In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented...In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented product FGPA-G 2-H on Aβ25-35-induced PC 12 cells were explored.The structure of GPA-G 2-H was determined by means of zeta potential analysis,FTIR,HPLC,XRD,GC-MS and NMR.The backbone of GPA-G 2-H was mainly composed of→4)-α-D-Glcp-(1→with branches substituted at O-3.Notably,GPA-G 2-H was degraded by intestinal microbiota in vitro with total sugar content and pH value decreasing,and short-chain fatty acids(SCFAs)increasing.Moreover,GPA-G 2-H significantly promoted the proliferation of Lactobacillus,Muribaculaceae and Weissella,thereby making positive alterations in intestinal microbiota composition.Additionally,FGPA-G 2-H activated the Nrf 2/HO-1 signaling pathway,enhanced HO-1,NQO 1,SOD and GSH-Px,while inhabited Keap 1,MDA and LDH,which alleviated Aβ-induced oxidative stress in PC 12 cells.These provide a solid theoretical basis for the further development of ginseng polysaccharides as functional food and antioxidant drugs.展开更多
Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'...Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.展开更多
To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ...To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.展开更多
Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-ins...Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-inspired lattice structures feature a square-grid 2D lattice with double diagonal bracings and are additively manufactured via digital light processing(DLP).The collapse strength and energy absorption capacity of sea sponge lattice structures are evaluated under various impact conditions and are compared to those of their constituent square-grid and double diagonal lattices.This study demonstrates that sea sponge lattices can achieve an 11-fold increase in energy absorption compared to the square-grid lattice,due to the stabilizing effect of the double diagonal bracings prompting the structure to collapse layer-bylayer under impact.By adjusting the thickness ratio in the sea sponge lattice,up to 76.7%increment in energy absorption is attained.It is also shown that sea-sponge lattices outperform well-established energy-absorbing materials of equal weight,such as hexagonal honeycombs,confirming their significant potential for impact mitigation.Additionally,this research highlights the enhancements in energy absorption achieved by adding a small amount(0.015 phr)of Multi-Walled Carbon Nanotubes(MWCNTs)to the photocurable resin,thus unlocking new possibilities for the design of innovative lightweight structures with multifunctional attributes.展开更多
Co-based materials usually undergo in-situ surface reconstruction during oxidation reactions,forming high-valent Co_(3)+/Co4+species as the true active sites.However,conventional bulk structures of Co-based materials ...Co-based materials usually undergo in-situ surface reconstruction during oxidation reactions,forming high-valent Co_(3)+/Co4+species as the true active sites.However,conventional bulk structures of Co-based materials hinder deep phase transformation,limiting the utilization of internal Co sites and suppressing catalytic efficiency.Here,we report the hollow engineering of cobalt phosphide(CoP)to facilitate exposure of Co sites and promote in-situ transformation to Co_(3+)/Co^(4+)active species for enhanced oxidation activity.Hollow CoP(H-CoP)is derived from ZIF-67 via controlled etching and phosphorization,with electrochemically active surface area 2.1 times that of conventional solid CoP(S-CoP).H-CoP achieves a current density of 10 mA·cm^(-2) at a lower potential(1.26 V vs.reversible hydrogen electrode(RHE))in 5-hydroxymethylfurfural oxidation reaction(HMFOR),with a HMF conversion of 99.5%,2,5-furandicarboxylic acid yield of 98.6%,and Faraday efficiency of 97.5% at 1.45 V(vs.RHE),much superior to S-CoP.When applied as a bifunctional catalyst in the HMFOR coupled with hydrogen evolution reaction(HER)electrolyzer,H-CoP requires an ultralow voltage of 1.64 V to reach 10 mA·cm^(-2),with the cell voltage reduced by 190 mV compared to the conventional oxygen evolution reaction coupled with HER water splitting system.展开更多
To synergistically recover alumina and alkali from red mud(RM),the structural stability and conversion mechanism of hydroandradite(HA)from hydrogarnet(HG)were investigated via the First-principles,XRF,XRD,PSD and SEM ...To synergistically recover alumina and alkali from red mud(RM),the structural stability and conversion mechanism of hydroandradite(HA)from hydrogarnet(HG)were investigated via the First-principles,XRF,XRD,PSD and SEM methods,and a novel hydrothermal process based on the conversion principle was finally proposed.The crystal structure simulation shows that the HA with varied silicon saturation coefficients is more stable than HG,and the HA with a high iron substitution coefficient is more difficult to be converted from HG.The(110)plane of Fe_(2)O_(3) is easier to combine with HG to form HA,and the binding energy is 81.93 kJ/mol.The effects of raw material ratio,solution concentration and hydrothermal parameters on the conversion from HG to HA were revealed,and the optimal conditions for the alumina recovery were obtained.The recovery efficiencies of alumina and Na_(2)O from the RM are 63.06%and 97.34%,respectively,and the Na_(2)O content in the treated RM is only 0.13%.展开更多
