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Optimising the balance between propene selectivity, propene/ethene ratio and catalytic stability and unravelling the explicit mechanism on formation of the first carbon–carbon bond are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the nature of active sites within the pores of commercial MFI-zeolites by incorporating tantalum(V) and aluminium(III) centres into the framework. The resultant TaAlS-1 zeolite exhibits simultaneously remarkable propene selectivity (51%), propene/ethene ratio (8.3) and catalytic stability (>50 h) at full methanol conversion. In situ synchrotron X-ray powder diffraction, X-ray absorption spectroscopy and inelastic neutron scattering coupled with DFT calculations reveal that the first carbon–carbon bond is formed between an activated methanol molecule and a trimethyloxonium intermediate. The unprecedented cooperativity between tantalum(V) and Brønsted acid sites creates an optimal microenvironment for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins., We thank EPSRC (EP/P011632/1), the Royal Society, National Natural Science Foundation of China (21733011, 21890761, 21673076), and the University of Manchester for funding. We thank EPSRC for funding and the EPSRC National Service for EPR Spectroscopy at Manchester. A.M.S. is supported by a Royal Society Newton International Fellowship. We are grateful to the STFC/ISIS Facility, Oak Ridge National Laboratory (ORNL) and Diamond Light Source (DLS) for access to the beamlines TOSCA/MAPS, VISION and I11/I20, respectively. We acknowledge Dr. L. Keenan for help at I20 beamline (SP23594-1). UK Catalysis Hub is kindly thanked for resources and support provided via our membership of the UK Catalysis Hub Consortium and funded by EPSRC grant: EP/R026939/1, EP/R026815/1, EP/R026645/1, EP/R027129/1 or EP/M013219/1 (biocatalysis). We acknowledge the support of The University of Manchester’s Dalton Cumbrian Facility (DCF), a partner in the National Nuclear User Facility, the EPSRC UK National Ion Beam Centre and the Henry Royce Institute. We recognise Dr. R. Edge and Dr. K. Warren for their assistance during the 60Co γ-irradiation processes. We thank Prof. A. Jentys from the Technical University of Munich for the measurement of the INS spectrum of iso-butene. We thank C. Webb, E. Enston and G. Smith for help with GC–MS; Dr. L. Hughes for help with SEM and EDX; M. Kibble for help at TOSCA/MAPS beamlines. Computing resources (time on the SCARF compute cluster for some of the CASTEP calculations) was provided by STFC’s e-Science facility. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by ORNL. The computing resources at ORNL were made available through the VirtuES and the ICE-MAN projects, funded by Laboratory Directed Research and Development programme and Compute and Data Environment for Science (CADES)

This study presents the reliability of diamond-like carbon (DLC) ultrathin films fabricated by DC magnetron sputtering as the gate dielectric layer in metal–insulator–semiconductor (MIS) devices. Stress-induced leakage current (SILC) and time-dependent dielectric breakdown (TDDB) measurements were performed to determine the reliability of the devices. The MIS device with DLC film deposited at 1100-V bias exhibited little variation of SILC under different constant voltage stress times and had a long TDDB lifetime. The results indicate excellent reliability of DLC films used as gate dielectrics. Moreover, several soft breakdown events occurred during TDDB measuring. An extended percolation model was adopted for explanation of the current versus time characteristics.

Temperature- or pressure-swing sorption in porous metal–organic framework (MOF) materials has been proposed for new gas separation technologies. The high tunability of MOFs toward particular adsorbates and the relatively low energy penalty for system regeneration indicate that reversible physisorption in MOFs has the potential to create economic and environmental benefits compared with state-of-the-art chemisorption systems. However, for MOF-based sorbents to be commercialized, they have to show long-term stability under the conditions imposed by the application. Here, we demonstrate the structural stability of MFM-300(Al) in the presence of a series of industrially relevant toxic and corrosive gases, including SO2, NO2, and NH3, over 4 years using long-duration synchrotron X-ray powder diffraction. Full structural analysis of gas-loaded MFM-300(Al) confirms the retention of these toxic gas molecules within the porous framework for up to 200 weeks, and cycling adsorption experiments verified the reusability of MFM-300(Al) for the capture of these toxic air pollutants.

The demand for xylenes is projected to increase over the coming decades. The separation of xylene isomers, particularly p- and m-xylenes, is vital for the production of numerous polymers and materials. However, current state-of-the-art separation is based upon fractional crystallisation at 220 K which is highly energy intensive. Here, we report the discrimination of xylene isomers via refinement of the pore size in a series of porous metal–organic frameworks, MFM-300, at sub-angstrom precision leading to the optimal kinetic separation of all three xylene isomers at room temperature. The exceptional performance of MFM-300 for xylene separation is confirmed by dynamic ternary breakthrough experiments. In-depth structural and vibrational investigations using synchrotron X-ray diffraction and terahertz spectroscopy define the underlying host–guest interactions that give rise to the observed selectivity (p-xylene < o-xylene < m-xylene) and separation factors of 4.6–18 for p- and m-xylenes., Separation of xylene isomers is essential for the production of a wide range of materials, but current separation methods are energy intensive. Here the authors report separation of the three xylene isomers at room temperature, via refinement of the pore size in a series of porous MOFs at sub-angstrom precision.

Zeolites that prefer alkynes Alkenes such as ethylene and propene must be separated from alkynes before they can be converted in polymers. Drawbacks in current methods, such as hydrogenation of alkynes producing unwanted alkanes, has spurred interest in sorption separation methods. Zeolites have generally been inefficient, given the similar sizes and volatilities of the molecules. Chai et al. incorporated atomically dispersed divalent transition metal cations into faujasite zeolite and found that the nickel-containing analog efficiently removed alkynes from olefins through chemoselective binding at open nickel(II) sites. At ambient conditions in the presence of water and carbon dioxide, the zeolites retained separation selectivities of 100 and 92, respectively, for acetylene over ethylene and propyne over propylene for 10 adsorption-desorption cycles. Science , this issue p. 1002

Author(s): Zhang, S; Guo, X; Jin, Z; Kang, R; Guo, D; Tang, WC | Abstract: Machining surface topography is a key factor affecting the properties of optical materials.It is generally accepted that the fracture mode tends to dominate practical concerns onmachined parts and the elastic recovery area decreases with the increase of normal load.However, material removal rate is low for ductile zone processing of brittle materials. In thiscase, pile-up and elastic recovery are key factors for surface quality. In this study, an accuratescratching and ploughing hardness model with consideration of both pile-up and elasticrecovery was established based on a series of continuous and constant nanoscratch tests.The hardness evolution mechanism under different nanoscratch deformation modes wasthen investigated. It was found that, in different modes, hardness values exhibited differentcharacteristics due to the change of elastic recovery rate and the intersection of elastic andplastic states. Further, the mapping relationship between hardness dispersion and surfacemorphology characteristics was also investigated. The results indicated that high degree ofhardness dispersion usually corresponded to modes I and II while stable hardness valuerepresented a steady plastic stage. Based on the intrinsic relationship between evolution ofhardness and deformation modes, predicting hardness distribution by in-situ testing dataand then adjusting deformation mode in real time would be helpful in optimizing surfacequality.

