To realize the practical application of anion exchange membrane water electrolysis(AEMWE),it is essential to develop highly active,durable,and cost-effective electrocatalyst for oxygen evolution reaction(OER).Herein,w...To realize the practical application of anion exchange membrane water electrolysis(AEMWE),it is essential to develop highly active,durable,and cost-effective electrocatalyst for oxygen evolution reaction(OER).Herein,we report a hollow-structured Ni_(x)Co_(1−x)O/Ni_(3)S_(2)/Co_(9)S_(8)heterostructure synthesized via sequential template-assisted growth,thermal oxidation,and controlled sulfidation process.The abundant bimetallic heterointerfaces not only provide additional active sites but also promote electronic modulation via charge redistribution.Additionally,the porous and hollow architecture enhances active surface area and mass transfer ability,thereby increasing the number of accessible active sites for alkaline OER.As a result,the prepared electrocatalyst achieves low overpotential of 310 mV at 10 mA cm^(−2)and small Tafel slope of 55.94 mV dec^(−1),demonstrating the exceptional electrocatalytic performance for alkaline OER.When integrated as the anode in an AEMWE cell,it delivers outstanding performance with only 1.657 V at 1.0 A cm^(−2)and reaches high current density of 5.0 A cm^(−2)at 1.989 V,surpassing those of commercial RuO_(2).The cell also shows excellent long-term durability over 100 h with minimal degradation.This study highlights the strong potential of rationally engineered oxide/sulfide heterostructures for next-generation alkaline water electrolysis.展开更多
Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler ...Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.展开更多
Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Her...Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.展开更多
Addressing the kinetic limitations of oxygen evolution reaction(OER)is paramount for advancing rechargeable Zn-air batteries,thus it is extremely urgent to drive the development of effective and affordable electrocata...Addressing the kinetic limitations of oxygen evolution reaction(OER)is paramount for advancing rechargeable Zn-air batteries,thus it is extremely urgent to drive the development of effective and affordable electrocatalysts.This work constructs the interfacial structure of cobalt-iron alloys@phosphates(denoted as CoFe/CoFePO)as OER catalyst through a two-step approach using water-bath and hydrothermal methods,which demonstrated significant OER activity in alkaline media,requiring a low overpotential of 271 mV to achieve 10 mA cm^(−2) and exhibiting a competitive Tafel slope of 65 mV dec^(-1),alongside sustained operational stability.The enhanced performance can be attributed to the improved electrical conductivity due to the participation of CoFe alloys and the increased number of active sites through partial phosphorylation,which synergistically enhances charge transfer processes and accelerates OER kinetics.Moreover,dynamic structural evolution during OER process was thoroughly probed,and the results show that alloys@phosphates gradually evolve into phosphate radicalmodified CoFe hydroxyoxides that act as the actual active phase.Highlighting its practical applicability,the integration of prepared catalyst into zinc-air batteries leads to markedly improved performance,thereby offering promising new strategic directions for the development of next-generation OER electrocatalysts.展开更多
Pyrochlore oxide(Y_(2)Ru_(2)O_(7))has been identified as a promising catalyst for the oxygen evolution reaction(OER)in advanced green energy strategies.However,its electrochemical inertness necessitates the exploratio...Pyrochlore oxide(Y_(2)Ru_(2)O_(7))has been identified as a promising catalyst for the oxygen evolution reaction(OER)in advanced green energy strategies.However,its electrochemical inertness necessitates the exploration of an effective strategy to facilitate electronic modulation.This study proposes a surface modification approach involving the integration of defective NiFe(D-NiFe)nanoparticles onto a Y_(2)Ru_(2)O_(7)(YRO)support(YRO@D-NiFeP/Ru)using a Prussian blue analog(PBA).Numerous cyanide(CN)vacancies are generated through the oxidation treatment of the NiFe PBA grown on the YRO support,yielding a defective PBA precursor(YRO@D-PBA).Subsequent annealing facilitates the transformation to the D-NiFe nanoparticles on the YRO support(YRO@D-NiFeP/Ru),which augments the exposure of Ni3+active sites beneficial for the OER.Moreover,the reduction of Ru cations from YRO results in the exsolution of Ru nanoparticles,which promotes synergistic charge transfer from the nanoparticles to the interior of Y_(2)Ru_(2)O_(7).Consequently,YRO@D-NiFeP/Ru exhibits a remarkable voltage of 1.49 V at 10 mA·cm^(−2) and the lowest Tafel slope of 42.4 mV·dec^(−1).In addition,a Zn–air battery constructed with YRO@D-NiFeP/Ru exhibits an outstanding power density of 136.2 mW·cm^(−2) and high charge–discharge stability,confirming the applicability of YRO@D-NiFeP/Ru in metal-air batteries.展开更多
Deep-buried tunnels traversing complex hydrogeological zones with clay-sand-filled structures are highly susceptible to water inrush hazards.High ground temperature,high in-situ stress,and highwater pressure render th...Deep-buried tunnels traversing complex hydrogeological zones with clay-sand-filled structures are highly susceptible to water inrush hazards.High ground temperature,high in-situ stress,and highwater pressure render these events a complex thermohydro-mechanical coupling problem.However,current research on water inrush often insufficiently investigates the multi-field coupled instability mechanisms within highly permeable filling media and frequently neglects the influence of temperature.This study aims to investigate the evolutionary mechanism of seepage instability in filling structures that trigger water inrush hazards under the complex conditions of deep-buried tunnels.Laboratory tests were conducted using a large-scale triaxial thermo-hydro-mechanical system,and a DEM-CFD coupled model was established to numerically simulate the seepage process.The influences of temperature,particle size distribution,and confining pressure were analyzed on the seepage characteristics of the filling media.By examining the variations in water inflow rate,discharged clay-sand particle mass,porosity and permeability,we analyzed the entire process of seepage behavior and instability evolution under the thermohydro-mechanical coupling effect.The results show that:(1)Temperature significantly affects water inflow,discharged particle mass,porosity,and permeability.Higher temperatures remarkably increase porosity and permeability,with the maximum permeability coefficient of filling media at 90℃being 1.6 times that at 45℃.(2)The Talbol power index exhibits a positive correlation with water inflow rate and discharged particle mass,while confining pressure is negatively correlated with water inflow rate.(3)For filling materials dominated by clay-sand particles or with favorable gradation,the seepage instability process exhibits distinct phase characteristics,with different stages reflected in changes in water inflow,porosity,and permeability.The experimental results are consistent with the numerical simulation results.(4)In high ground temperature environments,temperature enhances convective heat transfer and energy exchange between water and filling media,thereby accelerating the process of water inrush caused by seepage instability.The findings provide scientific support for risk assessment,early warning,and prevention of water inrush hazards in deep-buried tunnels crossing clay-sand-filled structures.展开更多
