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A layered charge composed of the JH-2 explosive enveloped by a thick-walled cylindrical casing (active aluminum/rubber and inert lithium fluoride/rubber composites) was designed and explosion experiments were conducted in a 1.3 m3 tank and a 113 m3 bunker. The blast parameters, including the quasistatic pressure (ΔpQS), special impulse (I), and peak overpressure (Δpmax), and images of the explosion process were recorded, and the influence of the Al content (30% and 50%) and Al particle size (1, 10, and 50 μm) on the energy release of aluminum/rubber composites were investigated. The results revealed that the use of an active layer increased the peak overpressure generated by the primary blast wave, as well as the quasistatic pressure and special impulse related to fuel burning within tens of milliseconds after detonation. When the Al content was increased from 30% to 50%, the increases of ΔpQS and I were not obvious, and Δpmax even decreased, possibly because of decreased combustion efficiency and greater absorption of the blast wave energy for layers with 50% Al. Compared with the pure JH-2 charge, the charge with 1 μm Al particles produced the highest Δpmax, indicating that better transient blast performance was generated by smaller Al particles. However, the charge with 10 μm Al particles showed the largest ΔpQS and I, suggesting that a stronger destructive effect occurred over a longer duration for charges that contained moderate 10 μm Al.

Li3PO4 coating Li0.98Mg0.01Ni0.83Co0.11Mn0.06O2 (NCM83-MP) composite powders are successfully synthesized by first doping Mg2+ into LiNi0.83Co0.11Mn0.06O2 by co-calcination processes and followed by H3PO4 modifying the obtained Li0.98Mg0.01Ni0.83Co0.11Mn0.06O2 composite powders by sol–gel methods. Related physicochemical characterization results demonstrate that Mg2+ doping can significantly enlarge the lattice space along the c-axis to 14.1431 A and lower the Li/Ni mixing degree to 1.58 %, and H3PO4 modifying can effectively reduce the residual lithium content and generate a homogeneous Li3PO4 covering with a thickness of about 11.7 nm on the surface of the composite particles. Furthermore, the battery performance tests indicate that the coin cells assembled with NCM83-MP can exhibit excellent cycling performance, in which the distinguished discharge specific capacity of 157.4 mAh g−1 at 2.0 C at 25 °C after 200 cycles and 154.6 mAh g−1 at 2.0 C at 60 °C after 100cycles are amazingly retained, respectively. Additionally, the electrode can present a smaller gap of redox peaks of 0.10 V and a lower resistance value of 193.8 Ω compared to the ones of 0.49 V and 451.8 Ω of NCM83-0 after cycles. Those enhanced electrochemical properties are mainly ascribed to the synergetic effect of Mg2+ doping and H3PO4 modifying, which can not only stabilize the lattice structure but also provide fast transfer channels to facilitate Li ions migrating. Therefore, the proposed strategy may excavate new ideas to the further investigation of high-performance Ni-rich cathode materials for lithium ion battery.

Here we show the most significant steps in the design of hemoperfusion adsorbents. Selection of materials, functionalization methods and matrix structures are both necessary and will directly affect the adsorption efficiency.

The nitrogen-doped carbon (NC) coating encapsulating heterostructural Sn/SnO2 microcube powders (Sn/SnO2@NC) are successfully fabricated through hydrothermal, polymerization of hydrogel, and carbonization processes, in which the SnO precursor powders exhibit regular microcube structure and uniform size distribution in the presence of optimized N2H4·H2O (3.0 mL of 1.0 mol/L). Interestingly, the precursor powders are easily subjected to a disproportionated reaction to yield the desirable heterostructural Sn/SnO2@NC microcube powders after being calcined at 600 °C in N2 atmosphere in the presence of home-made hydrogel. The coin cells assembled with the Sn/SnO2@NC electrode present a high initial discharge specific capacity (1058 mAh g−1 at 100 mA g−1), improved rate capability (an excellent DLi+ value of 2.82 × 10-15 cm2 s−1) and enhanced cycling stability (a reversible discharge specific capacity of 486.5 mAh g−1 after 100 cycles at 100 mA g−1). The enhanced electrochemical performance can be partly ascribed to the heterostructural microcube that can accelerate the transfer rate of lithium ions by shortening the transmission paths, and be partly to the NC coating that can accommodate the volume effect and contribute to partial lithium storage capacity. Therefore, the strategy may be able to extend the fabrication of Sn/SnO2 heterostructural microcube powders and further application as promising anode materials in lithium ion batteries.

PurposeThe purpose of this paper is to perform the thermo-hydro-mechanical (THM) numerical analysis in order to study the thawing process for frozen soil and to predict the thawing settlement.Design/methodology/approachA new one-dimensional multi-field physical coupled model was proposed here to describe the thawing process of saturated frozen soil, whereby the void ratio varied linearly with effective stress (Eq. 10) and hydraulic conductivity (Eq. 27b). The thawing process was simulated with different initial and boundary conditions in an open system with temperature variations. The mechanical behavior and water migration of the representative cases were also investigated.FindingsThe comparisons of representative cases with experimental data demonstrated that the model predicts thawing settlement well. It was found that the larger temperature gradient, higher overburden pressure and higher water content could lead to larger thawing settlement. The temperature was observed that to distribute height linearly in both frozen zone and unfrozen zone of the sample. Water migration forced to a decrease in the water content of the unfrozen zone and an increase in water content at the thawing front.Research limitations/implicationsIn this study, only the one-directional thawing processes along the frozen soil samples were investigated numerically and compared with test results, which can be extended to two-dimensional analysis of thawing process in frozen soil.Originality/valueThis study helps to understand the thawing process of frozen soil by coupled thermo-hydro-mechanical numerical simulation.