This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw ...This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.展开更多
Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,...Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.展开更多
Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical pr...Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.展开更多
Methanol oxidation reaction(MOR)is a key process in direct methanol fuel cells(DMFCs),determining both energy efficiency and stability.Despite efforts,the impact of dynamic structural changes of Pt-based catalysts on ...Methanol oxidation reaction(MOR)is a key process in direct methanol fuel cells(DMFCs),determining both energy efficiency and stability.Despite efforts,the impact of dynamic structural changes of Pt-based catalysts on MOR performance remains poorly understood.Here,we report on the impact mechanism of dynamic changes on MOR performance in the Pd-Pt concave nanocubes(CNCs)system.Pt with high-index facets exposed abundant active sites for methanol oxidation,resulting in an exceptional mass activity of 0.89 A·mg_(Pt)^(-1).Pd underwent an oxidationredeposition process during MOR,dynamically restructuring the catalyst and producing a volcano-type activity.Pd^(δ+)species generated during oxidative etching promoted OH*formation,accelerating CO oxidation on Pt sites,thus mitigating poisoning.With continued cycling,redeposited Pd partially blocked Pt sites,counteracting the positive effect of the generated Pd^(δ+).The dynamic balance of Pd oxidation and redeposition governed the activity evolution while sustaining the exceptional durability of Pd-Pt CNCs during prolonged cycling.展开更多
In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honey...In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honeycomb cells,was created by constructing arrangement matrices to achieve structural lightweight.The machine learning(ML)framework consisted of a neural network(NN)forward regression model for predicting impact resistance and a multi-objective optimization algorithm for generating high-performance designs.The surrogate of the local design space was initially realized by establishing the NN in the small sample dataset,and the active learning strategy was used to continuously extended the local optimal design until the model converged in the global space.The results indicated that the active learning strategy significantly improved the inference capability of the NN model in unknown design domains.By guiding the iteration direction of the optimization algorithm,lightweight designs with high impact resistance were identified.The energy absorption capacity of the optimal design reached 94.98%of the EARE honeycomb,while the initial peak stress and mass decreased by 28.85%and 19.91%,respectively.Furthermore,Shapley Additive Explanations(SHAP)for global explanation of the NN indicated a strong correlation between the arrangement mode of HCS and its impact resistance.By reducing the stiffness of the cells at the top boundary of the structure,the initial impact damage sustained by the structure can be significantly improved.Overall,this study proposed a general lightweight design method for array structures under impact loads,which is beneficial for the widespread application of honeycomb-based protective structures.展开更多
Cement stands as a dominant contributor to global energy consumption and carbon emissions in the construction industry.With the upgrading of infrastructure and the improvement of building standards,traditional cement ...Cement stands as a dominant contributor to global energy consumption and carbon emissions in the construction industry.With the upgrading of infrastructure and the improvement of building standards,traditional cement fails to reconcile ecological responsibility with advanced functional performance.By incorporating tailored fillers into cement matrices,the resulting composites achieve enhanced thermoelectric(TE)conversion capabilities.These materials can harness solar radiation from building envelopes and recover waste heat from indoor thermal gradients,facilitating bidirectional energy conversion.This review offers a comprehensive and timely overview of cementbased thermoelectric materials(CTEMs),integrating material design,device fabrication,and diverse applications into a holistic perspective.It summarizes recent advancements in TE performance enhancement,encompassing fillers optimization and matrices innovation.Additionally,the review consolidates fabrication strategies and performance evaluations of cement-based thermoelectric devices(CTEDs),providing detailed discussions on their roles in monitoring and protection,energy harvesting,and smart building.We also address sustainability,durability,and lifecycle considerations of CTEMs,which are essential for real-world deployment.Finally,we outline future research directions in materials design,device engineering,and scalable manufacturing to foster the practical application of CTEMs in sustainable and intelligent infrastructure.展开更多