Barium zirconate perovskites have been systematically investigated as protonic supports for ruthenium nanoparticles in the Haber-Bosch ammonia synthesis reaction. A series of supports based on barium zirconate were synthesized, for which the B-site of the ABO3 perovskite was doped with different aliovalent acceptor cations and in varying ratios, resulting in varying proton conductivities and trapping behaviors. Crucially, we provide direct evidence of the importance of a hydrogen-migration mechanism for ammonia synthesis over these proton-conducting materials from the studies of reaction kinetics, in situ X-ray photoelectron spectroscopy, and neutron powder diffraction (NPD), which requires the proper balance of oxygen vacancy concentration (B-site doping), trapping-site concentration, and proton-hopping activation energy. We report evidence of a large dynamic coverage of OH groups on the support and the first visualization of both weak and strong proton trap sites within the perovskite lattice through the use of NPD.

The transmission of a detonation wave across a layer of inert gas is studied via one- and two-dimensional numerical simulations based on the reactive Euler equations. The resulting transient transmission process from the one-dimensional simulations is first explored in detail, and is analyzed via distance-time characteristic diagrams. The physics of this transient process is the same until the end of a quasi-steady period. Afterward, the energy release from the combustion may couple to the gas dynamics. Through this coupling, the pressure pulse accompanying the energy release can be rapidly amplified, and consequently, leads to detonation onset. If the inert layer is too thick, the detonation cannot be successfully re-initiated downstream. This inert-layer thickness beyond which a detonation fails to be re-initiated is determined as the critical thickness, δ i,cr. The mechanisms underlying the scenarios with a successful and unsuccessful re-initiation are demonstrated in detail. A parametric study considering simplified and detailed chemical kinetics (i.e., a stoichiometric mixture of hydrogen and air at various initial pressure from 0.1−1atm) demonstrate that δ i,cr normalized by the intrinsic ZND induction length, Δ I, asymptotically decreases with an increase of the effective activation energy, E a. The one-dimensional simulations under-predict the experimental results [1, 2] of δ i,cr/Δ I by at least one order of magnitude. In the two-dimensional scenarios, transverse-wave instabilities are present and allow the detonation wave to re-initiate in cases where re-initiation is unsuccessful in one dimension. The two-dimensional results of δ i,cr are in a closer agreement with the experimental findings.

Mueller matrix imaging polarimetry (MMIP) is a promising technique for the textural characterization of biological tissue structures. To reveal the influence of imaging magnification on the robustness of Mueller matrix parameters (MMPs), the spatial scale stability of MMPs was studied. We established a new MMIP detector and derived the mathematical model of the spatial scale stability of MMPs. The biological tissues with well-defined structural components were imaged under different magnifications. Then, we compared and analyzed the textural features of the MMPs in the resulting images. The experimental results match the predictions of the mathematical model in these aspects: (i) magnification exhibits a strong nonlinear effect on the textural contrasts of MMPs images; (ii) higher magnification does not necessarily lead to superior contrast for textural characterization; and (iii) for different biological tissues, MMPs contrasts can be optimized differently, with some showing superior results. This study provides a reference for the experimental design and operation of the MMIP technique and is helpful for improving the characterization ability of MMPs. This article is protected by copyright. All rights reserved.

The clean and reproducible conditions provided by microfluidic devices are ideal sample environments for in situ analyses of chemical and biochemical reactions and assembly processes. However, the small size of microchannels makes investigating the crystallization of poorly soluble materials on-chip challenging due to crystal nucleation and growth that result in channel fouling and blockage. Here, we demonstrate a reusable insert-based microfluidic platform for serial X-ray diffraction analysis and examine scale formation in response to continuous and segmented flow configurations across a range of temperatures. Under continuous flow, scale formation on the reactor walls begins almost immediately on mixing of the crystallizing species, which over time results in occlusion of the channel. Depletion of ions at the start of the channel results in reduced crystallization towards the end of the channel. Conversely, segmented flow can control crystallization, so it occurs entirely within the droplet. Consequently, the spatial location within the channel represents a temporal point in the crystallization process. Whilst each method can provide useful crystallographic information, time-resolved information is lost when reactor fouling occurs and changes the solution conditions with time. The flow within a single device can be manipulated to give a broad range of information addressing surface interaction or solution crystallization.

This work demonstrates precision control of hydrogen content in La(Fe,Co,Si)13Hδ for the development of environmentally friendly magnetocaloric-based cooling technologies, using an electrolytic hydriding technique. We show the Curie temperature, a critical parameter which directly governs the temperature window of effective cooling, can be varied easily and reproducibly in 1 K steps within the range 274 K to 402 K. Importantly, both partially (up to 10%) and fully hydrided compositions retain favorable entropy change values comparable to that of the base composition. Crucially, we show in these second-order phase transition compounds, partial hydriding is stable and not susceptible against phase separation.

We investigate the geometric and electronic properties of single-atom catalysts (SACs) within metal-organic frameworks (MOFs) with respect to electrocatalytic CO2 reduction as a model reaction. A series of mid-to-late 3d transition metals have been immobilised within the microporous cavity of UiO-66-NH2. By employing Rietveld refinement of new-generation synchrotron diffraction, we not only identified the crystallographic and atomic parameters of the SACs that are stabilised with a robust MN(MOF) bonding of ca. 2.0 Å, but also elucidated the end-on coordination geometry with CO2. A volcano trend in the FEs of CO has been observed. In particular, the confinement effect within the rigid MOF can greatly facilitate redox hopping between the Cu SACs, rendering high FEs of CH4 and C2H4 at a current density of -100 mA cm-2. Although only demonstrated in selected SACs within UiO-66-NH2, this study sheds light on the rational engineering of molecular interactions(s) with SACs for the sustainable provision of fine chemicals.

