Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant paramete...Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.展开更多
Alzheimer's disease,a progressively degenerative neurological disorder,is the most common cause of dementia in the elderly.While its precise etiology remains unclear,researchers have identified diverse pathologica...Alzheimer's disease,a progressively degenerative neurological disorder,is the most common cause of dementia in the elderly.While its precise etiology remains unclear,researchers have identified diverse pathological characteristics and molecular pathways associated with its progression.Advances in scientific research have increasingly highlighted the crucial role of non-coding RNAs in the progression of Alzheimer's disease.These non-coding RNAs regulate several biological processes critical to the advancement of the disease,offering promising potential as therapeutic targets and diagnostic biomarkers.Therefore,this review aims to investigate the underlying mechanisms of Alzheimer's disease onset,with a particular focus on microRNAs,long non-coding RNAs,and circular RNAs associated with the disease.The review elucidates the potential pathogenic processes of Alzheimer's disease and provides a detailed description of the synthesis mechanisms of the three aforementioned non-coding RNAs.It comprehensively summarizes the various non-coding RNAs that have been identified to play key regulatory roles in Alzheimer's disease,as well as how these noncoding RNAs influence the disease's progression by regulating gene expression and protein functions.For example,miR-9 targets the UBE4B gene,promoting autophagy-mediated degradation of Tau protein,thereby reducing Tau accumulation and delaying Alzheimer's disease progression.Conversely,the long non-coding RNA BACE1-AS stabilizes BACE1 mRNA,promoting the generation of amyloid-βand accelerating Alzheimer's disease development.Additionally,circular RNAs play significant roles in regulating neuroinflammatory responses.By integrating insights from these regulatory mechanisms,there is potential to discover new therapeutic targets and potential biomarkers for early detection and management of Alzheimer's disease.This review aims to enhance the understanding of the relationship between Alzheimer's disease and non-coding RNAs,potentially paving the way for early detection and novel treatment strategies.展开更多
Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements hav...Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.展开更多
The combustion behavior of Ti-Al-Mo-Zr-Sn-W alloy(TC25G)was studied in a high-temperature and high-speed air flow environment using the laser ignition method combined with ultra-high temperature infrared thermometer,s...The combustion behavior of Ti-Al-Mo-Zr-Sn-W alloy(TC25G)was studied in a high-temperature and high-speed air flow environment using the laser ignition method combined with ultra-high temperature infrared thermometer,scanning electron microscope,X-ray diffractometer,and transmission electron microscope.The burn-resistant performance of TC25G and TC11 alloys was compared.Meanwhile,the microstructural characteristics,crystal structure,and formation mechanism of the combustion products of TC25G alloy were analyzed in detail.The results show that the high-temperature and high-speed air flow promotes combustion within the air flow temperature range of 200–400℃and the air flow velocity range of 0–100 m/s.The combustion path advances along the direction of the air flow.The combustion of TC25G alloy mainly relies on the diffusion of the oxygen and the expansion of the combustion area caused by the movement of the melt.Based on the microstructure and composition of combustion product,it can be divided into the combustion zone,the melting zone,and the heat affected zone.During combustion,the formation of microstructures is closely correlated with the behavior of alloying elements and their selective combination with O.The major oxidation products of Ti are TiO and TiO_(2).The oxides formed by Mo and W hinder the movement of the melt during the combustion.Al and Zr tend to undergo internal oxidation.Al_(2)O_(3)precipitates on the surface of ZrO_(2),forming a protective oxide layer that inhibits the inward diffusion of O.Moreover,the element enrichment at the interface between the melting zone and the heat affected zone increases the melting point on the solid side,hindering the migration of the solid-liquid interface.展开更多
Photocatalysis is an important technology for using solar energy to produce hydrogen,convert CO_(2) to synthetic fuels,and decrease persistent pollutant.However,conventional photocatalysts have limitations,including p...Photocatalysis is an important technology for using solar energy to produce hydrogen,convert CO_(2) to synthetic fuels,and decrease persistent pollutant.However,conventional photocatalysts have limitations,including poor spectral absorption,inefficient charge separation,and structural instability under operational stress,which demand innovative durable materials with tailored electronic properties.Nanodiamond(ND)has recently been recognized as a suitable material because of its exceptional chemical stability,superior charge carrier mobility,and possible surface functionalization.While its intrinsic wide bandgap limits its response to visible-light,different methods have been demonstrated to activate its catalytic potential.Here,several emerging strategies for improving the catalytic performance of ND-based photocatalytic systems are summarized,including surface functionalization,plasmonic hybridization,heteroatom doping,and heterostructure design.And the structure-activity relationship and design principle are proposed to improve the light harvesting,charge transport,and redox kinetics for constructing high efficiency ND-based photocatalysts used in the renewable energy and environmental industries.展开更多
Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape...Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape fragmentation and identify its key drivers is an important foundation for regional biodiversity conservation and ecosystem restoration.Taking the Guanzhong Plain Urban Agglomeration(GPUA),China as the research object,this paper proposes a comprehensive framework that integrates landscape pattern index,principal component analysis,random forest(RF)and other methods to quantitatively analyze the spatial and temporal evolution of ecological landscape fragmentation and its driving factors.The results show that:1)cropland,forestland and grassland showed significant spatial differentiation in the landscape pattern index,and the change of their mean values indicated that cropland and forestland show a trend of‘little decrease-continuous increase’.Spatially,the northwestern and southeastern regions showed significant fragmentation and prominent spatial heterogeneity.2)From 2010 to 2020,the landscape fragmentation of cropland and forestland increased by 71%and 20%,respectively,while that of grassland decreased by 33%,indicating that the degree of landscape fragmentation of cropland changed more drastically than that of other ecological land.3)It was found that slope was the most important factor affecting landscape fragmentation of ecological land.In addition,road density had a significant effect on landscape fragmentation of cropland and forestland,but the min-distance between patches and the county center had an important effect on landscape fragmentation of grassland.This study can provide theoretical references for urban agglomeration planning and sustainable landscape management on a regional scale.展开更多
Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD...Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD)plays a crucial role in the aerodynamic analysis of eccentric compressors.However,conventional full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)simulations are prohibitively expensive for routine design and analysis purposes.To address this issue,the paper presents a novel Fourier-based method,called the Time-Space Collocation(TSC)method,for efficient simulations of eccentric compressors.This method coherently treats temporal and spatial harmonics,making it well-suited to tackle the rotor eccentricity problem,as the perturbation waves induced by eccentricity are time-periodic with respect to the rotor and space-periodic with respect to the stator.Three numerical cases,including NASA Rotor 67,original Stage 67,and Stage 67 with a reduced rotor-stator axial gap,were conducted to verify the effectiveness of the TSC method.The results indicate that,for the rotor eccentricity levels studied in this paper,the influence of weak rotor-stator interactions can be disregarded in the original Stage 67.In this situation,applying three harmonics can accurately capture both the performance variations and the non-uniformly distributed flowfields of eccentric compressors,while achieving a reduction in run time by two orders of magnitude compared to full-annulus URANS simulations.However,in Stage 67 with a reduced rotor-stator axial gap,the results that include rotor-stator interactions align much more closely with the URANS results.Nevertheless,the TSC simulations can still achieve speed-ups of several dozen times.Overall,the TSC method shows promising potential for application within the engineering community.展开更多
Terrestrial ecosystems are vital for maintaining equilibrium in the global carbon cycle.Land use and land cover change(LUCC),which is influenced mainly by urbanization and ecological policies,impacts terrestrial ecosy...Terrestrial ecosystems are vital for maintaining equilibrium in the global carbon cycle.Land use and land cover change(LUCC),which is influenced mainly by urbanization and ecological policies,impacts terrestrial ecosystem carbon storage significantly.In this study,spatiotemporal carbon storage changes in the urban belt along the Yellow River in the Ningxia Hui Autonomous Region,China,were estimated through a model that integrated patch-generating land use simulation(PLUS)and integrated valuation of ecosystem services and tradeoffs(InVEST)models from 1993 to 2033.The results revealed that:(1)from 1993 to 2023,the expansion of built-up land and cropland was derived mainly from unused land and grassland,whereas water body and woodland remained relatively stable.Projections to 2033 have indicated that LUCC will continue and be concentrated primarily in the Ningxia Plain;(2)carbon storage increased by a net 5.01×10^(6) Mg C from 1993 to 2023;(3)the spatial distribution of carbon storage revealed that high-value areas were predominantly located in the Helan Mountains and the Ningxia Plain,whereas low-value areas were found in the Tengger Desert;(4)scenario projections indicated that by 2033,the ecological protection scenario(EPS)would achieve a 0.18×10^(6) Mg C increase by reducing the conversion of woodland to cropland and grassland to built-up land,while increasing the conversion of unused land to grassland.In contrast,the natural development scenario(NDS),cropland protection scenario(CPS),and urban development scenario(UDS)decreased carbon storage by 0.60×10^(6),0.21×10^(6),and 0.42×10^(6) Mg C,respectively;and(5)spatial autocorrelation analysis revealed that high–high carbon storage clusters formed belt-like patterns along the Ningxia Plain and the Helan Mountains,whereas the low–low carbon storage clusters were concentrated in northern Zhongwei City,western Qingtongxia City,western Dawukou District,and the urbanized areas within the central Ningxia Plain.Overall,the study results revealed the close coupling relationship between LUCC and carbon storage functions.Furthermore,the study establishes a framework for carbon management that balances ecological protection with coordinated urban development for the urban belt as well as for similar arid and semi-arid areas.On the basis of these findings,this study provides decision-makers with guidance to optimize ecosystem carbon storage via land use,which plays a key role in developing future land use policies and achieving the"dual carbon"goals.展开更多
Banana(Musa spp.)is one of the most important fruit crop worldwide,and plays a critical role in human diet and agricultural economies across tropical and subtropical regions,including China(Jiang et al.,2025;Wu et al....Banana(Musa spp.)is one of the most important fruit crop worldwide,and plays a critical role in human diet and agricultural economies across tropical and subtropical regions,including China(Jiang et al.,2025;Wu et al.,2025).However,its rapid softening severely limits shelf life,causing substantial economic losses during transport and storage.Recently,the enhanced shelf-life can be generated by compromising the key ripening regulators,such as RIN,but other fruit quality traits including flavor and color also can be impaired concurrently(Kitagawa et al.,2005).展开更多