Large-area and free-standing photonic crystal(PC)polymer films exhibit highly saturated iridescence and robust structural colors,making them promising for applications in the field of display,anti-counterfeiting,and c...Large-area and free-standing photonic crystal(PC)polymer films exhibit highly saturated iridescence and robust structural colors,making them promising for applications in the field of display,anti-counterfeiting,and camouflage.However,their practical utilization has been hindered by challenges in achieving both vivid coloration and reusability.Here,we design a sandwich-structured PC film that simultaneously addresses issues of color appearance and reusability by combining colloid evaporative self-assembly on porous substrate and knife coating of polymers.The unique“sandwich”structure,comprising a self-assembled PC intermediate layer and protective polymer encapsulation,demonstrates a great synergistic effect(“1+1>2”),including unprecedented color fastness stability(affordable for 100 times dye/wet fastness),bright iridescent color,and certain flexibility and reusability.In addition,by replacing the bottom polymer with a double-sided adhesive,a flexible PC sticker can be further obtained,broadening its range of applications to surfaces of different materials.This strategy opens a new avenue for constructing functionalized iridescent PC-polymer films.展开更多
Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development...Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development of highly efficient SACs and a comprehensive understanding of their structure-activity relationships remain enormously challenging.Herein,a novel kind of Fe-based SAC featuring an asymmetric FeN_(5)-TeN_(4) coordination structure was precisely designed by introducing Te atom adjacent to the Fe active center to enhance the catalytic activity.Theoretical calculations reveal that the neighboring Te atom modulates the local coordination environment of the central Fe site,elevating the d-band center closer to the Fermi level and strengthening the d-p orbital hybridization between the catalyst and sulfur species,thereby immobilizing polysulfides and improving the bidirectional catalysis of Li-S redox.Consequently,the Fe-Te atom pair catalyst endows Li-S batteries with exceptional rate performance,achieving a high specific capacity of 735 mAh g^(−1) at 5 C,and remarkable cycling stability with a low decay rate of 0.038%per cycle over 1000 cycles at 1 C.This work provides fundamental insights into the electronic structure modulation of SACs and establishes a clear correlation between precisely engineered atomic configurations and their enhanced catalytic performance in Li-S electrochemistry.展开更多
Extreme cold weather seriously harms human thermoregulatory system,necessitating high-performance insulating garments to maintain body temperature.However,as the core insulating layer,advanced fibrous materials always...Extreme cold weather seriously harms human thermoregulatory system,necessitating high-performance insulating garments to maintain body temperature.However,as the core insulating layer,advanced fibrous materials always struggle to balance mechanical properties and thermal insulation,resulting in their inability to meet the demands for both washing resistance and personal protection.Herein,inspired by the natural spring-like structures of cucumber tendrils,a superelastic and washable micro/nanofibrous sponge(MNFS)based on biomimetic helical fibers is directly prepared utilizing multiple-jet electrospinning technology for high-performance thermal insulation.By regulating the conductivity of polyvinylidene fluoride solution,multiple-jet ejection and multiple-stage whipping of jets are achieved,and further control of phase separation rates enables the rapid solidification of jets to form spring-like helical fibers,which are directly entangled to assemble MNFS.The resulting MNFS exhibits superelasticity that can withstand large tensile strain(200%),1000 cyclic tensile or compression deformations,and retain good resilience even in liquid nitrogen(-196℃).Furthermore,the MNFS shows efficient thermal insulation with low thermal conductivity(24.85 mW m^(-1)K^(-1)),close to the value of dry air,and remains structural stability even after cyclic washing.This work offers new possibilities for advanced fibrous sponges in transportation,environmental,and energy applications.展开更多
As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security ...As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.展开更多
Sluggish sulfur redox kinetics remain a critical bottleneck in the advancement of high-performance lithiumsulfur batteries(LSBs).Single-atom catalysts(SACs)offer a promising solution to this limitation,particularly wh...Sluggish sulfur redox kinetics remain a critical bottleneck in the advancement of high-performance lithiumsulfur batteries(LSBs).Single-atom catalysts(SACs)offer a promising solution to this limitation,particularly when their coordination structures are carefully engineered.Here,we develop a chromium-based SAC featuring a unique undercoordinated CrN_(3) configuration to boost sulfur electrochemistry.Compared with conventional CrN_(4),the CrN_(3) motif lowers 3d orbital occupancy and meanwhile activates the in-plane hybridizations with S 3p orbitals upon interaction with polysulfides,contributing to moderate adsorption strength and reduced energy barriers for bidirectional sulfur conversions.Additionally,the integration of the two-dimensional(2D)porous framework ensures abundant electrochemically active surfaces and efficiently exposed active sites.As a result,CrN_(3)-based cells demonstrate fast and durable sulfur redox reactions,enabling an ultralow capacity decay of 0.0075%per cycle over 1000 cycles and a high-rate capability of 651.9 mAh·g^(-1)at 5 C.The CrN_(3) catalyst retains robust catalytic efficiency under demanding conditions,delivering a high areal capacity of 5.53 mAh·cm^(-2) at high sulfur loading and lean electrolyte.This work establishes a compelling paradigm of SAC coordination engineering for designing advanced sulfur electrocatalysts for next-generation LSBs.展开更多
