This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ra...This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ratio and thickness of steel tube influence the bond strength characteristics.The results show that as the enhancement of the steel tube wall thickness,the ultimate bond strength at the interface improves significantly,whereas the initial bond strength exhibits only slight variations.The influence of steel fiber volumetric ratio presents a nonlinear trend,with initial bond strength decreasing at low fiber content and increasing significantly as fiber content rises.Additionally,finite element(FE)simulations were applied to replicate the experimental conditions,and the outcomes showed strong correlation with the experimental data,confirming the exactitude of the FE model in predicting the bond behavior at the UHPC-Steel interface.These findings provide valuable insights for optimizing the design of UHPC-Filled steel tubes in high-performance structure.展开更多
Flexible strain sensors have received tremendous attention because of their potential applications as wearable sensing devices.However, the integration of key functions into a single sensor, such as high stretchabilit...Flexible strain sensors have received tremendous attention because of their potential applications as wearable sensing devices.However, the integration of key functions into a single sensor, such as high stretchability, low hysteresis, self-adhesion, andexcellent antifreezing performance, remains an unmet challenge. In this respect, zwitterionic hydrogels have emerged asideal material candidates for breaking through the above dilemma. The mechanical properties of most reported zwitterionichydrogels, however, are relatively poor, significantly restricting their use under load-bearing conditions. Traditional improve-ment approaches often involve complex preparation processes, making large-scale production challenging. Additionally,zwitterionic hydrogels prepared with chemical crosslinkers are typically fragile and prone to irreversible deformation underlarge strains, resulting in the slow recovery of structure and function. To fundamentally enhance the mechanical properties ofpure zwitterionic hydrogels, the most effective approach is the regulation of the chemical structure of zwitterionic monomersthrough a targeted design strategy. This study employed a novel zwitterionic monomer carboxybetaine urethane acrylate(CBUTA), which contained one urethane group and one carboxybetaine group on its side chain. Through the direct polym-erization of ultrahigh concentration monomer solutions without adding any chemical crosslinker, we successfully developedpure zwitterionic supramolecular hydrogels with significantly enhanced mechanical properties, self-adhesive behavior, andantifreezing performance. Most importantly, the resultant zwitterionic hydrogels exhibited high tensile strength and tough-ness and displayed ultralow hysteresis under strain conditions up to 1100%. This outstanding performance was attributedto the unique liquid–liquid phase separation phenomenon induced by the ultrahigh concentration of CBUTA monomers inan aqueous solution, as well as the enhanced polymer chain entanglement and the strong hydrogen bonds between urethanegroups on the side chains. The potential application of hydrogels in strain sensors and high-performance triboelectric nano-generators was further explored. Overall, this work provides a promising strategy for developing pure zwitterionic hydrogelsfor flexible strain sensors and self-powered electronic devices.展开更多
The excellent bonding performance between bolt and anchor materials is crucial for controlling the deformation of deep-buried surrounding rock and strengthening the rock and soil mass in the slope.This paper conducted...The excellent bonding performance between bolt and anchor materials is crucial for controlling the deformation of deep-buried surrounding rock and strengthening the rock and soil mass in the slope.This paper conducted an anchoring test and ABAQUS numerical simulation of an anchoring system comprising a micro-NPR(microscopic negative Poisson’s ratio)bolt and cement mortar as the anchoring material.The failure mode of this system and the distribution of average bonding strength,axial force,and shear stress along the anchoring depth were studied.We also evaluated the bonding properties at the micro-NPR(microscopic negative Poisson’s ratio)bolt-cement mortar interface.The findings indicate that the cement mortar is partially spalled from the micro-NPR bolt surface.The average bonding strength at the micro-NPR bolt-cement mortar interface is positively correlated with anchoring length and cement mortar strength.In contrast,it exhibits a negative correlation with bolt diameter.The axial force is generated at the starting point of the anchorage and decreases non-uniformly across the anchoring region.The axial force transfers or diffuses toward the deeper sections of the anchoring segment with increasing loads.The shear stress at the micro-NPR bolt-cement mortar interface exhibits a single-peak pattern,i.e.,it climbs to a peak value and decreases along the anchoring depth.The peak position varies with changes in bolt diameter and anchoring length.By comparison,it is independent of cement mortar strength.The simulated bonding properties of the micro-NPR bolt-cement mortar interface are consistent with experimental results.The findings can provide a reference for engineering applications and anchoring design of micro-NPR.展开更多
The self-healing function is considered one of the effective ways to address structural damage and improve interfacial bonding in Energetic composite materials(ECMs).However,the currently prepared ECMs with self-heali...The self-healing function is considered one of the effective ways to address structural damage and improve interfacial bonding in Energetic composite materials(ECMs).However,the currently prepared ECMs with self-healing function have problems such as irregular particle shape and uneven distribution of components,which affect the efficient play of self-healing function.In this paper,HMX-based energetic microspheres with self-healing function were successfully prepared by microchannel technology,which showed excellent self-healing effect in both Polymer-bonded explosives(PBXs)and Composite solid propellants(CSPs).The experimental results show that the HMX-based energetic microspheres with different binder contents prepared by microchannel technology show regular shape,HMX crystal particles are uniformly wrapped by self-healing binder(GAPU).When the content of GAPU in HMX-based energetic microspheres is 10%,PBXs show excellent self-healing effect and mechanical safety is improved by 400%(raw HMX vs S4,5 J vs 25 J).As a high-energy component,the burning rate of CSPs is increased by 359.4%,the time(burning temperature>1700℃)is prolonged by 333.3%,and the maximum impulse force is increased by 107.3%(CSP-H vs CSP-S4,0.84 mm/s vs 3.87 mm/s,0.06 s vs 0.26 s,0.82 m N vs 1.70 m N).It also has excellent storage performance.The preparation of HMX-based energetic microspheres with self-healing function by microchannel technology provides a new strategy to improve the storage performance of ECMs and the combustion performance of CSPs.展开更多
