Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes...Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.展开更多
Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is p...Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.展开更多
La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation pr...La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation properties.However,the cycling stability is not currently satisfactory enough which plagues its application.Herein,a strategy of partially substituting La with the Y element is proposed to boost the capacity durability of La-Mg-Ni-based alloys.Furthermore,phase structure regulation is implemented simultaneously to obtain the A5 B19-type alloy with good crystal stability specifically.It is found that Y promotes the phase formation of the Pr5 Co19-type phase after annealing at 985℃.The alloy containing Y contributes to the superior rate capability resulting from the promoted hydrogen diffusion rate.Notably,Y substitution enables strengthening the anti-pulverization ability of the alloy in terms of increasing the volume match between[A_(2)B_(4)]and[AB5]subunits,and effectively enhances the anti-corrosion ability of the alloy due to high electronegativity,realizing improved long-term cycling stability of the alloy from 74.2%to 78.5%after cycling 300 times.The work is expected to shed light on the composition and structure design of the La-Mg-Ni-based hydrogen storage alloy for Ni-MH batteries.展开更多
Understanding the evolution of microstructures in nuclear fuels under high-burn-up conditions is critical for extending fuel refueling cycles and enhancing nuclear reactor safety.In this study,a phase-field model is p...Understanding the evolution of microstructures in nuclear fuels under high-burn-up conditions is critical for extending fuel refueling cycles and enhancing nuclear reactor safety.In this study,a phase-field model is proposed to examine the evolution of high-burn-up structures in polycrystalline UO_(2).The formation and growth of recrystallized grains were initially investigated.It was demonstrated that recrystallization kinetics adhere to the Kolmogorov–Johnson–Mehl–Avrami(KJMA)equation,and that recrystallization represents a process of free-energy reduction.Subsequently,the microstructural evolution in UO_(2) was analyzed as the burn up increased.Gas bubbles acted as additional nucleation sites,thereby augmenting the recrystallization kinetics,whereas the presence of recrystallized grains accelerated bubble growth by increasing the number of grain boundaries.The observed variations in the recrystallization kinetics and porosity with burn-up closely align with experimental findings.Furthermore,the influence of grain size on microstructure evolution was investigated.Larger grain sizes were found to decrease porosity and the occurrence of high-burn-up structures.展开更多
The rapid development of 5G communication technology and smart electronic and electrical equipment will inevitably lead to electromagnetic radiation pollution.Enriching heterointerface polarization relaxation through ...The rapid development of 5G communication technology and smart electronic and electrical equipment will inevitably lead to electromagnetic radiation pollution.Enriching heterointerface polarization relaxation through nanostructure design and interface modifica-tion has proven to be an effective strategy to obtain efficient electromagnetic wave absorption.Here,this work implements an innovative method that combines biomimetic honeycomb superstructure to constrain hierarchical porous heterostructure composed of Co/CoO nano-particles to improve the interfacial polarization intensity.The method effectively controlled the absorption efficiency of Co^(2+)through de-lignification modification of bamboo,and combined with the bionic carbon-based natural hierarchical porous structure to achieve uniform dispersion of nanoparticles,which is conducive to the in-depth construction of heterogeneous interfaces.In addition,the multiphase struc-ture brought about by high-temperature pyrolysis provides the best dielectric loss and impedance matching for the material.Therefore,the obtained bamboo-based Co/CoO multiphase composite showed excellent electromagnetic wave absorption performance,achieving excel-lent reflection loss(RL)of-79 dB and effective absorption band width of 4.12 GHz(6.84-10.96 GHz)at low load of 15wt%.Among them,the material’s optimal radar cross-section(RCS)reduction value can reach 31.9 dB·m^(2).This work provides a new approach to the micro-control and comprehensive optimization of macro-design of microwave absorbers,and offers new ideas for the high-value utiliza-tion of biomass materials.展开更多
The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-...The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.展开更多
The swelling behavior and stability in solid electrolyte interphase(SEI)have been proved to determine the battery cycle life.A high swollen,unstable SEI shows a high permeability to electrolyte,which results in the ra...The swelling behavior and stability in solid electrolyte interphase(SEI)have been proved to determine the battery cycle life.A high swollen,unstable SEI shows a high permeability to electrolyte,which results in the rapid battery performance degradation.Here,we customize two SEIs with different spatial structures(bilayer and mosaic)by simply regulating the proportion of additive fluoroethylene carbonate.Surprisingly,due to the uniform distribution of dense inorganic nano-crystals in the inner,the bilayer SEI exhibits low-swelling and excellent mechanical properties,so the undesirable side reactions of the electrolyte are effectively suppressed.In addition,we put forward the growth rate of swelling ratio(GSR)as a key indicator to reveal the swelling change in SEI.The GSR of bilayer SEI merely increases from1.73 to 3.16 after the 300th cycle,which enables the corresponding graphite‖Li battery to achieve longer cycle stability.The capacity retention is improved by 47.5% after 300 cycles at 0.5 C.The correlation among SEI spatial structure,swelling behavior,and battery performance provides a new direction for electrolyte optimization and interphase structure design of high energy density batteries.展开更多