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t...Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.展开更多
An MW6.0 earthquake struck Jishishan County in Linxia Prefecture,Gansu Province,on December 18,2023.In this research,Sentinel-1A satellite radar observations were used to obtain the field of coseismic deformation of t...An MW6.0 earthquake struck Jishishan County in Linxia Prefecture,Gansu Province,on December 18,2023.In this research,Sentinel-1A satellite radar observations were used to obtain the field of coseismic deformation of the Jishishan earthquake in 2023,and the geometric and fine slip distribution of the seismogenic fault were inverted using this as a constraint.The results show that the earthquake is characterized by thrust movement.The coseismic slip distribution results show that the maximum slip of this earthquake is 0.3 m.The Coulomb stress distribution shows that the whole section of the southern edge of Lajishan fault,the NWW trending segment of the northern edge of Lajishan fault and its NNW trending segment to the south of the epicenter,the northern edge of the West Qinling fault and the segment to the east of the epicenter of the Daotanghe Linxia fault are under stress loading,which indicates an increase in the potential risk of earthquakes.This research discussed the seismogenic characteristics of earthquakes and the tendency of faults.We speculate that the Jishishan earthquake is the result of the joint action of regional faults and tectonic stress.Based on the observation of seismic data,geodesy,and other geological and geophysical data,we believe that the earthquake was caused by the activation of weak areas under the crust by the local stress from the driving mechanism of the northeast expansion of Qinghai-Xizang Plateau.The seismogenic fault of this earthquake is more likely to be northeast dipping under the comprehensive consideration of various factors,which occurred on the concealed fault belonging to the eastern edge of the Jishishan fault zone.展开更多
As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and ...As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and diverse communication needs.It is crucial to design control sequences with robust randomness and conflict-freeness to properly address differentiated access control in data link.In this paper,we propose a hierarchical access control scheme based on control sequences to achieve high utilization of time slots and differentiated access control.A theoretical bound of the hierarchical control sequence set is derived to characterize the constraints on the parameters of the sequence set.Moreover,two classes of optimal hierarchical control sequence sets satisfying the theoretical bound are constructed,both of which enable the scheme to achieve maximum utilization of time slots.Compared with the fixed time slot allocation scheme,our scheme reduces the symbol error rate by up to 9%,which indicates a significant improvement in anti-interference and eavesdropping capabilities.展开更多
In order to overcome the embrittlement of metastable titanium alloys caused by the precipitation ofωiso phase during aging,regulation of isothermalωprecipitation was investigated in Ti−15Mo alloy.The results show th...In order to overcome the embrittlement of metastable titanium alloys caused by the precipitation ofωiso phase during aging,regulation of isothermalωprecipitation was investigated in Ti−15Mo alloy.The results show that the sample is brittle when direct aging(A)is applied at 350℃for 1 h after solution treatment(ST).If pre-deformation(D)is performed on the ST sample to induce{332}twins and secondaryα″phase,subsequent aging at 350℃(STDA350)improves the strength to 931 MPa with a good ductility of about 20%maintained.However,when aging is performed at 400℃or 450℃(STDA400/450),the strength can be further improved,but the ductility is dramatically reduced.Atomic-scale characterizations show that the partial collapse ofωphase in the STDA350 sample effectively eliminates aging-induced embrittlement,but complete collapse leads to poor ductility in the STDA400/450 sample.展开更多
Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenizatio...Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenization methods based on the classical elasticity theory struggle to accurately describe the non-classical mechanical behaviors of lattice materials,especially when dealing with complex unit-cell geometries featured by non-symmetric configurations or non-single central node connections.In response to this limitation,this study establishes a generalized homogenization model based on the micropolar theory framework,employing Hill's boundary conditions to precisely predict the equivalent moduli of complex lattice materials.By introducing the independent rotational degree of freedom(DOF)characteristic of the micropolar theory,the proposed model successfully overcomes the limitation of conventional methods in accurately describing the asymmetric deformation and scale effects.We initially calculate the constitutive relations of two-dimensional(2D)cross-shaped multi-node chiral lattices and subsequently extend the method to three-dimensional(3D)lattices,successfully predicting the mechanical properties of both traditional and eccentric body-centered cubic(BCC)lattices.The theoretical model is validated through the finite element numerical verification which shows excellent consistency with the theoretical predictions.A further parametric study investigates the influence of geometric parameters,revealing the underlying size-effect mechanism.This paper provides a reliable theoretical tool for the design and property optimization of complex lattice materials.展开更多
