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Magnetism has revolutionized important technologies, and continues to bring forth new phenomena in emergent materials and reduced dimensions. Here, using first-principles calculations, we demonstrate that the already-synthesized two-dimensional (2D) Ni-tetracyanoquinodimethane (Ni2(TCNQ)2) lattice is a stable ferromagnetism material with multiple spin-polarized Dirac cones. The conical bands in proximity of the Fermi level can be tuned by external tensile strain and show the fourfold degenerate electronic states at the critical tensile strain of ∼2.35%, whose energy dispersion is consistent with 2D Cairo pentagonal lattice. In addition, spin-orbital coupling can open a band gap at the Dirac point of A, leading to topologically nontrivial electronic states characterized by the non-zero Chern number and the edge states of nanoribbon. Our results offer versatile platforms for the realization of massless spintronics with full-spin polarization in 2D Cairo pentagonal Ni2(TCNQ)2 Lattice.

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.

Two-dimensional (2D)/quasi-2D perovskite solar cells (PSCs) incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs. Most reported organic spacer cations are based on ammonium, whereas formamidinium (FA+) has been seldom applied despite that FA has been extensively used in high-efficiency 3D PSCs. Herein, a novel FA-based organic spacer cation, 4-chloro-phenylformamidinium (CPFA+), is applied in quasi-2D Ruddlesden-Popper (RP) PSCs for the first time, and methylammonium chloride (MACl) is employed to promote crystal growth and orientation of perovskite film, resulting in high power conversion efficiency (PCE) with improved stability. Upon incorporating CPFA+ organic spacer cation and MACl additive, high-quality quasi-2D CPFA2MAn−1Pbn(I0.857Cl0.143)3n+1 (n = 9) perovskite film forms, exhibiting improved crystal orientation, reduced trap state density, prolonged carrier lifetime and optimized energy level alignment. Consequently, the CPFA2MAn−1Pbn(I0.857Cl0.143)3n+1 (n = 9) quasi-2D RP PSC devices deliver a highest PCE of 14.78%. Moreover, the un-encapsulated CPFA-based quasi-2D RP PSC devices maintain ∼ 80% of its original PCE after exceeding 2000 h storage under ambient condition, whereas the 3D MAPbI3 counterparts retain only ∼ 45% of its original PCE. Thus, the ambient stability of quasi-2D RP PSC devices is improved obviously relative to its 3D MAPbI3 counterpart.

The volatile combustion and NO release characteristics of pulverized fuel (PF) flames in an optical flat-flame entrained-flow reactor were investigated by CH*/NO* chemiluminescence imaging. Pyrolyzed bituminous (PB) char with an ultralow volatile content (Vdaf≈10%) and a comparative coal sample of Shenhua (SH) bituminous coal with a high volatile content (Vdaf = 34.2%) were studied under different ambient O2 mole fractions (10%∼30%). The initiation of the combustion region of PB char occurs later than SH bituminous coal, owing to its low volatile contents, a slow devolatilization rate, and homogeneous-heterogeneous ignition/combustion mode. By measuring probed solid and gas samples, the conversion ratios of fuel-N to NO and the releasing ratios of volatile-N/char-N were determined in ignition process. Semi-quantitative NO release integral intensity and volatile combustion intensity results were obtained by integrating the NO* or CH* chemiluminescence intensity in the corresponding reaction region. The volatile combustion and NO release show good synchronous for Shenhua bituminous coal, which means that the NO releasing originated predominantly and owned higher conversion ratio from the volatile-N in the ignition region. The NO release integral intensity and NO emission of SH bituminous coal decreased with O2 concentration increased from 20% to 30%, which indicates that the enriched-O2 environment is beneficial for high volatiles bituminous to decrease NOx emission in ignition stage. For PB char, NO releasing originated predominantly from the char heterogeneous reactions of char-N in its ignition and combustion late stage.

Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen (H2) production from acidic water electrolysis. Herein we report the one-pot precise synthesis of ultrafine Au core-PtAu alloy shell nanowires (Au@PtxAu UFNWs). Among them, Au@Pt0.077Au UFNWs exhibit the best performance for formic acid oxidation reaction (FAOR) and hydrogen evolution reaction (HER), which only require applied potentials of 0.29 V and −22.6 mV to achieve a current density of 10 mA cm−2, respectively. The corresponding formic acid electrolyzer realizes the electrochemical H2 production at a voltage of only 0.51 V with 10 mA cm−2 current density. Density functional theory (DFT) calculations reveal that the Au-riched PtAu alloy structure can facilitates the direct oxidation pathway of FAOR and consequently elevates the FAOR activity of Au@Pt0.077Au UFNWs. This work provides meaningful insights into the electrochemical H2 production from both the construction of advanced bifunctional electrocatalysts and the replacement of OER.

The electrosynthesis of valuable chemicals via carbon dioxide reduction reaction (CO2RR) has provided a promising way to address global energy and sustainability problems. However, the selectivity and activity of deep-reduction products (DRPs) still remain as big challenges. Here, a copper–carbon-based catalyst with a hydrophobic core–shell architecture has been constructed and was found to exhibit excellent DRPs of methane generation with a faradaic efficiency of 81 ± 3% in a neutral medium and a maximum partial current density of −434 mA cm−2 in a flow cell configuration, which is among the best of CO2-to-CH4 electrocatalysts. Density functional theory calculations suggest that the hydrophobic structure decreasing the water coverage on the catalyst surface can promote the protonation of the *CO intermediate and block CO production, further favoring the generation of methane. These results provide a new insight into the electrosynthesis of DRPs via constructing a hydrophobic core–shell architecture for tuning the surface water coverage.

