This paper examines a model that combines vortex generators and leading-edge tubercles for controlling the laminar separation bubble(LSB)over an airfoil at low Reynolds numbers(Re).This new concept of passive flow con...This paper examines a model that combines vortex generators and leading-edge tubercles for controlling the laminar separation bubble(LSB)over an airfoil at low Reynolds numbers(Re).This new concept of passive flow control technique utilizing a tubercle and vortex generator(VG)close to the leading edge was analyzed numerically for a NACA0015 airfoil.In this study,the Shear Stress Transport(SST)turbulence model was employed in the numerical modelling.Numerical modelling was completed using the ANSYS-Fluent 18.2 solver.Analyses were conducted to investigate the flow pattern and understand the underlying LSB control phenomena that enabled the new passive flow control method to provide this significant performance benefit.The findings indicated that the new concept of passive flow control technique suppressed the formation of an LSB at the suction surface of the NACA0015 airfoil,resulting in a higher lift coefficient and improved aerodynamic performance.Improvements in LSB dynamics and aerodynamic performance through the passive flow control method lead to increased energy output and enhanced stability.展开更多
The China-ASEAN Free Trade Area(CAFTA)3.0Upgrade Protocol added a section on“Supply Chain Connectivity,”which emphasizes that all parties recognize the lessons learned from the COVID-19 pandemic and cooperate to enh...The China-ASEAN Free Trade Area(CAFTA)3.0Upgrade Protocol added a section on“Supply Chain Connectivity,”which emphasizes that all parties recognize the lessons learned from the COVID-19 pandemic and cooperate to enhance the resilience of the regional supply chain.This is an inevitable trend amid the current accelerated restructuring of the global supply chain,the complex and severe international economic and trade situation,and the impact on the regional industrial chain.It also represents a fundamental shift and consensus on the logic of supply chain cooperation between China and ASEAN countries—a transformation from“Efficiency First”to“Resilience First.”展开更多
Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’...Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’s disease.In this review,we summarize the changes in short-chain fatty acid levels and the abundance of short-chain fatty acid-producing bacteria in various samples from patients with Parkinson’s disease,highlighting the critical role of gut homeostasis imbalance in the pathogenesis and progression of the disease.Focusing on the nervous system,we discuss the molecular mechanisms by which short-chain fatty acids influence the homeostasis of both the enteric nervous system and the central nervous system.We identify key processes,including the activation of G protein-coupled receptors and the inhibition of histone deacetylases by short-chain fatty acids.Importantly,structural or functional disruptions in the enteric nervous system mediated by these fatty acids may lead to abnormalα-synuclein expression and gastrointestinal dysmotility,which could serve as an initiating event in Parkinson’s disease.Furthermore,we propose that short-chain fatty acids help establish communication between the enteric nervous system and the central nervous system via the vagal nerve,immune circulation,and endocrine signaling.This communication may shed light on their potential role in the transmission ofα-synuclein from the gut to the brain.Finally,we elucidate novel treatment strategies for Parkinson’s disease that target short-chain fatty acids and examine the challenges associated with translating short-chain fatty acid-based therapies into clinical practice.In conclusion,this review emphasizes the pivotal role of short-chain fatty acids in regulating gut-brain axis integrity and their significance in the pathogenesis of Parkinson’s disease from the perspective of the nervous system.Moreover,it highlights the potential value of short-chain fatty acids in early intervention for Parkinson’s disease.Future research into the molecular mechanisms of short-chain fatty acids and their synergistic interactions with other gut metabolites is likely to advance the clinical translation of innovative short-chain fatty acid-based therapies for Parkinson’s disease.展开更多
Chain graphs are{2K_(2),C_(3),C_(5)}-free graphs.Balaban index and sum-Balaban index are two important topological indices.In this paper,we concentrate on the subclass of bicyclic connected chain graphs,identifying th...Chain graphs are{2K_(2),C_(3),C_(5)}-free graphs.Balaban index and sum-Balaban index are two important topological indices.In this paper,we concentrate on the subclass of bicyclic connected chain graphs,identifying the extremal graphs that exhibit the minimum or maximum Balaban index and sum-Balaban index within this class.Moreover,we provide a systematic ordering of all bicyclic connected chain graphs according to the magnitude of their Balaban index and sum-Balaban index.展开更多
Despite demonstrating significant anti-tumor potential as an artemisinin derivative,artesunate faces delivery efficiency challenges due to low water solubility and insufficient targeting specificity.To improve the del...Despite demonstrating significant anti-tumor potential as an artemisinin derivative,artesunate faces delivery efficiency challenges due to low water solubility and insufficient targeting specificity.To improve the delivery efficiency,we engineered three artesunate(ART) derivatives,AC_(15)-L(linear),AC_(15)-B(branched),and AC_(15)-C(cyclic) with distinct aliphatic chain architectures.Unexpectedly,we observed that AC_(15)-C exhibited superior cytotoxicity against 4T1 breast cancer cells,and had the highest binding affinity for Lon protease 1(LONP1)(-72.6 kcal/mol).Subsequently,disulfide bond-containing lipid-PEG(DSPESS-PEG2K) modified chain architecture-engineered ART derivatives nanoassemblies(NAs) were developed to mitigate solubility-related limitations while enhancing targeting precision.Molecular docking and experimental validation demonstrated that ART derivatives inhibited LONP1 through hydrophobic interactions while preserved Fe^(2+)-mediated Fenton-like reaction activity.In vitro and in vivo evaluations demonstrated that AC_(15)-C NAs outperformed free ART and other NAs,suppressing 4T1 tumor growth via dual action:LONP1-directed mitochondrial proteostasis collapse and reactive oxygen species(ROS) amplification through Fe^(2+)-ART interactions.This study elucidated a novel anti-tumor mechanism of ART through the rational design of derivatives with spatially configured aliphatic chains,and developed reductionresponsive NAs to provide an advanced delivery strategy.展开更多