In order to prolong the service life of ZrO_(2) thermal barrier coatings,HS188 alloy was used as the substrate,and NiCrAlY powder(base layer,d_(50)=106μm)and yttria stabilized zirconia(YSZ,d_(50)=50μm)were employed ...In order to prolong the service life of ZrO_(2) thermal barrier coatings,HS188 alloy was used as the substrate,and NiCrAlY powder(base layer,d_(50)=106μm)and yttria stabilized zirconia(YSZ,d_(50)=50μm)were employed as the sprayed feeder to prepare NiCrALY+YSZ thermal barrier coatings using high-energy plasma spraying equipment with a progressive exploration method.The microstructure of the coatings was controlled by adjusting the stand-off distance(85,95,105 and 115 mm)and air-cooling manner(rear air cooling,rear air cooling+gun cooling,front air cooling,and front air cooling+gun cooling).The bonding strength of the coatings was evaluated by the drawing method.The results indicate that under the conditions of long stand-off distance and low cooling rate,it is difficult for the coatings to form a vertical crack structure due to the low instantaneous heating temperature and insufficient quenching on the sample surface.However,when the instantaneous heating temperature reaches the critical value and the air cooling rate is excessive,un-melted spray particles exist.When the stand-off distance is 85 mm and the cooling method is front air cooling,a thermal barrier ceramic coating with vertical crack morphology was obtained on HS188 alloy.Simultaneously,it has a moderate density of vertical cracks,the highest bonding strength and the best toughness.展开更多
In this study, to meet the development and application requirements for high-strength and hightoughness energetic structural materials, a representative volume element of a TA15 matrix embedded with a TaZrNb sphere wa...In this study, to meet the development and application requirements for high-strength and hightoughness energetic structural materials, a representative volume element of a TA15 matrix embedded with a TaZrNb sphere was designed and fabricated via diffusion bonding. The mechanisms of the microstructural evolution of the TaZrNb/TA15 interface were investigated via SEM, EBSD, EDS, and XRD.Interface mechanical property tests and in-situ tensile tests were conducted on the sphere-containing structure, and an equivalent tensile-strength model was established for the structure. The results revealed that the TA15 titanium alloy and joint had high density and no pores or cracks. The thickness of the planar joint was approximately 50-60 μm. The average tensile and shear strengths were 767 MPa and 608 MPa, respectively. The thickness of the spherical joint was approximately 60 μm. The Zr and Nb elements in the joint diffused uniformly and formed strong bonds with Ti without forming intermetallic compounds. The interface exhibited submicron grain refinement and a concave-convex interlocking structure. The tensile fracture surface primarily exhibited intergranular fracture combined with some transgranular fracture, which constituted a quasi-brittle fracture mode. The shear fracture surface exhibited brittle fracture with regular arrangements of furrows. Internal fracture occurred along the spherical interface, as revealed by advanced in-situ X-ray microcomputed tomography. The experimental results agreed well with the theoretical predictions, indicating that the high-strength interface contributes to the overall strength and toughness of the sphere-containing structure.展开更多
The adsorptive denitrification performance of MIL-101(Cr)-0.5 toward pyridine,aniline or quinoline in simulated fuels with basic nitrogen content of 1732μg/g was evaluated separately.Furthermore,the effects of adsorp...The adsorptive denitrification performance of MIL-101(Cr)-0.5 toward pyridine,aniline or quinoline in simulated fuels with basic nitrogen content of 1732μg/g was evaluated separately.Furthermore,the effects of adsorption temperature,adsorption time and adsorbent dosage on their adsorptive denitrification performance were systematically investigated.The experimental results demonstrated that under a fixed adsorbent dosage of 0.05 g and a simulated fuel volume of 10 mL,the optimal removal efficiency for aniline was achieved at 30℃ within 30 min,whereas higher temperatures and longer times(40℃and 40 min)were required for effective removal of pyridine and quinoline.Density Functional Theory(DFT)calculations were conducted via Materials Studio(MS)software to study the adsorptive denitrification mechanism of MIL-101(Cr)toward these three basic nitrogen-containing compounds.The simulation calculation results revealed that the interaction between pyridine and MIL-101(Cr)primarily involved coordination adsorption.In contrast,the interaction between aniline or quinoline and MIL-101(Cr)proceeded mainly through coordination,with additional contributions fromπ-complexation and hydrogen bonding.The overall adsorption strength order is pyridine>aniline>quinoline.During the adsorption process,pyridine and quinoline transfer electrons to the MIL-101(Cr)surface through the H→C→N→Cr^(3+)pathway,while aniline transfers electrons to the MIL-101(Cr)surface through various pathways,including N→Cr^(3+),N→C→Cr^(3+)and N→H→O.Furthermore,adsorption kinetics studies indicated that the adsorption processes for all three basic nitrogen-containing compounds followed the quasi second order kinetic models.The experimental results on the effect of benzene on the adsorptive denitrification performance of MIL-101(Cr)-0.5 demonstrated that benzene exerted a more significant impact on the adsorption of aniline and quinoline.Finally,the adsorbent was regenerated using ethanol washing.It was found that MIL-101(Cr)-0.5 retained stable denitrification performance after two regeneration cycles.展开更多
The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various...The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.展开更多
To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ...To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.展开更多
Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigat...Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigates the muscle strength performance(MSP)of 289 adult and teenage CA,exercisers,and physically inactive individuals(PI),and proposes predictive models of MSP for adults.Methods:Muscle maximal,speed,and explosive strength(MMS/MSS/MES)at unilateral maximal concentric flexion and extension contraction(FC/EC)were evaluated using Biodex System 3 PRO^(TM)at 60°/s,180°/s,and 300°/s,while additional performance markers were assessed through field ergometric testing.Participants were interviewed about their lifestyle,dietary habits,physical activity,injury,and medical history.Body composition was assessed via bioelectrical impedance.gDNA was extracted from biochemical samples and then genotyped.Statistical analysis was conducted using IBM SPSS Statistics v21.0 and R.Results:Age,fitness,and sex impacted correlations of MSP with body composition and anthropometric measurements(p<0.05).Among CA,females outperformed males in accuracy(p<0.001)while,males outperformed females in anaerobic power,MSP,speed,and endurance(p<0.001).Adult CA outperformed exercisers and PI in MMS,MSS,and MES(p<0.05).Multiple linear regression models,with predictors age,FFM,body extremity,training load explained the majority of variation in MMS(R^(2)_(adj):71.4%–88.9%),MSS(R^(2)_(adj):64.8%–78.4%),and MES(R^(2)_(adj):52.7%–68.4%)at EC,FC,and their mean(p<0.001).Conclusions:Muscle-strengthening strategies should be customized according to individual fitness levels,body composition,and anthropometric measurements.The innovative sex-specific regression models assessing MMS,MSS,and MES at EC and FC provide a framework for personalizing rehabilitation and skill-specific training strategies.展开更多