Hydrogen production coupled with small molecule oxidation derived by renewable energy power has been widely studied as an effective method to reduce energy consumption and prepare added value production.Here,the coppe...Hydrogen production coupled with small molecule oxidation derived by renewable energy power has been widely studied as an effective method to reduce energy consumption and prepare added value production.Here,the copper-cobalt phosphide with a multilevel structure has been designed based on the hard and soft acids and bases theory.The nanocone composed of lamellas presented a sharp tip,which a positive effect on the mass transfer enhanced by a local electric field,and the nanolamellas contain CoP/Cu_(3)P interface provide the highly selective active site for the gluconic acid(GNA)synthesis and hydrogen evolution.The catalyst can drive hydrogen evolution at 5 A·cm^(-2)up to 437 h without active decay,and the electrocatalytic glucose oxidation at anode presents high efficiency due to Cu(I)introduction and the synergetic effect between interfaces.Density functional theory(DFT)calculation shows that water splitting more readily occurs at the CoP,which provides adsorbed H and-OH for hydrogen evolution and glucose oxidation,respectively,and glucose adsorption more readily occurs at the Cu_(3)P,which presents lower conversion energy for high value-added GNA.Efficient hydrogen evolution and glucose conversion indicate its high intrinsic activity and synergetic effect.This work provides a special interface construction strategy for the catalytic conversion of hydrogen and small molecules.展开更多
The development of cost-effective and highly stable electrocatalysts for oxygen evolution reactions holds paramount importance in practical hydrogen production.Herein,we present a novel self-supported electrode compri...The development of cost-effective and highly stable electrocatalysts for oxygen evolution reactions holds paramount importance in practical hydrogen production.Herein,we present a novel self-supported electrode comprising Ce-doped Ni-Fe-Se nanosheets grown on carbon cloth(Ni-Fe-Ce-Se/CC).This electrode was synthesized through a selenylation process,utilizing Ni-Fe-Ce-layered double hydroxide/carbon cloth(Ni-Fe-Ce LDH/CC)as the precursor.Notably,Ni-Fe-Ce-Se/CC electrode demonstrates remarkable performance,requiring a low overpotential of 300 mV to attain a current density of 100 mA·cm^(-2)under harsh alkaline conditions.Furthermore,the electrode exhibits exceptional stability during continuous operation for 100 h.Insight into the underlying mechanisms was gained through a combination of experimental results and density functional theory calculations.Our findings reveal that Ce doping induces crystal structure deformation in Ni-Fe-Se and enhances electron enrichment around Ni atoms.This structural modification optimizes the adsorption energy of oxygen-based intermediates on the Ni-Fe-Se surface.This work offers a valuable strategy for regulating the electron transfer and adsorption capabilities of transition metal selenide electrocatalysts through RE atoms doping,opening new avenues for enhanced electrocatalytic performance.展开更多
The toughness of thermoplastic polymers such as polypropylene(PP)can be improved by adding elastomers-based toughening agents,and the phase morphology of these toughening agents is very important for the strength and ...The toughness of thermoplastic polymers such as polypropylene(PP)can be improved by adding elastomers-based toughening agents,and the phase morphology of these toughening agents is very important for the strength and toughness of PP.The low-temperature toughness of PP was improved by inserting high-density polyethylene(HDPE)between PP and polystyrene-b-ethylene-co-propyleneb-polystyrene(SEPS)to form an unusual SEPS@HDPE core–shell structure,with SEPS as the core and HDPE as the shell.Based on the microtopography and rheological behavior characterization,HDPE in PP/SEPS/HDPE composites was found to serve as an emulsifier,decrease the size of SEPS particles,and promote the homogeneous dispersion of dispersed phase particles in the matrix.An increase in the HDPE content shifted the toughening mechanism of PP composites from cavitation to matrix shear yielding.The reduction in the distance between the dispersed core–shell structure particles promoted shear yielding in the PP composites,leading to increased toughness.The creation of an intermediate HDPE layer with a moderate modulus was crucial for dispersing stress concentrations and significantly improving toughness without compromising the tensile strength.These findings will facilitate the fabrication of high-toughness PP products at low temperatures.展开更多
AZ31 Mg alloy plates with bimodal grain structures were fabricated via conventional extrusion under varying temperatures and speeds to investigate the mechanisms governing dynamic recrystallization(DRX)and texture evo...AZ31 Mg alloy plates with bimodal grain structures were fabricated via conventional extrusion under varying temperatures and speeds to investigate the mechanisms governing dynamic recrystallization(DRX)and texture evolution.Although all samples exhibited similar DRXed grain sizes(5.0–6.5μm)and fractions(76%–80%),they developed distinct c-axis orientations and mechanical properties.The P1 sample(350℃,0.1 mm/min)exhibited the lowest yield strength(∼192 MPa)but the highest elongation(∼18.2%),whereas the P3 sample(400℃,0.6 mm/min)showed the highest yield strength(∼241 MPa)and the lowest elongation(∼14.2%).The P2 sample(400℃,0.1 mm/min)demonstrated intermediate behavior(∼226 MPa,∼17.7%).These variations were primarily attributed to differences in c-axis orientations,particularly their alignment with respect to the normal direction(ND)and their slight deviation from the extrusion direction(ED).Microstructural analysis revealed that distinct DRX mechanisms were activated under different extrusion conditions.P1 predominantly exhibited twinning-induced dynamic recrystallization(TDRX)and continuous dynamic recrystallization(CDRX),whereas P3 primarily showed CDRX and discontinuous dynamic recrystallization(DDRX).These DRX mechanisms,in combination with the activated slip systems governed by the evolving local stress state,collectively contributed to orientation rotation and texture development.During the early stage of extrusion,tensile strain along the ED promoted basalslip,rotating the c-axes toward the ND.As deformation progressed,compressive strain along the ND became dominant.In P1,basalslip remained active,aligning the c-axes along the ND and forming a smaller angle with the ED.In contrast,P3 exhibited predominant pyramidal<c+a>slip,resulting in a pronounced deviation of the c-axes from the ND and a slightly larger angle relative to the ED.The P2 sample exhibited a transitional texture state between those of P1 and P3.展开更多
The development of atomically dispersed platinum-based catalysts with high performance and welldefined active site structures is crucial for the commercialization of water electrolysis for hydrogen production.Herein,w...The development of atomically dispersed platinum-based catalysts with high performance and welldefined active site structures is crucial for the commercialization of water electrolysis for hydrogen production.Herein,we propose a coordination dual-shell synergistic regulation mechanism of coal pitchderived carbon-supported single atom Pt-N_(x)O_(y)-S_(1)catalytic sites by a self-assembly-pyrolysis strategy for promoting hydrogen evolution reaction(HER).The Pt-N_(3)O1-S_(1)sites exhibited the highest HER performance,with an overpotential of 92 mV at a current density of 400 mA cm^(-2).At 50 mV,the turnover frequency was 34.04 s^(-1)and the mass activity was 22.83 A mg_(Pt)^(-l),which is 63.4 times that of the 20%Pt/C catalyst.Theoretical calculations revealed that the coordination dual-shell impacts the electronic structure of the Pt atoms and the adsorption strength towards reactants synergistically.The S atoms in the second coordination shell weakened the strength of Pt-N first shell,resulting the more surface valence electrons around Pt atoms,exhibiting the most suitable adsorption free energy and enhancing the adsorption of H^(+)on Pt-N_(3)O_(1)-S_(1)sites,thus enhancing the electrocatalytic HER process by promoting Volmer step.This work reveals that coordination dual-shell synergistic regulation is an effective strategy for enhancing the electrocatalytic reaction process.展开更多