Heating concentrations widely exist in microwave heating, which may destroy heated samples. In this article, we report that with spheres being surrounded in dielectrics, the heating concentration of spheres can be reduced in microwave applicators with moving elements. First, electric field properties in electrically large cavities with moving elements are analyzed by the statistical approach. It reveals that the heating concentration can be studied under exposure to plane waves. Second, based on the Mie theory and the quasi-physical optics, the method for controlling the concentration locations of spheres is discussed. Then, the theoretical model utilizing dielectrics is presented to reduce the concentration of spheres in microwave applicators with moving elements. The results show that when the concentration location is far from the sphere center, the concentration can be reduced in the motion of moving elements. Finally, the heating process of a potato sphere with a radius of 3.0 cm is studied in a practical microwave applicator with the alumina ceramics (AC). Experiments show that both the heating efficiency and heating uniformity can be improved significantly by the proposed method.

Bending Pneumatic Artificial Muscles (PAMs) are particularly attractive and extensively applied to the soft grasper, snake-like robot, etc. To extend the application of PAMs, we fabricate a Multi-directional Bending Pneumatic Artificial Muscle (MBPAM) that can bend in eight directions by changing the pressurized chambers. The maximum bending angle and output force are 151° and 0.643 N under the pressure of 100 kPa, respectively. Additionally, the Finite Element Model (FEM) is established to further investigate the performance. The experimental and numerical results demonstrate the nonlinear relationship between the pressure and the bending angle and output force. Moreover, the effects of parameters on the performance are studied with the validated FEM. The results reveal that the amplitude of waves and the thickness of the base layer can be optimized. Thus, multi-objective optimization is performed to improve the bending performance of the MBPAM. The optimization results indicate that the output force can be increased by 7.8% with the identical bending angle of the initial design, while the bending angle can be improved by 8.6% with the same output force. Finally, the grasp tests demonstrate the grip capability of the soft four-finger gripper and display the application prospect of the MBPAM in soft robots.

To optimize the electrochemical performance of Ni-rich cathode materials, the 0.005 mol of Mg2+ and 0.005 mol of Ti4+ co-doping LiNi0.83Co0.11Mn0.06O2 composite powders, labeled as NCM-11, are successfully prepared by being calcinated at 750 °C for 15 h following by an appropriate post-treatment, which are confirmed by XRD, EDS and XPS. The results suggest that NCM-11 presents a well-ordered layered structure with a low Li+/Ni2+ mixing degree of 1.46% and Mg2+ and Ti4+ ions are uniformly distributed across the lattice. The cell assembled with NCM-11 can deliver an initial discharge specific capacity of 194.2 mAh g−1 and retain a discharge specific capacity of 163.0 mAh g−1 after 100cycles at 2.0C at 25 °C. Furthermore, it still maintains a discharge specific capacity of 166.7 mAh g−1 after 100cycles at 2.0C at 60 °C. More importantly, it also exhibits a higher discharge specific capacity of about 150.7 mAh g−1 even at 5.0C. Those superior electrochemical performance can be mainly ascribed to the synergistic effect of Mg2+ and Ti4+ co-doping, in which Mg2+ ions can occupy the Li+ layer to act as pillar ions and Ti4+ ions can occupy the transition metal ions layer to enlarge the interplane spacing. Thus, the heterovalent cations co-doping strategy can be considered as a simple and practical method to improve the electrochemical performance of Ni-rich layered cathode materials for lithium-ion batteries.

The Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte powders doped with LiF are successfully synthesized by spray-drying and calcination methods, and the corresponding physicochemical properties are investigated using X-ray diffraction, a field emission-scanning electron microscope, and an X-ray photoelectron spectroscope. The results show that the LiF-doped LATP (LATP-0.15) solid electrolyte presents excellent performance compared with the pure LATP solid electrolyte when the weight ratio of LiF vs. LATP maintains at 0.15, in which the LATP-0.15 solid electrolyte possesses a higher compacted density of 2.887 g cm−2 and a higher ionic conductivity at room temperature of 1.767 × 10–4 S cm−1 with lower activation energy of 0.276 eV. Furthermore, the assembled LiCoO2/LATP-0.15/Li coin cell delivers a relatively high discharge specific capacity of 136.7 mAh g−1 at 0.1 C after only five active cycles and maintains up to 97.77% of capacity retention ratio after 290 cycles. Those results indicate that the as-prepared LATP-0.15 solid electrolyte may be employed to be a potential candidate in the future all-solid-state lithium-ion batteries.

To enhance the ionic conductivity and electrochemical stability of Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolytes, different contents of indium doping Li1.3Al0.3InxTi1.7-x(PO4)3 (LAITP) solid electrolyte powders are successfully synthesized by spray-drying and calcination processes. The characteristic results confirmed by X-ray diffraction, Fourier transform infrared spectrometer, and field emission scanning electron microscope show that the LAITP-0.12 solid electrolyte exhibits a uniform cube-like morphology, an excellent crystallinity, as well as a high compacted density of 2.239 g cm−3 compared to the pure LATP solid electrolyte when the content of indium doping is up to 12 wt. % vs. the pure LATP powders in the terms of the molar ratio. Moreover, the LAITP-0.12 solid electrolyte presents a high ionic conductivity of 1.779 × 10–4 S cm−1 at 30 oC. The assembled Li/LAITP-0.12/Li symmetric cell can present excellent lithium platting/striping cycle performance for 500 h. Furthermore, the all-solid-state cell assembled with the LAITP-0.12 solid electrolyte shows extremely superior rate performance compared to other cells and delivers a high discharge specific capacity of 149.9 mAh g−1 at 30 oC at 0.1 C. The surface and the characteristic diffraction peak of the disassembled LAITP-0.12 solid electrolytes exhibits dense cube-likes morphology and no distinct difference after cycles, respectively. Those results suggest that the effective In ion doping strategy may promote the development of the solid electrolytes for all-solid-state lithium-ion batteries.