DBD-catalytic system has been widely studied for volatile organic compounds abatement, whereas how to obtain high mineralization rate and low zone emission synchronously remains a challenge. In view of this, a new type of multi-stage DBD-catalytic system (MS1) was established to abatement toluene in this study. The mineralization rates of reactors IPC (63.81%) and MS1 (61.14%) were much higher than MS2, PPC1 and PPC2 reactors, which were 48.36%, 46.84%, and 5.8% at 33.8 (Vp-p) kV, respectively. For export ozone concentration, IPC reactor had the highest concentration of 160 ppm, and the values of reactors MS1, MS2, PPC1, and PPC2 were 79, 34.2, 34.25 and 29 ppm, respectively. The catalyst filled in zone II can be utilized to further decompose the residual toluene and intermediates and also promote the decomposition of ozone, which lead to the superior performance of the MS1 reactor. The influence of applied voltage, adsorbed amount, and discharge time on the toluene removal performance was investigated to optimize the operation parameters of MS1 reactor, their appropriate values were 28.3–31.1 (Vp-p) kV, 0.179–0.223 mmol, ∼1 h, respectively. Lastly, the contribution of disparate zones in multi-stage DBD-catalytic system to the toluene degradation were elucidated on the basis of the GC–MS results.

Owing to their high surface area, stable structure and easy fabrication, composite nanomaterials with encapsulation structures have attracted considerable research interest as sensing materials to detect volatile organic compounds. Herein, a hydrothermal route is designed to prepare foam shaped α-MoO3@SnS2 nanosheets that exhibit excellent sensing performance for triethylamine (TEA). The developed sensor, based on α-MoO3@SnS2 nanosheets, displays a high response of 114.9 for 100 ppm TEA at a low working temperature of 175 °C with sensitivity higher than many other reported sensors. In addition, the device shows a wide concentration detection range (from 500 ppb to 500 ppm), good stability after exposure to air for 80 days, and excellent selectivity. The superior sensing characteristics of the developed sensor are attributed to the high crystallinity of α-MoO3/SnS2, excessive and accessible active sites provided by the good permeability of porous SnS2 shells, and the excellent conductivity of the encapsulation heterojunction structure. Thus, the foam shaped α-MoO3@SnS2 nanosheets presented herein have promising practical applications in TEA gas sensing devices.

The development of hydrogen evolution activity (HER) electrocatalyst that can run durably and efficiently under the large current density is of special significance but still challengeable for the massive production of hydrogen. Herein, a CoP/Ni(OH)2 nanowire catalysts grown on Co foam (CF) with a three-dimensional heterojunction structure has been successfully prepared by electrodepositing nickel hydroxide on the surface of cobalt phosphide. The prepared CoP/Ni(OH)2–15 min sample reveals a superior HER activity and stability. It merely requires ultralow overpotentials of 108 and 175 mV to 100 and 500 mA cm−2, respectively. In addition, the long-term stability test shows that the catalyst (CoP/Ni(OH)2–15 min) can operate stably for at least 70 h at 400 mA cm−2. Utilizing NiFe-LDH/IF with high OER activity, the NiFe-LDH/IF || CoP/Ni(OH)2–15 min catalyst system possesses the same outstanding performance for overall water splitting (OWS), which can accomplish ≈ 500 mA cm−2 at 1.74 V in 1 M KOH electrolyte. Moreover, the NiFe-LDH/IF || CoP/Ni(OH)2–15 min couple can work for more than 80 h at 500 mA cm−2, indicating its a great prospect in the area of electrolysis water. Such excellent catalytic performance is mainly attributed to the armor effect of Ni(OH)2, which can not only promote the rapid decomposition of water molecules, but also prevent the loss of phosphorus and enhance the synergistic effect of CoP and Ni(OH)2. This work can offer a significant reference for the design with high-performance and durable transition metal phosphide electrocatalysts.

Aqueous zinc-ion batteries present their unique advantages, such as cost-efficient and non-flammability for large-scale energy storage. However, their widespread application is hindered by the development of cathode materials, sluggish intrinsic ion/electron kinetics, and unsatisfied structural stability. Herein, we report a high-performance NH4V4O10 cathode with oxygen vacancy (denoted as NH4V4O10-x) and reduced graphene oxide (rGO) surface modification. The oxygen vacancies enhance the Zn2+ diffusion ability and stabilize the NH4V4O10 structure. Meanwhile, the density functional theory calculations further confirm the deficiency engineering leads to high electronic conductivity, weak electrostatic interaction, and low Zn2+ diffusion barrier. In addition, the rGO surface modification provides fast electron transfer. The NH4V4O10-x@rGO delivers high capacity (391 mAh g−1 at 1 A g−1), impressive rate ability (211 mAh g−1 at the 15 A g−1), and stable cycle performance with 90.5% capacity retention after 2000 cycles. This work provides a reasonable strategy to design cathode materials with deficiency and surface engineering to improve the electrochemical performance of zinc-ion batteries.