Electronic devices capable of perceiving and responding to environmental changes are essential for applications in human-machine interaction,monitoring systems,and robotics.However,most existing devices struggle with ...Electronic devices capable of perceiving and responding to environmental changes are essential for applications in human-machine interaction,monitoring systems,and robotics.However,most existing devices struggle with the separation of sensing and actuation,resulting in complex integration and limited responsiveness.Here,inspired by the interplay between sensory and muscle cells in sea anemones,we present an intelligent thermoelectric device that seamlessly combines multimodal sensing with autonomous thermal actuation,achieving a closed-loop sensory-motor reflex.The device exhibits excellent temperature sensitivity(0.2℃)and pressure resolution(0.03 mm),attributable to its threedimensional(3D)architecture and hierarchical conductive network.Molecular dynamics simulations reveal that a dynamic hydrogen-bonding network enhances stress dissipation and interfacial adhesion,ensuring exceptional mechanical stability over 140,000 cycles.Notably,it also features thermal self-adaptation,actively triggering a protection mechanism to avoid high-temperature stimuli via thermoresponsive deformation,with an adjustable actuation threshold.This work advances intelligent electronics with real-time decision-making and environmental interaction.展开更多
Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled t...Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.展开更多
基金Supported by the National Key Research and Development Program of Traditional Chinese Medicine Modernization Project,China(No.2023YFC3504000)the Science and Technology Development Project of Jilin Province,China(No.20240404043ZP)the Science and Technology Innovation Cooperation Project of Changchun Science and Technology Bureau and Chinese Academy of Sciences,China(No.23SH14)。
文摘In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented product FGPA-G 2-H on Aβ25-35-induced PC 12 cells were explored.The structure of GPA-G 2-H was determined by means of zeta potential analysis,FTIR,HPLC,XRD,GC-MS and NMR.The backbone of GPA-G 2-H was mainly composed of→4)-α-D-Glcp-(1→with branches substituted at O-3.Notably,GPA-G 2-H was degraded by intestinal microbiota in vitro with total sugar content and pH value decreasing,and short-chain fatty acids(SCFAs)increasing.Moreover,GPA-G 2-H significantly promoted the proliferation of Lactobacillus,Muribaculaceae and Weissella,thereby making positive alterations in intestinal microbiota composition.Additionally,FGPA-G 2-H activated the Nrf 2/HO-1 signaling pathway,enhanced HO-1,NQO 1,SOD and GSH-Px,while inhabited Keap 1,MDA and LDH,which alleviated Aβ-induced oxidative stress in PC 12 cells.These provide a solid theoretical basis for the further development of ginseng polysaccharides as functional food and antioxidant drugs.
文摘Six new lanthanide complexes:[Ln(3,4-DEOBA)3(4,4'-DM-2,2'-bipy)]2·2C_(2)H_(5)OH,[Ln=Dy(1),Eu(2),Tb(3),Sm(4),Ho(5),Gd(6);3,4-DEOBA-=3,4-diethoxybenzoate,4,4'-DM-2,2'-bipy=4,4'-dimethyl-2,2'-bipyridine]were successfully synthesized by the volatilization of the solution at room temperature.The crystal structures of six complexes were determined by single-crystal X-ray diffraction technology.The results showed that the complexes all have a binuclear structure,and the structures contain free ethanol molecules.Moreover,the coordination number of the central metal of each structural unit is eight.Adjacent structural units interact with each other through hydrogen bonds and further expand to form 1D chain-like and 2D planar structures.After conducting a systematic study on the luminescence properties of complexes 1-4,their emission and excitation spectra were obtained.Experimental results indicated that the fluorescence lifetimes of complexes 2 and 3 were 0.807 and 0.845 ms,respectively.The emission spectral data of complexes 1-4 were imported into the CIE chromaticity coordinate system,and their corre sponding luminescent regions cover the yellow light,red light,green light,and orange-red light bands,respectively.Within the temperature range of 299.15-1300 K,the thermal decomposition processes of the six complexes were comprehensively analyzed by using TG-DSC/FTIR/MS technology.The hypothesis of the gradual loss of ligand groups during the decomposition process was verified by detecting the escaped gas,3D infrared spectroscopy,and ion fragment information detected by mass spectrometry.The specific decomposition path is as follows:firstly,free ethanol molecules and neutral ligands are removed,and finally,acidic ligands are released;the final product is the corresponding metal oxide.CCDC:2430420,1;2430422,2;2430419,3;2430424,4;2430421,5;2430423,6.