Polytetrafluoroethylene has many excellent properties and a wide range of applications, but its poor wear resistance, hardness, and creep resistance have severely limited the use of the polytetrafluoroethylene composites. In this work, the surface of carbon fibers was treated with silane coupling agent acetone solution, and then sintering technology was used to prepare carbon fibers/polyetheretherketone (PEEK)/ polytetrafluoroethylene composites. The mechanical and frictional wear properties of the composites were analyzed using an electronic tensile tester, a Shore hardness tester, and a frictional wear tester, and scanning electron microscopy was applied to analyze the surface morphology of the composites after wear. The experimental results shown that the addition of carbon fibers could significantly improve the mechanical properties of the composites, reduce the radial shrinkage, and increase the Shore hardness of the composites. Under the same experimental conditions, the carbon fibers (20 wt.%) /polyetheretherketone/polytetrafluoroethylene composites has the best wear resistance, with a friction coefficient of 0.196 and the wear rate of 2.41 × 10−6 mm3/N·m. In the theoretical simulation, the thermal conductivity of polytetrafluoroethylene composites was predicted using ANSYS software, with the changes in the temperature and friction force in the friction process. The theoretical simulation results matched with the experimental values, which proved the accuracy of the theoretical simulations.

Metal-N4 single-atom catalysts have emerged as the frontier of catalysis. However, the low metal loading and abundance of single atoms embedded in carbon skeleton hinder their practical application. Herein, we report an effective “trapping and exposing” strategy for constructing single-atom Fe–N4 catalysts with high density of single-atom active sites. The strategy involves the strong binding of metal ions to sucrose (trapping) to prevent the migration and agglomeration of Fe3+, followed by the introduction of a mesoporous structure using an SBA-15 template to achieve sufficient exposure of the Fe–N4 sites (exposing). The as-prepared catalyst comprises Fe–N4 moieties (10.8 wt%) with a hierarchical structure. Density functional theory calculations reveal that the chelating reaction between sucrose and Fe3+ ions has a low free energy, resulting in the formation of highly dispersed Fe–N4 single atoms. The single-atom catalyst displays a high peak power density of 0.784 W cm−2 in a H2–O2 proton exchange membrane fuel cell and achieves an impressive CO current density of 109 A g−1 at negligible overpotentials in a flow cell. This work provides an efficient strategy for designing high-performance single-atom catalysts for practical electrocatalysis applications.

In this paper, dopamine hydrochloride (DPH) is introduced to synthesize ZIF-8@ZIF-67@DPH in the preparation of ZIF-8@ZIF-67. ZnSe/CoSe/NCDPH (N-doped carbon) composites are calcined in a high-temperature inert atmosphere with ZIF-8@ZIF-67@DPH as the precursor, selenium powder as the selenium source. ZnSe/CoSe/NCDPH has high discharge specific capacity, good cycle stability and outstanding rate performance. The first discharge capacity of ZnSe/CoSe/NCDPH is 1616.6 mAh g−1 at the current density of 0.1 A g−1, and the reversible capacity remains at 1214.2 mAh g−1 after 100 cycles, the reversible capacity is 416.7 mAh g−1 after 1000 cycles at 1 A g−1. Therefore, ZnSe/CoSe/NCDPH composites provide a new step for the research and synthesis of new stable, high-capacity, and safe high-performance lithium ion batteries. The bimetallic selenide composites not only have bimetallic active sites, but also can form synergistic effect between different metal phases, which can effectively reduce the capacity attenuation caused by volume expansion and reactive stress enrichment during lithium storage of metal oxide anode materials. Meanwhile, N-doped carbon can improve the conductivity and provide more active sites to store lithium, thus improving its lithium storage capacity.

The poor interface bonding between graphene and aluminum is one of the main challenges which could impede wider application of graphene/Al composites. Coating metals on graphene layer could be an effective method to solve this problem. In this research, the pullout processes and uniaxial tensile tests were performed by using molecular dynamics (MD) simulation method to explore how the coating metals, such as Ni, Cu and Ti, affect the interfacial strength between C-Al bonds and the mechanical properties of nanocomposites, respectively. The results reveal that Ni is the most powerful coating metal among these three candidates in enhancing interfacial strength since it has the highest value of pullout force. Also, it leads to an enhancement of 26.39% in the Young’s modulus when compared with the one without coating treatment. As for the impact of various amounts of Ni coating, it is demonstrated that the interfacial bonding can be enhanced up to 87.65%, 92.67%, 111.27% and 145.34% with the percentage of Ni coating was 25%, 50%, 75%, 100%, respectively. In terms of the mechanical property, the various percentage of Ni has little impact on Young’s modulus while the value of tensile strength falls slightly, from 58.94 GPa to 51.88 GPa.

Moisturizing strategy that controls the water evaporation rate of the wet material and thus the relative humidity in the drying chamber was proposed for hot air drying of mushroom slices for the first time. To assess the effectiveness of moisturizing strategy, drying kinetics, moisture diffusivities, mass transfer coefficients, surface color and rehydration capacity of dried products, energy and exergy efficiencies were evaluated. Mushroom slices were dried at constant drying temperature of 60 °C and air velocity of 3 m/s. The strategies of moisturizing for 0, 15, 30, and 45 min were applied in the initial drying stage. Compared to the continuous dehumidifying strategy (moisturizing time is 0 min), the strategies of moisturizing for 15 and 30 min reduced drying time by 5% and 15%, respectively. The proper moisturizing time (30 min) enhanced the heat transfer by increasing the enthalpy of the drying air, improved surface color, and increased rehydration capacity of dried mushroom slices by reducing cell shrinkage. The energy utilization and energy utilization ratio of drying process varied from 0.16 to 3.48 kJ/s and 0.065 to 0.572, respectively, while the exergy efficiency varied from 8.04% to 84.66%. The strategy of moisturizing for 30 min reduced 23.4% total energy utilization compared to continuous dehumidifying strategy. Both the highest average energy utilization ratio, i.e. 0.156 and average exergy efficiency, i.e. 70.19% were obtained for moisturizing time of 30 min. The increase of moisturizing time from 30 to 45 min showed an adverse impact on drying time, energy utilization ratio, exergy loss, and exergy efficiency due to the inhibition of water evaporation. This study shows that moisturizing strategy can be considered as a promising method to enhance energy and exergy efficiency of hot air dryer with the improvement of products quality and sustainability of drying systems.