The results of X-ray diffraction studies of the Gd(Mg0.95−x,ZnxMn−0.05)B5O10 down-converting phosphor as a function of Mg–Zn composition are presented. The lattice parameters and unit cell volumes of GdMg0.95−xZnxMn0.05B5O10 pentaborates are examined. The relationships between the structure and optical properties of these materials are explicated based on the results of theoretical calculations of the energy structure. The effect of pressure on the luminescence of Mn2+ in this system was studied up to ca. 32 GPa. The observed quenching of Mn2+ luminescence is due to the crossing of the emitting 4T1g level with the non-emitting 2T2g state. This crossing sets a long-wavelength limit on the possibility of observing the emission of Mn2+ ions, which is around 850 nm.

The efficient production of light olefins from renewable biomass is a vital and challenging target to achieve future sustainable chemical processes. Here we report a hetero-atomic MFI-type zeolite (NbAlS-1), over which aqueous solutions of γ-valerolactone (GVL), obtained from biomass-derived carbohydrates, can be quantitatively converted into butenes with a yield of >99% at ambient pressure under continuous flow conditions. NbAlS-1 incorporates simultaneously niobium(v) and aluminium(iii) centres into the framework and thus has a desirable distribution of Lewis and Bronsted acid sites with optimal strength. Synchrotron X-ray diffraction and absorption spectroscopy show that there is cooperativity between Nb(v) and the Bronsted acid sites on the confined adsorption of GVL, whereas the catalytic mechanism for the conversion of the confined GVL into butenes is revealed by in situ inelastic neutron scattering, coupled with modelling. This study offers a prospect for the sustainable production of butene as a platform chemical for the manufacture of renewable materials. Production of olefins from biomass-derived γ-valerolactone could lead to sustainable chemical processes, but catalysts suffer from deactivation due to water. Here, a MFI-type zeolite doped with Nb(v) and Al(iii) shows >99% yield at 320 °C and catalyst stability over 180 hours.

Researchers have been aiming to replace copper with carbon nanotube/copper nanocomposites, which are lighter and exhibit better electrical, mechanical, and thermal properties. However, the strength is far below pure carbon nanotube assembly and even much lower than some copper-based alloys. This disadvantage hinders the extensive application of carbon nanotube/copper nanocomposites. In this study, the carbon nanotube/aluminum-copper nanocomposites with ultra-strength and stiffness were prepared. The strength and elasticity modulus of composite reached as high as 6.6 and 500 GPa, respectively, while a high conductivity of 1.8 × 107 S/m was maintained. This can be attributed to the diffusion of Cu and Al atoms into the carbon nanotube fiber, which enhances friction between the carbon nanotubes by "pinning" and "bridging". This structure provides us with novel insights into the design of carbon nanotubes/metal nanocomposites with ultrahigh strength and conductivity.

(1-x)Na0.5Bi0.5TiO3-xNaNbO3 (x=0.02, 0.04, 0.06 and 0.08) ceramics were fabricated by solid state reaction. High-resolution synchrotron x-ray powder diffraction (SXPD) data, coupled with macroscopic electromechanical measurements, reveal the occurrence of an electric field-induced irreversible crystallographic transformation for x=0.02 and 0.04, from a pseudo-cubic non-ergodic relaxor to a rhombohedral or coexisting rhombohedral-tetragonal long range-ordered ferroelectric phase respectively. The highest unipolar electrostrain, corresponding to an effective longitudinal piezoelectric strain coefficient of approximately 340 pm V-1, was obtained for x=0.04; this effect is attributed to enhanced domain switching as a result of the co-existing rhombohedral and tetragonal phases for this composition, which is critical for piezoelectric actuator applications.

We report studies of quasi-remanent polarization states in Pb0.99Nb0.02[(Zr0.57Sn0.43)0.94Ti0.06]0.98O3 (PNZST) anti-ferroelectric ceramics and investigation of their relaxation effects using unique in-situ electrically activated time-resolved Synchrotron X-ray powder diffraction (SXPD) and 119Sn Mossbauer Spectroscopy (MS). The SXPD patterns are consistent with a phase transition from quasi-tetragonal perovskite in 0 V relaxed anti-ferroelectric state to rhombohedral distortion in ferroelectric state under saturating applied voltages of ±2 kV. The observed quasi-remanent polarization relaxation processes are due to the fact that tetragonal to rhombohedral distortion does not occur at the applied voltage required to access the quasi-remanent polarization states, and the tetragonal symmetry restored after the removal of the applied electric field is preserved. Since these quasi-remanent polarization states were seen as possibly suitable for memory applications, the implications of this study are that anti-ferroelectrics are more feasible for multi-state dynamic random access memories (DRAM), while their application to non-volatile memories requires development of more sophisticated “read-out” protocols, possibly involving dc electrical biasing.

Summary Application of thermal and solvent enhanced-oil-recovery (EOR) technologies for viscous heavy-oil recovery in naturally fractured reservoirs is generally challenging because of low permeability, unfavorable wettability and mobility, and considerable heat losses. Vapor/oil gravity drainage (VOGD) is a modified solvent-only injection technology, targeted at improving viscous oil recovery in fractured reservoirs. It uses high fluid conductivity in vertical fractures to rapidly establish a large solvent/oil contact area and eliminates the need for massive energy and water inputs, compared with thermal processes, by operating at significantly lower temperatures with no water requirement. An investigation of the effects of solvent-injection rate, temperature, and solvent type [n-butane and dichloromethane (DCM)] on the recovery profile was performed on a single-fracture core model. This work combines the knowledge obtained from experimental investigation and analytical modeling using the Butler correlation (Das and Butler 1999) with validated fluid-property models to understand the relative importance of various recovery mechanisms behind VOGD—namely, molecular diffusion, asphaltene precipitation and deposition, capillarity, and viscosity reduction. Experimental and analytical model studies indicated that molecular diffusion, convective dispersion, viscosity reduction by means of solvent dissolution, and gravity drainage are dominant phenomena in the recovery process. Material-balance analysis indicated limited asphaltene precipitation. High fluid transmissibility in the fracture along with gravity drainage led to early solvent breakthroughs and oil recoveries as high as 75% of original oil in place (OOIP). Injecting butane at a higher rate and operating temperature enhanced the solvent-vapor rate inside the core, leading to the highest ultimate recovery. Increasing the operating temperature alone did not improve ultimate recovery because of decreased solvent solubility in the oil. Although with DCM, lower asphaltene precipitation should maximize the oil-recovery rate, its higher solvent (vapor)/oil interfacial tension (IFT) resulted in lower ultimate recovery than butane. Ideal density and nonideal double-log viscosity-mixing rules along with molecular diffusivity as a power function of oil viscosity were used to obtain an accurate physical description of the fluids for modeling solvent/oil behavior. With critical phenomena such as capillarity and asphaltene precipitation missing, the Butler analytical model underpredicts recovery rates by as much as 70%.