Forest structure is fundamental in determining ecosystem function,yet the impact of bamboo invasion on these structural characteristics remains unclear.We investigated 219 invasion transects at 41 sites across the dis...Forest structure is fundamental in determining ecosystem function,yet the impact of bamboo invasion on these structural characteristics remains unclear.We investigated 219 invasion transects at 41 sites across the distribution areas of Moso bamboo(Phyllostachys edulis)in China to explore the effects of bamboo invasion on forest structural attributes and diameter–height allometries by comparing paired plots of bamboo,mixed bamboo-tree,and non-bamboo forests along the transects.We found that bamboo invasion decreased the mean and maximum diameter at breast height,maximum height,and total basal area,but increased the mean height,stem density,and scaling exponent for stands.Bamboo also had a higher scaling exponent than tree,particularly in mixed forests,suggesting a greater allocation of biomass to height growth.As invasion intensity increased,bamboo allometry became more plastic and decreased significantly,whereas tree allometry was indirectly promoted by increasing stem density.Additionally,a humid climate may favour the scaling exponents for both bamboo and tree,with only minor contributions from topsoil moisture and nitrogen content.The inherent superiority of diameter–height allometry allows bamboo to outcompete tree and contributes to its invasive success.Our findings provide a theoretical basis for understanding the causes and consequences of bamboo invasion.展开更多
The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and ...The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.展开更多
Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based elect...Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based electrode exhibit multi-scale structural characteristics including macroscopic electrode morphologies,mesoscopic microcrystals and pores,and microscopic defects and dopants in the carbon basal plane.Therefore,the ordered combination of multi-scale structures of carbon electrode is crucial for achieving dense energy storage and high volumetric performance by leveraging the functions of various scale structu re.Considering that previous reviews have focused more on the discussion of specific scale structu re of carbon electrodes,this review takes a multi-scale perspective in which recent progresses regarding the structureperformance relationship,underlying mechanism and directional design of carbon-based multi-scale structures including carbon morphology,pore structure,carbon basal plane micro-environment and electrode technology on dense energy storage and volumetric property of supercapacitors are systematically discussed.We analyzed in detail the effects of the morphology,pore,and micro-environment of carbon electrode materials on ion dense storage,summarized the specific effects of different scale structures on volumetric property and recent research progress,and proposed the mutual influence and trade-off relationship between various scale structures.In addition,the challenges and outlooks for improving the dense storage and volumetric performance of carbon-based supercapacitors are analyzed,which can provide feasible technical reference and guidance for the design and manufacture of dense carbon-based electrode materials.展开更多
As the proportion of composite materials used in aircraft continues to increase, the electromagnetic Shielding Effectiveness (SE) of these materials becomes a critical factor in the electromagnetic safety design of ai...As the proportion of composite materials used in aircraft continues to increase, the electromagnetic Shielding Effectiveness (SE) of these materials becomes a critical factor in the electromagnetic safety design of aircraft structures. The assessment of electromagnetic SE for Slotted Composite Structures(SCSs) is particularly challenging due to their complex geometries and there remains a lack of suitable models for accurately predicting the SE performance of these intricate configurations. To address this issue, this paper introduces SCS-Net, a Deep Neural Network (DNN) method designed to accurately predict the SE of SCS. This method considers the impacts of various structural parameters, material properties and incident wave parameters on the SE of SCSs. In order to better model the SCS, an improved Nicolson-Ross-Weir (NRW) method is introduced in this paper to provide an equivalent flat structure for the SCS and to calculate the electromagnetic parameters of the equivalent structure. Additionally, the prediction of SE via DNNs is limited by insufficient test data, which hinders support for large-sample training. To address the issue of limited measured data, this paper develops a Measurement-Computation Fusion (MCF) dataset construction method. The predictions based on the simulation results show that the proposed method maintains an error of less than 0.07 dB within the 8–10 GHz frequency range. Furthermore, a new loss function based on the weighted L1-norm is established to improve the prediction accuracy for these parameters. Compared with traditional loss functions, the new loss function reduces the maximum prediction error for equivalent electromagnetic parameters by 47%. This method significantly improves the prediction accuracy of SCS-Net for measured data, with a maximum improvement of 23.88%. These findings demonstrate that the proposed method enables precise SE prediction and design for composite structures while reducing the number of test samples needed.展开更多