Microporous polyimides(PIM-PIs)have emerged as promising high-performance membranes for gas separation.However,achieving an optimal balance between permeability and selectivity remains a major challenge.In this study,...Microporous polyimides(PIM-PIs)have emerged as promising high-performance membranes for gas separation.However,achieving an optimal balance between permeability and selectivity remains a major challenge.In this study,we designed and synthesized a series of PIM-PIs by combining rigid dianhydrides 9-bis(trifluoromethyl)-2,3,6,7-xanthenetetracarboxylic dianhydride(6FCDA)and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)with contorted diamines,including 9,9-bis(4-aminophenyl)fluorene(FDA),9,9′-spirobifluorene-2,2′-diamine(SBFDA),and 3,3,3′,3′-tetramethyl-1,1′-spirobiindane-5,5′-diamine-6,6′-diol(TSDA),to systematically elucidate the relationship between hierarchical microstructure and gas transport behavior.Comprehensive characterization revealed that the 6FCDA-based polymers exhibited a higher microporosity(V_(micro)/V_(total)up to 54.7%)and fractional free volume compared to their 6FDA counterparts.Gas permeation measurements showed that the 6FCDA/SBFDA membrane delivered a CO_(2)permeability of 386 Barrer and CO_(2)/CH_(4)selectivity of 30.2,exceeding the 2008 Robeson upper bound.Structure-property correlation analyses indicated that diffusion selectivity predominantly governed gas separation performance,with rigid,spirocyclic architectures suppressing chain packing to generate sub-5Åmicropores,as further validated by molecular simulations.The optimized 6FCDA/FDA membrane achieved a BET surface area of 423 m^(2)·g^(−1),while maintaining excellent mechanical strength and high thermal stability.This work establishes an effective monomer design strategy to overcome the permeability-selectivity trade-off through backbone rigidification,thereby advancing PIM-PIs for practical applications in natural gas purification and carbon capture.展开更多
The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited im...The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).展开更多
Purpose-This study explores how managerial leadership and organizational innovation interact to enhance resilience and risk management in railway supply chains and how these capabilities contribute to sustained compet...Purpose-This study explores how managerial leadership and organizational innovation interact to enhance resilience and risk management in railway supply chains and how these capabilities contribute to sustained competitive advantage.It emphasizes the strategic importance of resilience in railway systems that face operational complexity,regulatory pressures and increasing exposure to systemic risks.Design/methodology/approach-A mixed-methods design was employed,integrating survey data from 186 railway organizations with six case studies involving railway operators,rolling stock manufacturers and supply chain partners across multiple regions.Constructs were measured using validated scales and hypothesized relationships were tested using Structural Equation Modeling(SEM).Case study interviews were analyzed thematically to provide contextual understanding of leadership practices and innovation strategies.Findings-The results confirm that transformational managerial leadership significantly predicts innovation adoption,which in turn strengthens resilience and risk management capabilities.Resilience emerged as a powerful driver of competitive advantage,reinforcing its role as a strategic capability rather than a reactive response to disruptions.Furthermore,innovation was shown to partially mediate the relationship between leadership and resilience,highlighting its function as the operational channel through which vision translates into capability.Originality/value-This study contributes to the literature by integrating the Resource-Based View(RBV)and Dynamic Capabilities(DC)framework into the context of railway supply chains.It is among the first to empirically validate the mediating role of innovation between leadership and resilience,offering both theoretical advancements and actionable strategies for building resilient and competitive railway systems.展开更多
With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving...With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.展开更多
The efficient flotation separation of rare earth elements(REEs)from gangue minerals is crucial in mineral processing.This study synthesized a quaternary ammonium salt ionic liquid collector,tetrabutylammonium salicylh...The efficient flotation separation of rare earth elements(REEs)from gangue minerals is crucial in mineral processing.This study synthesized a quaternary ammonium salt ionic liquid collector,tetrabutylammonium salicylhydroxamate(T-S),and investigated its performance in separating bastnaesite and fluorite.T-S was synthesized from salicylhydroxamic acid(SHA)and tetrabutylammonium chloride(TBAC),and its molecular structure was characterized using Fourier transform infrared(FTIR)spectroscopy.Microflotation tests indicate that T-S outperforms SHA and TBAC in both collecting ability and selectivity for bastnaesite.Adsorption,zeta potential,and infrared spectroscopy measurements reveal that T-S exhibits stronger adsorption on bastnaesite compared to SHA and TBAC.X-ray photoelectron spectroscopy(XPS)and molecular dynamics simulations(MDS)results confirm that chemical adsorption occurs between Ce on the bastnaesite surface and the-C(=O)NHOH groups of T-S.Moreover,the interaction between T-S and the bastnaesite surface is stronger than that with the fluorite surface.This work provides valuable insights for designing ionic liquid collectors for the flotation separation of bastnaesite and fluorite.展开更多
Against a backdrop of rising global trade protectionism and accelerated restructuring of international industrial and supply chains,regional institutional cooperation is becoming a key force in stabilizing cross-borde...Against a backdrop of rising global trade protectionism and accelerated restructuring of international industrial and supply chains,regional institutional cooperation is becoming a key force in stabilizing cross-border trade and investment.The ASEAN region enjoys strong economic growth momentum with a distinct demographic advantage while China boasts a complete industrial system and manufacturing capacity.展开更多
Developing advanced polymeric materials with enhanced mechanical properties and functionalities has been a long-standing goal in materials science.Recently,supramolecular polymeric materials (SPMs) have drawn increase...Developing advanced polymeric materials with enhanced mechanical properties and functionalities has been a long-standing goal in materials science.Recently,supramolecular polymeric materials (SPMs) have drawn increased attention due to their unique properties and potential applications in self-healing,shape memory,sensors,and flexible electronics.Here,we develop an ionic cluster-optimized microphase separation strategy to enhance the toughening and energy dissipation capabilities of polydisulfide-based supramolecular polymers.The mechanical properties,including Young’s modulus and toughness,are significantly improved by integrating the quadruple H-bonding 2-ureido-4-pyrimidone (UPy) induced microphase separation with iron(Ⅲ)-to-carboxylate ionic clusters.By combining established chemical approaches with adjustable polymer phase ratios,it is revealed that the synergistic effect of these factors expands the interchain spacing,facilitates the formation of microphase domains,and enhances the tolerance of polythioctic acid-based polymers to external mechanical and thermal stimuli,meeting the practical requirements for industrial plastic applications.Moreover,the UPy-functionalized polymers incorporating iron carboxylate clusters exhibit good one-way shape memory behavior with practical applicability at a relatively low recovery temperature.Our work demonstrates a novel strategy for constructing industrially viable shape memory dynamic SPMs and paves the way for future innovations in developing SPMs.展开更多