The mechanism of oxide inclusions in fatigue crack initiation in the very-high cycle fatigue (VHCF) regime was clarified by subjecting bearing steels deoxidized by Al (Al-deoxidized steel) and Si (Si-deoxidized steel) to ultrasonic tension-compression fatigue tests (stress ratio, R = −1) and analyzing the characteristics of the detected inclusions. Results show that the main types of inclusions in Si- and Al-deoxidized steels are silicate and calcium aluminate, respectively. The content of calcium aluminate inclusions larger than 15 µm in Si-deoxidized steel is lower than that in Al-deoxidized steel, and the difference observed may be attributed to different inclusion generation processes during melting. Despite differences in their cleanliness and total oxygen contents, the Si- and Al-deoxidized steels show similar VHCF lives. The factors causing fatigue failure in these steels reveal distinct differences. Calcium aluminate inclusions are responsible for the cracks in Al-deoxidized steel. By comparison, most fatigue cracks in Si-deoxidized steel are triggered by the inhomogeneity of a steel matrix, which indicates that the damage mechanisms of the steel matrix can be a critical issue for this type of steel. A minor portion of the cracks in Si-deoxidized steel could be attributed to different types of inclusions. The mechanisms of fatigue fracture caused by calcium aluminate and silicate inclusions were further analyzed. Calcium aluminate inclusions first separate from the steel matrix and then trigger crack generation. Silicate inclusions and the steel matrix are closely combined in a fatigue process; thus, these inclusions have mild effects on the fatigue life of bearing steels. Si/Mn deoxidation is an effective method to produce high-quality bearing steel with a long fatigue life and good liquid steel fluidity.

With booming development of electronics, electromagnetic interference (EMI) shielding materials based on conductive polymer composites (CPCs) have received increasing attention. However, it remains challenging to develop flexible and lightweight CPCs with excellent stretchability, breathability, durability, and high EMI shielding effectiveness (EMI SE). Here, we propose a facile polyvinylpyrrolidone (PVP) assisted preparation of highly electrically conductive and durable nanofiber composites for high performance EMI shielding. The PVP layer could not only greatly enhance the interfacial interaction between the Ag nanoparticles (AgNPs) and hence the mechanical properties (both tensile strength, Young's modulus and elongation at break) of the polymer nanofiber membrane but also forms a protection layer preventing the AgNPs from oxidizing. The electrical conductivity of the nanofiber composite can reach up to 245.7 ± 30.6 S/cm, which is, to a large degree, maintained after cyclic stretching, abrasion, and ultrasonic washing. In addition, the nanofiber composite exhibits excellent breathability, antibacterial, and Joule heating performance. When used as the EMI shielding material, the nanofiber composite shows an extremely high SE and SSE of ∼96.9 dB and 169.7 dB cm3/g, respectively, and EMI shielding performance possesses outstanding stability and durability. This multifunctional nanofibrous composite membrane exhibits promising applications in wearable electronics.

The formaldehyde gas sensing properties of transition metal-doped graphene have been systematically investigated by first-principles calculations. The optimized geometries of transition metal-doped graphene with and without HCHO adsorption, adsorption energies, charge transfers and magnetic moments are obtained for various doped graphene systems. The calculated results show that Co-, Ni-, Cu-, Zn-, Pd- and Ag-doped systems have moderate adsorption energies, implying their potential applications as HCHO sensors. The two-probe sensor devices consisting of the central scattering region and pristine graphene electrodes with the armchair or zigzag transport directions are built, and the spin-polarized current–voltage curves are calculated by the non-equilibrium Green’s function method within the framework of density functional theory. For the Cu-, Zn- and Ag-doped systems, the average sensor response is over 80%, 40% and 290%, respectively. In particular, the Cu- and Ag-doped graphene devices have the highest value of response over 200% and 900% at low voltages, indicating a short response time and high sensitivity of these devices. The present study provides a theoretical basis for exploring practical applications of the transition metal-functionalized graphene as superior HCHO gas sensors.

A forced ignition probability analysis method is developed for turbulent combustion, in which kernel formation is analyzed with local kernel formation criteria, and flame propagation and stabilization are simulated with Lagrangian flame particle tracking. For kernel formation, the effect of turbulent scalar transport on flammability is modelled through the incorporation of turbulence-induced diffusion in a spherically outwardly propagating flame kernel model. The dependence of flammability limits on turbulent intensities is tabulated and serves as the flammability criterion for kernel formation. For Lagrangian flame particle tracking, flame particles are tracked in a structured grid with flow fields being interpolated from a Computational Fluid Dynamics (CFD) solution. The particle velocity follows a Langevin model consisting of a linear drift and an isotropic diffusion term. The Karlovitz number is employed for the extinction criterion, which compares chemical and turbulent timescales. The integration of the above two-step analysis approach with non-reacting CFD is achieved through a general interpolation interface suitable for general unstructured CFD grids. The method is demonstrated for a methane/air bluff-body flame, in which flow and fuel/air mixing characteristics are extracted from a non-reacting simulation. Results show that the computed ignition probability map agrees qualitatively with experimental results. A reduction of the ignition probability in the recirculation zone and a high ignition probability on the shear layer of the recirculation zone near the mean stoichiometric surface are well captured. The tools can facilitate optimization of spark placement and offer insights into ignition processes.

Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environmental and energy sustainability. We herein demonstrate a molten salt thermoelectrolysis of rice husks (RHs) mainly consisting of organic mass and biosilica to achieve high-efficiency and upgraded utilization of both Si and C in RHs. By coupling pyrolysis of organic mass with electrochemical reduction of silica in molten salts, the thermoelectrolysis of RHs in molten CaCl2–NaCl at 800 °C refines the RHs and acid-leached RHs to SiC nanowire/C (SiC-NW/C) and Si nanoparticle/C (Si-NP/C), respectively. The present study highlights the molten salt thermoelectrolysis for reclamation of biomass wastes in an affordable and controllable manner.

Industrial hydrogen production based on methane steam reforming (MSR) remains challenges in intensive carbon emissions, retarded hydrogen generation owing to coke deposition over catalysts and huge consumption of water. We herein report an electrochemical splitting of methane (ESM) in molten salts at 500 °C to produce hydrogen in an energy saving, emission-free and water-free manner. Following the most energy-saving route on methane-to-hydrogen conversion, methane is electrochemically oxidized at anode to generate carbon dioxide and hydrogen. The generated anodic carbon dioxide is in situ captured by the melts and reduced to solid carbon at cathode, enabling a spatial separation of anodic hydrogen generation from cathodic carbon deposition. Life-cycle assessment on hydrogen-generation technologies shows that the ESM experiences an equivalent carbon emission much lower than MSR, and a lower equivalent energy input than alkaline water electrolysis.

In this paper, confined explosions of HMX-based aluminized explosives in a spherical chamber are studied. The effects of aluminum particles on the afterburning reaction and explosive performance are obtained by changing the size of the particles and the gas environment. The results show that the concentration of oxygen in air is not sufficient to support complete combustion of aluminum particles. The estimated oxidation rate of aluminum particles is 87–93%, and it tends to decrease with increasing particle size. Part of aluminum particles oxidize with detonation products, and the reaction can last for hundreds of microseconds. However, the degree of oxidation between the large-sized aluminum particles and detonation products is small. A new method is used to estimate the initial energy of detonation by observing the time difference between sensing the initial light and the pressure wave. This method leads to a conclusion that some of the aluminum particles are oxidized during detonation and provide additional energy to the primary blast wave. Small micron-sized aluminum particles in the range of 48.9 nm to 46.7 $$\mu$$ m extend the duration of the fireball.

The practical application of silicon oxycarbide (SiOC) based electrodes has been restricted by poor rate performance and under capacity retention on account of sluggish electronic and ionic transport of the SiOC glass. To tackle this issue, we synthesized silicon oxycarbide-carbon hybrid nanofibers by using an economically efficient approach, which involves several steps: electrospinning the PAN nanofibers (PNFs), grafting polysiloxanes onto the PNFs and thermal conversion of the silicone/PNFs (SPNFs). The obtained 1D nanostructure endows the hybrids electrode with rapid electron transfer kinetics, robust structural stability, fast lithium ion conduction, and efficient electronic pathway. When tested as an active electrode material, the hybrids electrode delivers a reversible specific capacity of 715.8 mAh g−1 at 1C (1C = 372 mA g−1), excellent high rate performance (422.1 mAh g−1 at 20C) and outstanding capacity retention capability of 95.4% after 2000 cycles at 10C. The results well testify the potential application of silicon oxycarbide-carbon hybrid nanofibers anode for the next-generation lithium ion batteries.

Polytetrafluoroethylene (PTFE) has many excellent properties and wide applications, but its low wear resistance limits its use. Copper powder and antioxidants were mixed and composite samples were prepared by high-temperature sintering method to investigate the influence of antioxidants content on friction performance of the composite materials. A friction and wear testing machine was used to test the friction and wear performance, and a scanning electron microscope (SEM) was applied to analyze the composites surface morphology their wear positions. The results showed that antioxidants content greatly influenced the composites tribological wear performance. In the theoretical simulation, ANSYS software was used to simulate the antioxidant content effect on thermal conductivity, friction and wear properties of the composite materials. The simulation data were compared with the experimental results. The theoretical simulation data showed that the model could simulate friction and wear experimental processes accurately. Both results were consistent, which proved the reliability of the theoretical analysis.

Summary Perovskite solar cells (PSCs) suffer from significant nonradiative recombination, limiting their power conversion efficiencies. Here, for the first time, we directly observe a complete transformation of perovskite MAPbI3 surface region energetics from p- to n-type during defect passivation caused by natural additive capsaicin, attributed to the spontaneous formation of a p-n homojunction in perovskite active layer. We demonstrate that the p-n homojunction locates at ∼100 nm below perovskite surface. The energetics transformation and defect passivation promote charge transport in bulk perovskite layer and at perovskite/PCBM interface, suppressing both defect-assisted recombination and interface carrier recombination. As a result, an efficiency of 21.88% and a fill factor of 83.81% with excellent device stability are achieved, both values are the highest records for polycrystalline MAPbI3 based p-i-n PSCs reported to date. The proposed new concept of synergetic defect passivation and energetic modification via additive provides a huge potential for further improvement of PSC performance.

The effects of three different drying tecnologies (PVD, THC-HAD, and IR-HAD) on drying kinetics, microstructure, energy consumption, and quality, that is, rehydration ratio (RR), color parameters (...