Electronic metal–support interactions (EMSI) describe the electron flow between metal sites and a metal oxide support. It is generally used to follow the mechanism of redox reactions. In this study of CuO-CeO2 redox, an additional flow of electrons from metallic Cu to surface carbon species is observed via a combination of operando X-ray absorption spectroscopy, synchrotron X-ray powder diffraction, near ambient pressure near edge X-ray absorption fine structure spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. An electronic metal–support–carbon interaction (EMSCI) is proposed to explain the reaction pathway of CO oxidation. The EMSCI provides a complete picture of the mass and electron flow, which will help predict and improve the catalytic performance in the selective activation of CO2, carbonate, or carbonyl species in C1 chemistry., Angewandte Chemie. International Edition, 60 (26), ISSN:1433-7851, ISSN:1521-3773, ISSN:0570-0833

Efficient catalytic conversion of NO2 to non-harmful species remains an important target for research. State-of-the-art deNOx processes are based upon ammonia (NH3)-assisted selective catalytic reduction (NH3-SCR) over Cu-exchanged zeolites at elevated temperatures. Here, we describe a highly efficient non-thermal plasma (NTP) deNOx process catalyzed by a Cu-embedded metal-organic framework, Cu/MFM-300(Al), at room temperature. Under NTP activation at 25°C, Cu/MFM-300(Al) enables direct decomposition of NO2 into N2, NO, N2O, and O2 without the use of NH3 or other reducing agents. NO2 conversion of 96% with a N2 selectivity of 82% at a turnover frequency of 2.9 h−1 is achieved, comparable to leading NH3-SCR catalysts that use NH3 operating at 250°C–550°C. The mechanism for the rate-determining step (NO→N2) is elucidated by in operando diffuse reflectance infrared Fourier transform spectroscopy, and electron paramagnetic resonance spectroscopy confirms the formation of Cu2+⋯NO nitrosylic adducts on Cu/MFM-300(Al), which facilitates NO dissociation and results in the notable N2 selectivity. Nitrogen oxide causes significant effects on the environment and human health. Xu et al. report, to the best of their knowledge, the first example of nonthermal plasma-activated direct decomposition of NO2 over stable and efficient metal-organic framework-based catalysts at room temperature and without the use of NH3 or other reducing agents.

MFM-722(Pb)-DMA undergoes a single-crystal-to-single-crystal (SCSC) transformation to give MFM-722(Pb)-H2O via ligand substitution upon exposure to water vapour. In situ single crystal impedance spectroscopy reveals an increase in proton conductivity due to this structural transition, with MFM-722(Pb)-H2O showing a proton conductivity of 6.61 × 10-4 S cm-1 at 50 °C and 98% RH. The low activation energy (Ea = 0.21 eV) indicates that the proton conduction follows a Grotthuss mechanism.

TiO2-based powder materials have been widely studied as efficient photocatalysts for water splitting due to their low cost, photo-responsivity, earthly abundance, chemical and thermal stability, etc. In particular, the recent breakthrough of nitrogen-doped TiO2, which enhances the presence of structural defects and dopant impurities at elevated temperatures, exhibits an impressive visible-light absorption for photocatalytic activity. Although their electronic and optical properties have been extensively studied, the structure-activity relationship and photocatalytic mechanism remain ambiguous. Herein, we report an in-depth structural study of rutile, anatase and mixed phases (commercial P25) with and without nitrogen-doping by variable-temperature synchrotron X-ray powder diffraction. We report that an unusual anisotropic thermal expansion of the anatase phase can reveal the intimate relationship between sub-surface oxygen vacancies, nitrogen-doping level and photocatalytic activity. For highly doped anatase, a new cubic titanium oxynitride phase is also identified which provides important information on the fundamental shift in absorption wavelength, leading to excellent photocatalysis using visible light., Nitrogen-doped TiO2 exhibits improved photocatalytic water-splitting activity partially due to enhanced oxygen vacancy formation. Here, authors demonstrate the temperature-dependent lattice distortion of oxygen vacancies, and identify the presence of a titanium oxynitride phase in high activity catalysts.

International audience; Multiple anion materials are of particular interest for the discovery of new crystal structures and offer an original way to modulate physical properties, including energy storage materials with enhanced performances. Through careful synthesis optimization, a new Na2Fe2OS2 phase was prepared by two different routes: high temperature solid-state synthesis and simple mechanochemical synthesis. The long-range and local structure of Na2Fe2OS2 was studied by Rietveld refinement of neutron and X-ray diffraction data combined with EXAFS data refinement. The phase comprises an amorphous and a crystalline part which has an anti-K2NiF4 structure, corresponding to the n = 1 member of the homologous anti-Ruddlesden–Popper [AX][ABX3]n series. Its electrochemical properties as a cathode material were studied in Na half cells and Na-ion full cells, revealing that the material becomes fully amorphous upon initial desodiation to Na0.5Fe2OS2, but maintains a reversible capacity of 135 mA h g−1 in full cells where up to 1.2 Na+ can be reversibly extracted and reinserted when compensating for the Na lost in SEI formation. The stability of the pristine material and its structural evolution upon charging are discussed, paving the way for further optimization of this material. Being composed exclusively of earth-abundant elements and stable under dry air, Na2Fe2OS2 perfectly illustrates the great opportunity of multiple anion chemistry to explore new structure types and develop better energy storage systems.