基金Supported by the Science and Technology Cooperation and Exchange special project of Cooperation of Shanxi Province(202404041101014)the Fundamental Research Program of Shanxi Province(202403021212333)+3 种基金the Joint Funds of the National Natural Science Foundation of China(U24A20555)the Lvliang Key R&D of University-Local Cooperation(2023XDHZ10)the Initiation Fund for Doctoral Research of Taiyuan University of Science and Technology(20242026)the Outstanding Doctor Funding Award of Shanxi Province(20242080).
文摘To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.
基金supported by the Khalifa University of Science and Technology internal grants(Nos.2021-CIRA-109,2020-CIRA-007,and 2020-CIRA-024).
文摘Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-inspired lattice structures feature a square-grid 2D lattice with double diagonal bracings and are additively manufactured via digital light processing(DLP).The collapse strength and energy absorption capacity of sea sponge lattice structures are evaluated under various impact conditions and are compared to those of their constituent square-grid and double diagonal lattices.This study demonstrates that sea sponge lattices can achieve an 11-fold increase in energy absorption compared to the square-grid lattice,due to the stabilizing effect of the double diagonal bracings prompting the structure to collapse layer-bylayer under impact.By adjusting the thickness ratio in the sea sponge lattice,up to 76.7%increment in energy absorption is attained.It is also shown that sea-sponge lattices outperform well-established energy-absorbing materials of equal weight,such as hexagonal honeycombs,confirming their significant potential for impact mitigation.Additionally,this research highlights the enhancements in energy absorption achieved by adding a small amount(0.015 phr)of Multi-Walled Carbon Nanotubes(MWCNTs)to the photocurable resin,thus unlocking new possibilities for the design of innovative lightweight structures with multifunctional attributes.
基金the National Natural Science Foundation of China(Nos.22422806,22378136,and 22138003)the Guangdong Pearl River Talents Program(Nos.2021QN02C847 and 2021ZT09Z109)+4 种基金the Natural Science Foundation of Guangdong Province(Nos.2024A1515011196 and 2023B1515040005)the Guangzhou Municipal Science and Technology Project(No.2025A04J5244)the Fundamental Research Funds for the Central Universities(No.2024ZYGXZR011)the State Key Laboratory of Pulp and Paper Engineering(Nos.2023PY06 and 2024ZD09)the TCL Young Talent Program.
文摘Co-based materials usually undergo in-situ surface reconstruction during oxidation reactions,forming high-valent Co_(3)+/Co4+species as the true active sites.However,conventional bulk structures of Co-based materials hinder deep phase transformation,limiting the utilization of internal Co sites and suppressing catalytic efficiency.Here,we report the hollow engineering of cobalt phosphide(CoP)to facilitate exposure of Co sites and promote in-situ transformation to Co_(3+)/Co^(4+)active species for enhanced oxidation activity.Hollow CoP(H-CoP)is derived from ZIF-67 via controlled etching and phosphorization,with electrochemically active surface area 2.1 times that of conventional solid CoP(S-CoP).H-CoP achieves a current density of 10 mA·cm^(-2) at a lower potential(1.26 V vs.reversible hydrogen electrode(RHE))in 5-hydroxymethylfurfural oxidation reaction(HMFOR),with a HMF conversion of 99.5%,2,5-furandicarboxylic acid yield of 98.6%,and Faraday efficiency of 97.5% at 1.45 V(vs.RHE),much superior to S-CoP.When applied as a bifunctional catalyst in the HMFOR coupled with hydrogen evolution reaction(HER)electrolyzer,H-CoP requires an ultralow voltage of 1.64 V to reach 10 mA·cm^(-2),with the cell voltage reduced by 190 mV compared to the conventional oxygen evolution reaction coupled with HER water splitting system.