Non-noble metal catalysts are suitable for the oxygen evolution reaction (OER) owing to their original oxidation states and oxygen coordination environments, which can regulate the adsorption of OH...

The flexible hydrogel sensors in the field of artificial intelligence have been widely concerned, which could be applied in medical monitoring, human motion detection, and intelligent robots. However, the integration of the synergistic properties of excellent mechanical properties, temperature sensitivity, adhesion ability and self-healing ability for preparation of hydrogel-type strain sensor is still a challenge. Moreover, how can we recover cumulated sensors without affecting the environment? Herein, a self-healing hydrogel was prepared based on deep eutectic solvent (DES) combined with polyvinyl alcohol (PVA), and cellulose nanocrystals (CNCs), which has the peotential application as wearable strain sensors. The DES network crosslinks PVA/CMC-Na/CNCs through ionic bonds, and the overall network is further linked through physical entanglement and hydrogen bonding interactions. Interestingly, the hydrogel could sensitively detect large or subtle movements (such as finger bending, wrist bending, knee bending, pulse and pronounce), indicating its potential applications in human–computer interaction and personal health monitoring.

The influence of formulation components of cold-mixed epoxy asphalt (CMEA) on the corresponding mechanical properties was studied. For the purpose of minimising the number of experiments, the simpl...

Alkali metal-oxygen batteries possess a higher specific capacity than alkali-ion batteries and stand out as the most competitive next-generation energy source. The core reaction mechanism of the battery is mainly the formation of alkali metal oxide during the discharge process and the decomposition of these oxides during the charge process. A large number of researchers have devoted themselves to seeking promising catalysts for the reaction. Two-dimensional Nb2 O5 was discovered to be a highly potential catalyst that can promote the reaction of alkali-metal-oxygen batteries, but few studies focus on it. In this study, the catalytic performance of both pristine Nb2 O5 and oxygen-deficiency modified Nb2 O5 was investigated. Furthermore, the effect of oxygen defects on catalytic performance was analyzed from multiple angles, namely, the reaction mechanism, d-band center theory, and the diffusion behavior of alkali metals. The exploration revealed the microscopic mechanism of oxygen deficiency affecting the alkali-metal battery reaction and provided a theoretical basis for quantitatively changing the d-band center of the catalyst through oxygen deficiency to ultimately change the performance of the catalyst.

Photocatalytic nitrogen reduction for the green synthesis of ammonia at ambient conditions has been slowed by the narrow light harvesting range, low activity and high charge recombination of photocatalysts. Plasmonic semiconducting nanomaterials are becoming the promising candidates for nitrogen photofixation because of the broad absorption spectrum, rich defects and hot carriers. In the present study, plasmonic SrMoO4 is developed by regulating the concentration of oxygen vacancies that are accompanied in the reduction process from Mo6+ to Mo5+. The stable and tunable localized surface plasmon resonance (LSPR) absorption in visible and near infrared light range makes the wide bandgap SrMoO4 utilize the solar energy more efficiently. Energetic electrons from both the intrinsic band excitation and the LSPR excitation enable the reduction of dinitrogen molecules thermodynamically in ultrapure water to ammonia. This work provides a unique clue to design efficient photocatalysts for nitrogen fixation.

The Al–Mg alloy with high Mg addition (Al–9.2Mg–0.8Mn–0.2Zr-0.15Ti, in wt.%) was subjected to different passes (1, 2 and 4) of high strain rate rolling (HSRR), with the total thickness reduction of 72%, the rolling temperature of 400 °C and strain rate of 8.6 s−1. The microstructure evolution was studied by optical microscope (OM), scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and transmission electron microscope (TEM). The alloy that undergoes 2 passes of HSRR exhibits an obvious bimodal grain structure, in which the average grain sizes of the fine dynamic recrystallization (DRX) grains and the coarse non-DRX regions are 6.4 and 47.7 μm, respectively. The high strength ((507±9) MPa) and the large ductility ((24.9±1.3)%) are obtained in the alloy containing the bimodal grain distribution. The discontinuous dynamic recrystallization (DDRX) mechanism is the prominent grain refinement mechanism in the alloy subjected to 2 passes of HSRR.

For new renewable clean energy, triboelectric nanogenerators (TENGs) have shown great potential in response to the world energy crisis. Nevertheless, the alternating-current signal generated by a TENG needs to be converted into a direct-current signal to be effective in applications. Therefore, a power management circuit, comprising a clamp rectifier circuit and a mechanical switch, is proposed for the conversion and produces a signal having a low ripple coefficient. The power management circuit adopts a clamp circuit as the rectifier circuit to increase the rectified voltage, and reduces the loss resulted from the components by reducing the use of discrete components; the electronic switch in the buck regulator circuit is replaced with a mechanical switch to reduce cost and complexity. In a series of experiments, this power management circuit displayed a stable output voltage with a ripple voltage of 0.07 V, crest factor of 1.01, and ripple coefficient of 2.2%. The TENG provides a feasible method to generate stable electric energy and to supply power to low-consumption electronic devices.