In this study, we developed a new type of ferroelectret cellular film by using commercial polypropylene film (PQ60). We first use gas diffusion expansion method to create the void structure inside PQ60 followed by using corona discharge to trap charges in the voids. Then dynamic method was chosen to measure the piezoelectric constant d33. The measured d33 value was above 150 pC/N. We further use Laser-Intensity-Modulation Method to measure the heat induced current from the surface of the cellular PQ60 film at various intensity-modulated frequencies. The result of LIMM can be used to analyze sensor and actuator performance in ferroelectret.

Significant efforts have been devoted to developing trace-level quantification of Hg2+. In this work, a novel fluorescence detection (FD) approach combined with preconcentration of Hg2+ in ionic liquid (IL), N-octylpyridinium tetrafluoroborate ([OPy]+[BF4]−), was developed for the determination of trace Hg2+ in water. The temperature-controlled ionic liquid dispersive liquid–liquid microextraction (TC-IL-DLLME) technique was used to improve the enrichment factor. After extraction and centrifugal separation, precipitated IL was diluted with water and acetonitrile containing the fluorescent probe. Under optimum conditions, the photoluminescence intensity of the fluorescence emission peak was found to be linear with the concentration of Hg2+ in the range from 0.1 to 0.5 μg L−1. The limit of detection for the TC-IL-DLLME-FD method was calculated to be 0.0342 μg L−1 (S/N = 3). Further, the selectivity of the sensor was measured by evaluating its response to other heavy-metal ions and was shown to be excellent. Recoveries were assessed by spiking water samples with different Hg2+ standard stock solutions, giving satisfactory recoveries from 80 to 110%.

In this study, we develop a tomographic technique based on the use of both mechanical wave (i.e. stress wave and acoustic wave) and electromagnetic wave (i.e. laser beam) for evaluating the defects in tree trunk. In the experimental work, the tomographic technique was used to inspect tree trunk with an air hole fabricated at the centric position and air gaps made at 5–50 mm near from surface. The result indicates that the internal air hole and the air gap located within 5–20 mm below the tree surface can be effectively detected and quantified. Compared to the results from conventional sonic tomography, our tomographic technique can achieve a more accurate and reliable detection of internal defect in tree system, especially if the internal defects are close to the free surface (i.e. critical defects associated with bending failure).

Ni-rich layered cathode materials are among the most promising candidates for high-energy-density Li-ion batteries, yet their degradation mechanisms are still poorly understood. We report a structure-driven degradation mechanism for NMC811 (LiNi0.8Mn0.1Co0.1O2), in which a proportion of the material exhibits a lowered accessible state of charge at the end of charging after repetitive cycling and becomes fatigued. Operando synchrotron long-duration X-ray diffraction enabled by a laser-thinned coin cell shows the emergence and growth in the concentration of this fatigued phase with cycle number. This degradation is structure driven and is not solely due to kinetic limitations or intergranular cracking: no bulk phase transformations, no increase in Li/Ni antisite mixing and no notable changes in the local structure or Li-ion mobility of the bulk are seen in aged NMCs. Instead, we propose that this degradation stems from the high interfacial lattice strain between the reconstructed surface and the bulk layered structure that develops when the latter is at states of charge above a distinct threshold of approximately 75%. This mechanism is expected to be universal in Ni-rich layered cathodes. Our findings provide fundamental insights into strategies to help mitigate this degradation process. Ni-rich layered cathode materials are promising for high-energy-density Li-ion batteries, but their degradation mechanisms are still poorly understood. A structure-driven mechanism with a lowered accessible state of charge after repetitive cycling is proposed for a typical NMC811 cathode.

Ni-rich layered cathode materials are among the most promising candidates for high energy density Li-ion batteries. However, the low cobalt containing materials suffer from rapid degradation, the underlying mechanism of which is still poorly understood. We herein report a novel structure-drive degradation mechanism for the NMC811(LiNi0.8Mn0.1Co0.1O2) cathode, in which a proportion of the material exhibits a lowered accessible state-of-charge (SoC) at the end of charge after repetitive cycling, i.e. becomes fatigued. Ex-situ and operando long- duration high-resolution X-ray diffraction enabled by a laser-thinned coin cell design clearly shows the emergence of the fatigued phase and the increase in its population as the cycling progresses. We show that the fatigue degradation is a structure-driven process rather than originating solely due to kinetic limitations or inter-granular cracking. No bulk phase transformations or increase in Li/Ni antisite mixing were observed by diffraction; no significant change in the local structure or Li-ion mobility of the bulk were observed by 7Li solid-state NMR spectroscopy. Instead, we propose that the fatigue process is a result of the high interfacial lattice strain between the reconstructed surface and the bulk layered structure when the latter is at SoCs above a distinct threshold of ~75 %. This mechanism is expected to be universal to Ni-rich layer cathodes, and our findings provide a fundamental guide for designing effective approaches to mitigate such deleterious processes.

This article highlights the recent fundamental study in using achiral and chiral porous materials for the potential applications in asymmetric catalysis. Thanks to the new-generation synchrotron X-ray powder diffraction (SXRD) facilities, we reveal the presence of the unique 'chiral region' in achiral zeolites with the MFI topology. Both the inherent site-isolation effect of the active sites and internal confinement restraints in zeolites are critical for creating 'chiral regions' that can aid the design of more enantioselective catalytic reactions. We also offer an outlook on the challenges and opportunities of this research area.