Compared to lithium, potassium possesses abundant storage, a similar standard potential, and lower desolvation energy. However, the bulkier atom size seriously weakens its ionic kinetic properties, conductivity and storage in most of the traditional electrode materials, impeding its practical application in devices of energy conversion and storage. In this work, the two commercially available nanomaterials, one-dimensional (1D) nanofibrillated cellulose (NFC) and two-dimensional (2D) reduced graphene oxide (rGO), were assembled to one kind of porous thin-film, predominantly driven via van der Waals interactions. The nanoporous structures of these thin-films were significantly revealed by Brunauer–Emmett–Teller (BET) analysis, obtaining specific areas up to 120 m2 g−1. Meanwhile, substantial open amphiphilic nanochannels over the whole of the thin-film, and which are associated with the presence of coulombic repulsion of carboxylic groups on the backbones of NFC, were constructed. Moreover, their highly compact character was evaluated at a density of 1.6 g cm−3, providing them with excellent conductivity (up to 128 s cm−1). Such porous thin-films can undergo reversible assembly and disassembly for several cycles without significant changes to their structural characters, thus allowing for recyclable utilization. The as-prepared porous thin-films enable rapid transportation of K+ with a diffusion coefficient range of 1.2 × 10−13 to 5.4 × 10−10 cm2 s−1, with voltages from 3 V to 0 V in galvanostatic intermittent titration technique (GITT) measurements. As the electrodes of the symmetry supercapacitor, they provided an excellent volumetric energy density of 68 W h L−1 with KPF6 electrolyte, and this is similar to the values of 70 W h L−1 for LiPF6 and 74 W h L−1 for NaPF6 electrolytes, but there is better stability in the former case. These results represent a reliable and sustainable strategy approach for green energy storage.

Solar-driven photosynthesis to produce biomass and photocatalysis to reduce carbon dioxide are both carbon sinks. Efficient harvesting of high-performance photocatalysts from photosynthesis-derived biomass is hence promising to relieve carbon footprints. Herein, a molten-salt electrochemical biorefinery of rice husks and silver chloride to silicon-carbide nanowires embedded in carbon matrix with surface-loaded silver nanoparticles (SiC/C/Ag) is reported as a showcase of carbon-neutral utilization of biomass. The molten-salt electrochemical biorefinery features with reduced CO2 emissions, low energy consumption, and compositional/structural refining of cathodic SiC/C/Ag. The resulting SiC/C/Ag shows noticeably enhanced overall CO2 photoreduction. Life cycle assessment (LCA) shows that the CO2 equivalent emission from the production of SiC/C/Ag is compensated by photocatalytic reduction of gaseous CO2 for only 24.77 hours over the SiC/C/Ag.

Tunneling electroresistance (TER) is the change in tunneling resistance induced by ferroelectric polarization reversal in ferroelectric tunnel junctions (FTJs), and how to achieve a giant TER has always been a central topic in the study of FTJs. In this work, by considering the NaTiO3/BaTiO3/LaTiO3 junction with asymmetric polar interfaces as an example, we propose a novel scheme to realize a giant TER based on the reversible partial metallization of ferroelectric barrier upon the switching of ferroelectric polarization. Density functional theory calculations indicate that high on-state and low off-state conductances are obtained and the TER ratio is as high as 3.20 × 108% due to the reversible partial barrier metallization, which leads to a great difference in the effective tunneling barrier widths. The reversible partial barrier metallization, accompanied by the ferroelectric polarization reversal, is driven by the parallel or anti-parallel alignment of the depolarization electrical field of the ferroelectrical barrier and a strong built-in electrical field cooperatively contributed by the asymmetric polar interfaces and the difference in the work functions of the two leads. The findings suggest a feasible scheme for constructing promising high performance FTJ memory devices by combining both asymmetric polar interfaces and substantially different work functions.

DSC-TG-FTIR-MS coupling technology was used to study the mechanism of two typical binders, that is, BR and F2604, on the thermal decomposition behavior of the HMX crystal. The results show that both BR and F2604 can induce premature decomposition of HMX and increase the activation energy of HMX. Especially in the case of HMX/BR particles, the decomposition temperature is the lowest, but the activation energy is the highest. Based on the results of DSC-TG-FTIR-MS, it is found that the rapid mechanism of binder and active intermediate products inhibits the reaction of relatively inert intermediate products and prolongs the continuous generation time of gas products in the composite particles, which delays the decomposition of HMX to a certain extent. This study is helpful for us to better understand the thermal decomposition behavior of HMX composite particles and provides reference for the application of high-energy composites.

Triggered by the recent experimental synthesis of the Janus PtSSe monolayer, we use the first-principles calculations to predict two new Janus photocatalysts PtXO (X = S, Se), based on the systematic investigations of the structural stabilities, electronic structures, band alignments, catalytic activity and optical absorption. The two Janus structures are found to be mechanically, dynamically and thermodynamically stable, and have suitable band edge positions for the overall water splitting. Owing to the high electron mobility (up to 2164.95 cm2 V−1 s−1) and large disparity between the electron and hole mobilities, together with the indirect band gaps and the intrinsic dipole induced built-in electric fields, the photogenerated electrons/holes can be efficiently separated in PtXO. Moreover, the S/Se vacancy can effectively lower the free energy difference of the HER, making the catalytic reactions occur spontaneously under the potentials of photoexcited electrons and holes. Large optical absorption coefficients (105 cm−1) are also confirmed in the visible light range, and the biaxial tensile strain can further enhance the optical absorption while maintaining the capability of the overall water splitting. Our results not only propose two new Janus materials by demonstrating the possibility of experimental realization, but also indicate that PtXO are peculiar candidates for photocatalytic water splitting.