Bayan Obo rare earth mine is the largest light rare earth resource worldwide,primarily extracts rare earth elements(REEs)from mixed RE concentrates with bastnaesite and monazite.Nevertheless,the adoption of the concen...Bayan Obo rare earth mine is the largest light rare earth resource worldwide,primarily extracts rare earth elements(REEs)from mixed RE concentrates with bastnaesite and monazite.Nevertheless,the adoption of the concentrated sulfuric acid roasting metallurgical process has resulted in damage to the environment.Therefore,this paper adopted the method of selective mineral phase transformation(MPT)followed by enhanced micro-flotation.By determining the optimal MPT co nditions,the flotation recovery of bastnaesite-roasted products by the collector(phthalic acid,PA)is improved,and the enhanced separation of bastnaesite with monazite is realized.The results show that with the increase of roasting temperature and time,the bastnaesite decomposition product is CeOF and monazite does not change significantly.Subsequent micro-flotation exhibits a gradual decline in the PA consumption of bastnaesiteroasted products,while the flotation recovery of monazite-roasted products remains poor.The artificial mixed ore experiments result in a CeOF foam product with a content of 94.14%and a recovery of 85.80%,and a monazite tank product with a content of 73.53%and a recovery of 87.87%.Compared with the preroasting ore,the surface and interior of bastnaesite-roasted products develop numerous cracks and porosities,and no obvious structural damage is observed in monazite-roasted particles.As the roasting temperature increases,the mineral particles undergo recrystallization or closure,reducing the specific surface area of bastnaesite-roasted products and enhancing hydrophobicity,leading to diminished PA consumption.Fourier transform infrared and other flotation-relation tests show that PA is chemisorbed on the surface of CeOF.The MPT conditions are optimized in this study,which provides a reference for further advancing the efficient separation of bastnaesite and monazite.展开更多
To develop an efficient filter for removing white blood cells from whole blood,hydrophilic large-pore blended membranes of poly(vinylidene fluoride)(PVDF),polyvinyl pyrrolidone and polyethylene glycol,with good biocom...To develop an efficient filter for removing white blood cells from whole blood,hydrophilic large-pore blended membranes of poly(vinylidene fluoride)(PVDF),polyvinyl pyrrolidone and polyethylene glycol,with good biocompatibility,were prepared using the process of vapor-induced phase separation at various PVDF concentrations.The results demonstrated that at a PVDF mass concentration of 14%,the membrane had increased surface roughness,significantly enhanced hydrophilicity and wettability,and a wetting time of 8 s.The surface roughness of the membrane was also reduced to 31.637 nm.Furthermore,hemolysis rate and protein adsorption tests indicated that the blended membranes possessed excellent biocompatibility.They were reduced to 2.48%and 34.44μg·cm^(−2),respectively.The pore size of the fabricated membrane was relatively large,which reached approximately 8μm respectively,satisfying the filtration requirements.Lastly,the effects of different temperatures and multi-layered filters on leukocyte removal and the retention of red blood cells and platelets from whole blood were evaluated.The results revealed that the leukocyte removal rate was highest at 4℃ and with three membrane layers,the leukocyte removal rate was highest,reaching 98.36%,while the RBC and platelet content remained nearly unchanged compared with the original blood.This study provides a new approach for blood cell separation that is expected to play a significant role in medical fields such as blood transfusion demonstrating great potential for application and innovation.展开更多
Lignocellulosic biomass is the most abundant re-newable resource on Earth,boasting advan-tages such as wide avail-ability and negative car-bon emissions.Especial-ly,efficient separation of lignocellulose into cellu-lo...Lignocellulosic biomass is the most abundant re-newable resource on Earth,boasting advan-tages such as wide avail-ability and negative car-bon emissions.Especial-ly,efficient separation of lignocellulose into cellu-lose,hemicellulose and lignin,and realizing val-orization of these compo-nents are more responsive to the development needs of biomass refinery and the green chem-istry era.This review outlines the main components of lignocellulose and briefly summerizes their utilization in chemical raw materials and energy production.It mainly focused on cur-rent advances in component separation methods of lignocellulose by organic solvents,ionic liquids and deep eutectic solvents.The design of separation methods,understanding of sepa-ration mechanisms,and optimization of reaction systems in each method are highlighted in detail.Furthermore,the ongoing challenges and future directions based on mechanism and in-dustrialization are critically discussed.Our goal is to elucidate the separation mechanisms and principles of method design,providing guidance for the development of highly efficient com-ponent separation methods of lignocellulose.展开更多
On December 18,2023,a magnitude 6.2 earthquake struck Jishishan County,Gansu Province,triggering a liquefaction-induced flow slide along the loess-mudstone contact zone and causing significant casualties and property ...On December 18,2023,a magnitude 6.2 earthquake struck Jishishan County,Gansu Province,triggering a liquefaction-induced flow slide along the loess-mudstone contact zone and causing significant casualties and property losses.The event featured low-slope,large-scale,runout distance sliding and exhibited a clear cascading disaster chain.Its characteristics closely resemble the catastrophic mudflow at the nearby Lajia Ruins approximately 4,000 years ago.Using high-resolution oblique photogrammetry,cone penetration testing,surface wave analysis,and horizontal-to-vertical spectral ratio methods,this study examines the stratigraphy,groundwater conditions,and geomechanical properties of the affected zone.Results indicate that saturated loess overlying impermeable mudstone formed a high-moisture mass vulnerable to seismic disturbance.Seismic resonance triggered the liquefaction of weakly structured loess,which slide along the contact interface and evolved into a runout distance mudflow.Underground water and terrain modification created a composite weak zone of saturated loess and softened mudstone,which intensified the disaster chain-from earthquake to liquefaction,flow slide,and mudflow.This study contributes to the understanding of deep-seated liquefaction-flow slide disasters,thereby advancing more effective risk mitigation strategies in the Loess Plateau and comparable loess-covered seismic regions.展开更多