Aluminum alloy 7050 is widely used in the aeronautical industries. However, owing to their highly ductile property, chips created during high-speed machining cannot be naturally broken, and long continuous chips are unavoidably formed, impacting the machining stability and quality of the parts. Because a smaller cutting allowance is required compared with conventional machining operations, the behavior of the chips during reaming operation may be more complex and different from those determined in previous investigations. Therefore, studying the characteristics of chip formation and hole quality during the reaming process is essential to improve the machinability of aluminum alloy 7050. In this study, three different cooling conditions were applied to reaming aluminum alloy 7050-T7451 with polycrystalline diamond (PCD) reamers. The finite element models (FEMs) were established to simulate the chip formation. The macro- and micro-morphologies of chips under the three cooling conditions were compared to analyze the chip behaviors. The diameter, surface roughness, and micro-morphologies of the reamed holes were also analyzed to evaluate the hole quality. The results showed that the chip morphology was strongly influenced by the cutting parameters and cooling strategies. It was found that the desired chip morphologies, satisfactory geometrical accuracy and surface quality during the reaming of aluminum alloy 7050-T7451 could be achieved using internal cooling at a spindle speed of 8 000 r/min and a feed rate of 0.01 mm/z. This study also demonstrates the feasibility of an internal cooling strategy for breaking chips when reaming aluminum alloy 7050-T7451, which opens new possibilities for improving the chip-snarling that occurs during hole machining.

The fuel flow pattern in the fuel injection nozzle of diesel engine is a complex and changeable phenomenon, which is easily affected by various factors, bringing the differences of flow patterns between multiple injection cycles. To solve the above problem, a visual experimental platform of fuel injection nozzle was built, in which the 100 injection cycles of diesel engine on the same working condition were photographed via shadowgraphy to study the difference in fuel flow pattern in the nozzle by ensemble average processing method. The cyclic variation rate K of fuel flow pattern is defined. Results demonstrate that the fuel flow pattern tends to be the same in multiple fuel injection cycles, but there is a strong randomness at the starting of injection and after ending of injection; the K can be reduced by decreasing the injection pressure and the inclination angle of orifice, so that the fuel flow pattern in the nozzle tends to be consistent.

Temperature-responsive resistance transition behaviors of the melamine sponges wrapped with different graphene oxide derivatives (i.e. nanoribbon, wide-ribbon and sheet) were investigated. Melamine sponge composites coated by three types of GO derivatives were prepared by a simple dip-coating approach. All these composites show good mechanical flexibility and reliability (almost unchanged compressive stress at 70 % strain after 100 cycles), high hydrophobicity (water contact angle >120°), excellent flame resistance (self-extinguishing) and structural stability even after burning, which was used to construct the resistance-based fire alarm/warning sensor. Notably, the different resistance response behaviors of such sensors are strongly dependent on the GO size and network formed on the MF skeleton surface. Typically, at a fixed high temperature of ∼350 ℃, the three fire alarm sensors show different response time (to trigger the alarm light) of 6.3, 8.4 and 11.1 s for nanoribbon, wide-ribbon and sheet at the same concentration, respectively. The structural observation and chemical analysis demonstrated that the discrepancy of temperature-responsive resistance transition behaviors of various GO derivatives was strongly determined by their different thermal reduction degrees during the high-temperature or flame treating process. This work offers a design and development for construction of smart fire alarm device for potential fire prevention and safety applications.

Morphology transformation and crystal growth strategies of metal oxide semiconductors are extensive studied in material science recently, because the morphology and crystallinity of the nanomaterial have significant effect on the physicochemical characteristics. However, understanding the morphology changes of α-MoO3 induced by annealing temperature is still a challenge. Herein, the nanostructure transition of MoO3 induced by calcined temperature has been investigated through XRD and SEM method. It can be found that crystallization is highly dependent on the annealing temperature. In addition, the MoO3 nanoflowers can change into nanosheets at 500 ºC. Afterwards, the nanosheets turn into microrods, especially at 900 ºC due to the growth of MoO3 crystal. On the other hand, MoO3 is a traditional sensing material, which is sensitive to many volatile organic compounds. Thus, the sensing performances of various MoO3 nanostructures were measured. Compared with MoO3 nanoflowers and microrods. The MoO3 nanosheets based sensor has excellent sensing performance towards ethanol, and the maximum gas response value is 8.06.

Under the high-pressure and low-temperature environment of the deep sea, wax deposition will occur in the wellbore. This study discusses the effect of gas–liquid two-phase bubbly flow on wax deposition. In this study, wax deposition experiments of a gas–liquid two-phase flow in vertical pipelines were carried out using waxy white oil and air as the experimental medium. The results show that under the bubble flow pattern, within a short period of time from the start of wax deposition, it rapidly accumulates to the peak, then rapidly cuts off part of it, and then presents a simple harmonic dynamic trend until the final stability. The average wax-deposit thickness decreases first and then increases with the increase of superficial gas velocity, and it increases first and then decreases with the increase of superficial liquid velocity. The average wax-deposit thickness decreases with the increase of oil temperature. The average wax-deposit thickness was substantially constant and then decreases with the increase of ambient temperature. The wax-deposit thickness increases with the increase of wax content in oil flow. This research is useful for people to further understand the changes in the wax deposition process.