A light-controlled artificial synapse, which mimics the human brain has been considered to be one of the ideal candidates for the fundamental physical architecture of a neuromorphic computing system owing to the possible abilities of high bandwidth and low power calculation. However, the low photosensitivity of synapse devices can affect the accuracy of recognition and classification in neuromorphic computing tasks. In this work, a planar light-controlled artificial synapse having high photosensitivity (Ion/Ioff > 1000) with a high photocurrent and a low dark current is realized based on a ZnO thin film grown by radiofrequency sputtering. The synaptic functions of the human brain such as sensory memory, short-term memory, long-term memory, duration-time-dependent-plasticity, light-intensity-dependent-plasticity, learning-experience behavior, neural facilitation, and spike-timing-dependent plasticity are successfully emulated using persistent photoconductivity characteristic of a ZnO thin film. Furthermore, the high classification accuracy of 90%, 92%, and 86% after 40 epochs for file type datasets, small digits, and large digit is realized with a three-layer neural network based on backpropagation where the numerical weights in the network layer are mapped directly to the conductance states of the experimental synapse devices. Finally, characterization and analysis reveal that oxygen vacancy defects and chemisorbed oxygen on the surface of the ZnO film are the main factors that determine the performance of the device.

Conversion of carbon dioxide into a hydrogen-evolution electrocatalyst is an ideal protocol to promote carbon neutrality by eliminating emissions of carbon dioxide and producing carbon-free hydrogen energy. Electrochemical fixation of carbon dioxide in molten salts by using a Mo-plate cathode and a Ni–Cr anode is herein demonstrated to produce a cathodic Mo2C film and anodic oxygen. The molten salt electrochemical method offers an efficient modulation of thickness, adhesion and more importantly, interfacial confinement between the Mo2C film and Mo. The resulting Mo2C–Mo binder-free electrode hence shows enhanced electrocatalytic activity towards hydrogen evolution, as rationalized by the lower hydrogen adsorption energy at the Mo2C–Mo interface. The electrochemical reduction of carbon dioxide over a metal substrate is therefore a generic method integrating fixation of carbon dioxide and surface carbonization of a metal to functional films.

It is always a challenge to quickly and effectively inspect the embedment depth of highway guardrail posts. This paper focuses on an electromagnetic ultrasonic transducer (EMAT) array that can excites torsional mode (T-mode) guided waves and applies it to check the embedment depth of guardrail posts. First of all, we presented a torsional guided wave EMAT array that can be used to quickly inspect the embedment depth of guardrail posts. The working principle of the EMAT array was described in detail. Secondly, a torsional guided wave EMAT array composed of 12 racetrack coils and 24 permanent magnets was simulated to verify the excitation and propagation process of torsional guided wave in a post. Then, a method for detecting the embedment depth of a post using the travel time of a torsional guided wave in the post was put forward. Finally, an experimental system was set up to carry out embedment depth detection experiments on posts with different depths buried in soil and concrete. Experiments have verified the feasibility of using the torsional guided wave EMAT array to inspect the embedment depth of the guardrail post.

Pyrolysis of the Ta2O5/melamine mixture in molten chlorides is herein demonstrated as a facile and controllable method to nitridize and functionalize Ta2O5. The influence of the stoichiometry and composition of Ta2O5/melamine in molten salts on the nitridation process is rationalized to ensure the controllable preparation of Ta3N5 and Ta3N5/TaON. The characterization results, including scanning electron microscopy, transmission electron microscopy, elemental mapping, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy, all confirm the existence of the Ta3N5/TaON heterojunction, in which the TaON nanoparticles are closely anchored to the Ta3N5 nanorods. Benefiting from its composition and structure, the Ta3N5/TaON composites show enhanced photocatalytic activity for the degradation of methylene blue. The present study highlights that the molten salt method using a solid nitrogen source can be a new technique for rationalizing the design of nitrides and oxynitrides.

The electrochemical reduction of CO2 to capacitive carbon in molten Li2CO3–Na2CO3–K2CO3 is an effective strategy for capturing and utilizing CO2. This paper reports the effects of the cell voltages and operating temperatures (450–650 °C) of the molten salt electrolysis on the capacitive performance of electrolytic carbon. The electrolytic carbon delivers excellent specific capacitance when the cell voltage is 4.5 V and the temperature of molten salt is 450 °C. The carbon obtained at 450 °C and under 4.5 V delivers a specific capacitance of 550 F g−1 at 0.2 A g−1 in 1 M aqueous H2SO4, and the capacity retention rate is 73% after 10000 cycles. The specific capacitance of the electrolytic carbon increases as the electrolysis temperature decreases, and the optimal cell voltage is 4.5 V.

The separator has an important influence on safety and charge-discharge performances of lithium-ion batteries. In this work, a multilayer composite separator is designed and fabricated by alternate electrospinning of poly (vinyl alcohol) (PVA) nanofibers and electrospraying of ZrO2 nanoparticles. The physical-chemical properties of the separator are systematically investigated. The design of such a layer-by-layer structure not only enhances the electrolyte uptake/retention and thermal resistance but also improves the mechanical strength of the composite separator. In comparison with PE separator and pure PVA electrospun separator, this PVA-ZrO2 composite separator exhibits satisfactory thermal resistance (area shrinkage ratio of 0% at 160 °C), ionic conductivity (2.19 mS/cm), electrolyte wettability (uptake of 350%) and tensile strength (14.5 MPa) as well as better interface compatibility. Moreover, a LiFePO4–Li half-cell with PVA-ZrO2 composite separator displays superior C-rate and cycling performances. It shows a high discharge capacity of 73.0 mA h/g at 16C, which is about 50% of that at 0.2C. The reason for the high capacity retention is the efficient Li+ transmission through the separator, resulting from the well-defined porous structure and the Lewis acid-base interactions of the PVA-ZrO2 composite separator. It can be concluded that this type composite separator with layer-by-layer structure possesses good application prospects for high-performance lithium-ion batteries.

Three methods of shade (MI), open sun (MII) and new designed of solar (MIII) drying were used for peppermint dehydration. The air velocity (u) and temperature (Td ) of MI, MII and MIII were 0.5, 0....