基金the financial support from the National Key R&D Program of China(No.2022YFC2904405)the National Natural Science Foundation of China(Nos.22078055,51774079)。
文摘To synergistically recover alumina and alkali from red mud(RM),the structural stability and conversion mechanism of hydroandradite(HA)from hydrogarnet(HG)were investigated via the First-principles,XRF,XRD,PSD and SEM methods,and a novel hydrothermal process based on the conversion principle was finally proposed.The crystal structure simulation shows that the HA with varied silicon saturation coefficients is more stable than HG,and the HA with a high iron substitution coefficient is more difficult to be converted from HG.The(110)plane of Fe_(2)O_(3) is easier to combine with HG to form HA,and the binding energy is 81.93 kJ/mol.The effects of raw material ratio,solution concentration and hydrothermal parameters on the conversion from HG to HA were revealed,and the optimal conditions for the alumina recovery were obtained.The recovery efficiencies of alumina and Na_(2)O from the RM are 63.06%and 97.34%,respectively,and the Na_(2)O content in the treated RM is only 0.13%.
基金Funded by the Science and Technology Program of Gansu Province(Nos.25JRRA497,23ZDFA017)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0950000)High-level Talent Funding of Kashi。
文摘This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.
基金supported by the National Key Research and Development Program of China(2024YFA1612900)the National Natural Science Foundation of China(Grant No.52103365 and No.12375270)the Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2021ZT09L227).
文摘Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.
基金Funded by Shandong Provincial Youth Innovation Team Development Plan of Colleges and Universities(No.2022KJ100)National Natural Science Foundation of China(No.52172019)。
文摘Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.
基金supported by the National Natural Science Foundation of China(Nos.12222508 and 12475325)the National Key Research and Development Program of China(Nos.2024YFA1509201 and 2023YFA1506304)the beamlines BL10B(No.31131.02.HLS.PES)and BL01B(No.31131.02.HLS.IRSM)in NSRL,and BL11B(No.31124.02.SSRF.BL11B)in SSRF for synchrotron radiation measurements.
文摘Methanol oxidation reaction(MOR)is a key process in direct methanol fuel cells(DMFCs),determining both energy efficiency and stability.Despite efforts,the impact of dynamic structural changes of Pt-based catalysts on MOR performance remains poorly understood.Here,we report on the impact mechanism of dynamic changes on MOR performance in the Pd-Pt concave nanocubes(CNCs)system.Pt with high-index facets exposed abundant active sites for methanol oxidation,resulting in an exceptional mass activity of 0.89 A·mg_(Pt)^(-1).Pd underwent an oxidationredeposition process during MOR,dynamically restructuring the catalyst and producing a volcano-type activity.Pd^(δ+)species generated during oxidative etching promoted OH*formation,accelerating CO oxidation on Pt sites,thus mitigating poisoning.With continued cycling,redeposited Pd partially blocked Pt sites,counteracting the positive effect of the generated Pd^(δ+).The dynamic balance of Pd oxidation and redeposition governed the activity evolution while sustaining the exceptional durability of Pd-Pt CNCs during prolonged cycling.
基金the financial supports from National Key R&D Program for Young Scientists of China(Grant No.2022YFC3080900)National Natural Science Foundation of China(Grant No.52374181)+1 种基金BIT Research and Innovation Promoting Project(Grant No.2024YCXZ017)supported by Science and Technology Innovation Program of Beijing institute of technology under Grant No.2022CX01025。
文摘In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honeycomb cells,was created by constructing arrangement matrices to achieve structural lightweight.The machine learning(ML)framework consisted of a neural network(NN)forward regression model for predicting impact resistance and a multi-objective optimization algorithm for generating high-performance designs.The surrogate of the local design space was initially realized by establishing the NN in the small sample dataset,and the active learning strategy was used to continuously extended the local optimal design until the model converged in the global space.The results indicated that the active learning strategy significantly improved the inference capability of the NN model in unknown design domains.By guiding the iteration direction of the optimization algorithm,lightweight designs with high impact resistance were identified.The energy absorption capacity of the optimal design reached 94.98%of the EARE honeycomb,while the initial peak stress and mass decreased by 28.85%and 19.91%,respectively.Furthermore,Shapley Additive Explanations(SHAP)for global explanation of the NN indicated a strong correlation between the arrangement mode of HCS and its impact resistance.By reducing the stiffness of the cells at the top boundary of the structure,the initial impact damage sustained by the structure can be significantly improved.Overall,this study proposed a general lightweight design method for array structures under impact loads,which is beneficial for the widespread application of honeycomb-based protective structures.
基金supported by the National Natural Science Foundation of China(No.52242305).