Objective:To analyze the impact of maternal-infant separation on the physical and mental state of high-risk pregnancy patients and explore the clinical efficacy of targeted nursing interventions.Methods:A total of 80 ...Objective:To analyze the impact of maternal-infant separation on the physical and mental state of high-risk pregnancy patients and explore the clinical efficacy of targeted nursing interventions.Methods:A total of 80 high-risk pregnancy patients treated in our hospital from January 2023 to January 2024 were selected as the study subjects.These patients were randomly divided into an observation group and a control group(40 cases each)using a random number table.The control group received routine high-risk pregnancy nursing care,while the observation group received specialized maternal-infant separation nursing interventions in addition to routine care.The psychological and physiological states and nursing satisfaction of the two groups were compared before and after the intervention.Results:The SAS scores,SDS scores,and sleep quality scores of the observation group were significantly lower than those of the control group,with statistically significant differences(p<0.05).The incidence of postpartum hemorrhage in the observation group was significantly lower than that in the control group,and the initiation time of lactation was significantly earlier than that in the control group,with both differences being statistically significant(p<0.05).The nursing satisfaction of the observation group was significantly higher than that of the control group(80%vs.32/40),with a statistically significant difference(p<0.05).Conclusion:Maternal-infant separation exacerbates anxiety and depression in high-risk pregnancy patients,reduces sleep quality,increases the risk of postpartum hemorrhage,and delays the initiation of lactation.Specialized nursing interventions for maternal-infant separation can improve the physical and mental state of high-risk pregnancy patients,reduce the incidence of postpartum complications,and enhance nursing satisfaction,making them worthy of clinical application and promotion.展开更多
This review sums up existing information on the environmental issues of critical materials in new energy vehicles(NEVs)on a combined mining to mobility approach.With the increase in the rate of NEV adoption,the enviro...This review sums up existing information on the environmental issues of critical materials in new energy vehicles(NEVs)on a combined mining to mobility approach.With the increase in the rate of NEV adoption,the environmental cost of operating vehicles will decline as the burden moves to upstream and downstream material life-cycle activities,such as extraction,beneficiation,refining,component manufacturing,use-phase performance,and end-of-life management.We focus on key material categories that provide electrified mobility,such as battery-related material(e.g.,Li,Ni,Co,Mn,graphite),high-performance motor-related material(e.g.,rare earth elements),conductive and lightweighting material(e.g.,Cu and Al).In the supply chain,the prevailing environmental forces consist of high energy requirements and related greenhouse gas emissions,excessive water consumption and water pollution risks,toxicity and human health issues pertaining to chemical inputs and metal discharges,land-use shift,and ecosystem and biodiversity effects.The review notes that there is high regional heterogeneity,which is fueled by ore grades,processing technologies,electricity mixes,and governance capacity,and that when measurements are narrowed to carbon measures,there is a risk of shifting the problem across geographies and categories of impacts.Mitigation pathways are analyzed,such as cleaner extraction and refining,material substitution and dematerialization,battery design,longevity and recyclability,and also the strategies of the circular economy,such as recycling and second-life use.Lastly,we establish research gaps in important areas of supply-chain data disclosure,multi-impact life-cycle assessment approaches,and integrated environmental-social analysis to enable sound policy formulation that can be used to achieve sustainable electrified mobility.展开更多
Dirac nodal line semimetals with topologically protected drumhead surface states have attracted intense theoretical and experimental attention over a decade.However,the study of type-ⅡDirac nodal line semimetals is r...Dirac nodal line semimetals with topologically protected drumhead surface states have attracted intense theoretical and experimental attention over a decade.However,the study of type-ⅡDirac nodal line semimetals is rare,especially the type-Ⅱnodal chain semimetals have not been confirmed by experiment due to the lack of ideal material platform.In this study,based on symmetry analysis and the first-principles electronic structure calculations,we predict that CrB_(4) is an ideal type-ⅡDirac nodal chain semimetal protected by the mirror symmetry.Moreover,there are two nodal rings protected by both space-inversion and time-reversal symmetries in CrB_(4).More importantly,in CrB_(4) the topologically protected drumhead surface states span the entire Brillouin zone at the Fermi level.Considering the fact that CrB_(4) has been synthesized experimentally and the spin-orbit coupling is very weak,CrB_(4) provides an ideal material platform for studying the exotic properties of type-ⅡDirac nodal chain semimetals in experiment.展开更多
Glacier landslide cascading hazards pose threats to communities and infrastructure,affected by complex processes including the amplification of mass flow volume through erosion and entrainment,transformation of hazard...Glacier landslide cascading hazards pose threats to communities and infrastructure,affected by complex processes including the amplification of mass flow volume through erosion and entrainment,transformation of hazard types,ice-water phase change,and enhanced mobility of the mass flow.Scientifically simulating these physical phenomena proves challenging.This study introduces GMFA(glacier mass flow analysis),an integrated numerical model that advances the field by:(1)proposing depth-averaged fluctuation energy and internal energy equations,(2)incorporating the ice-water phase change and the entrainment-deposition process,and(3)capturing their effects on mass flow runout characteristics.The model employs the finite volume method to solve the multi-physics coupled governing equations,enabling efficient large-scale simulations.The model is verified through three numerical tests covering flow dynamics,temperature evolution,and thermo-hydro-mechanical runout processes.The model is applied to analyze a hazard chain that occurred on 10 September 2020 on the Tibetan Plateau.The multi-scenario simulation results indicate an entrained mass volume of(4.95±0.11)×10^(5)m^(3),and a ratio of entrained mass volume to source material volume of 0.44.The solid concentration decreases from 0.6-0.7 to 0.1-0.15 with increasing runout distance,indicating a transition from avalanche to debris flood.The internal energy rises by(3-4)×10^(3)kJ/m^(3),driving rapid ice melting from 0.1 to 0.2 to near-zero concentration.The model effectively quantifies volume amplification,ice-water phase changes,and multi-hazard transformations.This model pushes the geoscience frontier,extending computational capability from single-to multi-hazard simulations and providing a powerful tool for analyzing glacier cascading hazards.展开更多
基金the Scientific Research Projects Unit of Erciyes University under contract no:FDS-2022-11532 and FOA-2025-14773.
