X-ray Diffraction Imaging Research Articles

Triazine-based covalent organic framework/carbon nanotube fiber nanocomposites for high-performance supercapacitor electrodes

In this study we synthesized the triazine-based two-dimensional covalent organic frameworks (COFs) TPTP-COF and TPDA-COF through Schiff base (imine) condensations of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine (TPT-3CHO) with 2,4,6-tris(4-aminophenyl)triazine (TPT-3NH2) and diaminoanthraquinone (DAAQ), respectively. Moreover, we used carbon nanotube fibers (f-CNFs) as a template to synthesize TPTP-COF@f-CNF and TPDA-COF@f-CNF nanocomposite materials. X-ray diffraction image analysis revealed that our two COF materials possessed hexagonal crystal structures, with the crystallinity of TPTP-COF being much higher than that of TPDA-COF. Through simulations using Material Studio software, we determined an AA stacking structure for TPTP-COF and an AB stacking structure for TPDA-COF. These COF materials had high specific surface areas, charge transfer capability, and high redox properties, making them suitable for use in supercapacitor applications. TPTP-COF– and TPDA-COF–based electrodes provided specific capacitances of 577.4 and 640.4 F g−1, respectively, at a scan rate of 5 mV s−1. The specific capacitance of the TPTP-COF@f-CNF and TPDA-COF@f-CNF electrodes decreased upon increasing the f-CNF content. The maximum specific capacitances of TPTP-COF– and TPDA-COF–based symmetric supercapacitor devices were 56.4 and 70.6 F g−1, respectively. The TPTP-COF– and TPDA-COF–based devices both exhibited good electrochemical stability, preserving 78.60 and 81.54%, respectively, of their initial capacitances after 10,000 cycles. The energy density and power density of the TPDA-COF–based device were slightly better than those of the TPTP-COF–based device.

Method of sparse-view coded-aperture x-ray diffraction tomography

Objective. X-ray diffraction (XRD) has been considered as a valuable diagnostic technology providing material specific ‘finger-print’ information i.e. XRD pattern to distinguish different biological tissues. XRD tomography (XRDT) further obtains spatial-resolved XRD pattern distribution, which has become a frontier biological sample inspection method. Currently, XRD computed tomography (XRD-CT) featured by the conventional CT scan mode with rotation has the best spatial resolution among various XRDT methods, but its scan process takes hours. Meanwhile, snapshot XRDT methods such as coded-aperture XRDT (CA-XRDT) aim at direct imaging without scan movements. With compressed-sensing acquisition applied, CA-XRDT significantly shortens data acquisition time. However, the snapshot acquisition results in a significant drop in spatial resolution. Hence, we need an advanced XRDT method that significantly accelerates XRD-CT acquisition and still maintains an acceptable imaging accuracy for biological sample inspection. Approach. Inspired by the high spatial resolution of XRD-CT from rotational scan and the fast compressed-sensing acquisition in snapshot CA-XRDT (SnapshotCA-XRDT), we proposed a new XRDT imaging method: sparse-view rotational CA-XRDT (RotationCA-XRDT). It takes SnapshotCA-XRDT as a preliminary depth-resolved XRDT method, and combines rotational scan to significantly improve the spatial resolution. A model-based iterative reconstruction (MBIR) method is adopted for RotationCA-XRDT. Moreover, we suggest a refined system model calculation for the RotationCA-XRDT MBIR which is a key factor to improve reconstruction image quality. Main results. We conducted our experimental validation based on Monte-Carlo simulation for a breast sample. The results show that the proposed RotationCA-XRDT method succeeded in producing good images for detecting 2 mm square carcinoma with a 15-view scan. The spatial resolution is significantly improved from current SnapshotCA-XRDT methods. With our refined system model, MBIR can obtain high quality images with little artifacts. Significance. In this work, we proposed a new high spatial resolution XRDT method combining coded-aperture compressed-sensing acquisition and sparse-view scan. The proposed RotationCA-XRDT method obtained significantly better image resolution than current SnapshotCA-XRDT methods in the field. It is of great potential for biological sample XRDT inspection. The proposed RotationCA-XRDT is the fastest millimetre-resolution XRDT method in the field which reduces the scan time from hours to minutes.