文摘Cement stands as a dominant contributor to global energy consumption and carbon emissions in the construction industry.With the upgrading of infrastructure and the improvement of building standards,traditional cement fails to reconcile ecological responsibility with advanced functional performance.By incorporating tailored fillers into cement matrices,the resulting composites achieve enhanced thermoelectric(TE)conversion capabilities.These materials can harness solar radiation from building envelopes and recover waste heat from indoor thermal gradients,facilitating bidirectional energy conversion.This review offers a comprehensive and timely overview of cementbased thermoelectric materials(CTEMs),integrating material design,device fabrication,and diverse applications into a holistic perspective.It summarizes recent advancements in TE performance enhancement,encompassing fillers optimization and matrices innovation.Additionally,the review consolidates fabrication strategies and performance evaluations of cement-based thermoelectric devices(CTEDs),providing detailed discussions on their roles in monitoring and protection,energy harvesting,and smart building.We also address sustainability,durability,and lifecycle considerations of CTEMs,which are essential for real-world deployment.Finally,we outline future research directions in materials design,device engineering,and scalable manufacturing to foster the practical application of CTEMs in sustainable and intelligent infrastructure.
基金financially supported by the National Natural Science Foundation of China(Nos.22178047 and 21878042)the Fundamental Research Funds for the Central Universities(No.DUT22LAB610)Liaoning province science and technology plan projects(No.2022JH2/101300233).
文摘Large-area and free-standing photonic crystal(PC)polymer films exhibit highly saturated iridescence and robust structural colors,making them promising for applications in the field of display,anti-counterfeiting,and camouflage.However,their practical utilization has been hindered by challenges in achieving both vivid coloration and reusability.Here,we design a sandwich-structured PC film that simultaneously addresses issues of color appearance and reusability by combining colloid evaporative self-assembly on porous substrate and knife coating of polymers.The unique“sandwich”structure,comprising a self-assembled PC intermediate layer and protective polymer encapsulation,demonstrates a great synergistic effect(“1+1>2”),including unprecedented color fastness stability(affordable for 100 times dye/wet fastness),bright iridescent color,and certain flexibility and reusability.In addition,by replacing the bottom polymer with a double-sided adhesive,a flexible PC sticker can be further obtained,broadening its range of applications to surfaces of different materials.This strategy opens a new avenue for constructing functionalized iridescent PC-polymer films.
基金supported by the National Natural Science Foundation(52302284,22002086,22204096)Shanghai Sailing Program(23YF1412200)the Fundamental Research Funds for the Central Universities(22120240314).
文摘Single-atom catalysts(SACs)have garnered significant attention in lithium-sulfur(Li-S)batteries for their potential to mitigate the severe polysulfide shuttle effect and sluggish redox kinetics.However,the development of highly efficient SACs and a comprehensive understanding of their structure-activity relationships remain enormously challenging.Herein,a novel kind of Fe-based SAC featuring an asymmetric FeN_(5)-TeN_(4) coordination structure was precisely designed by introducing Te atom adjacent to the Fe active center to enhance the catalytic activity.Theoretical calculations reveal that the neighboring Te atom modulates the local coordination environment of the central Fe site,elevating the d-band center closer to the Fermi level and strengthening the d-p orbital hybridization between the catalyst and sulfur species,thereby immobilizing polysulfides and improving the bidirectional catalysis of Li-S redox.Consequently,the Fe-Te atom pair catalyst endows Li-S batteries with exceptional rate performance,achieving a high specific capacity of 735 mAh g^(−1) at 5 C,and remarkable cycling stability with a low decay rate of 0.038%per cycle over 1000 cycles at 1 C.This work provides fundamental insights into the electronic structure modulation of SACs and establishes a clear correlation between precisely engineered atomic configurations and their enhanced catalytic performance in Li-S electrochemistry.
基金supported by Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2022QNRC001)the National Natural Science Foundation of China(No.52273053)the Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.21CGA41)。
文摘Extreme cold weather seriously harms human thermoregulatory system,necessitating high-performance insulating garments to maintain body temperature.However,as the core insulating layer,advanced fibrous materials always struggle to balance mechanical properties and thermal insulation,resulting in their inability to meet the demands for both washing resistance and personal protection.Herein,inspired by the natural spring-like structures of cucumber tendrils,a superelastic and washable micro/nanofibrous sponge(MNFS)based on biomimetic helical fibers is directly prepared utilizing multiple-jet electrospinning technology for high-performance thermal insulation.By regulating the conductivity of polyvinylidene fluoride solution,multiple-jet ejection and multiple-stage whipping of jets are achieved,and further control of phase separation rates enables the rapid solidification of jets to form spring-like helical fibers,which are directly entangled to assemble MNFS.The resulting MNFS exhibits superelasticity that can withstand large tensile strain(200%),1000 cyclic tensile or compression deformations,and retain good resilience even in liquid nitrogen(-196℃).Furthermore,the MNFS shows efficient thermal insulation with low thermal conductivity(24.85 mW m^(-1)K^(-1)),close to the value of dry air,and remains structural stability even after cyclic washing.This work offers new possibilities for advanced fibrous sponges in transportation,environmental,and energy applications.