文摘This paper examines a model that combines vortex generators and leading-edge tubercles for controlling the laminar separation bubble(LSB)over an airfoil at low Reynolds numbers(Re).This new concept of passive flow control technique utilizing a tubercle and vortex generator(VG)close to the leading edge was analyzed numerically for a NACA0015 airfoil.In this study,the Shear Stress Transport(SST)turbulence model was employed in the numerical modelling.Numerical modelling was completed using the ANSYS-Fluent 18.2 solver.Analyses were conducted to investigate the flow pattern and understand the underlying LSB control phenomena that enabled the new passive flow control method to provide this significant performance benefit.The findings indicated that the new concept of passive flow control technique suppressed the formation of an LSB at the suction surface of the NACA0015 airfoil,resulting in a higher lift coefficient and improved aerodynamic performance.Improvements in LSB dynamics and aerodynamic performance through the passive flow control method lead to increased energy output and enhanced stability.
文摘The China-ASEAN Free Trade Area(CAFTA)3.0Upgrade Protocol added a section on“Supply Chain Connectivity,”which emphasizes that all parties recognize the lessons learned from the COVID-19 pandemic and cooperate to enhance the resilience of the regional supply chain.This is an inevitable trend amid the current accelerated restructuring of the global supply chain,the complex and severe international economic and trade situation,and the impact on the regional industrial chain.It also represents a fundamental shift and consensus on the logic of supply chain cooperation between China and ASEAN countries—a transformation from“Efficiency First”to“Resilience First.”
基金supported by the National Key R&D Program of China,No.2021YFC2501200(to PC).
文摘Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’s disease.In this review,we summarize the changes in short-chain fatty acid levels and the abundance of short-chain fatty acid-producing bacteria in various samples from patients with Parkinson’s disease,highlighting the critical role of gut homeostasis imbalance in the pathogenesis and progression of the disease.Focusing on the nervous system,we discuss the molecular mechanisms by which short-chain fatty acids influence the homeostasis of both the enteric nervous system and the central nervous system.We identify key processes,including the activation of G protein-coupled receptors and the inhibition of histone deacetylases by short-chain fatty acids.Importantly,structural or functional disruptions in the enteric nervous system mediated by these fatty acids may lead to abnormalα-synuclein expression and gastrointestinal dysmotility,which could serve as an initiating event in Parkinson’s disease.Furthermore,we propose that short-chain fatty acids help establish communication between the enteric nervous system and the central nervous system via the vagal nerve,immune circulation,and endocrine signaling.This communication may shed light on their potential role in the transmission ofα-synuclein from the gut to the brain.Finally,we elucidate novel treatment strategies for Parkinson’s disease that target short-chain fatty acids and examine the challenges associated with translating short-chain fatty acid-based therapies into clinical practice.In conclusion,this review emphasizes the pivotal role of short-chain fatty acids in regulating gut-brain axis integrity and their significance in the pathogenesis of Parkinson’s disease from the perspective of the nervous system.Moreover,it highlights the potential value of short-chain fatty acids in early intervention for Parkinson’s disease.Future research into the molecular mechanisms of short-chain fatty acids and their synergistic interactions with other gut metabolites is likely to advance the clinical translation of innovative short-chain fatty acid-based therapies for Parkinson’s disease.
文摘Chain graphs are{2K_(2),C_(3),C_(5)}-free graphs.Balaban index and sum-Balaban index are two important topological indices.In this paper,we concentrate on the subclass of bicyclic connected chain graphs,identifying the extremal graphs that exhibit the minimum or maximum Balaban index and sum-Balaban index within this class.Moreover,we provide a systematic ordering of all bicyclic connected chain graphs according to the magnitude of their Balaban index and sum-Balaban index.
基金financially supported by the Liaoning Revitalization Talents Program (No.XLYC2403107)the Excellent Youth Science Foundation of Liaoning Province (No.2024JH3/10200046)the Basic Scientific Research Project of Liaoning Provincial Department of Education (No.LJ212410163015)。
文摘Despite demonstrating significant anti-tumor potential as an artemisinin derivative,artesunate faces delivery efficiency challenges due to low water solubility and insufficient targeting specificity.To improve the delivery efficiency,we engineered three artesunate(ART) derivatives,AC_(15)-L(linear),AC_(15)-B(branched),and AC_(15)-C(cyclic) with distinct aliphatic chain architectures.Unexpectedly,we observed that AC_(15)-C exhibited superior cytotoxicity against 4T1 breast cancer cells,and had the highest binding affinity for Lon protease 1(LONP1)(-72.6 kcal/mol).Subsequently,disulfide bond-containing lipid-PEG(DSPESS-PEG2K) modified chain architecture-engineered ART derivatives nanoassemblies(NAs) were developed to mitigate solubility-related limitations while enhancing targeting precision.Molecular docking and experimental validation demonstrated that ART derivatives inhibited LONP1 through hydrophobic interactions while preserved Fe^(2+)-mediated Fenton-like reaction activity.In vitro and in vivo evaluations demonstrated that AC_(15)-C NAs outperformed free ART and other NAs,suppressing 4T1 tumor growth via dual action:LONP1-directed mitochondrial proteostasis collapse and reactive oxygen species(ROS) amplification through Fe^(2+)-ART interactions.This study elucidated a novel anti-tumor mechanism of ART through the rational design of derivatives with spatially configured aliphatic chains,and developed reductionresponsive NAs to provide an advanced delivery strategy.
基金financially supported by the Sinopec Seed Program Project(No.223281)State Key Laboratory of Advanced Papermaking and Paper-based Materials(No.2024ZD06)+3 种基金Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515110543 and 2023A1515110170)the Natural Science Foundation of Guangdong Province(No.2024B1515040023)Guangjuyingcai program of Guangzhou(No.2024D03J0002)111 Project(No.B18023).