As the main component of the aircraft leading edge,the radome is often the first to be hit by raindrops and cause structural damage when passing through a rain field.Rain resistant coating is usually applied to ensure...As the main component of the aircraft leading edge,the radome is often the first to be hit by raindrops and cause structural damage when passing through a rain field.Rain resistant coating is usually applied to ensure the performance protection requirements.In order to clarify the rain erosion damage mechanism of radome coating and explore the influencing factors and mechanisms of coating material damage under different jet impact conditions,impact tests were conducted on three types of skin coating samples,and the damage mode was observed through electron microscopy characterization.The experimental results show that the typical morphology of rain erosion damage is annular surface peeling damage.The damage area and volume of the three coating samples increase with the continuous increase of raindrop impact velocity.The threshold velocity for initial damage to the coating is about 360 m/s;under the influence of the velocity component,the reduction in impact angle leads to a gradual reduction in the degree of damage to the sample.ABAQUS finite element simulation software was used to establish a constitutive model for coating rain erosion simulation and obtain the propagation law of stress waves during the impact process.The simulation results show that at the 75°impact angle,the jet impacts the surface of the specimen at different velocities,and as the impact velocity increases,the Mises equivalent stress on the surface shows an increasing trend,which is one of the main factors causing damage with increasing velocity.The effectiveness,rain erosion damage mode,and influencing mechanism of the model were verified based on the test results;the dynamic failure mechanism of the sample was further studied,and the stress propagation process at different impact angles was compared,revealing the influence mechanism and damage law of the impact angle on the high-speed raindrop impact of the material.展开更多
Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic ...Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic rolled SF-7055 Al alloy is elongated to form a fiber texture.Numerous proliferating dislocations in the microstructure accumulate into dislocation walls and cells,and eventually form subgrains.These subgrain boundaries divide the original grain,thereby reducing the grain size.Under severe deformation conditions,they even enable the formation of nanograins.Meanwhile,the Cu-rich precipitates in the matrix are also broken and refined under the action of large rolling stress.In the process of cryogenic rolling,the tensile strength and hardness of SF-7055 Al alloy gradually increase,while the plasticity decreases.Moreover,the fracture morphology of cryogenic rolled SF-7055 Al alloy gradually transforms to the ductile and quasi-cleavage hybrid fracture characteristics with increased reduction.展开更多
The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and med...The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and medical sectors.However,conventional machining of titanium alloys leads to elevated tool wear,development of surface defects,and reduced machining efficiency due to their low heat conductivity,and chemical affinity.These issues can be somewhat counteracted by integrating ultrasonic vibration in the conventional machining of titanium alloys and also enhance sustainability.This review article offers a holistic evaluation of the influence of ultrasonic vibration-assisted milling and turning on cutting forces,temperature,tool wear,and surface integrity,encompassing surface morphology,surface roughness,surface residual stress,surface hardness,and surface tribological properties during titanium alloys machining.Furthermore,it investigates the sustainability aspect that has not been previously examined.Studies on the performance of ultrasonic-assisted cutting revealed several advantages,including decreased cutting forces and cutting temperature,improved tool life,and a better-machined surface during machining.Consequently,the sustainability factor is improved due to minimized energy consumption and residual waste.In conclusion,the key challenges and future prospects in the ultrasonic-assisted cutting of titanium alloys are also discussed.This review article provides beneficial knowledge for manufactur-ers and researchers regarding ultrasonic vibration-assisted cutting of titanium alloy and will play an important role in achieving sustainability in the industry.展开更多
The strength improvement in the heat-treatable Al-Zn-Mg-Cu alloys is generally achieved by increasing the volume fraction of nanoprecipitates and reducing the grain size.However,utilizing one of them usu-ally leads to...The strength improvement in the heat-treatable Al-Zn-Mg-Cu alloys is generally achieved by increasing the volume fraction of nanoprecipitates and reducing the grain size.However,utilizing one of them usu-ally leads to a drastic decrease in ductility.Herein,we architect a hierarchical microstructure integrating bimodal grain structures,nanoprecipitates,and hard-brittle coarse particles wrapped by ductility coarse grain(CG)bands via conventional cold rolling(CR)deformation and heat treatment methods to break the strength-ductility dilemma in the Al-8.89Zn-1.98Mg-2.06Cu-0.12Zr-0.05Sc-0.05Hf(wt.%)alloy.The results reveal that the coupling of high-volume fraction(∼1.2%)nanoprecipitates,∼52%narrow CG bands,and most coarse particles encapsulated by CG bands contribute to the 45%CR sample with outstanding over-all mechanical properties(a tensile strength of 655 MPa,a yield strength of 620 MPa,and an elongation of 15.5%).Microstructure-based strength analysis confirms that the high strength relates to a trade-offbetween the hierarchical features,namely high-volume fraction nanoprecipitates to counterbalance the strength loss caused by grain coarsening.The excellent ductility is due to the introduction of medium CG content with a narrow width that can trigger a cross-scale strain distribution during plastic deforma-tion,suppressing the catastrophic failure in the fine grain(FG)regions and facilitating the dimple fracture along the CG bands.This study proposes a feasible approach for tailoring hierarchical microstructures in Al-Zn-Mg-Cu alloys to achieve a superior strength-ductility combination.展开更多
The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the compl...The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the complex precipitation sequences.Here,a detailed investigation has been carried out on the atomic struc-tural evolution of T_(1) precipitate in an aged Al-Cu-Li-Mg-Ag alloy using state-of-the-art Cs-corrected high-angle annular dark field(HAADF)-coupled with integrated differential phase contrast(iDPC)-scanning transmission electron microscopy(STEM)and energy-dispersive X-ray spectroscopy(EDXS)techniques.An intermediate T_(1)’phase between T_(1p) and T_(1) phase,with a crystal structure and orientation rela-tionship consistent with T_(1),but exhibiting different atomic occupancy and chemical composition was found.We observed the atomic structural transformation from T_(1p) to T_(1)’phase(fcc→hcp),involving only 1/12<112>Al shear component.DFT calculation results validated our proposed structural models and the precipitation sequence.Besides,the distributions of minor solute elements(Ag,Mg,and Zn)in the pre-cipitates exhibited significant differences.These findings may contribute to a further understanding of the nucleation mechanism of T_(1) precipitate.展开更多