Azobenzene-based polymer actuators show great promise for photoactuation owing to their unique photoisomerization behavior and tailorable molecular programmability.However,conventional systems are limited by inadequat...Azobenzene-based polymer actuators show great promise for photoactuation owing to their unique photoisomerization behavior and tailorable molecular programmability.However,conventional systems are limited by inadequate mechanical robustness,self-healing,and recyclability,hindering their practical implementation.Herein,we present a high-performance azobenzene-functionalized polyurethane(AzoPU)elastomer actuator designed via molecular engineering of photoactive azobenzene moieties and dynamic disulfide bonds.AzoPU exhibits exceptional mechanical properties with retained performance after multiple reshaping cycles,enabled by well-engineered hard-soft segments and synergistic stress dissipation from weak covalent bonds/hierarchical hydrogen bonds.It achieves over 93%self-healing efficiency at room temperature owing to the synergistic interplay of disulfide bonds in the polymer backbone and intermolecular hydrogen bonds.Furthermore,it demonstrates remarkable light-triggered actuation behavior,achieving a phototropic bending angle exceeding 180°toward the light source within 45 s.To showcase its practical potential,proof-of-concept photoactuated devices with flower-,hook-,and gripper-like and local-orientation processed strip-shaped structures were fabricated,which exhibited rapid and reversible light-triggered deformation.This study proposes a novel strategy for the development of intelligent polymeric materials that integrate light responsiveness,self-healing,and recyclability,thus holding great promise for applications in flexible electronics,smart actuators,and sustainable functional materials.展开更多
The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton trans...The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton transfer mechanism remains elusive.Herein,we reported a metal-free,room-temperature strategy utilizing 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)as a dual hydrogen bond catalyst to synergistically activate propylamine(PA)and dimethyl carbonate(DMC).This green catalytic system achieves a 10-fold acceleration in reaction rate compared to other hydrogen bonding catalysts under mild conditions.This is enabled by dual hydrogen bonding of TBD with PA and DMC,which facilitates rapid proton transfer and stabilizes tetrahedral intermediates.Theoretical calculations confirm that the dual hydrogen bond system significantly lowers activation energy compared to single hydrogen bond analogs.Furthermore,it was revealed that the hydrogen bonding network within the product is the primary factor responsible for the sluggish reaction rate.This study demonstrates the effectiveness of a dual hydrogen bond system in accelerating the carbonylation of amines and provides a green route to access carbamates.展开更多
Prussian blue analogs(PBAs)have emerged as environmentally friendly and structurally tunable cathode materials for aqueous ammonium-ion batteries(AIBs).However,the fundamental role of crystalline H_(2)O in regulating ...Prussian blue analogs(PBAs)have emerged as environmentally friendly and structurally tunable cathode materials for aqueous ammonium-ion batteries(AIBs).However,the fundamental role of crystalline H_(2)O in regulating ammonium-ion storage and transport remains poorly understood.In this study,we present a comprehensive comparison between hydrated NH_(4)NiHCF-H_(2)O and its anhydrous counterpart NH_(4)NiHCF,revealing the critical contribution of interstitial water to electrochemical performance.Structural and spectroscopic analyses confirm that interstitial water forms robust hydrogen bonds with NH_(4)+ions,stabilizing the PBA framework and mitigating structural degradation during cycling.Electrochemical measurements show that NH_(4)NiHCF-H_(2)O delivers a significantly higher specific capacity of 61 mA h g^(−1)at 0.2 C and markedly improved rate performance compared to NH_(4)NiHCF(48 mA h g^(−1)at 0.2 C).Kinetic analysis reveals that interstitial water enhances NH_(4)+diffusion,as evidenced by higher diffusion coefficients.Furthermore,density functional theory(DFT)calculations demonstrate that crystal water acts as a hydrogen bond acceptor,preferentially interacting with NH_(4)+and reducing the migration energy barrier,thereby facilitating fast ion transport.This work provides fundamental insights into the role of crystal water in PBAs and offers a rational design strategy for improving the kinetics,structural stability of PBAs cathodes for AIBs.展开更多
In composite solid propellants with high aluminum(Al)content and low burning rate,incomplete combustion of the Al powder may occur.In this study,varying lithium(Li)content in Al-Li alloy powder was utilized instead of...In composite solid propellants with high aluminum(Al)content and low burning rate,incomplete combustion of the Al powder may occur.In this study,varying lithium(Li)content in Al-Li alloy powder was utilized instead of pure aluminum particles to mitigate agglomeration and enhance the combustion efficiency of solid propellants(Combustion efficiency herein refers to the completeness of metallic fuel oxidation,quantified as the ratio of actual-to-theoretical energy released during combustion)with high Al content and low burning rates.The impact of Al-Li alloy with different Li contents on combustion and agglomeration of solid propellant was investigated using explosion heat,combustion heat,differential thermal analysis(DTA),thermos-gravimetric analysis(TG),dynamic high-pressure combustion test,ignition experiment of small solid rocket motor(SRM)tests,condensation combustion product collection,and X-ray diffraction techniques(XRD).Compared with pure Al,Al-Li alloys exhibit higher combustion heat,which contributes to improved combustion efficiency in Al-Li alloy-containing propellants.DTA and TG analyses demonstrated higher reactivity and lower ignition temperatures for Al-Li alloys.High-pressure combustion experiments at 5 MPa showed that Al-Li alloy fuel significantly decreases combustion agglomeration.The results from theφ75 mm andφ165 mm SRM and XRD tests further support this finding.This study provides novel insights into the combustion and agglomeration behaviors of high-Al,low-burning-rate composite solid propellants and supports the potential application of Al-Li alloys in advanced propellant formulations.展开更多
The rapid advancements in computer vision(CV)technology have transformed the traditional approaches to material microstructure analysis.This review outlines the history of CV and explores the applications of deep-lear...The rapid advancements in computer vision(CV)technology have transformed the traditional approaches to material microstructure analysis.This review outlines the history of CV and explores the applications of deep-learning(DL)-driven CV in four key areas of materials science:microstructure-based performance prediction,microstructure information generation,microstructure defect detection,and crystal structure-based property prediction.The CV has significantly reduced the cost of traditional experimental methods used in material performance prediction.Moreover,recent progress made in generating microstructure images and detecting microstructural defects using CV has led to increased efficiency and reliability in material performance assessments.The DL-driven CV models can accelerate the design of new materials with optimized performance by integrating predictions based on both crystal and microstructural data,thereby allowing for the discovery and innovation of next-generation materials.Finally,the review provides insights into the rapid interdisciplinary developments in the field of materials science and future prospects.展开更多
Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains...Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.展开更多
In the context of the revolution in new technologies,a key question is whether the rapid growth of the digital economy,driven by digital technologies,has improved regional innovation performance.Using inter-provincial...In the context of the revolution in new technologies,a key question is whether the rapid growth of the digital economy,driven by digital technologies,has improved regional innovation performance.Using inter-provincial panel data from China(2012–2022)and adopting a business environment perspective,this study applies a Panel Extended Regression Model(PERM),a Panel Simultaneous Equation Model(PSEM),and a Tobit-IV model to analyze how the development of the digital economy influences regional innovation.The results reveal a pronounced U-shaped relationship between the digital economy and the regional innovation performance at the provincial level in China,with the business environment serving as a significant mediator in this relationship.Moreover,regional innovation performance in China exhibits a“ratchet effect,”with the impact of the digital economy varying markedly across regions.While the eastern and western regions have entered an upward phase,whereby the digital economy boosts innovation,the central region displays a weaker effect.Further analysis indicates that the synergy between the business environment and the digital economy in driving innovation remains suboptimal.These findings were supported by robust checks.This study offers theoretical insights and empirical evidence that support the coordinated development of digital government and the digital factor market,as well as business environment reforms that are in alignment with the innovation demands of the digital era.展开更多
This work examines the microstructure and corrosion properties of fine-grained Al 7075 across different regions under varying cooling conditions during friction stir welding.The findings demonstrate that forced coolin...This work examines the microstructure and corrosion properties of fine-grained Al 7075 across different regions under varying cooling conditions during friction stir welding.The findings demonstrate that forced cooling significantly improves the corrosion resistance of the welded joints.Specifically,the corrosion resistance was the highest in the stir zone,followed by the thermo-mechanical affected zone,and then the heat affected zone.Forced cooling mitigates grain growth by controlling the welding thermal effects,thereby increasing the proportion ofΣ3 grain boundaries.The modification of these microstructural characteristics promotes the formation of a dense oxide layer,thereby enhancing the corrosion resistance.Furthermore,forced cooling mitigates the precipitation and coarsening of the anodic phase in the stir zone,which in turn reduces the susceptibility of the joint to pitting corrosion.Additionally,the lower recrystallization texture content in the joint,resulting from forced cooling,contributes to a reduction in the number of corrosion-active sites,thereby further improving the corrosion performance of the welded joint.展开更多
When stacking two-dimensional(2D)materials with a lattice mismatch and/or a small twist,moirésuperlattice emerges with fascinating electronic and optical properties.The fabrication of such stacked 2D materials us...When stacking two-dimensional(2D)materials with a lattice mismatch and/or a small twist,moirésuperlattice emerges with fascinating electronic and optical properties.The fabrication of such stacked 2D materials usually requires multiple transfer and stack processes,assisted by a certain transfer medium which needs to be removed afterwards,and it is very challenging to maintain pristine and clean surfaces/interfaces for these stacked structures.In this work,we report a facile direct bonding method for fabrication of twisted MoS_(2) bilayers with ultra-clean surfaces/interfaces.Novel interlayer interactions are revealed in the as-fabricated high-quality samples,leading to twist-angle related dispersion behavior of various Raman modes,such as layer breathing modes,shear modes and E_(2g)modes,as well as indirect bandgap excitons.Field-effect transistors(FETs)of twisted MoS_(2) bilayers also exhibit angle-dependent performance,which could be attributed to the band structure evolution.This facile method holds significance for the future integration of pre-designed multilayer 2D materials and paves a way to explore underlying physical mechanisms and potential applications.展开更多
Al/NH_(4)CoF_(3)-Φ(Φ=0.5,1.0,1.5,2.0,and 3.0)binary composites and Al-NH_(4)CoF_(3)@P(VDF-HFP)ternary composites are fabricated via ultrasonication-assisted blending and electrostatic spraying.The effect of equivale...Al/NH_(4)CoF_(3)-Φ(Φ=0.5,1.0,1.5,2.0,and 3.0)binary composites and Al-NH_(4)CoF_(3)@P(VDF-HFP)ternary composites are fabricated via ultrasonication-assisted blending and electrostatic spraying.The effect of equivalence ratio(Φ)on the reaction properties is systematically investigated in the binary Al/NH_(4)CoF_(3)system.For ternary systems,electrostatic spraying allows both components to be efficiently encapsulated by P(VDF-HFP)and to achieve structural stabilization and enhanced reactivity through synergistic interfacial interactions.Morphological analysis using SEM/TEM revealed that P(VDF-HFP)formed a protective layer on Al and NH_(4)CoF_(3)particles,improving dispersion,hydrophobicity(water contact angle increased by 80.5%compared to physically mixed composites),and corrosion resistance.Thermal decomposition of NH_(4)CoF_(3)occurred at 265℃,releasing NH_(3)and HF,which triggered exothermic reactions with Al.The ternary composites exhibited a narrowed main reaction temperature range and concentrated heat release,attributed to improved interfacial contact and polymer decomposition.Combustion tests demonstrated that Al-NH_(4)CoF_(3)@P(VDF-HFP)achieved self-sustaining combustion.In addition,a simple validation was done by replacing the Al component in the aluminium-containing propellant,demonstrating its potential application in the propellant field.This work establishes a novel strategy for designing stable,high-energy composites with potential applications in advanced propulsion systems.展开更多
基金supported by grants from the Natural Science Foundation of Fujian Province(2021J011062)Minjiang Scholars Funding(GY-633Z21067).
文摘This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ratio and thickness of steel tube influence the bond strength characteristics.The results show that as the enhancement of the steel tube wall thickness,the ultimate bond strength at the interface improves significantly,whereas the initial bond strength exhibits only slight variations.The influence of steel fiber volumetric ratio presents a nonlinear trend,with initial bond strength decreasing at low fiber content and increasing significantly as fiber content rises.Additionally,finite element(FE)simulations were applied to replicate the experimental conditions,and the outcomes showed strong correlation with the experimental data,confirming the exactitude of the FE model in predicting the bond behavior at the UHPC-Steel interface.These findings provide valuable insights for optimizing the design of UHPC-Filled steel tubes in high-performance structure.
基金supported by the National Natural Science Foundation of China(Nos.T2222013 and 52073203)Tianjin Natural Science Foundation(No.22JCQNJC01040)the State Key Laboratory of Molecular Engineering of Polymers(Fudan University)(No.K2024-19).