Developing alloys with exceptional strength-ductility combinations across a broad temperature range is crucial for advanced structural applications.The emerging face-centered cubic medium-entropy alloys(MEAs)demonstra...Developing alloys with exceptional strength-ductility combinations across a broad temperature range is crucial for advanced structural applications.The emerging face-centered cubic medium-entropy alloys(MEAs)demonstrate outstanding mechanical properties at both ambient and cryogenic temperatures.They are anticipated to extend their applicability to elevated temperatures,owing to their inherent advantages in leveraging multiple strengthening and deformation mechanisms.Here,a dual heterostructure,comprising of heterogeneous grain structure with heterogeneous distribution of the micro-scale Nb-rich Laves phases,is introduced in a CrCoNi-based MEA through thermo-mechanical processing.Additionally,a high-density nano-coherentγ’phase is introduced within the grains through isothermal aging treatments.The superior thermal stability of the heterogeneously distributed precipitates enables the dual heterostructure to persist at temperatures up to 1073 K,allowing the MEA to maintain excellent mechanical properties across a wide temperature range.The yield strength of the dual-heterogeneous-structured MEA reaches up to 1.2 GPa,1.1 GPa,0.8 GPa,and 0.6 GPa,coupled with total elongation values of 28.6%,28.4%,12.6%,and 6.1%at 93 K,298 K,873 K,and 1073 K,respectively.The high yield strength primar-ily stems from precipitation strengthening and hetero-deformation-induced strengthening.The high flow stress and low stacking fault energy of the dual-heterogeneous-structured MEA promote the formation of high-density stacking faults and nanotwins during deformation from 93 K to 1073 K,and their density increase with decreasing deformation temperature.This greatly contributes to the enhanced strainhardening capability and ductility across a wide temperature range.This study offers a practical solution for designing dual-heterogeneous-structured MEAs with both high yield strength and large ductility across a wide temperature range.展开更多
Solid-state electrolytes(SSEs),as the core component within the next generation of key energy storage technologies-solid-state lithium batteries(SSLBs)-are significantly leading the development of future energy storag...Solid-state electrolytes(SSEs),as the core component within the next generation of key energy storage technologies-solid-state lithium batteries(SSLBs)-are significantly leading the development of future energy storage systems.Among the numerous types of SSEs,inorganic oxide garnet-structured superionic conductors Li7La3Zr2O12(LLZO)crystallized with the cubic Iaˉ3d space group have received considerable attention owing to their highly advantageous intrinsic properties encompassing reasonable lithium-ion conductivity,wide electrochemical voltage window,high shear modulus,and excellent chemical stability with electrodes.However,no SSEs possess all the properties necessary for SSLBs,thus both the ionic conductivity at room temperature and stability in ambient air regarding cubic garnet-based electrolytes are still subject to further improvement.Hence,this review comprehensively covers the nine key structural factors affecting the ion conductivity of garnet-based electrolytes comprising Li concentration,Li vacancy concentration,Li carrier concentration and mobility,Li occupancy at available sites,lattice constant,triangle bottleneck size,oxygen vacancy defects,and Li-O bonding interactions.Furthermore,the general illustration of structures and fundamental features being crucial to chemical stability is examined,including Li concentration,Li-site occupation behavior,and Li-O bonding interactions.Insights into the composition-structure-property relations among cubic garnet-based oxide ionic conductors from the perspective of their crystal structures,revealing the potential compatibility conflicts between ionic transportation and chemical stability resulting from Li-O bonding interactions.We believe that this review will lay the foundation for future reasonable structural design of oxide-based or even other types of superionic conductors,thus assisting in promoting the rapid development of alternative green and sustainable technologies.展开更多
Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol ...Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.展开更多
Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the ...Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.展开更多
Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundame...Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundamental understanding on how they control the electrochemical performances.Herein,by harnessing the electrostatic adsorption of one-dimensional nanofiller(i.e.,surface-charged halloysite nanotubes,d-HNTs),we successfully fabricate a high-performance polymer nanocomposite electrolyte enabled by strong surface adsorption,referred as adsorption-state polymer electrolyte(ASPE).This ASPE shows fast ion transport(0.71±0.05 mS cm^(-1)at room temperature),high mechanical strength and toughness(10.3±0.05 MPa;15.73 MJ m^(-3)),improved lithium-ion transference number,and long cycle life with lithium metal anode,in comparison with the sample without the d-HNT adsorption effect.To fundamentally understand these high performances,an anion-rich asymmetric solvent structure model is further proposed and evidenced by both experiments and simulation studies.Results show that the electrostatic adsorption among the d-HNT,ionic liquid electrolyte,and polymer chain generates a nano filler-supported fast ion-conduction pathway with asymmetric Li+-coordination microenvironment.Meanwhile,the anion-rich asymmetric solvent structure model of ASPE also generates a fast de-solvation and anion-derived stable solid-electrolyte interphase for lithium metal anode.The high performance and understanding of the mechanism for ASPE provide a promising path to develop advanced polymer electrolytes.展开更多