Minimum quantity lubrication(MQL),as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining,utilizes a small amount of lubricant or coolan...Minimum quantity lubrication(MQL),as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining,utilizes a small amount of lubricant or coolant to reduce friction,tool wear,and heat during cutting processes.MQL technique has witnessed significant developments in recent years,such as combining MQL with other sustainable techniques to achieve optimum results,using biodegradable lubricants,and innovations in nozzle designs and delivery methods.This review presents an in-depth analysis of machining characteristics(e.g.,cutting forces,temperature,tool wear,chip morphology and surface integrity,etc.)and sustainability characteristics(e.g.,energy consumption,carbon emissions,processing time,machining cost,etc.)of conventional MQL and hybrid MQL techniques like cryogenic MQL,Ranque-Hilsch vortex tube MQL,nanofluids MQL,hybrid nanofluid MQL and ultrasonic vibration assisted MQL in machining of aeronautical materials.Subsequently,the latest research and developments are analyzed and summarized in the field of MQL,and provide a detailed comparison between each technique,considering advantages,challenges,and limitations in practical implementation.In addition,this review serves as a valuable source for researchers and engineers to optimize machining processes while minimizing environmental impact and operational costs.Ultimately,the potential future aspects of MQL for research and industrial execution are discussed.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFC2200100)the CAS's Strategic Pioneer Program on Space Science(Grant No.XDA1502110201)。
文摘Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.
文摘Alzheimer's disease,a progressively degenerative neurological disorder,is the most common cause of dementia in the elderly.While its precise etiology remains unclear,researchers have identified diverse pathological characteristics and molecular pathways associated with its progression.Advances in scientific research have increasingly highlighted the crucial role of non-coding RNAs in the progression of Alzheimer's disease.These non-coding RNAs regulate several biological processes critical to the advancement of the disease,offering promising potential as therapeutic targets and diagnostic biomarkers.Therefore,this review aims to investigate the underlying mechanisms of Alzheimer's disease onset,with a particular focus on microRNAs,long non-coding RNAs,and circular RNAs associated with the disease.The review elucidates the potential pathogenic processes of Alzheimer's disease and provides a detailed description of the synthesis mechanisms of the three aforementioned non-coding RNAs.It comprehensively summarizes the various non-coding RNAs that have been identified to play key regulatory roles in Alzheimer's disease,as well as how these noncoding RNAs influence the disease's progression by regulating gene expression and protein functions.For example,miR-9 targets the UBE4B gene,promoting autophagy-mediated degradation of Tau protein,thereby reducing Tau accumulation and delaying Alzheimer's disease progression.Conversely,the long non-coding RNA BACE1-AS stabilizes BACE1 mRNA,promoting the generation of amyloid-βand accelerating Alzheimer's disease development.Additionally,circular RNAs play significant roles in regulating neuroinflammatory responses.By integrating insights from these regulatory mechanisms,there is potential to discover new therapeutic targets and potential biomarkers for early detection and management of Alzheimer's disease.This review aims to enhance the understanding of the relationship between Alzheimer's disease and non-coding RNAs,potentially paving the way for early detection and novel treatment strategies.
基金financially supported by the National Natural Science Foundation of China (22350410386,W2412116,22375200,U22A202175,21961142006)。
文摘Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.
基金China“Ye Qisun”Science Foundation Project of National Natural Science Foundation(U2141222)Innovation Fund(8F231527Z)。
文摘The combustion behavior of Ti-Al-Mo-Zr-Sn-W alloy(TC25G)was studied in a high-temperature and high-speed air flow environment using the laser ignition method combined with ultra-high temperature infrared thermometer,scanning electron microscope,X-ray diffractometer,and transmission electron microscope.The burn-resistant performance of TC25G and TC11 alloys was compared.Meanwhile,the microstructural characteristics,crystal structure,and formation mechanism of the combustion products of TC25G alloy were analyzed in detail.The results show that the high-temperature and high-speed air flow promotes combustion within the air flow temperature range of 200–400℃and the air flow velocity range of 0–100 m/s.The combustion path advances along the direction of the air flow.The combustion of TC25G alloy mainly relies on the diffusion of the oxygen and the expansion of the combustion area caused by the movement of the melt.Based on the microstructure and composition of combustion product,it can be divided into the combustion zone,the melting zone,and the heat affected zone.During combustion,the formation of microstructures is closely correlated with the behavior of alloying elements and their selective combination with O.The major oxidation products of Ti are TiO and TiO_(2).The oxides formed by Mo and W hinder the movement of the melt during the combustion.Al and Zr tend to undergo internal oxidation.Al_(2)O_(3)precipitates on the surface of ZrO_(2),forming a protective oxide layer that inhibits the inward diffusion of O.Moreover,the element enrichment at the interface between the melting zone and the heat affected zone increases the melting point on the solid side,hindering the migration of the solid-liquid interface.