文摘Flexible strain sensors have received tremendous attention because of their potential applications as wearable sensing devices.However, the integration of key functions into a single sensor, such as high stretchability, low hysteresis, self-adhesion, andexcellent antifreezing performance, remains an unmet challenge. In this respect, zwitterionic hydrogels have emerged asideal material candidates for breaking through the above dilemma. The mechanical properties of most reported zwitterionichydrogels, however, are relatively poor, significantly restricting their use under load-bearing conditions. Traditional improve-ment approaches often involve complex preparation processes, making large-scale production challenging. Additionally,zwitterionic hydrogels prepared with chemical crosslinkers are typically fragile and prone to irreversible deformation underlarge strains, resulting in the slow recovery of structure and function. To fundamentally enhance the mechanical properties ofpure zwitterionic hydrogels, the most effective approach is the regulation of the chemical structure of zwitterionic monomersthrough a targeted design strategy. This study employed a novel zwitterionic monomer carboxybetaine urethane acrylate(CBUTA), which contained one urethane group and one carboxybetaine group on its side chain. Through the direct polym-erization of ultrahigh concentration monomer solutions without adding any chemical crosslinker, we successfully developedpure zwitterionic supramolecular hydrogels with significantly enhanced mechanical properties, self-adhesive behavior, andantifreezing performance. Most importantly, the resultant zwitterionic hydrogels exhibited high tensile strength and tough-ness and displayed ultralow hysteresis under strain conditions up to 1100%. This outstanding performance was attributedto the unique liquid–liquid phase separation phenomenon induced by the ultrahigh concentration of CBUTA monomers inan aqueous solution, as well as the enhanced polymer chain entanglement and the strong hydrogen bonds between urethanegroups on the side chains. The potential application of hydrogels in strain sensors and high-performance triboelectric nano-generators was further explored. Overall, this work provides a promising strategy for developing pure zwitterionic hydrogelsfor flexible strain sensors and self-powered electronic devices.
基金supported by the National Natural Science Foundation of China(Grant No.42377154)Henan Provincial Department of Science and Technology(Grant No.232102321009).
文摘The excellent bonding performance between bolt and anchor materials is crucial for controlling the deformation of deep-buried surrounding rock and strengthening the rock and soil mass in the slope.This paper conducted an anchoring test and ABAQUS numerical simulation of an anchoring system comprising a micro-NPR(microscopic negative Poisson’s ratio)bolt and cement mortar as the anchoring material.The failure mode of this system and the distribution of average bonding strength,axial force,and shear stress along the anchoring depth were studied.We also evaluated the bonding properties at the micro-NPR(microscopic negative Poisson’s ratio)bolt-cement mortar interface.The findings indicate that the cement mortar is partially spalled from the micro-NPR bolt surface.The average bonding strength at the micro-NPR bolt-cement mortar interface is positively correlated with anchoring length and cement mortar strength.In contrast,it exhibits a negative correlation with bolt diameter.The axial force is generated at the starting point of the anchorage and decreases non-uniformly across the anchoring region.The axial force transfers or diffuses toward the deeper sections of the anchoring segment with increasing loads.The shear stress at the micro-NPR bolt-cement mortar interface exhibits a single-peak pattern,i.e.,it climbs to a peak value and decreases along the anchoring depth.The peak position varies with changes in bolt diameter and anchoring length.By comparison,it is independent of cement mortar strength.The simulated bonding properties of the micro-NPR bolt-cement mortar interface are consistent with experimental results.The findings can provide a reference for engineering applications and anchoring design of micro-NPR.
基金support given by the Fundamental Research Program of Shanxi Province(Grant No.202203021212152)。
文摘The self-healing function is considered one of the effective ways to address structural damage and improve interfacial bonding in Energetic composite materials(ECMs).However,the currently prepared ECMs with self-healing function have problems such as irregular particle shape and uneven distribution of components,which affect the efficient play of self-healing function.In this paper,HMX-based energetic microspheres with self-healing function were successfully prepared by microchannel technology,which showed excellent self-healing effect in both Polymer-bonded explosives(PBXs)and Composite solid propellants(CSPs).The experimental results show that the HMX-based energetic microspheres with different binder contents prepared by microchannel technology show regular shape,HMX crystal particles are uniformly wrapped by self-healing binder(GAPU).When the content of GAPU in HMX-based energetic microspheres is 10%,PBXs show excellent self-healing effect and mechanical safety is improved by 400%(raw HMX vs S4,5 J vs 25 J).As a high-energy component,the burning rate of CSPs is increased by 359.4%,the time(burning temperature>1700℃)is prolonged by 333.3%,and the maximum impulse force is increased by 107.3%(CSP-H vs CSP-S4,0.84 mm/s vs 3.87 mm/s,0.06 s vs 0.26 s,0.82 m N vs 1.70 m N).It also has excellent storage performance.The preparation of HMX-based energetic microspheres with self-healing function by microchannel technology provides a new strategy to improve the storage performance of ECMs and the combustion performance of CSPs.
文摘In order to prolong the service life of ZrO_(2) thermal barrier coatings,HS188 alloy was used as the substrate,and NiCrAlY powder(base layer,d_(50)=106μm)and yttria stabilized zirconia(YSZ,d_(50)=50μm)were employed as the sprayed feeder to prepare NiCrALY+YSZ thermal barrier coatings using high-energy plasma spraying equipment with a progressive exploration method.The microstructure of the coatings was controlled by adjusting the stand-off distance(85,95,105 and 115 mm)and air-cooling manner(rear air cooling,rear air cooling+gun cooling,front air cooling,and front air cooling+gun cooling).The bonding strength of the coatings was evaluated by the drawing method.The results indicate that under the conditions of long stand-off distance and low cooling rate,it is difficult for the coatings to form a vertical crack structure due to the low instantaneous heating temperature and insufficient quenching on the sample surface.However,when the instantaneous heating temperature reaches the critical value and the air cooling rate is excessive,un-melted spray particles exist.When the stand-off distance is 85 mm and the cooling method is front air cooling,a thermal barrier ceramic coating with vertical crack morphology was obtained on HS188 alloy.Simultaneously,it has a moderate density of vertical cracks,the highest bonding strength and the best toughness.
基金supported by the National Natural Science Foundation of China(Grant No.12372351).
文摘In this study, to meet the development and application requirements for high-strength and hightoughness energetic structural materials, a representative volume element of a TA15 matrix embedded with a TaZrNb sphere was designed and fabricated via diffusion bonding. The mechanisms of the microstructural evolution of the TaZrNb/TA15 interface were investigated via SEM, EBSD, EDS, and XRD.Interface mechanical property tests and in-situ tensile tests were conducted on the sphere-containing structure, and an equivalent tensile-strength model was established for the structure. The results revealed that the TA15 titanium alloy and joint had high density and no pores or cracks. The thickness of the planar joint was approximately 50-60 μm. The average tensile and shear strengths were 767 MPa and 608 MPa, respectively. The thickness of the spherical joint was approximately 60 μm. The Zr and Nb elements in the joint diffused uniformly and formed strong bonds with Ti without forming intermetallic compounds. The interface exhibited submicron grain refinement and a concave-convex interlocking structure. The tensile fracture surface primarily exhibited intergranular fracture combined with some transgranular fracture, which constituted a quasi-brittle fracture mode. The shear fracture surface exhibited brittle fracture with regular arrangements of furrows. Internal fracture occurred along the spherical interface, as revealed by advanced in-situ X-ray microcomputed tomography. The experimental results agreed well with the theoretical predictions, indicating that the high-strength interface contributes to the overall strength and toughness of the sphere-containing structure.