A series of CoS_(2-x)Se_(x)(x=0.05,0.1,0.2,0.3,and 2)composite catalysts were synthesized on carbon fiber paper via the hydrothermal method with Se doping.By precisely controlling the reaction temperature and Se dopin...A series of CoS_(2-x)Se_(x)(x=0.05,0.1,0.2,0.3,and 2)composite catalysts were synthesized on carbon fiber paper via the hydrothermal method with Se doping.By precisely controlling the reaction temperature and Se doping level,a hollow spherical catalyst structure composed of CoSSe was successfully synthesized,which exhibited exceptional activity for hydrogen evolution in acidic solutions.The influences of Se doping on the microstructure and catalytic mechanism of hydrogen evolution reaction(HER)of these composites were systematically investigated.The experimental results reveal that the hollow spherical sample displays an overpotential value of 143 mV along with a Tafel slope value of 69.8 mV·dec^(-1)at a current density of 10 mA·cm^(-2)in an acid aqueous solution.Furthermore,it demonstrates remarkable cycling stability after undergoing 3000 cycles.The comprehensive analysis indicates that Se doping optimizes the electronic structure and enhances conductivity,meanwhile the unique hollow spherical architecture increases active sites for HER and significantly improves overall electrocatalytic performance.展开更多
Atomically precise palladium(Pd)clusters are emerging as versatile nanomaterials with applications in catalysis and biomedicine.This study explores the synthesis,structure evolution,and catalytic properties of Pd clus...Atomically precise palladium(Pd)clusters are emerging as versatile nanomaterials with applications in catalysis and biomedicine.This study explores the synthesis,structure evolution,and catalytic properties of Pd clusters stabilized by cyclohexanethiol(HSC_(6)H_(11))ligands.Using electrospray ionization mass spectrometry(ESI-MS)and single-crystal X-ray diffraction(SXRD),structures of the Pd clusters ranging from Pd4(SC_(6)H_(11))8 to Pd18(SC_(6)H_(11))36 were determined.This analysis revealed a structure evolution from polygonal to elliptical geometries of the PdnS2n frameworks as the cluster size increased.UV-Vis-NIR spectroscopy,combined with quantum chemical calculations,elucidated changes in the electronic structure of the clusters.Catalytic studies on the Sonogashira cross-coupling reactions demonstrated a size-dependent decline in activity attributed to variations in structural arrangements and electronic properties.Mechanistic insights proposed a distinctive Pd(Ⅱ)-Pd(Ⅳ)catalytic cycle.This research underscores how ligands and cluster size influence the structures and properties of Pd clusters,offering valuable insights for the future design and application of Pd clusters in advanced catalysis and beyond.展开更多
Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is s...Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is still needed.Here,the storage mechanism of Li^(+)in the tunnel structure of MnO_(2) as well as the dissolution and migration of Mn-ions were investigated based on multi-scale approaches.The Li/Mn ratio(at%)is determined at about 0.82 when the discharge voltage decreases to 2 V.The limited Li-ions transport rate in the bulk MnO_(2) restrains the reduction reaction,resulting in a low practical specific capacity.Moreover,utilizing spherical aberration-corrected transmission electron microscopy(TEM)coupled with electron energy loss spectroscopy(EELS),the presence of a mixed valence state layer of Mn^(2+)/Mn^(3+)/Mn^(4+)on the surface of the original 20 nm MnO_(2) particles was identified,which could contribute to the initial dissolution of Mn-ions.The battery separator exhibited channels for Mn-ions migration and diffusion and aggregated Mn particles.We put forward the discharge and degradation route in the ways of Mn-ions trajectories,and our findings provide a deep understanding of the high self-discharge rates and the capacity decay of Li-Mn primary batteries.展开更多
The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the micro...The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.展开更多
As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol syn...As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol synthesis,In_(2)O_(3)is an ideal catalyst and has garnered significant attention.Herein,cubic In_(2)O_(3)nanoparticles were prepared via the precipitation method and evaluated for CO_(2)hydrogenation to produce methanol.During the initial 10 h of reaction,CO_(2)conversion gradually increased,accompanied by a slow decrease of methanol selectivity,and the reaction reached equilibrium after 10-20 h on stream.This activation and induction stage may be attributed to the sintering of In_(2)O_(3)nanoparticles and the creation of more oxygen vacancies on In_(2)O_(3)surfaces.Further experimental studies demonstrate that hydrogen induction created additional oxygen vacancies during the catalyst activation stage,enhancing the performance of In_(2)O_(3)catalyst for CO_(2)hydrogenation.Density functional theory calculations and microkinetic simulations further demonstrated that surfaces with higher oxygen vacancy coverages or hydroxylated surfaces formed during this induction period can enhance the reaction rate and increase the CO_(2)conversion.However,they predominantly promote the formation of CO instead of methanol,leading to reduced methanol selectivity.These predictions align well with the above-mentioned experimental observations.Our work thus provides an in-depth analysis of the induction stage of the CO_(2)hydrogenation process on In_(2)O_(3)nano-catalyst,and offers valuable insights for significantly improving the CO_(2)reactivity of In_(2)O_(3)-based catalysts while maintaining long-term stability.展开更多
Aiming at the problem of dynamic instability of hard-brittle jointed rock surrounding in deep tunnel/roadway engineering,combining with the support concepts of"coupling rigidity with flexibility"and"ove...Aiming at the problem of dynamic instability of hard-brittle jointed rock surrounding in deep tunnel/roadway engineering,combining with the support concepts of"coupling rigidity with flexibility"and"overcoming rigidity by flexibility",the prevention and control method with"rigid-flexible coupling(R-F-C)"was put forward.Through numerical simulation calculation,the impact damage process,acoustic emission(AE)evolution characteristics,and element stress/displacement evolution characteristics of unsupported surrounding rock structure model,rigid supporting surrounding rock structure model,and"R-F-C"supporting surrounding rock structure model under horizontal bidirectional impact loading were compared and analyzed.Based on the theory of stress wave propagation,the dynamic instability catastrophe mechanism of three kinds of supporting structure models induced by horizontal bidirectional impact loading was revealed.Based on the Mohr-Coulomb strength theory,the stress discrimination methods of dynamic catastrophe of surrounding rock induced by horizontal bidirectional impact loading under three kinds of supporting structures were proposed.Combined with the above numerical simulation study,the explosion impact physical and mechanical test of"R-F-C"surrounding rock supporting plate structure was further designed and carried out.Finally,combined with the"conceptual model of ball-cliff potential energy instability",the energy driving theory and energy transformation mechanism of impact-induced rockburst under three kinds of supporting structures were discussed deeply.The research results provided a scientific basis for further promoting the effective application of"R-F-C"supporting structure in the prevention and control of dynamic instability of deep tunnel/roadway surrounding rock.展开更多