文摘Microporous polyimides(PIM-PIs)have emerged as promising high-performance membranes for gas separation.However,achieving an optimal balance between permeability and selectivity remains a major challenge.In this study,we designed and synthesized a series of PIM-PIs by combining rigid dianhydrides 9-bis(trifluoromethyl)-2,3,6,7-xanthenetetracarboxylic dianhydride(6FCDA)and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)with contorted diamines,including 9,9-bis(4-aminophenyl)fluorene(FDA),9,9′-spirobifluorene-2,2′-diamine(SBFDA),and 3,3,3′,3′-tetramethyl-1,1′-spirobiindane-5,5′-diamine-6,6′-diol(TSDA),to systematically elucidate the relationship between hierarchical microstructure and gas transport behavior.Comprehensive characterization revealed that the 6FCDA-based polymers exhibited a higher microporosity(V_(micro)/V_(total)up to 54.7%)and fractional free volume compared to their 6FDA counterparts.Gas permeation measurements showed that the 6FCDA/SBFDA membrane delivered a CO_(2)permeability of 386 Barrer and CO_(2)/CH_(4)selectivity of 30.2,exceeding the 2008 Robeson upper bound.Structure-property correlation analyses indicated that diffusion selectivity predominantly governed gas separation performance,with rigid,spirocyclic architectures suppressing chain packing to generate sub-5Åmicropores,as further validated by molecular simulations.The optimized 6FCDA/FDA membrane achieved a BET surface area of 423 m^(2)·g^(−1),while maintaining excellent mechanical strength and high thermal stability.This work establishes an effective monomer design strategy to overcome the permeability-selectivity trade-off through backbone rigidification,thereby advancing PIM-PIs for practical applications in natural gas purification and carbon capture.
基金supported by the Anhui Provincial Natural Science Foundation (Grant No.2508085J006)CASHIPS Director's Fund (Grant No.YZJJ202207-CX)。
文摘The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).
文摘Purpose-This study explores how managerial leadership and organizational innovation interact to enhance resilience and risk management in railway supply chains and how these capabilities contribute to sustained competitive advantage.It emphasizes the strategic importance of resilience in railway systems that face operational complexity,regulatory pressures and increasing exposure to systemic risks.Design/methodology/approach-A mixed-methods design was employed,integrating survey data from 186 railway organizations with six case studies involving railway operators,rolling stock manufacturers and supply chain partners across multiple regions.Constructs were measured using validated scales and hypothesized relationships were tested using Structural Equation Modeling(SEM).Case study interviews were analyzed thematically to provide contextual understanding of leadership practices and innovation strategies.Findings-The results confirm that transformational managerial leadership significantly predicts innovation adoption,which in turn strengthens resilience and risk management capabilities.Resilience emerged as a powerful driver of competitive advantage,reinforcing its role as a strategic capability rather than a reactive response to disruptions.Furthermore,innovation was shown to partially mediate the relationship between leadership and resilience,highlighting its function as the operational channel through which vision translates into capability.Originality/value-This study contributes to the literature by integrating the Resource-Based View(RBV)and Dynamic Capabilities(DC)framework into the context of railway supply chains.It is among the first to empirically validate the mediating role of innovation between leadership and resilience,offering both theoretical advancements and actionable strategies for building resilient and competitive railway systems.
基金supported by Shaanxi Key Research and Development Program(No.2024SF-YBXM-546)the National Natural Science Foundation of China(No.52470161)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF21007).
文摘With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.
基金Project supported by the National Key Research and Development Program of China(2022YFC2905800)National Natural Science Foundation of China(52374276,52274269)+2 种基金Yunnan Fundamental Re search Projects(202401AS070051)the Natural Science Foundation of Hubei Province of China(2024AFD123)Young Elite Scientists Sponsorship Program by CAST(YESS20200276)。
文摘The efficient flotation separation of rare earth elements(REEs)from gangue minerals is crucial in mineral processing.This study synthesized a quaternary ammonium salt ionic liquid collector,tetrabutylammonium salicylhydroxamate(T-S),and investigated its performance in separating bastnaesite and fluorite.T-S was synthesized from salicylhydroxamic acid(SHA)and tetrabutylammonium chloride(TBAC),and its molecular structure was characterized using Fourier transform infrared(FTIR)spectroscopy.Microflotation tests indicate that T-S outperforms SHA and TBAC in both collecting ability and selectivity for bastnaesite.Adsorption,zeta potential,and infrared spectroscopy measurements reveal that T-S exhibits stronger adsorption on bastnaesite compared to SHA and TBAC.X-ray photoelectron spectroscopy(XPS)and molecular dynamics simulations(MDS)results confirm that chemical adsorption occurs between Ce on the bastnaesite surface and the-C(=O)NHOH groups of T-S.Moreover,the interaction between T-S and the bastnaesite surface is stronger than that with the fluorite surface.This work provides valuable insights for designing ionic liquid collectors for the flotation separation of bastnaesite and fluorite.
文摘Against a backdrop of rising global trade protectionism and accelerated restructuring of international industrial and supply chains,regional institutional cooperation is becoming a key force in stabilizing cross-border trade and investment.The ASEAN region enjoys strong economic growth momentum with a distinct demographic advantage while China boasts a complete industrial system and manufacturing capacity.
基金supported by the National Natural Science Foundation of China(No.22375063)Science and Technology Commission of Shanghai Municipality(No.23JC1401700)the Fundamental Research Funds for the Central Universities.