The phase transformations of the directionally solidified (DS) and powder metallurgy (PM) Ni-base superalloys were investigated by JMatPro, synchrotron XRD (SXRD) and differential scanning calorimetry (DSC). The minor phases, such as MC, eutectic γ′ and Ni5Hf, and γ matrix with secondary γ′ existed in as-cast microstructure of DS DZ22. However, only γ matrix was found in PM625 alloy powders. The phase change in both heating (melting) and cooling (solidification) process was investigated by DSC on DZ22 test bar and PM625 alloy powders respectively. The DSC experiment with different heating/cooling rates (5-40°C/min) was performed on DS superalloy DZ22. The results indicated that the heating/cooling rate had obvious effect on the DSC results of the phase transformation temperatures of liquidus, MC carbides, solidus, eutectic (γ+γ′) and secondary γ′. The heating and cooling DSC curves shifted to high and low temperature direction respectively, accompanied by the heating/cooling rate increased. However, the average values of specific peaks of heating and cooling curves are relatively consistent which is close to the equilibrium phase change temperatures of the alloy and makes the results comparable. Besides the average value method, the liquidus temperature of the alloy (0°C/min) can also be obtained by method of linear-fit/extrapolating from 5-40°C/min heating/cooling rates or inflection point deviate from the baseline of DSC cooling curves which could minimize the heating/cooling rate effects. The DSC experiment was carried out on PM625 superalloy powders with different particle size range (0-355μm), the results indicated that the particle size had minor effect on liquidus and solidus temperatures of DSC heating curves, the differences were less than 2°C. The change in phase transformation temperatures under different heating/cooling rate should be considered for selecting the process parameter (heat treatment, HIP or casting) for manufacturing Ni-base superalloy components.

High-energy Li1.17Ni0.19Co0.10Mn0.54O2 (HE-NCM) is a lithium-rich layered oxide with alternating Li- and transition-metal (TM) layers in which excess lithium ions replace transition metals in the host structure. HE-NCM offers a capacity roughly 50 mAh g–1 higher compared to that of conventional layered oxides but suffers from capacity loss and voltage fade upon cycling. Differential capacity plots (taken over 100 cycles) show that the origin of the fading phenomenon is a bulk issue rather than a surface degradation. Although previous studies indicate only minor changes in the bulk material, long duration in situ synchrotron X-ray powder diffraction measurements, in combination with difference Fourier analysis of the data, revealed an irreversible transition-metal motion within the host structure. The extensive work provides new insights into the fading mechanism of the material.

Glass-ceramics (GCs) are preferred over glass or ceramics in certain optical applications including those requiring lower porosity than ceramics and higher transition temperatures than glass. However, due to its material heterogeneity, it is difficult to precisely control the microstructure in GCs to meet specific property targets. The chemical mechanism behind the microstructural changes in the two-phase heterogeneity has not yet been clearly elucidated. In this work, the continuous Reactive Force Field molecular dynamics nanoindentation algorithm was developed and used to study the mechanism of structural evolution during nanoindentation. It was found that crystalline phases (CP) had the maximum load at the same indentation depth. The number of point defects of CP was more than glass-crystalline phase (GCP) at the end of loading. However, after total unloading, the opposite was observed with the number of point defects in GCP more than that in CP. The details in GCP bonding indicated that the formation of irreversible supersaturated bonds hindered the healing of defects while promoting the annihilation of pores. The evolution of pores and the typical chemical changes of GCP in the nanoindentation process had also been explored, which proves to be helpful in understanding the behaviors of two-phase heterogeneous materials at the nanoscale.

Protective green coatings are advantageous because they are eco-friendly and sustainable. In this study, three natural seed oils, tung, linseed and soybean, were used to investigate how coatings with different oil compositions could inhibit fungal growth. The oils were placed under direct sunlight to form cured films on maple wood. The curing chemistry and its effect on chemical resistance, water resistance and thermal stability were characterized and evaluated by FTIR, 13C NMR, solvent immersion, water contact angle and thermogravimetric analysis. The oil-coated samples were then placed on agar petri dishes that were spread with white-rot fungi. The areas of growth inhibition were measured over several days using an agar diffusion assay. The results showed that all oil-based coatings inhibited the fungal growth, with tung oil being the most effective followed by linseed and soybean oils. By mixing with a small fraction of tung oil, both linseed and soybean oils showed curing rates at least two times faster than individual oils and demonstrated much better inhibition of growth against fungi. This class of green natural seed oil coatings could be beneficial both economically and socially, given their high abundance, low cost, and environmental friendliness.

peer-reviewed A nonporous square lattice (sql) coordination network [Co(bipy)2(NCS)2]n (sql-1-Co-NCS) exhibits recyclable switching induced by CO2. The sorption isotherms are stepped with moderate hysteresis, temperature controlled and saturation uptake is fixed. Such switching, which has rarely been observed, offers the promise of exceptional working capacity for gas storage.

Purpose Two-photon excitation fluorescence (2PEF) reveals information about tissue function. Concerns for phototoxicity demand lower light exposure during imaging. Reducing excitation light reduces the quality of the image by limiting fluorescence emission. We applied deep learning (DL) super-resolution techniques to images acquired from low light exposure to yield high-resolution images of retinal and skin tissues. Methods We analyzed two methods: a method based on U-Net and a patch-based regression method using paired images of skin (550) and retina (1200), each with low- and high-resolution paired images. The retina dataset was acquired at low and high laser powers from retinal organoids, and the skin dataset was obtained from averaging 7 to 15 frames or 70 frames. Mean squared error (MSE) and the structural similarity index measure (SSIM) were outcome measures for DL algorithm performance. Results For the skin dataset, the patches method achieved a lower MSE (3.768) compared with U-Net (4.032) and a high SSIM (0.824) compared with U-Net (0.783). For the retinal dataset, the patches method achieved an average MSE of 27,611 compared with 146,855 for the U-Net method and an average SSIM of 0.636 compared with 0.607 for the U-Net method. The patches method was slower (303 seconds) than the U-Net method (

Cu2ZnSnS4 (CZTS) is a very promising material for the absorber layer in sustainable thin-film solar cells. Its photovoltaic performance is currently limited by crystal structure disorder, which causes fluctuations in electrostatic potential that decrease open-circuit voltage. The origin of this disorder is still not fully understood. This work investigates five samples of CZTS over a range of compositions, fabricated by solid-state reaction. Their crystal structures are conclusively identified using high-resolution anomalous X-ray diffraction. Three of the samples display two distinct CZTS phases, evident in minute splitting of some diffraction peaks (by ~0.02°) due to different c/a lattice parameter ratios. These are attributed to different composition types of CZTS, defined by different charge-neutral defect complexes. In addition to such types previously reported, two new types are proposed: G-type, in which [2CuSn3- + CuZn- + Cui+ + 3VS2+] defects are prevalent, and H-type, in which [3Si2- + VCu- + ZnCu+ + 2SnCu3+] defects are prevalent. In both cases, the defects probably do not form a single complex due to their large number. Above the order-disorder phase transition the two CZTS phases generally converge to a single phase. A mechanism of phase formation in CZTS is thus proposed. This is the first time CZTS crystal structures have been investigated with sufficiently high resolution to distinguish these different CZTS phases, thereby establishing polymorphic behavior in CZTS.