基金Supported by Basic Scientific Research Project of the Liaoning Provincial Department of Education Has Been Unveiled to Facilitate Local Project Funding (JYTMS20230835)Enhanced Scientific Research Project Funded by the Departmentof Higher Education in Liaoning Province (General program)(JYTMS20230852)。
文摘The adsorptive denitrification performance of MIL-101(Cr)-0.5 toward pyridine,aniline or quinoline in simulated fuels with basic nitrogen content of 1732μg/g was evaluated separately.Furthermore,the effects of adsorption temperature,adsorption time and adsorbent dosage on their adsorptive denitrification performance were systematically investigated.The experimental results demonstrated that under a fixed adsorbent dosage of 0.05 g and a simulated fuel volume of 10 mL,the optimal removal efficiency for aniline was achieved at 30℃ within 30 min,whereas higher temperatures and longer times(40℃and 40 min)were required for effective removal of pyridine and quinoline.Density Functional Theory(DFT)calculations were conducted via Materials Studio(MS)software to study the adsorptive denitrification mechanism of MIL-101(Cr)toward these three basic nitrogen-containing compounds.The simulation calculation results revealed that the interaction between pyridine and MIL-101(Cr)primarily involved coordination adsorption.In contrast,the interaction between aniline or quinoline and MIL-101(Cr)proceeded mainly through coordination,with additional contributions fromπ-complexation and hydrogen bonding.The overall adsorption strength order is pyridine>aniline>quinoline.During the adsorption process,pyridine and quinoline transfer electrons to the MIL-101(Cr)surface through the H→C→N→Cr^(3+)pathway,while aniline transfers electrons to the MIL-101(Cr)surface through various pathways,including N→Cr^(3+),N→C→Cr^(3+)and N→H→O.Furthermore,adsorption kinetics studies indicated that the adsorption processes for all three basic nitrogen-containing compounds followed the quasi second order kinetic models.The experimental results on the effect of benzene on the adsorptive denitrification performance of MIL-101(Cr)-0.5 demonstrated that benzene exerted a more significant impact on the adsorption of aniline and quinoline.Finally,the adsorbent was regenerated using ethanol washing.It was found that MIL-101(Cr)-0.5 retained stable denitrification performance after two regeneration cycles.
基金supported by the National Natural Science Foundation of China(Nos.52231007,51872238,52074227,and 21806129)the Fundamental Research Funds for the Central Universities(Nos.3102018zy045,3102019AX11,and 5000220455)the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2017JQ5116 and 2020JM-118).
文摘The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.
基金Supported by the Science and Technology Cooperation and Exchange special project of Cooperation of Shanxi Province(202404041101014)the Fundamental Research Program of Shanxi Province(202403021212333)+3 种基金the Joint Funds of the National Natural Science Foundation of China(U24A20555)the Lvliang Key R&D of University-Local Cooperation(2023XDHZ10)the Initiation Fund for Doctoral Research of Taiyuan University of Science and Technology(20242026)the Outstanding Doctor Funding Award of Shanxi Province(20242080).
文摘To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.
文摘Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigates the muscle strength performance(MSP)of 289 adult and teenage CA,exercisers,and physically inactive individuals(PI),and proposes predictive models of MSP for adults.Methods:Muscle maximal,speed,and explosive strength(MMS/MSS/MES)at unilateral maximal concentric flexion and extension contraction(FC/EC)were evaluated using Biodex System 3 PRO^(TM)at 60°/s,180°/s,and 300°/s,while additional performance markers were assessed through field ergometric testing.Participants were interviewed about their lifestyle,dietary habits,physical activity,injury,and medical history.Body composition was assessed via bioelectrical impedance.gDNA was extracted from biochemical samples and then genotyped.Statistical analysis was conducted using IBM SPSS Statistics v21.0 and R.Results:Age,fitness,and sex impacted correlations of MSP with body composition and anthropometric measurements(p<0.05).Among CA,females outperformed males in accuracy(p<0.001)while,males outperformed females in anaerobic power,MSP,speed,and endurance(p<0.001).Adult CA outperformed exercisers and PI in MMS,MSS,and MES(p<0.05).Multiple linear regression models,with predictors age,FFM,body extremity,training load explained the majority of variation in MMS(R^(2)_(adj):71.4%–88.9%),MSS(R^(2)_(adj):64.8%–78.4%),and MES(R^(2)_(adj):52.7%–68.4%)at EC,FC,and their mean(p<0.001).Conclusions:Muscle-strengthening strategies should be customized according to individual fitness levels,body composition,and anthropometric measurements.The innovative sex-specific regression models assessing MMS,MSS,and MES at EC and FC provide a framework for personalizing rehabilitation and skill-specific training strategies.
基金financially supported by the National Natural Science Foundation of China(No.52503154)Shandong Provincial Natural Science Foundation(Nos.ZR2022MB034 and ZR2025QC512)。
文摘Azobenzene-based polymer actuators show great promise for photoactuation owing to their unique photoisomerization behavior and tailorable molecular programmability.However,conventional systems are limited by inadequate mechanical robustness,self-healing,and recyclability,hindering their practical implementation.Herein,we present a high-performance azobenzene-functionalized polyurethane(AzoPU)elastomer actuator designed via molecular engineering of photoactive azobenzene moieties and dynamic disulfide bonds.AzoPU exhibits exceptional mechanical properties with retained performance after multiple reshaping cycles,enabled by well-engineered hard-soft segments and synergistic stress dissipation from weak covalent bonds/hierarchical hydrogen bonds.It achieves over 93%self-healing efficiency at room temperature owing to the synergistic interplay of disulfide bonds in the polymer backbone and intermolecular hydrogen bonds.Furthermore,it demonstrates remarkable light-triggered actuation behavior,achieving a phototropic bending angle exceeding 180°toward the light source within 45 s.To showcase its practical potential,proof-of-concept photoactuated devices with flower-,hook-,and gripper-like and local-orientation processed strip-shaped structures were fabricated,which exhibited rapid and reversible light-triggered deformation.This study proposes a novel strategy for the development of intelligent polymeric materials that integrate light responsiveness,self-healing,and recyclability,thus holding great promise for applications in flexible electronics,smart actuators,and sustainable functional materials.
