsynthesis x-ray diffraction analysis.

From Alignment Laser to 3D Structures: Determining Structures of GPCRs in a Compact X‐ray Light Source

The Compact X‐ray Light Source (CXLS) at Arizona State University produces diffraction patterns with intense X‐ray by Inverse Compton Scattering (ICS). In ICS, a photon acquires energy from an electron to produce an X‐ray. With this system, we can study G‐Protein Coupled Receptors (GPCRs), which are peripheral membrane proteins targeted by 60% of FDA approved drugs. When GPCRs are activated, a series of reaction can occur. For example, opening and closing of ion channels, activation or deactivation of enzymes, and protein hydrolysis. The structural characterization of GPCRs can lead to optimization of drug development, by assessing a better targeting mechanism that will lead to fewer side‐effects and better drug biding. We conducted a laser alignment in the CXLS using a YAG screen, which is a fluorescent screen that helps determine the size and intensity of the beam. Furthermore, we provide the crystallization process of GPCRs using Lipidic Cubic Phase (LCP) and describe its potential for structure determination using the CXLS and CXFEL.

Ultra-short pulses generation’s precise influence on the light transmission in optical fibers

In this study, the numerical simulation of the fractional nonlinear third-order Schrödinger (3-FNLS) problem is processed by applying the novel homotopy perturbation (NHP) method. The 3-FNLS equation illustrates how quantum characteristics and ultra-short optical fiber pulses interact dynamically. Additionally, the wave function of a quantum mechanical system in which atomic particles act like waves is determined by this. When electrons, like light waves, travel through a double slit, they produce diffraction patterns. Consequently, it was reasonable to assume that the wave equation could effectively represent the behavior of atomic particles. The requested conditions for handling the investigated model by the NHP method through the Khater II method. Accurate approximate solutions are constructed and simulated in some distinct graphs.

Tumoricidal and Bactericidal Properties of ZnONPs Synthesized Using Cassia auriculata Leaf Extract.

In this work, we aimed to synthesize zinc oxide nanoparticles (ZnONPs) using an aqueous extract of Cassia auriculata leaves (CAE) at room temperature without the provision of additional surfactants or capping agents. The formation of as-obtained ZnONPs was analyzed by UV–visible (ultraviolet) absorption and emission spectroscopy, X-ray photoemission spectroscopy (XPS), X-ray diffraction analysis (XRD), energy dispersive X-ray diffraction (EDX), thermogravimetric analysis/differential thermal analysis (TGA-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The XRD results reflect the wurtzite structure of as-prepared ZnONPs, which produced diffraction patterns showing hexagonal phases. The SEM images indicate that the morphology of as-prepared ZnONPs is composed of hexagonal nanostructures with an average diameter of 20 nm. The HR-TEM result shows that the inter-planar distance between two lattice fringes is 0.260 nm, which coincides with the distance between the adjacent (d-spacing) of the (002) lattice plane of ZnO. The fluorescence emission spectrum of ZnONPs dispersed in ethanol shows an emission maximum at 569 nm, revealing the semiconductor nature of ZnO. As-obtained ZnONPs enhanced the tumoricidal property of CAE in MCF-7 breast cancer cells without significant inhibition of normal human breast cells, MCF-12A. Furthermore, we have studied the antibacterial effects of ZnONPs, which showed direct cell surface contact, resulting in the disturbance of bacterial cell integrity.

Carbonated Hydroxyapatite Derived from Cerastoderma edule, Paphia undulata, and Meretrix meretrix Shells

Carbonated hydroxyapatite (CHAp) derived from three different shells, Cerastoderma edule, Paphia undulata, and Meretrix meretrix shells, have been synthesized by precipitation method. Calcium oxide from extracting shells, diammonium hydrogen phosphate, and ammonium bicarbonate was used to synthesis as the starting precursors. The CHAp materials were analyzed by Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared (FT-IR), and X-Ray Diffractometer (XRD). EDS analysis showed that the Ca/P ratio of CHAp powders were around 1.75-1.77 (bigger than the Ca/P ratio of HAp) and carbonate content of the powder CHAp was 3.10-4.05wt%. XRD data has produced diffraction patterns from the three different shells similar to the apatite structure. The position of the main peak (2θ) diffraction patterns detected at 31.99°, 32.23°, and 31.95°. The lattice parameter of a-axis and c-axis were obtained around 9.37 Å and 6.89 Å. Crystallite size of CHAp samples was 30-40 nm. The FTIR spectra showed that there are functional groups of OH-, PO43-, and CO32- at wave number around 3447, 571, and 873 cm−1. Based on the results of the analysis, it shows that the CHAp characteristics that had successfully produced from Cerastoderma edule, Paphia undulata, and Meretrix meretrix shells were B-type CHAp.