文摘Photocatalysis is an important technology for using solar energy to produce hydrogen,convert CO_(2) to synthetic fuels,and decrease persistent pollutant.However,conventional photocatalysts have limitations,including poor spectral absorption,inefficient charge separation,and structural instability under operational stress,which demand innovative durable materials with tailored electronic properties.Nanodiamond(ND)has recently been recognized as a suitable material because of its exceptional chemical stability,superior charge carrier mobility,and possible surface functionalization.While its intrinsic wide bandgap limits its response to visible-light,different methods have been demonstrated to activate its catalytic potential.Here,several emerging strategies for improving the catalytic performance of ND-based photocatalytic systems are summarized,including surface functionalization,plasmonic hybridization,heteroatom doping,and heterostructure design.And the structure-activity relationship and design principle are proposed to improve the light harvesting,charge transport,and redox kinetics for constructing high efficiency ND-based photocatalysts used in the renewable energy and environmental industries.
基金Under the auspices of National Natural Science Foundation of China(No.42271214)Key Research Program of Gansu Province(No.23ZDKA0004)Natural Science Foundation of Gansu Province(No.25JRRA212,21JR7RA281,22JR11RA149,24JRR A250)。
文摘Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape fragmentation and identify its key drivers is an important foundation for regional biodiversity conservation and ecosystem restoration.Taking the Guanzhong Plain Urban Agglomeration(GPUA),China as the research object,this paper proposes a comprehensive framework that integrates landscape pattern index,principal component analysis,random forest(RF)and other methods to quantitatively analyze the spatial and temporal evolution of ecological landscape fragmentation and its driving factors.The results show that:1)cropland,forestland and grassland showed significant spatial differentiation in the landscape pattern index,and the change of their mean values indicated that cropland and forestland show a trend of‘little decrease-continuous increase’.Spatially,the northwestern and southeastern regions showed significant fragmentation and prominent spatial heterogeneity.2)From 2010 to 2020,the landscape fragmentation of cropland and forestland increased by 71%and 20%,respectively,while that of grassland decreased by 33%,indicating that the degree of landscape fragmentation of cropland changed more drastically than that of other ecological land.3)It was found that slope was the most important factor affecting landscape fragmentation of ecological land.In addition,road density had a significant effect on landscape fragmentation of cropland and forestland,but the min-distance between patches and the county center had an important effect on landscape fragmentation of grassland.This study can provide theoretical references for urban agglomeration planning and sustainable landscape management on a regional scale.
文摘Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD)plays a crucial role in the aerodynamic analysis of eccentric compressors.However,conventional full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)simulations are prohibitively expensive for routine design and analysis purposes.To address this issue,the paper presents a novel Fourier-based method,called the Time-Space Collocation(TSC)method,for efficient simulations of eccentric compressors.This method coherently treats temporal and spatial harmonics,making it well-suited to tackle the rotor eccentricity problem,as the perturbation waves induced by eccentricity are time-periodic with respect to the rotor and space-periodic with respect to the stator.Three numerical cases,including NASA Rotor 67,original Stage 67,and Stage 67 with a reduced rotor-stator axial gap,were conducted to verify the effectiveness of the TSC method.The results indicate that,for the rotor eccentricity levels studied in this paper,the influence of weak rotor-stator interactions can be disregarded in the original Stage 67.In this situation,applying three harmonics can accurately capture both the performance variations and the non-uniformly distributed flowfields of eccentric compressors,while achieving a reduction in run time by two orders of magnitude compared to full-annulus URANS simulations.However,in Stage 67 with a reduced rotor-stator axial gap,the results that include rotor-stator interactions align much more closely with the URANS results.Nevertheless,the TSC simulations can still achieve speed-ups of several dozen times.Overall,the TSC method shows promising potential for application within the engineering community.
基金supported by the National Natural Sciences Foundation of China(42261026)the Open Foundation of Xinjiang Key Laboratory of Water Cycle and Utilization in Arid Zone(XJYS0907-2023-01)the Light of the West Program for Young Scholars,Chinese Academy of Sciences(25JR6KA005).