The lamellar layer of intermetallic compounds(IMCs)was adversely affected the performance of welding-brazing joints in Al/steel dissimilar metals.In this study,a short fiber-like surface morphology was fabricated on t...The lamellar layer of intermetallic compounds(IMCs)was adversely affected the performance of welding-brazing joints in Al/steel dissimilar metals.In this study,a short fiber-like surface morphology was fabricated on the butt surface of Q235 steel via laser.The interaction behavior between the short fibers and the molten pool was captured using a high-speed camera.Laser-arc hybrid welding-brazing was then employed to join Al(6061-T6)to the steel.This process successfully created a short fiber-like interface structure at the joint.The relationship between microstructure and mechanical properties was investigated,compared with Al/bare steel(ABS)joint.The research results indicated that the IMCs layer consisted of FeAl_(3)and Fe_(2)Al_(5).The interface strength of the Al/short fiber-like surface structural steel(ASFSSS)joint reached 153.2 MPa,an 82.2%increase compared to the ABS joint,which reached 84.1 MPa.When the ASFSSS joints without the reinforcement were bent to 58.2°and 25.2°in the longitudinal and transverse direction,respectively,they remained intact.However,cracks were discovered when the bending angle of the ABS reached 39.1°and 0°in the two directions.Numerical simulation revealed that the short fiber-like interface structure significantly reduced residual stress and improved the stress distribution in the weld,thereby enhancing the strength and toughness of Al/steel dissimilar joints.The crack propagation path in the ASFSSS joint was deflected into the weld when it encountered short fibers,and the fracture morphology presented the characteristic of ductile-brittle mixed fracture.展开更多
The Pamir Plateau,at the northwestern margin of the Tibetan Plateau,is a key region for investigating continental collision and plateau uplifting.To probe its deep structure,we collected seismic data from 263 stations...The Pamir Plateau,at the northwestern margin of the Tibetan Plateau,is a key region for investigating continental collision and plateau uplifting.To probe its deep structure,we collected seismic data from 263 stations across 11 research projects.We applied cross-correlation to noise data and extracted surface wave dispersion data from cross-correlation functions.The extracted dispersion data were subsequently inverted using a 3-D transdimensional Bayesian inversion method(rj-3 DMcMC).The inversion result reveals several crustal low-velocity zones(LVZs).Their formation is likely related to crustal thickening,the exposure of gneiss domes,and thicker sedimentary sequences compared to surrounding areas.In the lower crust and upper mantle,the LVZs in southern Pamir and southeastern Karakoram evolve into high-velocity zones,which expand northeastward with increasing depth.This suggests northward underthrusting of the Indian Plate.We also analyzed the Moho using both the standard deviation of S-wave velocity and the S-wave velocity structure.Results show that significant variations in velocity standard deviation reliably delineate the Moho interface.展开更多
The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in ...The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices.Hence,a composite with three-dimensional network(Ho/U-BNNS/WPU)is developed by simultaneously incorporating magnetically modified boron nitride nanosheets(M@BNNS)and non-magnetic organo-grafted BNNS(U-BNNS)into waterborne polyurethane(WPU)to synchronous molding under a horizontal magnetic field.The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction,combined with the bridging structure established by U-BNNS,enable Ho/U-BNNS/WPU to exhibit exceptional in-plane(λ//)and through-plane thermal conductivities(λ_(⊥)).In particular,with the addition of 30 wt%M@BNNS and 5 wt%U-BNNS,theλ//andλ_(⊥)of composites reach 11.47 and 2.88 W m^(-1) K^(-1),respectively,which representing a 194.2%improvement inλ_(⊥)compared to the composites with a single orientation of M@BNNS.Meanwhile,Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips.The composites also demonstrate excellent flame retardancy,with a peak heat release and total heat release reduced by 58.9%and 36.9%,respectively,compared to WPU.Thus,this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites,presenting broad application potential in electronic packaging fields.展开更多
Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and...Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.展开更多
基金Supported by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.
基金supported by National Natural Science Foundation of China(No.52025055 and 52275571)Basic Research Operation Fund of China(No.xzy012024024).
文摘Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.
基金the financial support by the National Nat-ural Science Foundation of China(Nos.52201282,52071281,52371239)the China Postdoctoral Science Foundation(No.2023M742945)+4 种基金Hebei Provincial Postdoctoral Science Foundation(No.B2023003023)the Science Research Project of Hebei Education Department(No.BJK2022033)the Natural Science Foundation of Hebei Province(No.C2022203003)the Inner Mongolia Science and Technology Major Project(No.2020ZD0012)the Baotou Science and Technology Planning Project(No.XM2022BT09).
文摘La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation properties.However,the cycling stability is not currently satisfactory enough which plagues its application.Herein,a strategy of partially substituting La with the Y element is proposed to boost the capacity durability of La-Mg-Ni-based alloys.Furthermore,phase structure regulation is implemented simultaneously to obtain the A5 B19-type alloy with good crystal stability specifically.It is found that Y promotes the phase formation of the Pr5 Co19-type phase after annealing at 985℃.The alloy containing Y contributes to the superior rate capability resulting from the promoted hydrogen diffusion rate.Notably,Y substitution enables strengthening the anti-pulverization ability of the alloy in terms of increasing the volume match between[A_(2)B_(4)]and[AB5]subunits,and effectively enhances the anti-corrosion ability of the alloy due to high electronegativity,realizing improved long-term cycling stability of the alloy from 74.2%to 78.5%after cycling 300 times.The work is expected to shed light on the composition and structure design of the La-Mg-Ni-based hydrogen storage alloy for Ni-MH batteries.