Evidence of a 6.12×1018 GeV Particle: Detection and Mathematics

In a new approach the graviton is defined as the field particle of spacetime rather than the mediator of gravity. The unification equation is derived and used to predict that for a freely falling body, the energy of incident gravitons is $6.12\times 10^{18}$ GeV. Redshift and scattering of gravitons should produce diffraction patterns, galactic halos and expansion of the Universe. The energy of incident gravitons remains constant as the Universe evolves because of the Doppler shift as bodies fall towards redshifted gravitons. Complex space is used to represent gravitons and explain Young’s two-slit interference. The approach is corroborated by empirical data and extends establish theory.

Coherent diffraction imaging: consistency of the assembled three-dimensional distribution.

The short pulses of X-ray free-electron lasers can produce diffraction patterns with structural information before radiation damage destroys the particle. From the recorded diffraction patterns the structure of particles or molecules can be determined on the nano- or even atomic scale. In a coherent diffraction imaging experiment thousands of diffraction patterns of identical particles are recorded and assembled into a three-dimensional distribution which is subsequently used to solve the structure of the particle. It is essential to know, but not always obvious, that the assembled three-dimensional reciprocal-space intensity distribution is really consistent with the measured diffraction patterns. This paper shows that, with the use of correlation maps and a single parameter calculated from them, the consistency of the three-dimensional distribution can be reliably validated.

Scanning electron microscopy and transmitted electron backscatter diffraction examination of asbestos standard reference materials, amphibole particles of differing morphology, and particle phase discrimination from talc ores.

Since 1972, when the US Occupational Health and Safety Administration established the first limits on occupational exposure to asbestos fibers, numerous analytical methods employing several microscopy techniques have been developed to identify a group of minerals defined by legislation as asbestos. While transmission electron microscopy (TEM) is implemented in standardized analytical methods, these methods specify the use of selected area electron diffraction. Because of this constraint, the diffraction data a TEM can provide are often underutilized due to challenges associated with collecting and interpreting individual diffraction patterns. It has been shown that transmission electron backscatter diffraction (tEBSD) produces diffraction patterns nearly identical to electron backscatter diffraction, but from smaller crystal domains. This paper explores the utility of tEBSD for characterization of asbestiform particles from reference asbestos materials, a suite of amphibole minerals of varying morphologies to determine if there is a correlation between mineral habit (i.e., crystal form), microscopic particle shape preferred orientation, and mineral specimens from an industrial talc deposit to provide a case study of the utility and limitations of the technique.

X-ray diffraction from hexagonal dislocation networks

We built the honeycomb networks of misfit dislocations by combining angular dislocations. Two different models of the disorder in the dislocation network are explored, the random shifts of nodes and random sources of distortion. The displacement fields of disturbed dislocation networks are used to simulate the X-ray diffraction patterns by Monte Carlo method. We find that substantial disorder is needed for random shifts to be experimentally observable as diffuse scattering. The model of random distortion sources produces comparable diffuse scattering with the dislocation network looking closer to the initial perfect structure. The diffraction patterns due to distorted honeycomb dislocation networks are compared with the ones due to triangular networks of straight dislocations. The disorder parameters of the latter networks can be chosen to produce diffraction patterns similar to the former.

Rapid sample delivery by acoustic injection for serial protein crystallography

Continuous irradiation of a single protein crystal alters its physical structure. This typically manifests as photoelectric chemical transformations and a loss of diffraction, which can be counterproductive to structure determination. Serial crystallography methods overcome these effects by recording partial datasets from multiple crystals, effectively spreading the dose over many crystals. As the number of crystals per dataset increases, however, new methods are needed to rapidly replenish samples in the X-ray beam. Acoustic droplet ejection (ADE) technology offers a robust and reliable method for transferring crystals. Acoustic injectors based on ADE technology use focused sound waves to deliver crystals contained within picoliter and nanoliter droplets, and can generate hundreds of droplets each second. Acoustic injectors have been tested at the National Synchrotron Light Source, where crystal-containing droplets were deposited on a goniometer-mounted conveyor belt. The conveyor belt enabled translation and rotation in the X-ray beam, permitting small wedges of data to be collected on each crystal. Crystals were also directly injected into oncoming X-ray pulses at the Linac Coherent Light Source, producing diffraction patterns from several samples under conditions of ambient temperature and pressure. Development is underway to incorporate acoustic injectors into the microfocus and automated macromolecular crystallography beamlines at the National Synchrotron Light Source II.