文摘Terrestrial ecosystems are vital for maintaining equilibrium in the global carbon cycle.Land use and land cover change(LUCC),which is influenced mainly by urbanization and ecological policies,impacts terrestrial ecosystem carbon storage significantly.In this study,spatiotemporal carbon storage changes in the urban belt along the Yellow River in the Ningxia Hui Autonomous Region,China,were estimated through a model that integrated patch-generating land use simulation(PLUS)and integrated valuation of ecosystem services and tradeoffs(InVEST)models from 1993 to 2033.The results revealed that:(1)from 1993 to 2023,the expansion of built-up land and cropland was derived mainly from unused land and grassland,whereas water body and woodland remained relatively stable.Projections to 2033 have indicated that LUCC will continue and be concentrated primarily in the Ningxia Plain;(2)carbon storage increased by a net 5.01×10^(6) Mg C from 1993 to 2023;(3)the spatial distribution of carbon storage revealed that high-value areas were predominantly located in the Helan Mountains and the Ningxia Plain,whereas low-value areas were found in the Tengger Desert;(4)scenario projections indicated that by 2033,the ecological protection scenario(EPS)would achieve a 0.18×10^(6) Mg C increase by reducing the conversion of woodland to cropland and grassland to built-up land,while increasing the conversion of unused land to grassland.In contrast,the natural development scenario(NDS),cropland protection scenario(CPS),and urban development scenario(UDS)decreased carbon storage by 0.60×10^(6),0.21×10^(6),and 0.42×10^(6) Mg C,respectively;and(5)spatial autocorrelation analysis revealed that high–high carbon storage clusters formed belt-like patterns along the Ningxia Plain and the Helan Mountains,whereas the low–low carbon storage clusters were concentrated in northern Zhongwei City,western Qingtongxia City,western Dawukou District,and the urbanized areas within the central Ningxia Plain.Overall,the study results revealed the close coupling relationship between LUCC and carbon storage functions.Furthermore,the study establishes a framework for carbon management that balances ecological protection with coordinated urban development for the urban belt as well as for similar arid and semi-arid areas.On the basis of these findings,this study provides decision-makers with guidance to optimize ecosystem carbon storage via land use,which plays a key role in developing future land use policies and achieving the"dual carbon"goals.
基金supported by the Natural Science Foundation of China(Grant Nos.32172544,32441071)the special fund for scientific innovation strategy-construction of high level Academy of Agriculture Science(Grant No.R2023PY-JG003)+4 种基金the earmarked fund for CARS(Grant No.CARS-31-01)Guangdong Special Support Program(Grant No.NYLJ2024010)Guangdong S&T Program(Grant No.2025B0202070005)IAEA CRP D23033the Project from Guangzhou Municipal Science and Technology Bureau(2023B03J0991).
文摘Banana(Musa spp.)is one of the most important fruit crop worldwide,and plays a critical role in human diet and agricultural economies across tropical and subtropical regions,including China(Jiang et al.,2025;Wu et al.,2025).However,its rapid softening severely limits shelf life,causing substantial economic losses during transport and storage.Recently,the enhanced shelf-life can be generated by compromising the key ripening regulators,such as RIN,but other fruit quality traits including flavor and color also can be impaired concurrently(Kitagawa et al.,2005).
基金Supported by the National Natural Science Foundation of China under Grant No.51975138the High-Tech Ship Scientific Research Project from the Ministry of Industry and Information Technology under Grant No.CJ05N20the National Defense Basic Research Project under Grant No.JCKY2023604C006.
文摘Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.
基金National Natural Science Foundation of China(Grant Nos.41930101 and 42101096)the China Postdoctoral Science Foundation(No.2019M660091XB)+8 种基金the Key Research and Development Project of Ecological Civilization Construction in Gansu Province(No.24YFFA054)the Natural Science Foundation of Gansu Province(Grant Nos.23JRRA857,23JRRG0015,and 21JR7RA317)the Gansu Province Higher Education Institutions Young Doctor(2024QB-046)the Open Fund of Wuhan,Gravitational Field and Solid Tides,National Field Observation and Research Station(WHYWZ202403)the National Cryosphere Desert Data Center(No.E01Z790201/2021kf07)the Lanzhou Talent Innovation and Entrepreneurship(No.2022-RC-73)the Experimental Teaching Reform Project of Lanzhou Jiaotong University(2024002)the Undergraduate Teaching Reform Project of Lanzhou Jiaotong University(JGY202416)"Young Scientific and Technological Talents Supporting Project"Project of Gansu Province(Li Wei)。
文摘An MW6.0 earthquake struck Jishishan County in Linxia Prefecture,Gansu Province,on December 18,2023.In this research,Sentinel-1A satellite radar observations were used to obtain the field of coseismic deformation of the Jishishan earthquake in 2023,and the geometric and fine slip distribution of the seismogenic fault were inverted using this as a constraint.The results show that the earthquake is characterized by thrust movement.The coseismic slip distribution results show that the maximum slip of this earthquake is 0.3 m.The Coulomb stress distribution shows that the whole section of the southern edge of Lajishan fault,the NWW trending segment of the northern edge of Lajishan fault and its NNW trending segment to the south of the epicenter,the northern edge of the West Qinling fault and the segment to the east of the epicenter of the Daotanghe Linxia fault are under stress loading,which indicates an increase in the potential risk of earthquakes.This research discussed the seismogenic characteristics of earthquakes and the tendency of faults.We speculate that the Jishishan earthquake is the result of the joint action of regional faults and tectonic stress.Based on the observation of seismic data,geodesy,and other geological and geophysical data,we believe that the earthquake was caused by the activation of weak areas under the crust by the local stress from the driving mechanism of the northeast expansion of Qinghai-Xizang Plateau.The seismogenic fault of this earthquake is more likely to be northeast dipping under the comprehensive consideration of various factors,which occurred on the concealed fault belonging to the eastern edge of the Jishishan fault zone.
基金supported by the National Science Foundation of China(No.62171387)the Science and Technology Program of Sichuan Province(No.2024NSFSC0468)the China Postdoctoral Science Foundation(No.2019M663475).