基金supported by the National Natural Science Foundation of China(Grant Nos.U20B2013 and 12205286)the National Key Research and Development Program of China(Grant No.2022YFB1902401)。
文摘Understanding the evolution of microstructures in nuclear fuels under high-burn-up conditions is critical for extending fuel refueling cycles and enhancing nuclear reactor safety.In this study,a phase-field model is proposed to examine the evolution of high-burn-up structures in polycrystalline UO_(2).The formation and growth of recrystallized grains were initially investigated.It was demonstrated that recrystallization kinetics adhere to the Kolmogorov–Johnson–Mehl–Avrami(KJMA)equation,and that recrystallization represents a process of free-energy reduction.Subsequently,the microstructural evolution in UO_(2) was analyzed as the burn up increased.Gas bubbles acted as additional nucleation sites,thereby augmenting the recrystallization kinetics,whereas the presence of recrystallized grains accelerated bubble growth by increasing the number of grain boundaries.The observed variations in the recrystallization kinetics and porosity with burn-up closely align with experimental findings.Furthermore,the influence of grain size on microstructure evolution was investigated.Larger grain sizes were found to decrease porosity and the occurrence of high-burn-up structures.
基金supported by the National Key R&D Program of China(Nos.2023YFE0108300 and 2023YFD2202103)the National Natural Science Foundation of China(No.32371972)+2 种基金the Natural Science Foundation of Jiangsu Province,China(No.BK20221336)Jiangsu Agricultural Science and Technology Independent Innovation Fund,China(No.CX(23)3060)Jiangxi Forestry Bureau Forestry Science and Technology Innovation Special Project,China(No.202240).
文摘The rapid development of 5G communication technology and smart electronic and electrical equipment will inevitably lead to electromagnetic radiation pollution.Enriching heterointerface polarization relaxation through nanostructure design and interface modifica-tion has proven to be an effective strategy to obtain efficient electromagnetic wave absorption.Here,this work implements an innovative method that combines biomimetic honeycomb superstructure to constrain hierarchical porous heterostructure composed of Co/CoO nano-particles to improve the interfacial polarization intensity.The method effectively controlled the absorption efficiency of Co^(2+)through de-lignification modification of bamboo,and combined with the bionic carbon-based natural hierarchical porous structure to achieve uniform dispersion of nanoparticles,which is conducive to the in-depth construction of heterogeneous interfaces.In addition,the multiphase struc-ture brought about by high-temperature pyrolysis provides the best dielectric loss and impedance matching for the material.Therefore,the obtained bamboo-based Co/CoO multiphase composite showed excellent electromagnetic wave absorption performance,achieving excel-lent reflection loss(RL)of-79 dB and effective absorption band width of 4.12 GHz(6.84-10.96 GHz)at low load of 15wt%.Among them,the material’s optimal radar cross-section(RCS)reduction value can reach 31.9 dB·m^(2).This work provides a new approach to the micro-control and comprehensive optimization of macro-design of microwave absorbers,and offers new ideas for the high-value utiliza-tion of biomass materials.
基金sponsored by the National Natural Science Foundation of China(Nos.5210125 and 52375422)the Science Research Project of Hebei Education Department(No.BJK2023058)the Natural Science Foundation of Hebei Province(Nos.E2020208069,B2020208083 and E202320801).
文摘The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.
基金supported by the National Natural Science Foundation of China(22369011)the Gansu Key Research and Development Program(23YFGA0053 and 24YFGA025)the Hongliu Outstanding Youth Talent Support Program of Lanzhou University of Technology and Postgraduate research exploration project of Lanzhou University of Technology(256017)。
文摘The swelling behavior and stability in solid electrolyte interphase(SEI)have been proved to determine the battery cycle life.A high swollen,unstable SEI shows a high permeability to electrolyte,which results in the rapid battery performance degradation.Here,we customize two SEIs with different spatial structures(bilayer and mosaic)by simply regulating the proportion of additive fluoroethylene carbonate.Surprisingly,due to the uniform distribution of dense inorganic nano-crystals in the inner,the bilayer SEI exhibits low-swelling and excellent mechanical properties,so the undesirable side reactions of the electrolyte are effectively suppressed.In addition,we put forward the growth rate of swelling ratio(GSR)as a key indicator to reveal the swelling change in SEI.The GSR of bilayer SEI merely increases from1.73 to 3.16 after the 300th cycle,which enables the corresponding graphite‖Li battery to achieve longer cycle stability.The capacity retention is improved by 47.5% after 300 cycles at 0.5 C.The correlation among SEI spatial structure,swelling behavior,and battery performance provides a new direction for electrolyte optimization and interphase structure design of high energy density batteries.