ESRF/DBT/EMBL:BM14-2: MX station for in situ, dehydration and MAD experiments

BM14 was the first dedicated macromolecular crystallography (MX) beamline to come into operation at the ESRF during 1995. This experimental station has been designed specifically to produce MX diffraction data using Single/Multiple-wavelength Anomalous Diffraction (SAD/MAD) methods (www.bm14.eu). Currently, beamline is operated by a consortium between the ESRF, the EMBL-Grenoble and the Department of Biotechnology (DBT), India. Recently, the beamline optics was fully upgraded (hence the new denomination BM14-2). A four-time increase in beam brilliance is achieved with the concomitant reduction in average exposure time (~5s today versus 20s before), leading to a substantial gain in the screening capacity. Upgrade includes a new channel-cut crystal equipped with a second crystal pusher to reject high-energy harmonics. The latter device turned to be crucial for Sulphur-SAD experiment success rate. The special goniometer head is installed on microdiffractometer (MD2) goniometer which is capable of handling the CrystalDirect (CD) nanocrystallisation plates [1] so that any crystallisation hit can be exposed to the beam. The plate characteristics are optimal for in situ data collection and they produce diffraction patterns with significantly reduced background. A newly designed dehydration-to-cryogenic nozzle-changer device is also installed in order to avoid the down time between the experiments (such as, In situ screening, humidity control device (HC1), standard cryogenic data collection). European users may apply for access via the Biostruct-X program (www.biostruct-x.eu) both for CD plate nanocrystallisation trials and for beamtime. Users from India are encouraged to apply from DBT-Portal (http://process.mbu.iisc.ernet.in/BM14/index.jsp) for beamtime. The optics hutch refurbishment and implementation of the novel devices in the experimental hutch opens promising perspectives for collecting data at room temperature and that are of importance to the MX users.

Metallographic Preparation of Zn-21Al-2Cu Alloy for Analysis by Electron Backscatter Diffraction (EBSD)

Samples of Zn-21Al-2Cu alloy (Zinalco) that will be heavily deformed were prepared using five different manual mechanical metallographic methods. Samples were analyzed before tensile testing using the orientation imaging microscopy-electron backscatter diffraction (OIM-EBSD) technique. The effect of type and particle size during the final polishing stages for this material were studied in order to identify a method that produces a flat, damage free surface with a roughness of about 50 nm and clean from oxide layers, thereby producing diffraction patterns with high image quality (IQ) and adequate confidence indexes (CI). Our results show that final polishing with alumina and silica, as was previously suggested by other research groups for alloys that are difficult to prepare or alloys with low melting point, are not suitable for manual metallographic preparation of this alloy. Indexes of IQ and CI can be used to evaluate methods of metallographic preparation of samples studied using the OIM-EBSD technique.

Selection and orientation of different particles in single particle imaging

The short pulses of X-ray free electron lasers can produce diffraction patterns with structural information before radiation damage destroys the particle. The particles are injected into the beam in random orientations and they should be identical. However, in real experimental conditions it is not always possible to have identical particles. In this paper we show that the correlation maximization method, developed earlier, is able to select identical particles from a mixture and find their orientations simultaneously.

Fraunhofer diffraction of short-fiber-reinforced composites aligned by an electric field

This study aims to determine if aligned, short-fiber composites are capable of producing Fraunhofer diffraction patterns similar to those of human enamel sections and to validate the mechanism of diffraction by comparing the experimental and theoretical fiber spacings. Rectangular composite specimens were filled with short E-glass fibers (120 microm length, 15 microm diameter) to contents of 1, 5, 10, and 25% (vol%). The fibers were oriented perpendicular to the surface normal using an alternating electric field of 0.75 kV/mm. A He-Ne laser was used with thin slices of specimen placed behind a pinhole to produce diffraction patterns. The locations of the diffraction maxima were used to determine the theoretical slit spacings which were compared to the experimental slit spacings determined by microscopy. The specimens produced diffraction patterns analogous to the theoretical Fraunhofer diffraction of light through multiple slits. This was verified by comparing the theoretical spacing of the fibers calculated from the diffraction pattern with the experimental spacing of the fibers determined from the optical micrographs. This work has verified that orientation of short-fiber composites using an electric field can yield composites with sufficient order to produce Fraunhofer diffraction patterns that are qualitatively similar to the diffraction patterns of human enamel sections.

PROTEIN'S LIPID COAT REVEALED

RELATIVELY LITTLE IS KNOWN about how membrane proteins interact with the lipids that surround them because structural studies typically fail to capture these proteins' lipid environment. Now, a high-resolution structure of a membrane-embedded water channel protein has opened a window to how lipids pack around membrane proteins ( Nature 2005, 438 ,633). key to an effective membrane is to get the packing of the lipids and proteins right, explains Anthony G. Lee of the University of Southampton, England, in an accompanying Nature commentary. The new structural data clearly illustrate how this packing is achieved. Thomas Walz of Harvard Medical School and coworkers captured the 1.9-A structure of aquaporin-0 (AQP0) immersed in an artificial lipid bilayer. AQP0 is a water channel that is the most abundant membrane protein in the lens of the eye. They used electron crystallography, a well-established technique that employs the beam of an electron microscope to produce diffraction patterns from ...

Theory of the Kapitza-Dirac diffraction effect.

We treat the Kapitza-Dirac diffraction effect observed recently by Batelaan et al. using a newly developed nonperturbative quantum-field scattering theory. Our theory shows that an electron beam passing perpendicularly through a focused standing light wave can produce diffraction patterns. Our theory predicts (1) the minimum value of the ponderomotive energy is (Planck's over 2 pi omega)(2)/m(e)c(2), (2) the critical laser intensity above which the first pair of electron diffraction peaks will occur, and (3) the existence of sidebands in the electron spectra separated far from the central band by a momentum of several hundred photons. Our theory provides a unified explanation of the experimental results of Bucksbaum et al. and Batelaan et al.