基金financially supported by the National Key R&D Program of China(2023YFC3905400)the Clean Combustion and Low-carbon Utilization of Coal,Strategic Priority Research Program of the Chinese Academy of Sciences,Grant No.XDA 29000000.
文摘The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton transfer mechanism remains elusive.Herein,we reported a metal-free,room-temperature strategy utilizing 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)as a dual hydrogen bond catalyst to synergistically activate propylamine(PA)and dimethyl carbonate(DMC).This green catalytic system achieves a 10-fold acceleration in reaction rate compared to other hydrogen bonding catalysts under mild conditions.This is enabled by dual hydrogen bonding of TBD with PA and DMC,which facilitates rapid proton transfer and stabilizes tetrahedral intermediates.Theoretical calculations confirm that the dual hydrogen bond system significantly lowers activation energy compared to single hydrogen bond analogs.Furthermore,it was revealed that the hydrogen bonding network within the product is the primary factor responsible for the sluggish reaction rate.This study demonstrates the effectiveness of a dual hydrogen bond system in accelerating the carbonylation of amines and provides a green route to access carbamates.
基金supported by the National Natural Science Foundation of China (52172227)the Natural Science Foundation of Hubei Province (2023AFA114)+2 种基金the Guizhou Provincial Key Technology R&D Program (ZD[2025]019)provided by the Startup Fund (20QD80 and 22QD28)support from the Science&Technology Top Talents Program of Guizhou Province ([2024]349)
文摘Prussian blue analogs(PBAs)have emerged as environmentally friendly and structurally tunable cathode materials for aqueous ammonium-ion batteries(AIBs).However,the fundamental role of crystalline H_(2)O in regulating ammonium-ion storage and transport remains poorly understood.In this study,we present a comprehensive comparison between hydrated NH_(4)NiHCF-H_(2)O and its anhydrous counterpart NH_(4)NiHCF,revealing the critical contribution of interstitial water to electrochemical performance.Structural and spectroscopic analyses confirm that interstitial water forms robust hydrogen bonds with NH_(4)+ions,stabilizing the PBA framework and mitigating structural degradation during cycling.Electrochemical measurements show that NH_(4)NiHCF-H_(2)O delivers a significantly higher specific capacity of 61 mA h g^(−1)at 0.2 C and markedly improved rate performance compared to NH_(4)NiHCF(48 mA h g^(−1)at 0.2 C).Kinetic analysis reveals that interstitial water enhances NH_(4)+diffusion,as evidenced by higher diffusion coefficients.Furthermore,density functional theory(DFT)calculations demonstrate that crystal water acts as a hydrogen bond acceptor,preferentially interacting with NH_(4)+and reducing the migration energy barrier,thereby facilitating fast ion transport.This work provides fundamental insights into the role of crystal water in PBAs and offers a rational design strategy for improving the kinetics,structural stability of PBAs cathodes for AIBs.
基金the National Natural Science Foundation of China(Grant No.U2441263)for financial support of this work。
文摘In composite solid propellants with high aluminum(Al)content and low burning rate,incomplete combustion of the Al powder may occur.In this study,varying lithium(Li)content in Al-Li alloy powder was utilized instead of pure aluminum particles to mitigate agglomeration and enhance the combustion efficiency of solid propellants(Combustion efficiency herein refers to the completeness of metallic fuel oxidation,quantified as the ratio of actual-to-theoretical energy released during combustion)with high Al content and low burning rates.The impact of Al-Li alloy with different Li contents on combustion and agglomeration of solid propellant was investigated using explosion heat,combustion heat,differential thermal analysis(DTA),thermos-gravimetric analysis(TG),dynamic high-pressure combustion test,ignition experiment of small solid rocket motor(SRM)tests,condensation combustion product collection,and X-ray diffraction techniques(XRD).Compared with pure Al,Al-Li alloys exhibit higher combustion heat,which contributes to improved combustion efficiency in Al-Li alloy-containing propellants.DTA and TG analyses demonstrated higher reactivity and lower ignition temperatures for Al-Li alloys.High-pressure combustion experiments at 5 MPa showed that Al-Li alloy fuel significantly decreases combustion agglomeration.The results from theφ75 mm andφ165 mm SRM and XRD tests further support this finding.This study provides novel insights into the combustion and agglomeration behaviors of high-Al,low-burning-rate composite solid propellants and supports the potential application of Al-Li alloys in advanced propellant formulations.
基金financially supported by the National Science Fund for Distinguished Young Scholars,China(No.52025041)the National Natural Science Foundation of China(Nos.52450003,U2341267,and 52174294)+1 种基金the National Postdoctoral Program for Innovative Talents,China(No.BX20240437)the Fundamental Research Funds for the Central Universities,China(Nos.FRF-IDRY-23-037 and FRF-TP-20-02C2)。
文摘The rapid advancements in computer vision(CV)technology have transformed the traditional approaches to material microstructure analysis.This review outlines the history of CV and explores the applications of deep-learning(DL)-driven CV in four key areas of materials science:microstructure-based performance prediction,microstructure information generation,microstructure defect detection,and crystal structure-based property prediction.The CV has significantly reduced the cost of traditional experimental methods used in material performance prediction.Moreover,recent progress made in generating microstructure images and detecting microstructural defects using CV has led to increased efficiency and reliability in material performance assessments.The DL-driven CV models can accelerate the design of new materials with optimized performance by integrating predictions based on both crystal and microstructural data,thereby allowing for the discovery and innovation of next-generation materials.Finally,the review provides insights into the rapid interdisciplinary developments in the field of materials science and future prospects.