基金supported by the National Natural Science Foundation of China(No.31988102)Yunnan Province Major Program for Basic Research Project(No.202101BC070002)+1 种基金Yunnan Province Science and Technology Talents and Platform Program(No.202305AA160014)Yunnan Province Key Research and Development Program of China(No.202303AC100009)。
文摘Forest structure is fundamental in determining ecosystem function,yet the impact of bamboo invasion on these structural characteristics remains unclear.We investigated 219 invasion transects at 41 sites across the distribution areas of Moso bamboo(Phyllostachys edulis)in China to explore the effects of bamboo invasion on forest structural attributes and diameter–height allometries by comparing paired plots of bamboo,mixed bamboo-tree,and non-bamboo forests along the transects.We found that bamboo invasion decreased the mean and maximum diameter at breast height,maximum height,and total basal area,but increased the mean height,stem density,and scaling exponent for stands.Bamboo also had a higher scaling exponent than tree,particularly in mixed forests,suggesting a greater allocation of biomass to height growth.As invasion intensity increased,bamboo allometry became more plastic and decreased significantly,whereas tree allometry was indirectly promoted by increasing stem density.Additionally,a humid climate may favour the scaling exponents for both bamboo and tree,with only minor contributions from topsoil moisture and nitrogen content.The inherent superiority of diameter–height allometry allows bamboo to outcompete tree and contributes to its invasive success.Our findings provide a theoretical basis for understanding the causes and consequences of bamboo invasion.
文摘The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.
基金funded by the Joint Fund for Regional Innovation and Development of National Natural Science Foundation of China(U21A20143)the National Science Fund for Excellent Young Scholars(52322607)the Excellent Youth Foundation of Heilongjiang Scientific Committee(YQ2022E028)。
文摘Improving the volumetric energy density of supercapacitors is essential for practical applications,which highly relies on the dense storage of ions in carbon-based electrodes.The functional units of carbon-based electrode exhibit multi-scale structural characteristics including macroscopic electrode morphologies,mesoscopic microcrystals and pores,and microscopic defects and dopants in the carbon basal plane.Therefore,the ordered combination of multi-scale structures of carbon electrode is crucial for achieving dense energy storage and high volumetric performance by leveraging the functions of various scale structu re.Considering that previous reviews have focused more on the discussion of specific scale structu re of carbon electrodes,this review takes a multi-scale perspective in which recent progresses regarding the structureperformance relationship,underlying mechanism and directional design of carbon-based multi-scale structures including carbon morphology,pore structure,carbon basal plane micro-environment and electrode technology on dense energy storage and volumetric property of supercapacitors are systematically discussed.We analyzed in detail the effects of the morphology,pore,and micro-environment of carbon electrode materials on ion dense storage,summarized the specific effects of different scale structures on volumetric property and recent research progress,and proposed the mutual influence and trade-off relationship between various scale structures.In addition,the challenges and outlooks for improving the dense storage and volumetric performance of carbon-based supercapacitors are analyzed,which can provide feasible technical reference and guidance for the design and manufacture of dense carbon-based electrode materials.
基金supported by the National Natural Science Foundation of China(Nos.62101020 and 62141405)the Special Scientific Research Project of Civil Aircraft,China(No.MJZ5-2N22).
文摘As the proportion of composite materials used in aircraft continues to increase, the electromagnetic Shielding Effectiveness (SE) of these materials becomes a critical factor in the electromagnetic safety design of aircraft structures. The assessment of electromagnetic SE for Slotted Composite Structures(SCSs) is particularly challenging due to their complex geometries and there remains a lack of suitable models for accurately predicting the SE performance of these intricate configurations. To address this issue, this paper introduces SCS-Net, a Deep Neural Network (DNN) method designed to accurately predict the SE of SCS. This method considers the impacts of various structural parameters, material properties and incident wave parameters on the SE of SCSs. In order to better model the SCS, an improved Nicolson-Ross-Weir (NRW) method is introduced in this paper to provide an equivalent flat structure for the SCS and to calculate the electromagnetic parameters of the equivalent structure. Additionally, the prediction of SE via DNNs is limited by insufficient test data, which hinders support for large-sample training. To address the issue of limited measured data, this paper develops a Measurement-Computation Fusion (MCF) dataset construction method. The predictions based on the simulation results show that the proposed method maintains an error of less than 0.07 dB within the 8–10 GHz frequency range. Furthermore, a new loss function based on the weighted L1-norm is established to improve the prediction accuracy for these parameters. Compared with traditional loss functions, the new loss function reduces the maximum prediction error for equivalent electromagnetic parameters by 47%. This method significantly improves the prediction accuracy of SCS-Net for measured data, with a maximum improvement of 23.88%. These findings demonstrate that the proposed method enables precise SE prediction and design for composite structures while reducing the number of test samples needed.
基金supported by the Tianjin Science and Technology Plan Project(No.22JCQNJC01280)the Central Funds Guiding the Local Science and Technology Development of Hebei Province(Nos.226Z1001G and 226Z1012G)+1 种基金the National Natural Science Foundation of China(No.52002109,52071124)the Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001).