Low-temperature synthesis of colloidal few-layer WTe2 nanostructures for electrochemical hydrogen evolution

High-quality transition metal tellurides, especially for WTe2, have been demonstrated to be necessarily synthesized under close environments and high temperatures, which are restricted by the low formation Gibbs free energy, thus limiting the electrochemical reaction mechanism and application studies. Here, we report a low-temperature colloidal synthesis of few-layer WTe2 nanostructures with lateral sizes around hundreds of nanometers, which could be tuned the aggregation state to obtain the nanoflowers or nanosheets by using different surfactant agents. The crystal phase and chemical composition of WTe2 nanostructures were analyzed by combining the characterization of X-ray diffraction and high-resolution transmission electron microscopy imaging and elements mapping. The as-synthesized WTe2 nanostructures and its hybrid catalysts were found to show an excellent HER performance with low overpotential and small Tafel slope. The carbon-based WTe2–GO and WTe2–CNT hybrid catalysts also have been synthesized by the similar strategy to study the electrochemical interface. The energy diagram and microreactor devices have been used to reveal the interface contribution to electrochemical performance, which shows the identical performance results with as-synthesized WTe2–carbon hybrid catalysts. These results summarize the interface design principle for semimetallic or metallic catalysts and also confirm the possible electrochemical applications of two-dimensional transition metal tellurides.

Bismuth Coordination Polymers with Fluorinated Linkers: Aqueous Stability, Bivolatility, and Adsorptive Behavior.

Bismuth metal-organic frameworks and coordination polymers (CP) are challenging to synthesize, given the poor solubility of bismuth precursors and asymmetric and labile ligation of Bi3+ due to its intrinsic lone pair. Here, we synthesize and structurally characterize three Bi3+-CPs, exploiting a tetrafluoroterephtalate (F4BDC) linker to determine the effect of high acidity on these synthesis and coordination challenges. Single-crystal X-ray diffraction characterization showed that pi-pi stacking of linkers directs framework arrangement and generally deters open porosity in the three structures, respectively featuring Bi chains (Bi chain -F 4 BDC), Bi dimers (Bi 2 -F 4 BDC) linked into chains, and Bi tetramers (Bi 4 -F 4 BDC). Powder X-ray diffraction and microscopic imaging show the high purity and stability of these compounds in water. Naphthalenedisulfonate (NDS) was used as a mineralizer in the synthesis of (Bi chain -F 4 BDC) and (Bi 4 -F 4 BDC), and studies of its role in assembly pathways yielded two additional structures featuring mixed NDS and F4BDC, respectively, linking monomer and octamer Bi nodes, and confirmed that F4BDC is the preferred (less labile) linker. Methylene blue (MB) adsorption studies show differing efficacies of the three Bi-F4BDC phases, attributed to surface characteristics of the preferential growth facets, while generally most effective adsorption is attributed to the hydrophobicity of fluorinated ligands. Finally, thermogravimetric analysis of all three Bi-F4BDC phases indicates simultaneous ligand degradation and in situ formation of volatile Bi compounds, which could be exploited in the chemical vapor deposition of Bi-containing thin films.

Equation-of-state-constrained pressure dependence of x-ray elastic constants of gold for stress components calculation in a high-pressure anvil apparatus

In the resolution of the large divergence between pressure calculated by way of axial stress components from elastic constants and pressure determined by an equation of state, a 2nd order pressure dependency of elastic constants is introduced. Incorporating results from the equation of state and ultrasonic measurements in the literature, we determined the pressure dependency of x-ray elastic constants of gold and established functions for the calculation of macro-stress components from its macro-strain counterparts. The precision of stress components through these functions is estimated to be at 1% level. The determination of stress components, including crucial shear components, through analysis of an x-ray diffraction image, is demonstrated.

Influence of Surface-Modified Montmorillonite Clays on the Properties of Elastomeric Thin Layer Nanocomposites

In recent years, polyurethane nanocomposites have attracted more attention due to the massive demand for materials with increasingly exceptional mechanical, optical, electrical, and thermal properties. As nanofillers have a high surface area, the interaction between the nanofiller and the polymer matrix is an essential issue for these materials. The main aim of this study is to validate the impact of the montmorillonite nanofiller (MMT) surface structure on the properties of polyurethane thin-film nanocomposites. Despite the interest in polyurethane-montmorillonite clay nanocomposites, only a few studies have explored the impact of montmorillonite surface modification on polyurethane's material properties. For this reason, four types of polyurethane nanocomposites with up to 3% content of MMT were manufactured using the prepolymer method. The impact of montmorillonites on nanocomposites properties was tested by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), contact angle measurement, X-ray diffraction (XRD), and optical coherence tomography (OCT). The results showed that chemical and physical interactions between the polymer matrix and functional groups on the montmorillonite surface have a considerable impact on the final properties of the materials. It was noticed that the addition of MMT changed the thermal decomposition process, increased T2% by at least 14 °C, changed the hydrophilicity of the materials, and increased the glass transition temperature. These findings have underlined the importance of montmorillonite surface structure and interactions between nanocomposite phases for the final properties of nanocomposites.