基金financially supported by the National Natural Science Foundation of China(Nos.22272118,22172111,and 22309134)the Science and Technology Commission of Shanghai Municipality,China(Nos.22ZR1464100,20ZR1460300,and 19DZ2271500)+2 种基金the China Postdoctoral Science Foundation(2022M712402),the Shanghai Rising-Star Program(23YF1449200)the Zhejiang Provincial Science and Technology Project(2022C01182)the Fundamental Research Funds for the Central Universities(2023-3-YB-07)。
文摘Carbon superstructures with multiscale hierarchies and functional attributes represent an appealing cathode candidate for zinc hybrid capacitors,but their tailor-made design to optimize the capacitive activity remains a confusing topic.Here we develop a hydrogen-bond-oriented interfacial super-assembly strategy to custom-tailor nanosheet-intertwined spherical carbon superstructures(SCSs)for Zn-ion storage with double-high capacitive activity and durability.Tetrachlorobenzoquinone(H-bond acceptor)and dimethylbenzidine(H-bond donator)can interact to form organic nanosheet modules,which are sequentially assembled,orientally compacted and densified into well-orchestrated superstructures through multiple H-bonds(N-H···O).Featured with rich surface-active heterodiatomic motifs,more exposed nanoporous channels,and successive charge migration paths,SCSs cathode promises high accessibility of built-in zincophilic sites and rapid ion diffusion with low energy barriers(3.3Ωs-0.5).Consequently,the assembled Zn||SCSs capacitor harvests all-round improvement in Zn-ion storage metrics,including high energy density(166 Wh kg-1),high-rate performance(172 m Ah g^(-1)at 20 A g^(-1)),and long-lasting cycling lifespan(95.5%capacity retention after 500,000 cycles).An opposite chargecarrier storage mechanism is rationalized for SCSs cathode to maximize spatial capacitive charge storage,involving high-kinetics physical Zn^(2+)/CF_(3)SO_(3)-adsorption and chemical Zn^(2+)redox with carbonyl/pyridine groups.This work gives insights into H-bond-guided interfacial superassembly design of superstructural carbons toward advanced energy storage.
基金National Social Science Fund of China(18KXS009)the Sichuan Provincial Soft Science Program(22JDR0261)the Sichuan University“From 0 to 1”Innovation Research Program(2021CXC10)。
文摘In the context of the revolution in new technologies,a key question is whether the rapid growth of the digital economy,driven by digital technologies,has improved regional innovation performance.Using inter-provincial panel data from China(2012–2022)and adopting a business environment perspective,this study applies a Panel Extended Regression Model(PERM),a Panel Simultaneous Equation Model(PSEM),and a Tobit-IV model to analyze how the development of the digital economy influences regional innovation.The results reveal a pronounced U-shaped relationship between the digital economy and the regional innovation performance at the provincial level in China,with the business environment serving as a significant mediator in this relationship.Moreover,regional innovation performance in China exhibits a“ratchet effect,”with the impact of the digital economy varying markedly across regions.While the eastern and western regions have entered an upward phase,whereby the digital economy boosts innovation,the central region displays a weaker effect.Further analysis indicates that the synergy between the business environment and the digital economy in driving innovation remains suboptimal.These findings were supported by robust checks.This study offers theoretical insights and empirical evidence that support the coordinated development of digital government and the digital factor market,as well as business environment reforms that are in alignment with the innovation demands of the digital era.
基金Project(ASM-20240)supported by the Key Laboratory of Advanced Structural Materials(Changchun University of Technology),Ministry of Education,ChinaProject(2022TD-30)supported by the Scientific and Technological Innovation Team Project of Shaanxi Innovation Capability Support Plan,China。
文摘This work examines the microstructure and corrosion properties of fine-grained Al 7075 across different regions under varying cooling conditions during friction stir welding.The findings demonstrate that forced cooling significantly improves the corrosion resistance of the welded joints.Specifically,the corrosion resistance was the highest in the stir zone,followed by the thermo-mechanical affected zone,and then the heat affected zone.Forced cooling mitigates grain growth by controlling the welding thermal effects,thereby increasing the proportion ofΣ3 grain boundaries.The modification of these microstructural characteristics promotes the formation of a dense oxide layer,thereby enhancing the corrosion resistance.Furthermore,forced cooling mitigates the precipitation and coarsening of the anodic phase in the stir zone,which in turn reduces the susceptibility of the joint to pitting corrosion.Additionally,the lower recrystallization texture content in the joint,resulting from forced cooling,contributes to a reduction in the number of corrosion-active sites,thereby further improving the corrosion performance of the welded joint.
基金supported by Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030002)the National Key Research and Development Program(Grant No.2021YFA1202900)the National Natural Science Foundation of China(Grant Nos.62204166 and 62404145)。
文摘When stacking two-dimensional(2D)materials with a lattice mismatch and/or a small twist,moirésuperlattice emerges with fascinating electronic and optical properties.The fabrication of such stacked 2D materials usually requires multiple transfer and stack processes,assisted by a certain transfer medium which needs to be removed afterwards,and it is very challenging to maintain pristine and clean surfaces/interfaces for these stacked structures.In this work,we report a facile direct bonding method for fabrication of twisted MoS_(2) bilayers with ultra-clean surfaces/interfaces.Novel interlayer interactions are revealed in the as-fabricated high-quality samples,leading to twist-angle related dispersion behavior of various Raman modes,such as layer breathing modes,shear modes and E_(2g)modes,as well as indirect bandgap excitons.Field-effect transistors(FETs)of twisted MoS_(2) bilayers also exhibit angle-dependent performance,which could be attributed to the band structure evolution.This facile method holds significance for the future integration of pre-designed multilayer 2D materials and paves a way to explore underlying physical mechanisms and potential applications.
基金supported by the National Natural Science Foundation of China(No.51706105)。
文摘Al/NH_(4)CoF_(3)-Φ(Φ=0.5,1.0,1.5,2.0,and 3.0)binary composites and Al-NH_(4)CoF_(3)@P(VDF-HFP)ternary composites are fabricated via ultrasonication-assisted blending and electrostatic spraying.The effect of equivalence ratio(Φ)on the reaction properties is systematically investigated in the binary Al/NH_(4)CoF_(3)system.For ternary systems,electrostatic spraying allows both components to be efficiently encapsulated by P(VDF-HFP)and to achieve structural stabilization and enhanced reactivity through synergistic interfacial interactions.Morphological analysis using SEM/TEM revealed that P(VDF-HFP)formed a protective layer on Al and NH_(4)CoF_(3)particles,improving dispersion,hydrophobicity(water contact angle increased by 80.5%compared to physically mixed composites),and corrosion resistance.Thermal decomposition of NH_(4)CoF_(3)occurred at 265℃,releasing NH_(3)and HF,which triggered exothermic reactions with Al.The ternary composites exhibited a narrowed main reaction temperature range and concentrated heat release,attributed to improved interfacial contact and polymer decomposition.Combustion tests demonstrated that Al-NH_(4)CoF_(3)@P(VDF-HFP)achieved self-sustaining combustion.In addition,a simple validation was done by replacing the Al component in the aluminium-containing propellant,demonstrating its potential application in the propellant field.This work establishes a novel strategy for designing stable,high-energy composites with potential applications in advanced propulsion systems.