Purpose To develop a dark blood–late gadolinium enhancement (DB-LGE) sequence that improves scar–blood contrast and delineation of scar region. Methods The DB-LGE sequence uses an inversion pulse followed by T2 magnetization preparation to suppress blood and normal myocardium. Time delays inserted after preparation pulses and T2-magnetization-prep duration are used to adjust tissue contrast. Selection of these parameters was optimized using numerical simulations and phantom experiments. We evaluated DB-LGE in 9 swine and 42 patients (56 ± 14 years, 33 male). Improvement in scar–blood contrast and overall image quality was subjectively evaluated by two independent readers (1 = poor, 4 = excellent). The signal ratios among scar, blood, and myocardium were compared. Results Simulations and phantom studies demonstrated that simultaneous nulling of myocardium and blood can be achieved by selecting appropriate timing parameters. The scar–blood contrast score was significantly higher for DB-LGE (P 0.05). Scar–blood signal ratios for DB-LGE versus LGE were 5.0 ± 2.8 versus 1.5 ± 0.5 (P < 0.001) for patients, and 2.2 ± 0.7 versus 1.0 ± 0.4 (P = 0.0023) for animals. Scar–myocardium signal ratios were 5.7 ± 2.9 versus 6.3 ± 2.6 (P = 0.35) for patients, and 3.7 ± 1.1 versus 4.1 ± 2.0 (P = 0.60) for swine. Conclusions The DB-LGE sequence simultaneously reduces normal myocardium and blood signal intensity, thereby enhancing scar–blood contrast while preserving scar–myocardium contrast. Magn Reson Med 79:351–360, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

The world’s first dedicated synchrotron instrument for long-duration experiments has been built and commissioned at Diamond Light Source. The new beamline I11 user facility is designed for the study of slow kinetics in polycrystalline materials., A new synchrotron X-ray powder diffraction instrument has been built and commissioned for long-duration experiments on beamline I11 at Diamond Light Source. The concept is unique, with design features to house multiple experiments running in parallel, in particular with specific stages for sample environments to study slow kinetic systems or processes. The instrument benefits from a high-brightness X-ray beam and a large area detector. Diffraction data from the commissioning work have shown that the objectives and criteria are met. Supported by two case studies, the results from months of measurements have demonstrated the viability of this large-scale instrument, which is the world’s first dedicated facility for long-term studies (weeks to years) using synchrotron radiation.

Erythrocyte-based carriers can serve as theranostic platforms for delivery of imaging and therapeutic payloads. Engineering these carriers at micro- or nano-scales makes them potentially useful for broad clinical applications ranging from vascular diseases to tumor theranostics. Longevity of these carriers in circulation is important in delivering a sufficient amount of their payloads to the target. We have investigated the circulation dynamics of micro (~4.95 μm diameter) and nano (~91 nm diameter) erythrocyte-derived carriers in real time using near-infrared fluorescence imaging, and evaluated the effectiveness of such carrier systems in mediating photothermolysis of cutaneous vasculature in mice. Fluorescence emission half-lives of micro- and nano-sized carriers in response to a single intravenous injection were ~49 and ~15 minutes, respectively. A single injection of micro-sized carriers resulted in threefold increase in signal to noise ratio that remained nearly persistent over one hour of imaging time. Our results also suggest that a second injection of the carriers seven days later can induce a transient inflammatory response, as manifested by the apparent leakage of the carriers into the perivascular tissue. The administration of the carriers into the mice vasculature reduced the threshold laser fluence to induce photothermolysis of blood vessels from >65 to 20 J/cm(2). We discuss the importance of membrane physicochemical and mechanical characteristics in engineering erythrocyte-derived carriers, and considerations for their clinical translation.

Acidic macromolecules are traditionally considered key to calcium carbonate biomineralisation and have long been first choice in the bio-inspired synthesis of crystalline materials. Here, we challenge this view and demonstrate that low-charge macromolecules can vastly outperform their acidic counterparts in the synthesis of nanocomposites. Using gold nanoparticles functionalised with low charge, hydroxyl-rich proteins and homopolymers as growth additives, we show that extremely high concentrations of nanoparticles can be incorporated within calcite single crystals, while maintaining the continuity of the lattice and the original rhombohedral morphologies of the crystals. The nanoparticles are perfectly dispersed within the host crystal and at high concentrations are so closely apposed that they exhibit plasmon coupling and induce an unexpected contraction of the crystal lattice. The versatility of this strategy is then demonstrated by extension to alternative host crystals. This simple and scalable occlusion approach opens the door to a novel class of single crystal nanocomposites., Calcium carbonate biomineralisation has long been linked to acidic macromolecules. Here, the authors challenge this view and show that a huge number of gold nanoparticles coated with hydroxyl-rich proteins can be incorporated into a calcium carbonate crystal while maintaining single crystal character.

Journal of solid state chemistry 277, 37 - 45 (2019). doi:10.1016/j.jssc.2019.05.033, Hydrides Eu3Si4H2+x were obtained by exposing the Zintl phase Eu3Si4 to a hydrogen atmosphere at a pressure of 30 bar and temperatures from 25 to 300 °C. Structural analysis using powder X-ray diffraction (PXRD) data suggested that hydrogenations in a temperature range 25–200 °C afford a uniform hydride phase with an orthorhombic structure (Immm, a ≈ 4.40 Å, b ≈ 3.97 Å, c ≈ 19.8 Å), whereas at 300 °C mixtures of two orthorhombic phases with c ≈ 19.86 and ≈ 19.58 Å were obtained. The assignment of a composition Eu3Si4H2+x is based on first principles DFT calculations, which indicated a distinct crystallographic site for H in the Eu3Si4 structure. In this position, H atoms are coordinated in a tetrahedral fashion by Eu atoms. The resulting hydride Eu3Si4H2 is stable by −0.46 eV/H atom with respect to Eu3Si4 and gaseous H2. Deviations between the lattice parameters of the DFT optimized Eu3Si4H2 structure and the ones extracted from PXRD patterns pointed to the presence of additional H in interstitials also involving Si atoms. Subsequent DFT modeling of compositions Eu3Si4H3 and Eu3Si4H4 showed considerably better agreement to the experimental unit cell volumes. It was then concluded that the hydrides of Eu3Si4 have a composition Eu3Si4H2+x (x, Published by Academic Press, Orlando, Fla.