Influence of annealing time on the microstructure and properties of additively manufactured X2CrNiMoN25–7–4 duplex stainless steel: Experiment and simulation

Duplex stainless steels (DSS) manufactured additively using the powder bed fusion – laser beam/metal (PBF-LB/M) process exhibit a predominantly ferritic microstructure due to the process inherent ultrahigh cooling rates. In this microstructural constitution, the high potential of a balanced two-phase ferritic-austenitic microstructure typical for DSS is not exploited, which is why these steels are subsequently heat-treated. The present study focuses precisely on this heat treatment considering PBF-LB/M-processed X2CrNiMoN25–7–4 DSS solution annealed at different times and aims to explain the influence of the as-built microstructure on the phase formation during solution annealing as a function of heat-treatment time and how different annealing times affect the mechanical and corrosive properties. The as-built microstructure was investigated using electron backscattered diffraction (EBSD), X-ray diffraction (XRD), and atom probe tomography (APT) and the subsequently solution annealed ones using EBSD, XRD, secondary electron microscopy (SEM), energy dispersive (EDS) and wavelength dispersive X-ray spectrometry (WDS). Additionally, the results were compared to DICTRA® simulations. The corrosive properties were examined by potentiodynamic measurements in 0.5 molar sulfuric acid, whereas the mechanical properties were characterized by tensile testing. The ferritic microstructure in the as-built condition is characterized by a supersaturation with nitrogen, accompanied by the formation of nanoscale Cr2N. During heat treatment, these precipitates serve as nucleation sites for austenite formation, so that a balanced, ferritic-austenitic microstructure is already achieved after 3 min. Compared to longer annealing times (5 and 60 min), the highest strength and corrosion resistance is obtained with an annealing time of 3 min, as longer times result in grain coarsening.

Modelling and experimental investigation of Nb2O5 as a high-rate battery anode material

Modelling and understanding the battery electrochemical performance at high rates is a great challenge. Known for its fast rate and good cyclability, niobium pentoxide (Nb2O5) is a promising anode material for lithium-ion batteries and is specifically modelled and investigated in this work. Commercially sourced Nb2O5 was characterised using scanning electron microscopy, X-ray diffraction, and micro-computed tomography. The Nb2O5 material was found to contain large rod- and ball-like polycrystalline particles of tens of microns in size and have mixed T-Nb2O5 and H-Nb2O5 phases. The electrochemical performance of the material after ball milling was tested via cyclic voltammetry and constant-current cycling at different C-rates up to 50C (10,000 mA g−1). The material achieved a similar charge capacity (143 mAh g−1) to T-Nb2O5 at 0.5C and this capacity could be retained by more than 55% when C-rate was increased to 10C. The experimental results were used to support the development of the Doyle-Fuller-Newman electrochemical model for Nb2O5. By model parameterization, the reference exchange-current density and solid-state diffusivity of the present Nb2O5 were estimated to be 9.6 × 10−4 A m−2 and 6.2 × 10−14 m2 s−1, respectively. The model achieved accurate prediction of the battery performance up to currents of 5C with the obtained constant properties. However, the properties of Nb2O5 were found to be rate-dependent at higher C-rates when good agreements between the model and experiment were maintained. The decrease of the two properties at 10−50C revealed that there was a change of dominant charge storage mechanism from diffusion-controlled lithium insertion to capacitive effects, which was experimentally observed in the cyclic voltammetry.

Two-Step Solid State Synthesis of Medium Entropy LiNi0.5Mn1.5O4 Cathode with Enhanced Electrochemical Performance

Solid state reaction is widely used in the synthesis of electrode materials, due to its low cost and good scalability. However, the traditional solid-state reaction is not suitable for the synthesis of materials with multiple elements, such as high entropy or medium entropy materials, due to the poor homogeneity of raw material mixing. Here, we prepared multi-element doped LiNi0.5Mn1.5O4 (medium entropy) cathode material by two step solid state reaction. X-ray diffraction and Raman image show that the homogeneity of multi-element doped LiNi0.5Mn1.5O4 cathode has been greatly improved with this two-step method. As a result, the electrochemical performance is greatly improved, comparing to traditional solid-state reaction. First, the specific capacity at 0.1 C is increased from 126 mAh/g to 137 mAh/g. With a high current density of 10 C, the specific capacity is even increased from 64 mAh/g to 89 mAh/g with this two-step method. Second, the cycle stability is enhanced, with capacity retention of 86% after cycling at 1 C for 500 times (vs. 71% for the one-step method).