Exploring high-performance cathode materials for aqueous zinc ion batteries (ZIBs) is still one of the critical issues. Copper vanadate compound has become a potential cathode material for ZIBs with a novel displacement reaction mechanism of reversible reduction/oxidation of Cu2+/Cu0. Herein, we reported Cu0.95V2O5 nanoflowers prepared using a hydrothermal synthesis method as a capable cathode material for ZIBs. The Cu0.95V2O5 nanoflowers exhibit high specific capacity of 405 mAh·g−1 at the current density of 100 mA·g−1, benefiting from the displacement reaction mechanism and phase transformation mechanism from Cu0.95V2O5 to the open and stable architecture Cu0.4V2O5 and Zn3(OH)2V2O7·2H2O phase. The cathode exhibits excellent rate performance with a high capacity of ~ 200 mAh·g−1 at 5 A·g−1 and outstanding cycle stability with a capacity retention of 92% after 1000 cycles. It is anticipated that the novel Cu0.95V2O5 nanoflowers are promising cathode material in the application for zinc ion batteries.

Mesocrystals are types of fascinating multifunctional materials in fabricating rapid charge transport pathways, and surface engineering could be considered as a significant influencing factor in boosting charge separation for efficient photocatalytic application. In this work, surface engineered Ta2O5-x mesocrystals were synthesized by facile alkali treatment strategy for enhanced visible light photocatalytic tetracycline degradation. The highly enhanced photocatalytic activity could be attributed to the highly increased surface areas and surface hydroxyl groups to compare with those of commercial Ta2O5 and pristine Ta2O5-x mesocrystals, which could provide more surface reactive sites and high electron density center for trapping photo-generated holes. Besides, possible tetracycline transformation pathways over surface engineered Ta2O5-x mesocrystals and visible light photocatalytic mechanism were also proposed in this work. Current work also provides a facile strategy for regulating surface property of ultrawide bandgaps semiconductors for enhanced visible light photocatalytic performance.

Pristine REBa2Cu3O7−δ (REBCO, RE with Yb, Y, Dy, Gd, Eu and Sm) superconducting films are deposited on CeO2 buffered technical substrates by fluorine-free metal organic decomposition (FF-MOD) method. The structure and superconductivity are comprehensively characterized and studied. Under the optimal conditions, all the films form good crystallinity and strong biaxial texture examined by XRD. A smooth and dense morphology is observed in the YBCO, GdBCO, EuBCO and SmBCO films. For all the films, Tconset values are lower than that in the corresponding bulk materials, implying a certain degree of microstructure defects (e.g., RE-Ba substitution, and/or oxygen vacancies). Among all the compositions, the GdBCO film shows a high Tconset value (>90 K), while the high Jc values are achieved at 77 K in broad field regime, also being with the largest maximum pinning force of 2.3 GN m−3. On the other hand, a high Jc value (at 77 K self-field) is obtained in the YBCO film, however, the rapid Jc decay with increase of the magnetic fields is found. These results reveal that defects in the YBCO film could only serve as weak pinning centers at least at 77 K. According to Dew-Hughes fitting models, we found that the primary pinning mechanism in all the REBCO films attributes to typical 2D non-superconducting phase i.e., Normal surface pinning. This work for the first time systemically demonstrates feasibility of deposition REBCO with various rare earth elements on technical substrates through the FF-MOD route, and provides a guideline for further growth of nano-composited and mixed rare earth REBCO films.

MgH2, TiH2, and ZrH2 are three typical metal hydrides that have been gradually applied to composite explosives and propellants as additives in recent years. To evaluate ignition sensitivity and explosion severity, the Hartmann device and spherical pressure vessel were used to test ignition energy and explosion pressure, respectively. The results showed that the ignition sensitivity of ZrH2, TiH2 and MgH2 gradually increased. When the concentration of MgH2 is 83.0 g/m3 in Hartmann device, the ignition energy attained a minimum of 10.0 mJ. The explosion pressure of MgH2 were 1.44 times and 1.76 times that of TiH2 and ZrH2, respectively, and the explosion pressure rising rate were 3.97 times and 9.96 times that of TiH2 and ZrH2, respectively, through the spherical pressure vessel. It indicated that the reaction reactivity and reaction rate of MgH2 were higher than that of TiH2 and ZrH2. In addition, to conduct in–depth theoretical analysis of ignition sensitivity and explosion severity, gas production and combustion heat per unit mass of ZrH2, TiH2 and MgH2 were tested by mercury manometer and oxygen bomb calorimetry. The experimental results revealed that MgH2 had a relatively high gas production per unit mass (5.15 mL/g), while TiH2 and ZrH2 both had a gas production of less than 2.0 mL/g. Their thermal stability gradually increased, leading to a gradual increase in ignition energy. Furthermore, compared with theoretical combustion heat, the combustion ratio of MgH2, TiH2 and ZrH2 was more than 96.0 %, with combustion heat value of 29.96, 20.94 and 12.22 MJ/kg, respectively, which was consistent with the explosion pressure and explosion severity test results.

The theoretical modeling of a functionally graded (FG) graphene nanoplatelet (GPL)-reinforced assembled beam–plate structure resting on elastic supports is presented for the first time, and its free vibration analysis is performed. Herein, the assembled structure is modeled according to the Kirchhoff plate theory and the Rayleigh beam theory. The graphene nanoplatelets (GPLs) gradiently distribute in the beam’s radial direction and in the plate’s thickness direction, respectively. By adopting the rule of mixture and the Halpin–Tsai model, the effective material properties can be obtained. By employing the Lagrange’s equation and considering the effects of Coriolis force and centrifugal force, the coupled governing equations of the assembled structure are determined. Furthermore, the assumed modes method and substructure modal synthesis method are applied to obtain the frequencies of the assembled beam–plate structure. A comprehensive numerical investigation is carried out to discuss the influence of the structural and material parameters on the vibration behavior of the beam–plate structure.