An integrated centrifugal microfluidic device was developed to preconcentrate and detect hazardous mercury (II) in water with ionic liquid as environmentally friendly extractant. An automatically salt-controlled ionic liquid dispersive liquid&ndash, liquid microextraction on a centrifugal microfluidic device was designed, fabricated, and characterized. The entire liquid transport mixing and separation process was controlled by rotation speed, siphon valves, and capillary valves. Still frame images on the rotating device showed the process in detail, revealing the sequential steps of mixing, siphon priming, transportation between chambers, and phase separation. The preconcentration of red dye could be clearly observed with the naked eye. By combining fluorescence probe and microscopy techniques, the device was tested to determine ppb-level mercury (II) in water, and was found to exhibit good linearity and low detection limit.

The ability to control crystallization reactions is required in a vast range of processes including the production of functional inorganic materials and pharmaceuticals and the prevention of scale. However, it is currently limited by a lack of understanding of the mechanisms underlying crystal nucleation and growth. To address this challenge, it is necessary to carry out crystallization reactions in well-defined environments, and ideally to perform in situ measurements. Here, a versatile microfluidic synchrotron-based technique is presented to meet these demands. Droplet microfluidic-coupled X-ray diffraction (DMC-XRD) enables the collection of time-resolved, serial diffraction patterns from a stream of flowing droplets containing growing crystals. The droplets offer reproducible reaction environments, and radiation damage is effectively eliminated by the short residence time of each droplet in the beam. DMC-XRD is then used to identify effective particulate nucleating agents for calcium carbonate and to study their influence on the crystallization pathway. Bioactive glasses and a model material for mineral dust are shown to significantly lower the induction time, highlighting the importance of both surface chemistry and topography on the nucleating efficiency of a surface. This technology is also extremely versatile, and could be used to study dynamic reactions with a wide range of synchrotron-based techniques.

Micro-pillars oriented in austenite along [100], [110], and [111] crystallographic directions were fabricated on the corresponding edges of a single crystalline plate of the Ni48Fe20Co5Ga27 magnetic shape memory alloy exhibiting martensitic transformation (MT) at 150 K. Superelastic behavior of pillars, due to micro-compression-induced MT, was investigated at different temperatures from 298 K to 373 K. At room temperature, Young's moduli of the [100], [110], and [111] pillars in austenite are equal to 5.3 GPa, 7.9 GPa, and 9.9 GPa, respectively, resulting in the linear dependences of the elastic strain reaching up to the record-breaking value of 10%. On increasing temperature, the stress-strain dependencies exhibit changes that are interpreted in terms of the critical behavior on approaching to the end points on the martensite-austenite stress-temperature phase diagrams. This work was supported by JST CREST, Grant No. JPMJCR1433, Japan, and the Grant-in-Aid for Scientific Research (S) (JSPS KAKENHI Grant No. 26220907), as well as by Spanish Ministry of Science, Innovations and Universities (Project No. RTI2018-094683-B-C53-54) and by the Basque Government Department of Education (Project No. IT1245-19). Editorial

(1 − x)Na0.5Bi0.5TiO3-xKNbO3 (NBT-xKN) ceramics, with x in the range 0.01–0.09, were prepared by solid state reaction and conventional sintering. A progressive transformation from a nano-polar to a long-range ordered ferroelectric phase was observed after the application of a cyclic electric field with an amplitude of 5 kV mm−1. It is shown by analysis of the crushed ceramic pellets, using high resolution synchrotron x-ray diffraction, that the application the cyclic electric field induced an irreversible transformation from a pseudo-cubic nano-polar phase to a rhombohedral ordered ferroelectric phase having R3c symmetry. Furthermore, a systematic variation, from 89.6° to 90°, was observed in the rhombohedral interaxial angle as the KN content increased from 1 to 9%. By comparing the structural evidence with the ferroelectric polarization-electric field hysteresis loops, it is shown that the electric field-induced transformation is partially reversible for NBT-5KN and completely reversible or nonexistent for NBT-9KN.

In this work, potential anticorrosive coating resulted from the composite with synergistic effect of biomimetic epoxy thermoset (BET) morphology and incorporated superhydrophobic silica microspheres was presented. First of all, superhydrophobic methyl-modified silica (MS) microspheres were synthesized by performing the conventional base-catalyzed sol-gel process of MTMS and APTMS. The as-prepared MS microspheres were identified as having an average particle size of ~1 µm in diameter. The as-prepared MS microspheres were characterized by Fourier transform infrared spectrometry (FTIR), 29Si and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Morphological properties of MS microspheres and BET-silica composite coating were studied by scanning electron microscopy (SEM). Subsequently, 3 wt% of MS microspheres were incorporated into an epoxy slurry of DGEBA/T-403 in dimetyl acetamide (DMAc), followed by performing the programmed heating through nanocasting technique with PDMS as soft template materials for pattern transfer by using leaf of Xanthosoma Sagittifolium as natural template, leading to the formation of artificial biomimetic composite coating. The appearance/dispersion capability of silica microspheres in BET coating was confirmed by the energy dispersive X-ray spectroscopy (EDX) and Si-mapping. The roughness level of BET and BEC-3% were detected by AFM. The BETsilica composite was found to exhibit a contact angle (CA) of ~153°, revealing the synergistic effect of biomimetic epoxy morphology and incorporated superhydrophobic MS microspheres, which is found to be more hydrophobic than that of neat epoxy thermoset (CA = 81°). Corrosion protection of as-prepared coatings was demonstrated by performing a series of electrochemical measurements (Tafel, Nyquists and Bode plots) upon CRS electrodes in saline condition. It should be noted that the BET coatings upon CRS electrode revealed an effectively enhanced corrosion protection as compared to that coatings without biomimetic morphology. Moreover, the BET coating with superhydrophobic MS microspheres upon CRS electrode was found to exhibit better corrosion protection as compared to a counterpart coating without MS microspheres.