Dislocation Climb in AlN Crystals Grown at Low-Temperature Gradients Revealed by 3D X-ray Diffraction Imaging

The dislocation evolution in a cross-section a-plane cut through a sublimation-grown aluminum nitride (AlN) crystal grown with low-temperature gradients and subsequent low thermal stress is investigated with different X-ray diffraction imaging methods. Exploiting the so-called weak-beam contrast using monochromatic X-rays in combination with suitable three-dimensional (3D) interpretation and reconstruction allows the identification of individual dislocations as well as tracing their progression in the crystal volume, even in the considerably strained interface region. It is particularly striking that the laterally grown crystal volume is dislocation-free. The dislocation densities in the seed and the bulk volume are similar (1 × 103 cm–2), but while the dislocations in the seed are randomly arranged, the dislocations in the bulk volume show a uniform line shape, indicating a common mechanism of dislocation movement. Since the dislocation slings in the bulk do not lie in slip planes, it can be concluded that the lateral movement does not result from dislocation glide, but from impurity-driven climb of dislocations during growth. The absence of slip can be explained by the low-temperature gradients and the subsequent low thermal stress below the critical resolved shear stress (CRSS).

Polar–Nonpolar Transition-Type Negative Thermal Expansion with 11.1% Volume Shrinkage by Design

Chemical substitution for the tuning of the working temperature of phase-transition-type negative thermal expansion (NTE) materials generally reduces the volume shrinkage during the transition. We have investigated the effects of electron doping and reduction of 6s2 lone-pair activity in PbVO3 with a large polar distortion (c/a = 1.23) and found that the combination of Bi and Sr substitutions for Pb enables a temperature-induced polar to non-polar transition with 11% volume shrinkage, even larger than the pressure-induced volume collapse of PbVO3 (∼10.6%), and is the largest value among the NTE materials reported so far. The domain structure of the coexisting cubic and tetragonal phases with such a huge volume difference was successfully observed by high-angle annular dark-field scanning transmission electron microscopy and the spatial distribution of domains by Bragg coherent X-ray diffraction imaging. The temperature hysteresis is reduced by repeated heating/cooling cycles, suggesting that the changes in the domain structure dominate the NTE properties.

Silicone matrices for controlled dexamethasone release: toward a better understanding of the underlying mass transport mechanisms.

Dexamethasone-loaded silicone matrices offer an interesting potential as innovative drug delivery systems, e.g. for the treatment of inner ear diseases or for pacemakers. Generally, very long drug release periods are targeted: several years/decades. This renders the development and optimization of novel drug products cumbersome: experimental feedback on the impact of the device design is obtained very slowly. A better understanding of the underlying mass transport mechanisms can help facilitating research in this field. A variety of silicone films were prepared in this study, loaded with amorphous or crystalline dexamethasone. Different polymorphic drug forms were investigated, the film thickness was altered and the drug optionally partially/completely exchanged by much more water-soluble dexamethasone 'phosphate'. Drug release studies in artificial perilymph, scanning electron microscopy, optical microscopy, differential scanning calorimetry, X-ray diffraction and Raman imaging were used to elucidate the physical states of the drugs and polymer, and of the systems' structure as well as dynamic changes thereof upon exposure to the release medium. Dexamethasone particles were initially homogeneously distributed throughout the systems. The hydrophobicity of the matrix former very much limits the amounts of water penetrating into the system, resulting in only partial drug dissolution. The mobile drug molecules diffuse out into the surrounding environment, due to concentration gradients. Interestingly, Raman imaging revealed that even very thin silicone layers (<20 µm) can effectively trap the drug for prolonged periods of time. The physical state of the drug (amorphous, crystalline) did not affect the resulting drug release kinetics to a noteworthy extent.