The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface rupture.Traditional models attribute this to the Beichuan and...The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface rupture.Traditional models attribute this to the Beichuan and Pengguan faults,but our research reveals a complex fault system at the northern end,with inconsistencies in surface rupture,aftershock distribution,and focal mechanisms.We integrate shallow geology,active source seismic reflection,and magnetotelluric profiling to establish a deep structural model for the northern end of the Longmenshan structural belt.This area exhibits dominant reverse thrust nappe tectonics,and analyzing the tectonic evolution history provides insights into deformation propagation from the orogenic belt toward the Sichuan Basin.Focal mechanism analysis and relocated aftershock data reveals two distinct types of seismogenic structures in the northern end of the Longmenshan structural belt.In the middle to northern segments,the reverse fault type is attributed to reactivated pre-existing faults.Conversely,at the northern end,the strike-slip fault type originates from high-angle co-seismic rupture cutting through pre-existing reverse faults.This study enhances our understanding of fault complexity and seismic mechanisms in the northeastern Longmenshan structural belt,providing new insights into regional tectonics.展开更多
Detailed three-dimensional structural studies indicate that the Bixiling area, Dabie massif, central China shows the deepest exposed levels of the orogenic wedge formed during the Triassic Yangtze -Sino-Korean contine...Detailed three-dimensional structural studies indicate that the Bixiling area, Dabie massif, central China shows the deepest exposed levels of the orogenic wedge formed during the Triassic Yangtze -Sino-Korean continental collision. New 1 : 10 000 scale structural mapping, combined with detailed petrological analysis in this area, has enabled us to accurately distinguish structures related to the Triassic continental collision from those related to post-collisional deformation in the ultrahigh pressure (UHP) metamorphic unit. The collisional or compressional structures include the massive eclogite with a weak foliation, foliated eclogite or UHP ductile shear zones, as well as upper amphibolite facies shear zones, whereas the post-collisional deformation is characterized by a regionally, flat-lying foliation containing stretching lineations and common reclined folds. The former is present exclusively in the eclogite lenses and their margins, representing orogenic thickening or syn-collisional events, while the latter was best occurred on variable scales under amphibolite facies conditions, showing sub-vertical, extreme shortening and ductile thinning of the metamorphic rock stack. The eclogite facies tectonites that have a marked fabric discordance to the penetrative amphibolite facies extension flow fabric are common. It is emphasized that an extensional tectonic setting following the collision-orogenic thickening stage was, at least partly, responsible for exhumation of the UHP metamorphic rocks in the Dabie massif. A new tectonic evolution model is proposed for the UHP metamorphic belt on the scale of the Dabie massif. The Bixiling area thus provides a window, from which the dynamic processes concerning the formation and exhumation of the UHP rocks can be observed. Regional studies in the Dabie Mountains have confirmed this interpretation.展开更多
A large multi-country outbreak of Oropouche virus(OROV),a segmented negative-sense RNA virus,is emerging in Latin America.By analyzing publicly available whole-genome sequences spanning 1955 to 2024,this study reveals...A large multi-country outbreak of Oropouche virus(OROV),a segmented negative-sense RNA virus,is emerging in Latin America.By analyzing publicly available whole-genome sequences spanning 1955 to 2024,this study reveals accelerated spatiotemporal evolution of OROV,cooperatively driven by genome mutagenesis and segment reassortment.The strains responsible for the 2023-2024 outbreak are universally reassortants,but form two divergent lineages,namely the Brazil and western Amazon basin lineages.This epidemic spreading is primarily fueled by localized transmission within countries and cross-border spread.Phylogenomic analysis further suggests that the S segment of the viral genome originated in Brazil around the 1740s,underwent diversification into five distinct clusters by the 1970s,and experienced rapid proliferation during 2020-2024.In contrast,the L segment originated in Peru around the 1630s and evolved into two independent clusters by the 1850s.Divergent evolutionary pressures have driven distinct patterns of amino acid changes in viral proteins between the Brazil and the western Amazon basin lineages.These mutations are predicted to alter the protein structures and bear functional consequences for viral fitness and transmission.These findings provide critical insights into the evolutionary dynamics of OROV and underscore the necessity of genome surveillance to track the transmission pathways and spatiotemporal evolution.展开更多
基金supported by the Korea Institute for Advancement of Technology (KIAT)the Ministry of Trade,Industry&Energy (MOTIE) of the Republic of Korea (No. P0022130)by the Institute of Information&Communications Technology Planning&Evaluation(IITP)-Innovative Human Resource Development for Local Intellectualization program grant funded by the Korea government (MSIT)(IITP-2025-RS-2023-00259678)
文摘To realize the practical application of anion exchange membrane water electrolysis(AEMWE),it is essential to develop highly active,durable,and cost-effective electrocatalyst for oxygen evolution reaction(OER).Herein,we report a hollow-structured Ni_(x)Co_(1−x)O/Ni_(3)S_(2)/Co_(9)S_(8)heterostructure synthesized via sequential template-assisted growth,thermal oxidation,and controlled sulfidation process.The abundant bimetallic heterointerfaces not only provide additional active sites but also promote electronic modulation via charge redistribution.Additionally,the porous and hollow architecture enhances active surface area and mass transfer ability,thereby increasing the number of accessible active sites for alkaline OER.As a result,the prepared electrocatalyst achieves low overpotential of 310 mV at 10 mA cm^(−2)and small Tafel slope of 55.94 mV dec^(−1),demonstrating the exceptional electrocatalytic performance for alkaline OER.When integrated as the anode in an AEMWE cell,it delivers outstanding performance with only 1.657 V at 1.0 A cm^(−2)and reaches high current density of 5.0 A cm^(−2)at 1.989 V,surpassing those of commercial RuO_(2).The cell also shows excellent long-term durability over 100 h with minimal degradation.This study highlights the strong potential of rationally engineered oxide/sulfide heterostructures for next-generation alkaline water electrolysis.