文摘Developing advanced polymeric materials with enhanced mechanical properties and functionalities has been a long-standing goal in materials science.Recently,supramolecular polymeric materials (SPMs) have drawn increased attention due to their unique properties and potential applications in self-healing,shape memory,sensors,and flexible electronics.Here,we develop an ionic cluster-optimized microphase separation strategy to enhance the toughening and energy dissipation capabilities of polydisulfide-based supramolecular polymers.The mechanical properties,including Young’s modulus and toughness,are significantly improved by integrating the quadruple H-bonding 2-ureido-4-pyrimidone (UPy) induced microphase separation with iron(Ⅲ)-to-carboxylate ionic clusters.By combining established chemical approaches with adjustable polymer phase ratios,it is revealed that the synergistic effect of these factors expands the interchain spacing,facilitates the formation of microphase domains,and enhances the tolerance of polythioctic acid-based polymers to external mechanical and thermal stimuli,meeting the practical requirements for industrial plastic applications.Moreover,the UPy-functionalized polymers incorporating iron carboxylate clusters exhibit good one-way shape memory behavior with practical applicability at a relatively low recovery temperature.Our work demonstrates a novel strategy for constructing industrially viable shape memory dynamic SPMs and paves the way for future innovations in developing SPMs.
基金Project supported by the National Key R&D Program of China(2022YFC2905800)the National Natural Science Foundation of China(52174242)the National Youth Talent Support Program(QNBJ-2023-03)。
文摘Bayan Obo rare earth mine is the largest light rare earth resource worldwide,primarily extracts rare earth elements(REEs)from mixed RE concentrates with bastnaesite and monazite.Nevertheless,the adoption of the concentrated sulfuric acid roasting metallurgical process has resulted in damage to the environment.Therefore,this paper adopted the method of selective mineral phase transformation(MPT)followed by enhanced micro-flotation.By determining the optimal MPT co nditions,the flotation recovery of bastnaesite-roasted products by the collector(phthalic acid,PA)is improved,and the enhanced separation of bastnaesite with monazite is realized.The results show that with the increase of roasting temperature and time,the bastnaesite decomposition product is CeOF and monazite does not change significantly.Subsequent micro-flotation exhibits a gradual decline in the PA consumption of bastnaesiteroasted products,while the flotation recovery of monazite-roasted products remains poor.The artificial mixed ore experiments result in a CeOF foam product with a content of 94.14%and a recovery of 85.80%,and a monazite tank product with a content of 73.53%and a recovery of 87.87%.Compared with the preroasting ore,the surface and interior of bastnaesite-roasted products develop numerous cracks and porosities,and no obvious structural damage is observed in monazite-roasted particles.As the roasting temperature increases,the mineral particles undergo recrystallization or closure,reducing the specific surface area of bastnaesite-roasted products and enhancing hydrophobicity,leading to diminished PA consumption.Fourier transform infrared and other flotation-relation tests show that PA is chemisorbed on the surface of CeOF.The MPT conditions are optimized in this study,which provides a reference for further advancing the efficient separation of bastnaesite and monazite.
基金The National Key Research and Development Program of China(2020YFC0862903)Supported by Jiangsu Future Membrane Technology Innovation Center(BM2021804)National Foreign Expert Program(H20240294).
文摘To develop an efficient filter for removing white blood cells from whole blood,hydrophilic large-pore blended membranes of poly(vinylidene fluoride)(PVDF),polyvinyl pyrrolidone and polyethylene glycol,with good biocompatibility,were prepared using the process of vapor-induced phase separation at various PVDF concentrations.The results demonstrated that at a PVDF mass concentration of 14%,the membrane had increased surface roughness,significantly enhanced hydrophilicity and wettability,and a wetting time of 8 s.The surface roughness of the membrane was also reduced to 31.637 nm.Furthermore,hemolysis rate and protein adsorption tests indicated that the blended membranes possessed excellent biocompatibility.They were reduced to 2.48%and 34.44μg·cm^(−2),respectively.The pore size of the fabricated membrane was relatively large,which reached approximately 8μm respectively,satisfying the filtration requirements.Lastly,the effects of different temperatures and multi-layered filters on leukocyte removal and the retention of red blood cells and platelets from whole blood were evaluated.The results revealed that the leukocyte removal rate was highest at 4℃ and with three membrane layers,the leukocyte removal rate was highest,reaching 98.36%,while the RBC and platelet content remained nearly unchanged compared with the original blood.This study provides a new approach for blood cell separation that is expected to play a significant role in medical fields such as blood transfusion demonstrating great potential for application and innovation.
基金supported by National Key Technolo-gy R&D Program of China(2023YFD1701505)De-velopment Projects in Anhui Province(2022107020013).
文摘Lignocellulosic biomass is the most abundant re-newable resource on Earth,boasting advan-tages such as wide avail-ability and negative car-bon emissions.Especial-ly,efficient separation of lignocellulose into cellu-lose,hemicellulose and lignin,and realizing val-orization of these compo-nents are more responsive to the development needs of biomass refinery and the green chem-istry era.This review outlines the main components of lignocellulose and briefly summerizes their utilization in chemical raw materials and energy production.It mainly focused on cur-rent advances in component separation methods of lignocellulose by organic solvents,ionic liquids and deep eutectic solvents.The design of separation methods,understanding of sepa-ration mechanisms,and optimization of reaction systems in each method are highlighted in detail.Furthermore,the ongoing challenges and future directions based on mechanism and in-dustrialization are critically discussed.Our goal is to elucidate the separation mechanisms and principles of method design,providing guidance for the development of highly efficient com-ponent separation methods of lignocellulose.
基金National Natural Science Foundation of China Grant Nos.52378543,52378544 and 52408525the Natural Science Foundation of Heilongjiang Grant No.LH2024E119。
文摘On December 18,2023,a magnitude 6.2 earthquake struck Jishishan County,Gansu Province,triggering a liquefaction-induced flow slide along the loess-mudstone contact zone and causing significant casualties and property losses.The event featured low-slope,large-scale,runout distance sliding and exhibited a clear cascading disaster chain.Its characteristics closely resemble the catastrophic mudflow at the nearby Lajia Ruins approximately 4,000 years ago.Using high-resolution oblique photogrammetry,cone penetration testing,surface wave analysis,and horizontal-to-vertical spectral ratio methods,this study examines the stratigraphy,groundwater conditions,and geomechanical properties of the affected zone.Results indicate that saturated loess overlying impermeable mudstone formed a high-moisture mass vulnerable to seismic disturbance.Seismic resonance triggered the liquefaction of weakly structured loess,which slide along the contact interface and evolved into a runout distance mudflow.Underground water and terrain modification created a composite weak zone of saturated loess and softened mudstone,which intensified the disaster chain-from earthquake to liquefaction,flow slide,and mudflow.This study contributes to the understanding of deep-seated liquefaction-flow slide disasters,thereby advancing more effective risk mitigation strategies in the Loess Plateau and comparable loess-covered seismic regions.