Band gap determination by Tauc’s, ASF and DASF methods of alkaline earth modified lithium borate glasses co-doped with transition metal ions

In the current manuscript the inorganic glassy system with composition 15Li2O-25RO-59B2O3-0.7CuO-0.3Fe2O3 (R = Ca/Sr/Ba) have been synthesized through classical melt-quench method and investigated by XRD, and optical absorption techniques. The X-ray diffraction images of the synthesized glassy materials substantiated the inorganic glassy structure. The UV–Visible optical absorption spectra of the synthesized glassy materials were recorded with in the wavelength range 300 to 900 nm. The Tauc’s, ASF and DASF methods were employed to ascertain the optical and Urbach energies of the prepared glass system. The effect of alkaline earths on the optical absorption was discussed.

Effects of citric acid crosslinking on the structure and properties of ovotransferrin and chitosan composite films

In this study, ovotransferrin/chitosan (OVT/CS) composite films cross-linked by citric acid (CA) were prepared and the effects of CA cross-linking on the structure and physicochemical properties of the composite films were investigated. The cross-linking degree measured by 2,4,6-trinitrobenzenesulfonic acid (TNBS) method confirmed that CA was cross-linked with the matrix, and Fourier transform infrared spectroscopy confirmed that more hydrogen bonds and electrostatic interactions were formed between CA and the matrix. Differential scanning calorimetry, X-ray diffraction and Scanning electron microscope images revealed the compatibility between substances. The synergistic inhibition between the matrix results in a significantly higher antibacterial activity of the composite film than the pure film. Compared with uncross-linked films, the mechanical properties, barrier properties and water resistance of the cross-linked films were significantly improved. When the concentration of CA was 5 wt% (W/W, on a dry basis of the weight of OVT and CS), the most significant improvement in film performance was obtained. The tensile strength of the film increased from 32.05 MPa without cross-linking to 61.99 MPa and the swelling degree decreased from 51.5 % to 24.23 %. The observed phenomena suggest that cross-linking OVT and CS with CA can obtain functional edible films with improved properties.

Non-destructive structural studies of coins from the Uzundara Fortress using X-ray diffraction and neutron tomography

The copper Heliocles coin and two silver Demetrius coins dated to the II century BC from the archaeological works of the Uzundara fortress of the Greco-Bactrian Kingdom were studied using non-destructive structural diagnostics methods. The phase analysis of the coins was performed using the X-ray diffraction method. Also, the spatial distribution of the internal components of the coins was investigated by neutron imaging methods. It has been established that the dominant phase of the Heliocles coin is copper, however, a small volume of patina was found. It is mainly represented by tenorite CuO phase. The neutron tomography method indicates a deep penetration of tenorite into the thickness of the coin, and its volume fraction can reach 10% of the total volume. Two Demetrius coins consist entirely of silver. The complex profile of coins due to the features of a coinage was reconstructed. The phase composition, the content of the composite phases and three-dimensional models of the studied coins were obtained.

Arsenic removal from contaminated water utilizing novel green composite Chlorella vulgaris and nano zero-valent iron

Arsenic waste must be carefully managed because of the adverse effects of arsenic in wastewater on the ecosystem. In the present study, an environmentally friendly novel composite of Chlorella vulgaris microalgae and nano-zero valent iron (NZVI) was employed as an adsorbent to eliminate arsenic from the aqueous environment. Fourier Transform Infrared spectroscopy, X-ray diffraction, and scanning electron microscope images were used to characterize and analyze the CV/NZVI composites. Batch tests using initial arsenic concentrations ranging from 5 to 100 mg/L were conducted to evaluate removal efficiencies. According to kinetic analysis, the best model for fitting the experimental data was the pseudo first-order model, which had the lowest Akaike information criterion (AIC), and Bayesian information criterion (BIC) values of −23.878 and −7.902, respectively. Results alluded that physisorption is the primary mechanism influenced by As-removal by CV/NZVI composite. Due to the negative sign of the enthalpy and Gibbs free energy, the thermodynamic investigation revealed that the adsorption reaction was exothermic and spontaneous. The thermodynamic analysis also affirmed that the arsenic removal process involved primarily physisorption and slight chemisorption phenomena. Meanwhile, 1.5 g/L CV/NZVI dosage achieved 99 % As(V) removal efficiency in synthetic groundwater systems, confirming the high potential of the composite in complex aqueous systems.