基金National Natural Science Foundation of China(U22A20191)。
文摘Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.
基金supported by National Natural Science Foundation of China(No.523B2070,No.52225606).
文摘Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.
基金supported by the National Natural Science Foundation of China(No.52002122).
文摘Addressing the kinetic limitations of oxygen evolution reaction(OER)is paramount for advancing rechargeable Zn-air batteries,thus it is extremely urgent to drive the development of effective and affordable electrocatalysts.This work constructs the interfacial structure of cobalt-iron alloys@phosphates(denoted as CoFe/CoFePO)as OER catalyst through a two-step approach using water-bath and hydrothermal methods,which demonstrated significant OER activity in alkaline media,requiring a low overpotential of 271 mV to achieve 10 mA cm^(−2) and exhibiting a competitive Tafel slope of 65 mV dec^(-1),alongside sustained operational stability.The enhanced performance can be attributed to the improved electrical conductivity due to the participation of CoFe alloys and the increased number of active sites through partial phosphorylation,which synergistically enhances charge transfer processes and accelerates OER kinetics.Moreover,dynamic structural evolution during OER process was thoroughly probed,and the results show that alloys@phosphates gradually evolve into phosphate radicalmodified CoFe hydroxyoxides that act as the actual active phase.Highlighting its practical applicability,the integration of prepared catalyst into zinc-air batteries leads to markedly improved performance,thereby offering promising new strategic directions for the development of next-generation OER electrocatalysts.
基金supported by Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korea government(MOTIE)(No.RS-2024-00398346,ESS BigData-Based O&M and Asset Management Technical Manpower Training)the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2024-00350658).
文摘Pyrochlore oxide(Y_(2)Ru_(2)O_(7))has been identified as a promising catalyst for the oxygen evolution reaction(OER)in advanced green energy strategies.However,its electrochemical inertness necessitates the exploration of an effective strategy to facilitate electronic modulation.This study proposes a surface modification approach involving the integration of defective NiFe(D-NiFe)nanoparticles onto a Y_(2)Ru_(2)O_(7)(YRO)support(YRO@D-NiFeP/Ru)using a Prussian blue analog(PBA).Numerous cyanide(CN)vacancies are generated through the oxidation treatment of the NiFe PBA grown on the YRO support,yielding a defective PBA precursor(YRO@D-PBA).Subsequent annealing facilitates the transformation to the D-NiFe nanoparticles on the YRO support(YRO@D-NiFeP/Ru),which augments the exposure of Ni3+active sites beneficial for the OER.Moreover,the reduction of Ru cations from YRO results in the exsolution of Ru nanoparticles,which promotes synergistic charge transfer from the nanoparticles to the interior of Y_(2)Ru_(2)O_(7).Consequently,YRO@D-NiFeP/Ru exhibits a remarkable voltage of 1.49 V at 10 mA·cm^(−2) and the lowest Tafel slope of 42.4 mV·dec^(−1).In addition,a Zn–air battery constructed with YRO@D-NiFeP/Ru exhibits an outstanding power density of 136.2 mW·cm^(−2) and high charge–discharge stability,confirming the applicability of YRO@D-NiFeP/Ru in metal-air batteries.
基金funded by National Natural Science Foundation of China(Grant No.52278404)Taishan Young Scholar Program of Shandong Province(Grant No.tsqn202103002),which collectively funded this project。
文摘Deep-buried tunnels traversing complex hydrogeological zones with clay-sand-filled structures are highly susceptible to water inrush hazards.High ground temperature,high in-situ stress,and highwater pressure render these events a complex thermohydro-mechanical coupling problem.However,current research on water inrush often insufficiently investigates the multi-field coupled instability mechanisms within highly permeable filling media and frequently neglects the influence of temperature.This study aims to investigate the evolutionary mechanism of seepage instability in filling structures that trigger water inrush hazards under the complex conditions of deep-buried tunnels.Laboratory tests were conducted using a large-scale triaxial thermo-hydro-mechanical system,and a DEM-CFD coupled model was established to numerically simulate the seepage process.The influences of temperature,particle size distribution,and confining pressure were analyzed on the seepage characteristics of the filling media.By examining the variations in water inflow rate,discharged clay-sand particle mass,porosity and permeability,we analyzed the entire process of seepage behavior and instability evolution under the thermohydro-mechanical coupling effect.The results show that:(1)Temperature significantly affects water inflow,discharged particle mass,porosity,and permeability.Higher temperatures remarkably increase porosity and permeability,with the maximum permeability coefficient of filling media at 90℃being 1.6 times that at 45℃.(2)The Talbol power index exhibits a positive correlation with water inflow rate and discharged particle mass,while confining pressure is negatively correlated with water inflow rate.(3)For filling materials dominated by clay-sand particles or with favorable gradation,the seepage instability process exhibits distinct phase characteristics,with different stages reflected in changes in water inflow,porosity,and permeability.The experimental results are consistent with the numerical simulation results.(4)In high ground temperature environments,temperature enhances convective heat transfer and energy exchange between water and filling media,thereby accelerating the process of water inrush caused by seepage instability.The findings provide scientific support for risk assessment,early warning,and prevention of water inrush hazards in deep-buried tunnels crossing clay-sand-filled structures.
基金supported by the National Nature Science Foundation of China(No.22269021)Tianshan Talent Project of Xinjiang Uygur Autonomous Region(No.2023TSYCQNTJ0039)the Open project of Key Laboratory in Xinjiang Uygur Autonomous Region of China(No.2023D04027).