基金supported by the Key Project of Joint Fund of the National Natural Science Foundation of China“Research on Key Technologies and Demonstration Applications for Trusted and Secure Data Circulation and Trading”(U24A20241)the National Natural Science Foundation of China“Research on Trusted Theories and Key Technologies of Data Security Trading Based on Blockchain”(62202118)+4 种基金the Major Scientific and Technological Special Project of Guizhou Province([2024]014)Scientific and Technological Research Projects from the Guizhou Education Department(Qian jiao ji[2023]003)the Hundred-Level Innovative Talent Project of the Guizhou Provincial Science and Technology Department(Qiankehe Platform Talent-GCC[2023]018)the Major Project of Guizhou Province“Research and Application of Key Technologies for Trusted Large Models Oriented to Public Big Data”(Qiankehe Major Project[2024]003)the Guizhou Province Computational Power Network Security Protection Science and Technology Innovation Talent Team(Qiankehe Talent CXTD[2025]029).
文摘As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.
基金the National Natural Science Foundation of China(No.22379069)Fundamental Research Funds for the Central Universities(No.30922010304).
文摘Sluggish sulfur redox kinetics remain a critical bottleneck in the advancement of high-performance lithiumsulfur batteries(LSBs).Single-atom catalysts(SACs)offer a promising solution to this limitation,particularly when their coordination structures are carefully engineered.Here,we develop a chromium-based SAC featuring a unique undercoordinated CrN_(3) configuration to boost sulfur electrochemistry.Compared with conventional CrN_(4),the CrN_(3) motif lowers 3d orbital occupancy and meanwhile activates the in-plane hybridizations with S 3p orbitals upon interaction with polysulfides,contributing to moderate adsorption strength and reduced energy barriers for bidirectional sulfur conversions.Additionally,the integration of the two-dimensional(2D)porous framework ensures abundant electrochemically active surfaces and efficiently exposed active sites.As a result,CrN_(3)-based cells demonstrate fast and durable sulfur redox reactions,enabling an ultralow capacity decay of 0.0075%per cycle over 1000 cycles and a high-rate capability of 651.9 mAh·g^(-1)at 5 C.The CrN_(3) catalyst retains robust catalytic efficiency under demanding conditions,delivering a high areal capacity of 5.53 mAh·cm^(-2) at high sulfur loading and lean electrolyte.This work establishes a compelling paradigm of SAC coordination engineering for designing advanced sulfur electrocatalysts for next-generation LSBs.
基金supported by the National Natural Science Foundation of China(Nos.22175164,12232016,and 12172346)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0450402)+2 种基金the Youth Innovation Promotion Association CAS(No.2022465)the Fundamental Research Funds for the Central Universities(No.WK2090000087)the University of Science and Technology of China(USTC)Tang Scholar.
文摘Electronic devices capable of perceiving and responding to environmental changes are essential for applications in human-machine interaction,monitoring systems,and robotics.However,most existing devices struggle with the separation of sensing and actuation,resulting in complex integration and limited responsiveness.Here,inspired by the interplay between sensory and muscle cells in sea anemones,we present an intelligent thermoelectric device that seamlessly combines multimodal sensing with autonomous thermal actuation,achieving a closed-loop sensory-motor reflex.The device exhibits excellent temperature sensitivity(0.2℃)and pressure resolution(0.03 mm),attributable to its threedimensional(3D)architecture and hierarchical conductive network.Molecular dynamics simulations reveal that a dynamic hydrogen-bonding network enhances stress dissipation and interfacial adhesion,ensuring exceptional mechanical stability over 140,000 cycles.Notably,it also features thermal self-adaptation,actively triggering a protection mechanism to avoid high-temperature stimuli via thermoresponsive deformation,with an adjustable actuation threshold.This work advances intelligent electronics with real-time decision-making and environmental interaction.
基金supported by the Research Project on Strengthening the Construction of an Important Ecological Security Barrier in Northern China by Higher Education Institutions in the Inner Mongolia Autonomous Region(STAQZX202313)the Inner Mongolia Autonomous Region Education Science‘14th Five-Year Plan’2024 Annual Research Project(NGJGH2024635).
文摘Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.