Zn(CF3SO3)2 as an electrolyte has been widely used to improve the electrochemical performance for ZIBs due to that the bulky CF3SO3− can reduce the solvation effect of Zn2+ and promote the ionic diffusion. Herein, we found that Zn(CF3SO3)2 electrolyte can induce different electrochemical mechanisms from ZnSO4 electrolyte. Compared to the ZnSO4 electrolyte, the HNaV6O16·4H2O electrode with Zn(CF3SO3)2 electrolyte exhibits a high capacity of 444 mAh·g−1 at 500 mA·g−1 with a capacity retention of 92.3% after 80 cycles. Even, at a high rate of 5 A·g−1, the HNaV6O16·4H2O electrode delivers an initial discharge capacity of 328 mAh·g−1 with a capacity retention of 93.7% after 1000 cycles. Differing from the mechanism with ZnSO4 electrolyte, the excellent cycle stability of HNaV6O16·4H2O electrode can be attributed to the in-situ phase transformation to ZnxV2O5·nH2O based on the co-intercalation of Zn2+/H+.

Defects (oxygen vacancy and Ti3+) play crucial roles in determining band structure, light absorption, and catalytic activity of TiO2. Herein, a synchronous crystallization and constraint reduction strategy was reported to construct controllable defective TiO2 using sodium borohydride (NaBH4) as the reductant. The constraint decomposition effect of NaBH4 in pore channels of TiO2 aerogels enables the defects migrate from surface to bulk region effectively, and bulk defects are more stable. Moreover, the species and concentration of defects can be controlled by changing the calcination temperature in this case. An optimum temperature for the NaBH4 treatment was found to be 500 °C. After the reduction at 500 °C, defective TiO2 with maximum bulk oxygen vacancies shows excellent visible light absorption performance, effective separation of photogenerated charge carriers, and suitable band edge, and the removal rate was 94.9% for rhodamine B (RhB) under visible light which was about 325% higher than that of TiO2 without oxygen vacancy.

The mechanical properties of foam concrete with sand at different low temperatures and different strain rates were studied. Foam concrete with sand at low temperatures (−10, −20, and −30°C) were tested using a split Hopkinson pressure bar (SHPB) apparatus with different impact pressures (0.15, 0.20, 0.25, 0.30, and 0.35 MPa). The experimental results show that the porosity of sand containing foam concrete with a density of 1,000, 1,200, 1,400 kg/m3 decreases with increasing density. In the same strain rate range, the lower the temperature of the same density foam concrete with sand, the greater the ultimate compressive strength. The change in strength was caused by the presence of pore water or ice in the foam concrete with sand in low-temperature conditions. The dynamic compressive strength of foam concrete with sand decreases with increasing strain rate. The macroscopic failure of foam concrete was closely related to the energy absorption and dependent on the rate. The total dissipated energy of the low-temperature foam concrete with sand increased linearly as the temperature decreased. The research results provide the low-temperature mechanical properties of foam concrete with sand, which provides a reference for the application of foam concrete with sand.

X-ray diffractometer, field emission scanning electron microscope (SEM, Hitachi S-4800), laser confocal micro-region Raman spectrometer and vibration sample magnetometer were used to systematically study the effects of polyethyleneimine concentrations and exposure time on the morphology and size of ZnO nanowire arrays. The photoelectric property and the relationship between the morphology of nanowire arrays and ferromagnetism at room temperature were also analyzed. Under 15 min exposure time, when the polyethyleneimine concentration is 2.25 g / L, the obtained ZnO nanowire array film exhibits the smallest size, the optimal density and vertical orientation. According to the study of luminescence and room temperature magnetism, it is shown that the optical and ferromagnetic property are related to the variation tendency of oxygen defects and surface defects of the ZnO nanowires.

Fly ash is the most common solid waste in the industry, and its high value-added utilization has become a hot issue of study. Carrying out the green synthesis route of zeolite as the raw material of fly ash has become an extremely important scientific significance and practical value. In this paper, the research progress of fly ash-based zeolite was introduced from three aspects, including fly ash activation method, fly ash-based zeolite synthesis method and fly ash-based zeolite in the wastewater treatment sector. The relevant applications of fly ash-based zeolite as an adsorbent material in the treatment of wastewater pollution were summarized, and the development trend has prospected.

The dynamic performances of a polyurethane-reinforced ballast bed and an unreinforced ballast bed at an operation site were tested by using the impact excitation technique. The influences of the ballast beds with and without polyurethane reinforcement on the natural frequency were investigated, along with the vertical and longitudinal vibration transmission characteristics of the track structure. The results show the following. Compared to the ballast bed, the polyurethane ballast bed has an inhibitory effect on the rail vibration in the range of 200–400 Hz, but there is an increased rail vibration amplitude in the higher frequency range. The polyurethane-reinforced ballast bed significantly increases the amount and amplitude of the dominant vibration frequencies of the sleeper. As the frequency increases (> 90 Hz), the superstructure of the polyurethane track rapidly transfers from being flexible to rigid, and the track thus absorbs and dissipates the impact load, quickly damping the vibration in the range of 90–470 Hz. The calculation results of the displacement transmission ratio (DTR) proposed in this study also support this finding, suggesting the use of DTR to more intuitively evaluate the vibration damping effect of each component of the track. The polyurethane material reinforces the ballast bed rather than the damping vibration, thereby improving the stability of the track structure.