Non-noble electrocatalyst for the oxygen evolution reaction (OER) is essential for water electrolysis and electrochemical conversion of CO2 . Integrating electrochemical fixation of CO2 and electrochemical metallurgy to prepare advanced OER electrocatalyst is a promising solution to promote carbon neutrality and renewable energy. Herein, the electrochemical reduction of CO2 and Fe2 O3 are combined in molten salts to prepare cathodic Fe3 C-based electrocatalyst and anodic oxygen at 600 °C with enhanced current efficiency. The resulting Fe3 C-based electrocatalyst outperforms precious electrocatalyst towards the OER operation in 1 M KOH due to a dynamic structural evolution to form an interface of Fe3 C-FeOOH.

Implementation of non-precious electrocatalysts is key-enabling for water electrolysis to relieve challenges in energy and environmental sustainability. Self-supporting Ni-V2O3 electrodes consisting of nanostrip-like V2O3 perpendicularly anchored on Ni meshes are herein constructed via the electrochemical reduction of soluble NaVO3 in molten salts for enhanced electrocatalytic hydrogen evolution. Such a special configuration in morphology and composition creates a well confined interface between Ni and V2O3. Experimental and Density-Functional-Theory results confirm that the synergy between Ni and V2O3 accelerates the dissociation of H2O for forming hydrogen intermediates and enhances the combination of H* for generating H2.

In current work, the effects of drying temperature (60, 65, 70, and 75 °C), vacuum pressure duration (VPD; 6, 9, 12, and 15 min), and ambient pressure duration (APD; 2, 3, and 4 min) on drying kine...

ZnO decorated ZnFe2O4 nanoparticles were synthesized and combined with reduced graphene oxide (rGO) to form ZnFe2O4@ZnO@rGO ternary hierarchical nanocomposites by a controllable method. The microstructure, morphology, and microwave absorption performance of the ZnFe2O4@ZnO@rGO nanocomposites were investigated in detail. The permittivity and permeability of the composites can be effectively regulated by controlling the content of ZnO and rGO to achieve a good impedance matching. Due to the synergistic effect of dielectric loss and magnetic loss, the ZnFe2O4@ZnO@rGO nanocomposites exhibited strong wave absorption and wide absorption bandwidth. The optimal reflection loss (RL) of the ZnFe2O4@ZnO@rGO nanocomposites reached −35.2 dB at 12.0 GHz with a thickness of 2.0 mm and the effective absorption bandwidth was 3.7 dB. The ZnFe2O4@ZnO@rGO hierarchical architecture produced lots of heterogeneous interfaces which made a significant contribution to the wave absorption performance. The combination of interfacial polarization, dipole polarization, and eddy current loss enhanced the microwave absorption capacity of the ZnFe2O4@ZnO@rGO system. This work provides a feasible approach for the design and preparation of wave absorption materials with tunable permittivity and permeability.

The influence of initiation modes on the explosive dispersion process of the multi-layer composite charge (MCC) was studied. Overpressure sensors and high-speed photography system were used to investigate the energy release process of an MCC with a specific structure. The shock wave pressure and explosive dispersion characteristics of the MCC under different initiation modes were compared. The forming and expanding process of the shock wave of the composite charge under different initiation modes was determined. The separation position of the shock wave and fireball interface was determined. The calculation formulas of the shock radius and overpressure of the composite charge are presented. The radius of the shock wave of the composite charge was significantly affected by the initiation mode. Moreover, the development process of the composite explosive fireball under different initiation modes was analyzed, the variation rules of the composite charge dispersion radius and fireball dispersion velocity with time were obtained under the different initiation modes, the explosion energy release rate of composite charge under simultaneous initiation modes was the highest, and the peak overpressure under the simultaneous initiation mode was 1.61 times that of central single-point initiation.

Structural and compositional design of core-shell structure is an effective strategy towards enhanced catalysis. Herein, amorphous MnO2 nanosheets and K+-intercalated layered MnO2 nanosheets are controllably assembled over Fe2O3 spindles, in which the MnO2 nanosheets are perpendicularly anchored to the surface of Fe2O3. Such a core shell structure contributes to a high specific surface area and abundant pore channels on the surface of catalysts. In addition, the existence of K+ provides large numbers of basic sites and restrains the formation of unpleasant (Fe1−xMnx)3O4. Benefiting from the merits in structure and composition, CO adsorption is enhanced and remaining time of intermediates is prolonged on the surfaces of catalysts during the Fischer–Tropsch synthesis (FTS), facilitating to the formation of active iron carbides and C–C coupling reactions. Resultantly, the Fe2O3@ K+-MnO2 shows both a high CO conversion of 82.3% and a high C5+ selectivity of 73.1%. The present study provides structural and compositional rationales on design high-performance catalysts towards FTS.

Solid polymer electrolyte (SPE) is one of the choices for many ionic devices, including organic transistors, ion batteries, memristors, and more. However, uncontrollable conductive filament formation seriously affects the performance of the device. In this paper, the PEDOT:PSS was doped to improve the electronic and ionic conductivity of amorphous polymer electrolyte poly(vinylpyrrolidone) (PVP), realizing the transition of the filaments growth from cathode to anode in atomic switch memristors. Based on the difference in ion and electron mobility and scanning electron microscope observation, the in situ reductions of metal ions inside the dielectric layer can effectively prevent the formation of uncontrollable filaments. The formation of uniformly distributed metal particles in the dielectric layer is similar to co-sputter doping technology, which enables the device to exhibit excellent performance, such as smaller set/reset bias distribution, endurance, and retention. Obviously, this innovative way improves the conductive mechanism of ionic devices.

The aim of this study was to evaluate the storage stability of dried cranberry powders based on the moisture sorption isotherms and glass transition temperature (Tg). Microwave-vacuum dried (MWVD) ...

Currently, the microwave absorption materials with high absorbing efficiency are in urgent need to reduce electromagnetic pollution. Herein, the ZnFe2O4@SiO2 core–shell microspheres were synthesize...