文摘Hydrogen production coupled with small molecule oxidation derived by renewable energy power has been widely studied as an effective method to reduce energy consumption and prepare added value production.Here,the copper-cobalt phosphide with a multilevel structure has been designed based on the hard and soft acids and bases theory.The nanocone composed of lamellas presented a sharp tip,which a positive effect on the mass transfer enhanced by a local electric field,and the nanolamellas contain CoP/Cu_(3)P interface provide the highly selective active site for the gluconic acid(GNA)synthesis and hydrogen evolution.The catalyst can drive hydrogen evolution at 5 A·cm^(-2)up to 437 h without active decay,and the electrocatalytic glucose oxidation at anode presents high efficiency due to Cu(I)introduction and the synergetic effect between interfaces.Density functional theory(DFT)calculation shows that water splitting more readily occurs at the CoP,which provides adsorbed H and-OH for hydrogen evolution and glucose oxidation,respectively,and glucose adsorption more readily occurs at the Cu_(3)P,which presents lower conversion energy for high value-added GNA.Efficient hydrogen evolution and glucose conversion indicate its high intrinsic activity and synergetic effect.This work provides a special interface construction strategy for the catalytic conversion of hydrogen and small molecules.
基金supported by the National Key Technology R&D Program of China(Nos.2021YFB3500801,2022YFB3504302 and 2022YFC3901503)the Natural Science Foundation and Overseas Talent Projects of Jiangxi Province(Nos.0232BAB214025 and 20232BCJ25044)the Double Thousand Plan of Jiangxi Province(No.jxsq2023201002).
文摘The development of cost-effective and highly stable electrocatalysts for oxygen evolution reactions holds paramount importance in practical hydrogen production.Herein,we present a novel self-supported electrode comprising Ce-doped Ni-Fe-Se nanosheets grown on carbon cloth(Ni-Fe-Ce-Se/CC).This electrode was synthesized through a selenylation process,utilizing Ni-Fe-Ce-layered double hydroxide/carbon cloth(Ni-Fe-Ce LDH/CC)as the precursor.Notably,Ni-Fe-Ce-Se/CC electrode demonstrates remarkable performance,requiring a low overpotential of 300 mV to attain a current density of 100 mA·cm^(-2)under harsh alkaline conditions.Furthermore,the electrode exhibits exceptional stability during continuous operation for 100 h.Insight into the underlying mechanisms was gained through a combination of experimental results and density functional theory calculations.Our findings reveal that Ce doping induces crystal structure deformation in Ni-Fe-Se and enhances electron enrichment around Ni atoms.This structural modification optimizes the adsorption energy of oxygen-based intermediates on the Ni-Fe-Se surface.This work offers a valuable strategy for regulating the electron transfer and adsorption capabilities of transition metal selenide electrocatalysts through RE atoms doping,opening new avenues for enhanced electrocatalytic performance.
基金supported by the Taiyuan Major Science and Technology Project Fund in 2021,Fund for Shanxi“1331 Project,”Key Research and Development Program of Shanxi Province(202102040201011)the Zhanjiang Marine Equipment and Marine Biological Industry Unveiled the Talent Team Project(2021E05034).
文摘The toughness of thermoplastic polymers such as polypropylene(PP)can be improved by adding elastomers-based toughening agents,and the phase morphology of these toughening agents is very important for the strength and toughness of PP.The low-temperature toughness of PP was improved by inserting high-density polyethylene(HDPE)between PP and polystyrene-b-ethylene-co-propyleneb-polystyrene(SEPS)to form an unusual SEPS@HDPE core–shell structure,with SEPS as the core and HDPE as the shell.Based on the microtopography and rheological behavior characterization,HDPE in PP/SEPS/HDPE composites was found to serve as an emulsifier,decrease the size of SEPS particles,and promote the homogeneous dispersion of dispersed phase particles in the matrix.An increase in the HDPE content shifted the toughening mechanism of PP composites from cavitation to matrix shear yielding.The reduction in the distance between the dispersed core–shell structure particles promoted shear yielding in the PP composites,leading to increased toughness.The creation of an intermediate HDPE layer with a moderate modulus was crucial for dispersing stress concentrations and significantly improving toughness without compromising the tensile strength.These findings will facilitate the fabrication of high-toughness PP products at low temperatures.
基金supported by National Key Research&Development Program of China(Grant no.2022YFE0110600)National Natural Science Foundation(Grant no.52220105003)+3 种基金the State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology(Grant no.XNDCQQ2910201124)the National Natural Science Foundation for Young Scientists of China(Grant nos.51801042 and 51704088)Natural Science Foundation of Heilongjiang Province-Outstanding Youth Fund(Grant no.YQ2020E006)JSPS KAKENHI(Grant no.JP21H01669).
文摘AZ31 Mg alloy plates with bimodal grain structures were fabricated via conventional extrusion under varying temperatures and speeds to investigate the mechanisms governing dynamic recrystallization(DRX)and texture evolution.Although all samples exhibited similar DRXed grain sizes(5.0–6.5μm)and fractions(76%–80%),they developed distinct c-axis orientations and mechanical properties.The P1 sample(350℃,0.1 mm/min)exhibited the lowest yield strength(∼192 MPa)but the highest elongation(∼18.2%),whereas the P3 sample(400℃,0.6 mm/min)showed the highest yield strength(∼241 MPa)and the lowest elongation(∼14.2%).The P2 sample(400℃,0.1 mm/min)demonstrated intermediate behavior(∼226 MPa,∼17.7%).These variations were primarily attributed to differences in c-axis orientations,particularly their alignment with respect to the normal direction(ND)and their slight deviation from the extrusion direction(ED).Microstructural analysis revealed that distinct DRX mechanisms were activated under different extrusion conditions.P1 predominantly exhibited twinning-induced dynamic recrystallization(TDRX)and continuous dynamic recrystallization(CDRX),whereas P3 primarily showed CDRX and discontinuous dynamic recrystallization(DDRX).These DRX mechanisms,in combination with the activated slip systems governed by the evolving local stress state,collectively contributed to orientation rotation and texture development.During the early stage of extrusion,tensile strain along the ED promoted basalslip,rotating the c-axes toward the ND.As deformation progressed,compressive strain along the ND became dominant.In P1,basalslip remained active,aligning the c-axes along the ND and forming a smaller angle with the ED.In contrast,P3 exhibited predominant pyramidal<c+a>slip,resulting in a pronounced deviation of the c-axes from the ND and a slightly larger angle relative to the ED.The P2 sample exhibited a transitional texture state between those of P1 and P3.