Titanium alloys have been taken as Oil Country Tubular Goods (OCTG) owing to their higher strength, and better corrosion resistance, but there are some problems in their application process. The corrosion types of titanium alloys were emphatically discussed, and corrosion mechanism was analyzed in this paper. The results showed that the main corrosion type of titanium alloys in hydrochloric acid was pitting, and the surface roughness of titanium alloys could affect it. The critical current density of titanium alloys in phosphoric acid was closely related to temperature and phosphoric acid concentration. The passivation of titanium alloys could be carried out by the growing oxide film at low current density, to achieve the higher stability of passivating film in the concentrated sulfuric acid. Titanium alloys suffered from more serious corrosion in the CO2-containing completion fluid environment than that in the CO2-containing formation water environment. H2S would cause electrochemical corrosion and stress corrosion of titanium alloy pipe, leading to hydrogen embrittlement and even cracking of OCTG. Passivating film was the key to corrosion resistance of titanium alloys, and its composition would change with the depth of the film, presenting N-type. The dynamic corrosion of titanium alloys was mainly controlled by charge transfer.

Radiation dosimeters displaying conspicuous response of irradiance are highly desirable, owing to the growing demand of monitoring high-energy radiation and environmental exposure. Herein, we present a case of dosimetry based on a discrete nanocluster, [Th6(OH)4(O)4(H2O)6](TPC)8(HCOO)4∙4DMF∙H2O (Th-SINAP-100), by judiciously incorporating heavy Th6 polynuclear centers as radiation attenuator and organic linkers as photo-responsive sensor. Interestingly, dual-module photochromic transitions upon multiple external stimuli including UV, β-ray, and γ-ray are integrated into this single material. The striking color change, and more significantly, the visible color transition of luminescence in response to accumulating radiation dose allow an on-site quantitative platform for naked-eye detection of ionization radiations over a broad range (1–80 kGy). Single crystal X-ray diffraction and density functional theory calculations reveal that the dual-module photochromism can be attributed to the π(TPC) → π*(TPC) intermolecular charge transfer driven by enhanced π-π stacking interaction between the adjacent TPC moieties upon irradiation., Radiation dosimeters that measure ionizing radiations over a broad range and allow for direct readout are desirable. Here, the authors present a dual-mode photochromic thorium-based metal-organic nanocluster that enables direct visible colorimetric dosimetry of UV, β-ray, and γ-ray radiation.

In order to generate high quality regular optical vortex array (OVA), we present an experimental method for generating OVA using phase only liquid crystal spatial light modulator (LC-SLM) assisted two gratings. In the scheme, holograms of two grating are displayed on the screen of two LC-SLMs respectively; the diffraction optical fields are captured by a CCD camera. The simulated and experimental results show that the regular OVA can be generated by using double diffraction gratings. The generated OVAs have a constant topological charge of ±1. The method can provide a useful pathway to produce regular OVA for some applications in optical communication, particle trapping and optical metrology.

The development of a controlled and reliable method to construct well-defined sulfur-containing polymers has sparked great interest in polymer science. Herein, we present the trial on the copolymerization of isothiocyanates with episulfides in the presence of organic onium salts, which provides direct access to a class of sulfur-rich polymers. This methodology has combined advantages of simple operation, no metals, mild conditions (25-100 °C), controlled polymerization performance (

Electrocatalytic conversion of nitrate (NO3-) into ammonia can not only eliminate harmful pollutant but also provide a green method for a low-temperature ammonia synthesis. The electrochemical NO3- reduction reactions (NO3RRs) of a series of transition-metal-doped hexagonal boron phosphide (h-BP) monolayers were comprehensively evaluated using density functional theory. The V-doped h-BP monolayer was found to stand near the top of the volcano plot with the limiting potential of -0.22 V versus a reversible hydrogen electrode, exhibiting the lowest overpotential among the investigated systems in this work. Besides, the competing hydrogen evolution reaction is significantly suppressed due to the weak adsorption of the H atom. Importantly, the structure of the V-doped h-BP monolayer can be retained very well until 900 K, illustrating the initial indication of high thermal stability and great promise for synthesis. This study not only offers an eligible NO3RR electrocatalyst but also provides an atomic understanding of the behind mechanisms of the NO3RR process.

Geological tectonic movements, as well as complex and varying coal-forming conditions, have led to the formation of rock partings in most coal seams. Consequently, the coal in coal-rock composites is characterised by different mechanical properties than those of pure coal. Uniaxial compression tests were performed in this study to determine the mechanical properties and bursting liability of specimens of coal-rock composites (hereinafter referred to as “composites”) with rock partings with different dip angles θ and thicknesses D. The results showed that as θ increased, the failure mode of the composite changed from tensile and splitting failure to slip and shear failure, which was accompanied by a decrease in the brittleness of the composite and an increase in its ductility as well as a decrease in the extent of fragmentation of the coal in the composite. Additionally, as θ increased, the uniaxial compressive strength σu, elastic modulus E, and bursting energy index Ke of the composite decreased. The rock parting in the composite was the key area in which elastic energy accumulated. As D increased, σu, E, and Ke of the composite increased. In addition, as D increased, the ductility of the composite decreased, and the brittleness and extent of coal fragmentation in the composite increased. Notably, the curve for the cumulative acoustic emission (AE) counts of the composite corresponding to the stress-strain curve could be divided into four regimes: pore compaction and closure, a slowly ascending linear elastic section, prepeak steady crack propagation, and peak unsteady crack propagation. The experimental results were used to propose two technologies for controlling the stability of coal-rock composites to effectively ensure safe and efficient production at working faces.