文摘Objective:To analyze the impact of maternal-infant separation on the physical and mental state of high-risk pregnancy patients and explore the clinical efficacy of targeted nursing interventions.Methods:A total of 80 high-risk pregnancy patients treated in our hospital from January 2023 to January 2024 were selected as the study subjects.These patients were randomly divided into an observation group and a control group(40 cases each)using a random number table.The control group received routine high-risk pregnancy nursing care,while the observation group received specialized maternal-infant separation nursing interventions in addition to routine care.The psychological and physiological states and nursing satisfaction of the two groups were compared before and after the intervention.Results:The SAS scores,SDS scores,and sleep quality scores of the observation group were significantly lower than those of the control group,with statistically significant differences(p<0.05).The incidence of postpartum hemorrhage in the observation group was significantly lower than that in the control group,and the initiation time of lactation was significantly earlier than that in the control group,with both differences being statistically significant(p<0.05).The nursing satisfaction of the observation group was significantly higher than that of the control group(80%vs.32/40),with a statistically significant difference(p<0.05).Conclusion:Maternal-infant separation exacerbates anxiety and depression in high-risk pregnancy patients,reduces sleep quality,increases the risk of postpartum hemorrhage,and delays the initiation of lactation.Specialized nursing interventions for maternal-infant separation can improve the physical and mental state of high-risk pregnancy patients,reduce the incidence of postpartum complications,and enhance nursing satisfaction,making them worthy of clinical application and promotion.
文摘This review sums up existing information on the environmental issues of critical materials in new energy vehicles(NEVs)on a combined mining to mobility approach.With the increase in the rate of NEV adoption,the environmental cost of operating vehicles will decline as the burden moves to upstream and downstream material life-cycle activities,such as extraction,beneficiation,refining,component manufacturing,use-phase performance,and end-of-life management.We focus on key material categories that provide electrified mobility,such as battery-related material(e.g.,Li,Ni,Co,Mn,graphite),high-performance motor-related material(e.g.,rare earth elements),conductive and lightweighting material(e.g.,Cu and Al).In the supply chain,the prevailing environmental forces consist of high energy requirements and related greenhouse gas emissions,excessive water consumption and water pollution risks,toxicity and human health issues pertaining to chemical inputs and metal discharges,land-use shift,and ecosystem and biodiversity effects.The review notes that there is high regional heterogeneity,which is fueled by ore grades,processing technologies,electricity mixes,and governance capacity,and that when measurements are narrowed to carbon measures,there is a risk of shifting the problem across geographies and categories of impacts.Mitigation pathways are analyzed,such as cleaner extraction and refining,material substitution and dematerialization,battery design,longevity and recyclability,and also the strategies of the circular economy,such as recycling and second-life use.Lastly,we establish research gaps in important areas of supply-chain data disclosure,multi-impact life-cycle assessment approaches,and integrated environmental-social analysis to enable sound policy formulation that can be used to achieve sustainable electrified mobility.
基金supported by the National Natural Science Foundation of China(Grant Nos.11934020,12204533,62476278,and 62206299)the Fundamental Research Funds for the Central Universities+1 种基金the Research Funds of Renmin University of China(Grant No.24XNKJ15)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302402)。
文摘Dirac nodal line semimetals with topologically protected drumhead surface states have attracted intense theoretical and experimental attention over a decade.However,the study of type-ⅡDirac nodal line semimetals is rare,especially the type-Ⅱnodal chain semimetals have not been confirmed by experiment due to the lack of ideal material platform.In this study,based on symmetry analysis and the first-principles electronic structure calculations,we predict that CrB_(4) is an ideal type-ⅡDirac nodal chain semimetal protected by the mirror symmetry.Moreover,there are two nodal rings protected by both space-inversion and time-reversal symmetries in CrB_(4).More importantly,in CrB_(4) the topologically protected drumhead surface states span the entire Brillouin zone at the Fermi level.Considering the fact that CrB_(4) has been synthesized experimentally and the spin-orbit coupling is very weak,CrB_(4) provides an ideal material platform for studying the exotic properties of type-ⅡDirac nodal chain semimetals in experiment.
基金supports from the National Natural Science Foundation of China(Grant No.U20A20112)the Research Grants Council of the Hong Kong SAR Government,China(Grant Nos.T22-606/23-R and 16206923).
文摘Glacier landslide cascading hazards pose threats to communities and infrastructure,affected by complex processes including the amplification of mass flow volume through erosion and entrainment,transformation of hazard types,ice-water phase change,and enhanced mobility of the mass flow.Scientifically simulating these physical phenomena proves challenging.This study introduces GMFA(glacier mass flow analysis),an integrated numerical model that advances the field by:(1)proposing depth-averaged fluctuation energy and internal energy equations,(2)incorporating the ice-water phase change and the entrainment-deposition process,and(3)capturing their effects on mass flow runout characteristics.The model employs the finite volume method to solve the multi-physics coupled governing equations,enabling efficient large-scale simulations.The model is verified through three numerical tests covering flow dynamics,temperature evolution,and thermo-hydro-mechanical runout processes.The model is applied to analyze a hazard chain that occurred on 10 September 2020 on the Tibetan Plateau.The multi-scenario simulation results indicate an entrained mass volume of(4.95±0.11)×10^(5)m^(3),and a ratio of entrained mass volume to source material volume of 0.44.The solid concentration decreases from 0.6-0.7 to 0.1-0.15 with increasing runout distance,indicating a transition from avalanche to debris flood.The internal energy rises by(3-4)×10^(3)kJ/m^(3),driving rapid ice melting from 0.1 to 0.2 to near-zero concentration.The model effectively quantifies volume amplification,ice-water phase changes,and multi-hazard transformations.This model pushes the geoscience frontier,extending computational capability from single-to multi-hazard simulations and providing a powerful tool for analyzing glacier cascading hazards.