基金supported by the National Natural Science Foundation of China(22108306,22478432 and 22406191)Taishan Scholars Program of Shandong Province(tsqn201909065)the Natural Science Foundation of Shandong Province(ZR2024JQ004,ZR2021YQ15)。
文摘The development of atomically dispersed platinum-based catalysts with high performance and welldefined active site structures is crucial for the commercialization of water electrolysis for hydrogen production.Herein,we propose a coordination dual-shell synergistic regulation mechanism of coal pitchderived carbon-supported single atom Pt-N_(x)O_(y)-S_(1)catalytic sites by a self-assembly-pyrolysis strategy for promoting hydrogen evolution reaction(HER).The Pt-N_(3)O1-S_(1)sites exhibited the highest HER performance,with an overpotential of 92 mV at a current density of 400 mA cm^(-2).At 50 mV,the turnover frequency was 34.04 s^(-1)and the mass activity was 22.83 A mg_(Pt)^(-l),which is 63.4 times that of the 20%Pt/C catalyst.Theoretical calculations revealed that the coordination dual-shell impacts the electronic structure of the Pt atoms and the adsorption strength towards reactants synergistically.The S atoms in the second coordination shell weakened the strength of Pt-N first shell,resulting the more surface valence electrons around Pt atoms,exhibiting the most suitable adsorption free energy and enhancing the adsorption of H^(+)on Pt-N_(3)O_(1)-S_(1)sites,thus enhancing the electrocatalytic HER process by promoting Volmer step.This work reveals that coordination dual-shell synergistic regulation is an effective strategy for enhancing the electrocatalytic reaction process.
基金Funded by the Breeding Project of Anhui Polytechnic University(No.2019YQQ027)the Scientific Research Foundation of Anhui Polytechnic University(No.xjky2022016)+1 种基金the Open Research Found of Anhui Key Laboratory of High-performance Non-ferrous Metal Materials(No.YSJS-2023-07)the Innovative Entrepreneurship Training Program for College Students in Anhui Province(No.S202210363391)。
文摘A series of CoS_(2-x)Se_(x)(x=0.05,0.1,0.2,0.3,and 2)composite catalysts were synthesized on carbon fiber paper via the hydrothermal method with Se doping.By precisely controlling the reaction temperature and Se doping level,a hollow spherical catalyst structure composed of CoSSe was successfully synthesized,which exhibited exceptional activity for hydrogen evolution in acidic solutions.The influences of Se doping on the microstructure and catalytic mechanism of hydrogen evolution reaction(HER)of these composites were systematically investigated.The experimental results reveal that the hollow spherical sample displays an overpotential value of 143 mV along with a Tafel slope value of 69.8 mV·dec^(-1)at a current density of 10 mA·cm^(-2)in an acid aqueous solution.Furthermore,it demonstrates remarkable cycling stability after undergoing 3000 cycles.The comprehensive analysis indicates that Se doping optimizes the electronic structure and enhances conductivity,meanwhile the unique hollow spherical architecture increases active sites for HER and significantly improves overall electrocatalytic performance.
基金supported by the Start-Up Research Funding of Fujian Normal University(No.Y0720326K13)the National Natural Science Foundation of China(Nos.22103035 and 22033005)+2 种基金the National Key R&D Program of China(No.2022YFA1503900)Shenzhen Science and Technology Program(No.RCYX20231211090357078)Guangdong Provincial Key Laboratory of Catalysis(No.2020B121201002).
文摘Atomically precise palladium(Pd)clusters are emerging as versatile nanomaterials with applications in catalysis and biomedicine.This study explores the synthesis,structure evolution,and catalytic properties of Pd clusters stabilized by cyclohexanethiol(HSC_(6)H_(11))ligands.Using electrospray ionization mass spectrometry(ESI-MS)and single-crystal X-ray diffraction(SXRD),structures of the Pd clusters ranging from Pd4(SC_(6)H_(11))8 to Pd18(SC_(6)H_(11))36 were determined.This analysis revealed a structure evolution from polygonal to elliptical geometries of the PdnS2n frameworks as the cluster size increased.UV-Vis-NIR spectroscopy,combined with quantum chemical calculations,elucidated changes in the electronic structure of the clusters.Catalytic studies on the Sonogashira cross-coupling reactions demonstrated a size-dependent decline in activity attributed to variations in structural arrangements and electronic properties.Mechanistic insights proposed a distinctive Pd(Ⅱ)-Pd(Ⅳ)catalytic cycle.This research underscores how ligands and cluster size influence the structures and properties of Pd clusters,offering valuable insights for the future design and application of Pd clusters in advanced catalysis and beyond.
基金supported by the National Natural Science Foundation of China(Nos.U2030206,12104022,52271014 and 22075003)the Presidential Foundation of CAEP(No.YZJJZL2023173)Sichuan Science and Technology Program(No.2021YFH0092).
文摘Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is still needed.Here,the storage mechanism of Li^(+)in the tunnel structure of MnO_(2) as well as the dissolution and migration of Mn-ions were investigated based on multi-scale approaches.The Li/Mn ratio(at%)is determined at about 0.82 when the discharge voltage decreases to 2 V.The limited Li-ions transport rate in the bulk MnO_(2) restrains the reduction reaction,resulting in a low practical specific capacity.Moreover,utilizing spherical aberration-corrected transmission electron microscopy(TEM)coupled with electron energy loss spectroscopy(EELS),the presence of a mixed valence state layer of Mn^(2+)/Mn^(3+)/Mn^(4+)on the surface of the original 20 nm MnO_(2) particles was identified,which could contribute to the initial dissolution of Mn-ions.The battery separator exhibited channels for Mn-ions migration and diffusion and aggregated Mn particles.We put forward the discharge and degradation route in the ways of Mn-ions trajectories,and our findings provide a deep understanding of the high self-discharge rates and the capacity decay of Li-Mn primary batteries.
基金financially supported by the National Science Foundation of China(Nos.51974212 and 52274316)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202116)+1 种基金the Science and Technology Major Project of Wuhan(No.2023020302020572)the Foundation of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(No.FMRUlab23-04)。
文摘The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.
文摘As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol synthesis,In_(2)O_(3)is an ideal catalyst and has garnered significant attention.Herein,cubic In_(2)O_(3)nanoparticles were prepared via the precipitation method and evaluated for CO_(2)hydrogenation to produce methanol.During the initial 10 h of reaction,CO_(2)conversion gradually increased,accompanied by a slow decrease of methanol selectivity,and the reaction reached equilibrium after 10-20 h on stream.This activation and induction stage may be attributed to the sintering of In_(2)O_(3)nanoparticles and the creation of more oxygen vacancies on In_(2)O_(3)surfaces.Further experimental studies demonstrate that hydrogen induction created additional oxygen vacancies during the catalyst activation stage,enhancing the performance of In_(2)O_(3)catalyst for CO_(2)hydrogenation.Density functional theory calculations and microkinetic simulations further demonstrated that surfaces with higher oxygen vacancy coverages or hydroxylated surfaces formed during this induction period can enhance the reaction rate and increase the CO_(2)conversion.However,they predominantly promote the formation of CO instead of methanol,leading to reduced methanol selectivity.These predictions align well with the above-mentioned experimental observations.Our work thus provides an in-depth analysis of the induction stage of the CO_(2)hydrogenation process on In_(2)O_(3)nano-catalyst,and offers valuable insights for significantly improving the CO_(2)reactivity of In_(2)O_(3)-based catalysts while maintaining long-term stability.