In this work, CeO2 nanocrystal-decorated TiO2 nanobelt for forming a CeO2@TiO2 heterostructure. CeO2 plays a dual role in improving photocatalytic activity, not only by promoting the separation and transfer of photogenerated charge carriers, but also by increasing visible light absorption of the photocatalyst as a photosensitizer. The as-prepared CeO2@TiO2 heterostructure demonstrates the performance of organic degradation and H2 production (about 17 μmol/h/g, which is about 2.5 times higher than that of pure TiO2 nanobelts). Our work provides a facile and controllable synthesis method for high performance photocatalyst, which will have potential applications in synthesis clean/solar fuel, and photocatalytic water treatment.

Using a pyridine-derived molecule 1,3,5-tris(4-pyridyl)benzene (TPB) and a polycarboxylate linker 1,3-benzenedicarboxylic acid (H2BDC), a Co(II)-based coordination polymer {[Co(TPB)(BDC)]·0.5H2O} (...

Designing the specific crystal phase with better intrinsic activity and more active sites is a very promising strategy for earth-abundant electrocatalysts for oxygen evolution reaction (OER). Herein, a facile two-step method including the high-pressure microwave and the hydrothermal sulfurization is adopted to prepare the WSx/Ni9S8 hetero-catalyst on nickel foam (WSx/Ni9S8/NF). Firstly, WO3 polyhedrons homogeneously cover the surface of NF through the high-pressure microwave hydrothermal process. Secondly, WSx/Ni9S8 nanoparticles on the surface of NF can be synthesized after a hydrothermal sulfurization, which has been confirmed by scanning electron microscopy (SEM) elemental mapping and high-resolution transmission electron microscopy (HRTEM). The amorphous WSx and Ni9S8 phase may provide the dual active sites for OER. The electrochemical measurements show that WSx/Ni9S8/NF has superior OER activity with a low overpotential of 320 mV at the current density of 100 mA·cm−2, better than those of other samples. The enhanced OER performance may be due to the synergistic catalysis from Ni9S8 phase and high valence of W. Owing to the stable structure of Ni9S8, the long-term stability of WSx/Ni9S8/NF for at least 10 h can be obtained. This work may provide a new approach for the doped nickel sulfides crystal phase through high-pressure microwave hydrothermal assistance for OER.

In this work, highly hydrophobic carbon sponges with large specific surface area were successfully prepared (denoted as HHCS-1, HHCS-2 and HHCS-3). By simply increasing temperature and decreasing heating rate, the carbon sponge showed unique sphere structures at the points of each connection. Moreover, the unique sphere structure changes from no obvious fold to obvious fold. HHCS-3 with the largest surface area of 2926.2 m2 g−1 exhibited superior adsorption performance for methanol, acetone and toluene, and the largest saturated adsorption capacity reached as high as 172, 365 and 429 mg g−1. The ultralow water vapor absorption rate indicates that HHCSs have excellent hydrophobicity and water vapor uptakes are only 7.62%, 6.71% and 6.25% at the relative humidity of 50%. When water vapor was introduced into toluene gas (RH = 50%), the toluene-saturated adsorption capacities are only reduced by 7.2−8.6% compared with under dry conditions. The adsorption capacity of toluene on the HHCSs is higher than that of methanol and acetone. Kinetic adsorption models show that the adsorption of methanol, acetone and toluene onto HHCSs mainly depends on surface adsorption.

Due to wide applications of lithium-ion batteries (LIBs), scientists have never stopped pursuing larger-capacity and higher-stability lithium storage materials. To obtain better LIBs, three distinc...

It is still a challenge to develop the high-efficiency noble metal-based electrocatalyst with good dispersion and durability for hydrogen evolution reaction (HER) in wide pH range. Herein, we have successfully synthesized a nitrogen-doped carbon (NC) coated ultrafine ruthenium phosphides (RuP2) nanoparticles catalyst with a facile method. With the help of ethylene diamine tetraacetic acid (EDTA), the uniform RuP2 nanoparticles with ultrafine size of about 3 nm are well dispersed on the surface of the NC. The directed coordination between EDTA and Ru ion may be responsible for the excellent structure. Benefiting from the superior electrical conductivity of NC carrier and the reduced resistance of electrons to the active site, the prepared ultrafine RuP2@NC demonstrates the obviously enhanced electrocatalytic activity for HER, which results in higher current density and lower overpotentials (99, 98 and 196 mV to reach 10 mA cm−2 in 0.5 M H2SO4, 1 M KOH and 1 M PBS, respectively). The stability is also very good due to the close integration between ultrafine RuP2 and NC. This work provides a new view to rationally design and synthesize the highly effective, stable and great dispersion of phosphide-based electrocatalysts for HER.