文摘Developing alloys with exceptional strength-ductility combinations across a broad temperature range is crucial for advanced structural applications.The emerging face-centered cubic medium-entropy alloys(MEAs)demonstrate outstanding mechanical properties at both ambient and cryogenic temperatures.They are anticipated to extend their applicability to elevated temperatures,owing to their inherent advantages in leveraging multiple strengthening and deformation mechanisms.Here,a dual heterostructure,comprising of heterogeneous grain structure with heterogeneous distribution of the micro-scale Nb-rich Laves phases,is introduced in a CrCoNi-based MEA through thermo-mechanical processing.Additionally,a high-density nano-coherentγ’phase is introduced within the grains through isothermal aging treatments.The superior thermal stability of the heterogeneously distributed precipitates enables the dual heterostructure to persist at temperatures up to 1073 K,allowing the MEA to maintain excellent mechanical properties across a wide temperature range.The yield strength of the dual-heterogeneous-structured MEA reaches up to 1.2 GPa,1.1 GPa,0.8 GPa,and 0.6 GPa,coupled with total elongation values of 28.6%,28.4%,12.6%,and 6.1%at 93 K,298 K,873 K,and 1073 K,respectively.The high yield strength primar-ily stems from precipitation strengthening and hetero-deformation-induced strengthening.The high flow stress and low stacking fault energy of the dual-heterogeneous-structured MEA promote the formation of high-density stacking faults and nanotwins during deformation from 93 K to 1073 K,and their density increase with decreasing deformation temperature.This greatly contributes to the enhanced strainhardening capability and ductility across a wide temperature range.This study offers a practical solution for designing dual-heterogeneous-structured MEAs with both high yield strength and large ductility across a wide temperature range.
基金supported by the National Natural Science Foundation of China(Nos.22171102 and 22090044)the National Key R&D Program of China(Nos.2021YFF0500502 and 2023YFA1506304)+2 种基金the Jilin Province Science and Technology Development Plan(No.20230101024JC)the"Medicine+X"crossinnovation team of Bethune Medical Department of Jilin University"Leading the Charge with Open Competition"construction project(No.2022JBGS04)the Jilin University Graduate Training Office(Nos.2021JGZ08 and 2022YJSJIP20).
文摘Solid-state electrolytes(SSEs),as the core component within the next generation of key energy storage technologies-solid-state lithium batteries(SSLBs)-are significantly leading the development of future energy storage systems.Among the numerous types of SSEs,inorganic oxide garnet-structured superionic conductors Li7La3Zr2O12(LLZO)crystallized with the cubic Iaˉ3d space group have received considerable attention owing to their highly advantageous intrinsic properties encompassing reasonable lithium-ion conductivity,wide electrochemical voltage window,high shear modulus,and excellent chemical stability with electrodes.However,no SSEs possess all the properties necessary for SSLBs,thus both the ionic conductivity at room temperature and stability in ambient air regarding cubic garnet-based electrolytes are still subject to further improvement.Hence,this review comprehensively covers the nine key structural factors affecting the ion conductivity of garnet-based electrolytes comprising Li concentration,Li vacancy concentration,Li carrier concentration and mobility,Li occupancy at available sites,lattice constant,triangle bottleneck size,oxygen vacancy defects,and Li-O bonding interactions.Furthermore,the general illustration of structures and fundamental features being crucial to chemical stability is examined,including Li concentration,Li-site occupation behavior,and Li-O bonding interactions.Insights into the composition-structure-property relations among cubic garnet-based oxide ionic conductors from the perspective of their crystal structures,revealing the potential compatibility conflicts between ionic transportation and chemical stability resulting from Li-O bonding interactions.We believe that this review will lay the foundation for future reasonable structural design of oxide-based or even other types of superionic conductors,thus assisting in promoting the rapid development of alternative green and sustainable technologies.
基金supported by the Key Technologies Research and Development Program(No.2022YFB3504102)the National Natural Science Foundation of China(Nos.22035009,22002050,and 22202087)+2 种基金the National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2020B01)Fuyang Normal University Open Fund(No.FSKFKT006D)the Postdoctoral Science Foundation of China(Nos.2022T150765 and 2020M683154).
文摘Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.
基金Supported by Leading Talent Program of Autonomous Region(2022TSYCLJ0070)PetroChina Prospective and Basic Technological Project(2021DJ0108)Natural Science Foundation for Outstanding Young People in Shandong Province(ZR2022YQ30).
文摘Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.
基金financial support from the National Natural Science Foundation of China(52203123)the Sichuan Science and Technology Program(2023NSFSC0991)+2 种基金the State Key Laboratory of Polymer Materials Engineering(sklpme 2023-1-05 and sklpme 2024-2-04)the Fundamental Research Funds for the Central Universitiespartially sponsored by the Double First-Class Construction Funds of Sichuan University。
文摘Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundamental understanding on how they control the electrochemical performances.Herein,by harnessing the electrostatic adsorption of one-dimensional nanofiller(i.e.,surface-charged halloysite nanotubes,d-HNTs),we successfully fabricate a high-performance polymer nanocomposite electrolyte enabled by strong surface adsorption,referred as adsorption-state polymer electrolyte(ASPE).This ASPE shows fast ion transport(0.71±0.05 mS cm^(-1)at room temperature),high mechanical strength and toughness(10.3±0.05 MPa;15.73 MJ m^(-3)),improved lithium-ion transference number,and long cycle life with lithium metal anode,in comparison with the sample without the d-HNT adsorption effect.To fundamentally understand these high performances,an anion-rich asymmetric solvent structure model is further proposed and evidenced by both experiments and simulation studies.Results show that the electrostatic adsorption among the d-HNT,ionic liquid electrolyte,and polymer chain generates a nano filler-supported fast ion-conduction pathway with asymmetric Li+-coordination microenvironment.Meanwhile,the anion-rich asymmetric solvent structure model of ASPE also generates a fast de-solvation and anion-derived stable solid-electrolyte interphase for lithium metal anode.The high performance and understanding of the mechanism for ASPE provide a promising path to develop advanced polymer electrolytes.