基金Project(2023AH051167)supported by the Natural Science Research Project of Anhui Educational Committee,ChinaProject(AHBP2024B-04)supported by the Foundation of Anhui Engineering Research Center of New Explosive Materials and Blasting Technology,China+1 种基金Project(GXZDSYS2023103)supported by the Open Fund for Anhui Key Laboratory of Mining Construction Engineering,ChinaProjects(52274071,52404155)supported by the National Natural Science Foundation of China。
文摘Aiming at the problem of dynamic instability of hard-brittle jointed rock surrounding in deep tunnel/roadway engineering,combining with the support concepts of"coupling rigidity with flexibility"and"overcoming rigidity by flexibility",the prevention and control method with"rigid-flexible coupling(R-F-C)"was put forward.Through numerical simulation calculation,the impact damage process,acoustic emission(AE)evolution characteristics,and element stress/displacement evolution characteristics of unsupported surrounding rock structure model,rigid supporting surrounding rock structure model,and"R-F-C"supporting surrounding rock structure model under horizontal bidirectional impact loading were compared and analyzed.Based on the theory of stress wave propagation,the dynamic instability catastrophe mechanism of three kinds of supporting structure models induced by horizontal bidirectional impact loading was revealed.Based on the Mohr-Coulomb strength theory,the stress discrimination methods of dynamic catastrophe of surrounding rock induced by horizontal bidirectional impact loading under three kinds of supporting structures were proposed.Combined with the above numerical simulation study,the explosion impact physical and mechanical test of"R-F-C"surrounding rock supporting plate structure was further designed and carried out.Finally,combined with the"conceptual model of ball-cliff potential energy instability",the energy driving theory and energy transformation mechanism of impact-induced rockburst under three kinds of supporting structures were discussed deeply.The research results provided a scientific basis for further promoting the effective application of"R-F-C"supporting structure in the prevention and control of dynamic instability of deep tunnel/roadway surrounding rock.
基金supported by the National Key Research and Development Project of China(No.2021YFC3000600)。
文摘The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface rupture.Traditional models attribute this to the Beichuan and Pengguan faults,but our research reveals a complex fault system at the northern end,with inconsistencies in surface rupture,aftershock distribution,and focal mechanisms.We integrate shallow geology,active source seismic reflection,and magnetotelluric profiling to establish a deep structural model for the northern end of the Longmenshan structural belt.This area exhibits dominant reverse thrust nappe tectonics,and analyzing the tectonic evolution history provides insights into deformation propagation from the orogenic belt toward the Sichuan Basin.Focal mechanism analysis and relocated aftershock data reveals two distinct types of seismogenic structures in the northern end of the Longmenshan structural belt.In the middle to northern segments,the reverse fault type is attributed to reactivated pre-existing faults.Conversely,at the northern end,the strike-slip fault type originates from high-angle co-seismic rupture cutting through pre-existing reverse faults.This study enhances our understanding of fault complexity and seismic mechanisms in the northeastern Longmenshan structural belt,providing new insights into regional tectonics.
基金This study is supported by the National Natural Science Foundation of China (No. 49972067) the Major State Basic Research Development Program (No. G1999075506).
文摘Detailed three-dimensional structural studies indicate that the Bixiling area, Dabie massif, central China shows the deepest exposed levels of the orogenic wedge formed during the Triassic Yangtze -Sino-Korean continental collision. New 1 : 10 000 scale structural mapping, combined with detailed petrological analysis in this area, has enabled us to accurately distinguish structures related to the Triassic continental collision from those related to post-collisional deformation in the ultrahigh pressure (UHP) metamorphic unit. The collisional or compressional structures include the massive eclogite with a weak foliation, foliated eclogite or UHP ductile shear zones, as well as upper amphibolite facies shear zones, whereas the post-collisional deformation is characterized by a regionally, flat-lying foliation containing stretching lineations and common reclined folds. The former is present exclusively in the eclogite lenses and their margins, representing orogenic thickening or syn-collisional events, while the latter was best occurred on variable scales under amphibolite facies conditions, showing sub-vertical, extreme shortening and ductile thinning of the metamorphic rock stack. The eclogite facies tectonites that have a marked fabric discordance to the penetrative amphibolite facies extension flow fabric are common. It is emphasized that an extensional tectonic setting following the collision-orogenic thickening stage was, at least partly, responsible for exhumation of the UHP metamorphic rocks in the Dabie massif. A new tectonic evolution model is proposed for the UHP metamorphic belt on the scale of the Dabie massif. The Bixiling area thus provides a window, from which the dynamic processes concerning the formation and exhumation of the UHP rocks can be observed. Regional studies in the Dabie Mountains have confirmed this interpretation.
基金supported by the National Natural Science Foundation of China,32270161,82302506.Research Grant of Jiangsu Commission of Health,ZD2021036The Starting Grant for Talents of Xuzhou Medical University,D2021007,D2021008,D2024017The Natural Science Foundation of the Jiangsu Higher Education Institutions of China(23KJD310005,23KJB310028,24KJD310005).
文摘A large multi-country outbreak of Oropouche virus(OROV),a segmented negative-sense RNA virus,is emerging in Latin America.By analyzing publicly available whole-genome sequences spanning 1955 to 2024,this study reveals accelerated spatiotemporal evolution of OROV,cooperatively driven by genome mutagenesis and segment reassortment.The strains responsible for the 2023-2024 outbreak are universally reassortants,but form two divergent lineages,namely the Brazil and western Amazon basin lineages.This epidemic spreading is primarily fueled by localized transmission within countries and cross-border spread.Phylogenomic analysis further suggests that the S segment of the viral genome originated in Brazil around the 1740s,underwent diversification into five distinct clusters by the 1970s,and experienced rapid proliferation during 2020-2024.In contrast,the L segment originated in Peru around the 1630s and evolved into two independent clusters by the 1850s.Divergent evolutionary pressures have driven distinct patterns of amino acid changes in viral proteins between the Brazil and the western Amazon basin lineages.These mutations are predicted to alter the protein structures and bear functional consequences for viral fitness and transmission.These findings provide critical insights into the evolutionary dynamics of OROV and underscore the necessity of genome surveillance to track the transmission pathways and spatiotemporal evolution.