Microstructural investigation of mortars incorporating cockle shell and waste fishing net

Large amounts of cement and natural aggregates are used annually to produce concrete, and the high energy consumption required for the production of these materials is considered to be a major environmental concern globally. This study investigates the effect of marine wastes, such as cockle shells and waste fishing nets, on the microstructural characteristics of cement-based materials. Crushed cockle shells were used as a substitute for fine aggregates, and ground waste fishing nets were utilized as a fiber replacement to enhance the flexural performance of cementitious materials. Varying amounts of cockle shell and waste fishing net were washed and then used as substitutes for fine aggregates and fibers, respectively, in cement mortar specimens. 10, 20, and 30 wt% of cockle shells were substituted for fine aggregates, and the waste fishing net of 1.0 % of the total volume was also considered in the mixtures. The compressive and flexural strength of the specimens were measured to examine the effect of marine waste replacement on the mechanical properties of cement-based composites. Scanning electron microscopy, X-ray diffraction, and micro-computed tomography were utilized to investigate the microstructural characteristics of the materials with different substitution ratios of cockle shells and waste fishing nets. The obtained results confirm that properly washed and processed cockle shell powder can be used as an alternative to fine aggregates for conventional cement-based composites, and waste fishing nets can be utilized as a reinforcement for improving the flexural performance of cement mortar.

Analysing the Effect of Cassava Flour as a Mixture on the Physical, Mechanical, and Durability Properties of High-Strength Concrete

The availability, cost, and environmental impact of chemical admixtures are reduced when natural substitute materials are incorporated into the concrete as an admixture. This paper outlines the findings of a study that looked at the physical characteristics of fresh and hardened concrete made with Portland pozzolanic cement CEM II/B-P blended with cassava flour up to 5% by weight of cement. A low water/binder ratio of 0.35 was used together with a carboxylate-based superplasticizing admixture to produce high strength. In fresh-state concrete, the initial and final setting times, soundness, and consistency were found to increase with increased cassava flour content, whereas the compacting factor and slump were observed to decrease. In the hardened state, compressive strengths were determined at 3, 7, 14, 28, 56, and 90 days, while split tensile and flexural strengths were investigated at 28 days. Similarly, dry density and porosity were also investigated at 28 days. Water absorption was also studied as a potential indicator of durability in hardened concrete. Scanning electron microscopy characterization of cassava flour revealed porous particles of irregular shape. On the other hand, X-ray diffraction imaging showed that the primary chemicals in cassava flour are silicon dioxide (50%), calcium oxide (17%), and aluminium oxide (7%). All of the mixes that incorporated cassava flour were stronger than the control mix, with the 3% cassava flour combination producing the best results. Doi: 10.28991/CEJ-2022-08-12-015 Full Text: PDF

Modeling and experimental validation of dynamical effects in Bragg coherent x-ray diffractive imaging of finite crystals

Bragg coherent diffractive imaging (BCDI) is a noninvasive microscopy technique that can visualize the shape and internal lattice deviations of crystals with nanoscale spatial resolution and picometer deformation sensitivity. Its strain imaging capability relies on Fourier transform--based iterative phase retrieval algorithms, which are mostly developed under the kinematical approximation. Such approximation prohibits the application of BCDI on larger crystals, which are commonly seen in most emerging functional materials. Understanding the dynamical effect in BCDI, as well as developing a validated method for modeling BCDI at the dynamical diffraction limit, is crucial for applying BCDI to hierarchical systems that contain micron-sized crystals and grains. Here we report a comparative study on the impact of dynamical diffraction effects by comparing the reconstruction results from two measurements of the same crystal. Forward simulation is implemented to show subtle changes of interference fringes in the diffraction pattern due to the dynamical diffraction, and is compared directly with the experimental data.

Single-exposure Fourier-transform ghost imaging based on spatial correlation

Ultrafast x-ray diffraction imaging provides an opportunity to realize x-ray nanoimaging of biomolecules before radiation damage, while the image resolution is still restricted by the photon flux. Fourier-transform ghost imaging based on the temporal intensity correlation can achieve diffraction-limited imaging. However, a large number of temporal samplings are inevitable, which makes it almost impossible to be implemented in the ultrafast x-ray imaging. Here, we propose an x-ray single-exposure Fourier-transform ghost imaging (SFGI) approach. The Fourier information of an unknown sample can be obtained by measuring the spatial intensity correlation between two speckle fields, and the sample needs to be exposed only once. In our demonstration experiment of SFGI, the Fourier-transform diffraction pattern of a two-dimensional sample is achieved, and its face-centered-cubic feature in the spatial domain is retrieved successfully. The simulation results of the DNA origami and rice dwarf virus indicate that a spatial resolution of 10 nm may be reached, and x-ray ghost imaging with 0.1 photon/pixel speckle detection can be expected. Our research paves the way for the future application of ultrafast x-ray ghost imaging.