基金supported by the National Natural Science Foundation of China(No.52275306)the Beijing Municipal Natural Science Foundation(No.3232021).
文摘The lamellar layer of intermetallic compounds(IMCs)was adversely affected the performance of welding-brazing joints in Al/steel dissimilar metals.In this study,a short fiber-like surface morphology was fabricated on the butt surface of Q235 steel via laser.The interaction behavior between the short fibers and the molten pool was captured using a high-speed camera.Laser-arc hybrid welding-brazing was then employed to join Al(6061-T6)to the steel.This process successfully created a short fiber-like interface structure at the joint.The relationship between microstructure and mechanical properties was investigated,compared with Al/bare steel(ABS)joint.The research results indicated that the IMCs layer consisted of FeAl_(3)and Fe_(2)Al_(5).The interface strength of the Al/short fiber-like surface structural steel(ASFSSS)joint reached 153.2 MPa,an 82.2%increase compared to the ABS joint,which reached 84.1 MPa.When the ASFSSS joints without the reinforcement were bent to 58.2°and 25.2°in the longitudinal and transverse direction,respectively,they remained intact.However,cracks were discovered when the bending angle of the ABS reached 39.1°and 0°in the two directions.Numerical simulation revealed that the short fiber-like interface structure significantly reduced residual stress and improved the stress distribution in the weld,thereby enhancing the strength and toughness of Al/steel dissimilar joints.The crack propagation path in the ASFSSS joint was deflected into the weld when it encountered short fibers,and the fracture morphology presented the characteristic of ductile-brittle mixed fracture.
基金supported by the National Natural Science Foundation of China(Grant No.42174126)the Alliance of International Science Organizations(ANSO)Project(Grant No.ANSO-CR-PP2022-04)+1 种基金the Deep Earth Probe and Mineral Resources Exploration National Science and Technology Major Project(Grant Nos.2024ZD1002206,2024ZD1002201)Key R&D Program of Xinjiang Uyghur Autonomous Region(Grant No.2024B03013-2)。
文摘The Pamir Plateau,at the northwestern margin of the Tibetan Plateau,is a key region for investigating continental collision and plateau uplifting.To probe its deep structure,we collected seismic data from 263 stations across 11 research projects.We applied cross-correlation to noise data and extracted surface wave dispersion data from cross-correlation functions.The extracted dispersion data were subsequently inverted using a 3-D transdimensional Bayesian inversion method(rj-3 DMcMC).The inversion result reveals several crustal low-velocity zones(LVZs).Their formation is likely related to crustal thickening,the exposure of gneiss domes,and thicker sedimentary sequences compared to surrounding areas.In the lower crust and upper mantle,the LVZs in southern Pamir and southeastern Karakoram evolve into high-velocity zones,which expand northeastward with increasing depth.This suggests northward underthrusting of the Indian Plate.We also analyzed the Moho using both the standard deviation of S-wave velocity and the S-wave velocity structure.Results show that significant variations in velocity standard deviation reliably delineate the Moho interface.
基金support from the National Natural Science Foundation of China(22268025,52473083,and 22475176)Key Research and Development Program of Yunnan Province(202403AP140036)+2 种基金Natural Science Basic Research Program of Shaanxi(2024JC-TBZC-04)Applied Basic Research Program of Yunnan Province(202201AT070115 and 202201BE070001-031)supported by the Innovation Capability Support Program of Shaanxi(2024RS-CXTD-57).
文摘The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices.Hence,a composite with three-dimensional network(Ho/U-BNNS/WPU)is developed by simultaneously incorporating magnetically modified boron nitride nanosheets(M@BNNS)and non-magnetic organo-grafted BNNS(U-BNNS)into waterborne polyurethane(WPU)to synchronous molding under a horizontal magnetic field.The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction,combined with the bridging structure established by U-BNNS,enable Ho/U-BNNS/WPU to exhibit exceptional in-plane(λ//)and through-plane thermal conductivities(λ_(⊥)).In particular,with the addition of 30 wt%M@BNNS and 5 wt%U-BNNS,theλ//andλ_(⊥)of composites reach 11.47 and 2.88 W m^(-1) K^(-1),respectively,which representing a 194.2%improvement inλ_(⊥)compared to the composites with a single orientation of M@BNNS.Meanwhile,Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips.The composites also demonstrate excellent flame retardancy,with a peak heat release and total heat release reduced by 58.9%and 36.9%,respectively,compared to WPU.Thus,this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites,presenting broad application potential in electronic packaging fields.
基金National Natural Science Foundation of China(32201491)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)The authors extend their appreciation to the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-1101-02”.
文摘Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.