文摘As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and diverse communication needs.It is crucial to design control sequences with robust randomness and conflict-freeness to properly address differentiated access control in data link.In this paper,we propose a hierarchical access control scheme based on control sequences to achieve high utilization of time slots and differentiated access control.A theoretical bound of the hierarchical control sequence set is derived to characterize the constraints on the parameters of the sequence set.Moreover,two classes of optimal hierarchical control sequence sets satisfying the theoretical bound are constructed,both of which enable the scheme to achieve maximum utilization of time slots.Compared with the fixed time slot allocation scheme,our scheme reduces the symbol error rate by up to 9%,which indicates a significant improvement in anti-interference and eavesdropping capabilities.
基金the financial support from the National Natural Science Foundation of China (No. 52374380)the China Postdoctoral Science Foundation (Nos. 2023M730234, 2024T171126)。
文摘In order to overcome the embrittlement of metastable titanium alloys caused by the precipitation ofωiso phase during aging,regulation of isothermalωprecipitation was investigated in Ti−15Mo alloy.The results show that the sample is brittle when direct aging(A)is applied at 350℃for 1 h after solution treatment(ST).If pre-deformation(D)is performed on the ST sample to induce{332}twins and secondaryα″phase,subsequent aging at 350℃(STDA350)improves the strength to 931 MPa with a good ductility of about 20%maintained.However,when aging is performed at 400℃or 450℃(STDA400/450),the strength can be further improved,but the ductility is dramatically reduced.Atomic-scale characterizations show that the partial collapse ofωphase in the STDA350 sample effectively eliminates aging-induced embrittlement,but complete collapse leads to poor ductility in the STDA400/450 sample.
基金Project supported by the National Natural Science Foundation of China(No.12472077)the supports from Shanghai Gaofeng Project for University Academic Program Development,Fundamental Research Funds for the Central Universities(No.22120240353).
文摘Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenization methods based on the classical elasticity theory struggle to accurately describe the non-classical mechanical behaviors of lattice materials,especially when dealing with complex unit-cell geometries featured by non-symmetric configurations or non-single central node connections.In response to this limitation,this study establishes a generalized homogenization model based on the micropolar theory framework,employing Hill's boundary conditions to precisely predict the equivalent moduli of complex lattice materials.By introducing the independent rotational degree of freedom(DOF)characteristic of the micropolar theory,the proposed model successfully overcomes the limitation of conventional methods in accurately describing the asymmetric deformation and scale effects.We initially calculate the constitutive relations of two-dimensional(2D)cross-shaped multi-node chiral lattices and subsequently extend the method to three-dimensional(3D)lattices,successfully predicting the mechanical properties of both traditional and eccentric body-centered cubic(BCC)lattices.The theoretical model is validated through the finite element numerical verification which shows excellent consistency with the theoretical predictions.A further parametric study investigates the influence of geometric parameters,revealing the underlying size-effect mechanism.This paper provides a reliable theoretical tool for the design and property optimization of complex lattice materials.
基金supported by the National Natural Science Foundation of China(Nos.12261131505,U2241274)the Russian Science Fund(No.23-49-00133)+3 种基金the Aeronautical Science Foundation of China(No.20240002053002)the Natural Science Basic Research Program of Shaanxi,China(No.2025JC-YBMS-005)the Key Research and Development Program of Shaanxi,China(No.2024GX-YBXM-037)the Basic Research Programs of Taicang,China(No.TC2024JC10)。
文摘As the main component of the aircraft leading edge,the radome is often the first to be hit by raindrops and cause structural damage when passing through a rain field.Rain resistant coating is usually applied to ensure the performance protection requirements.In order to clarify the rain erosion damage mechanism of radome coating and explore the influencing factors and mechanisms of coating material damage under different jet impact conditions,impact tests were conducted on three types of skin coating samples,and the damage mode was observed through electron microscopy characterization.The experimental results show that the typical morphology of rain erosion damage is annular surface peeling damage.The damage area and volume of the three coating samples increase with the continuous increase of raindrop impact velocity.The threshold velocity for initial damage to the coating is about 360 m/s;under the influence of the velocity component,the reduction in impact angle leads to a gradual reduction in the degree of damage to the sample.ABAQUS finite element simulation software was used to establish a constitutive model for coating rain erosion simulation and obtain the propagation law of stress waves during the impact process.The simulation results show that at the 75°impact angle,the jet impacts the surface of the specimen at different velocities,and as the impact velocity increases,the Mises equivalent stress on the surface shows an increasing trend,which is one of the main factors causing damage with increasing velocity.The effectiveness,rain erosion damage mode,and influencing mechanism of the model were verified based on the test results;the dynamic failure mechanism of the sample was further studied,and the stress propagation process at different impact angles was compared,revealing the influence mechanism and damage law of the impact angle on the high-speed raindrop impact of the material.
基金financially and technically supported by the National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact,Beijing Institute of Technology,China(No.WDZC2024-1)。
文摘Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic rolled SF-7055 Al alloy is elongated to form a fiber texture.Numerous proliferating dislocations in the microstructure accumulate into dislocation walls and cells,and eventually form subgrains.These subgrain boundaries divide the original grain,thereby reducing the grain size.Under severe deformation conditions,they even enable the formation of nanograins.Meanwhile,the Cu-rich precipitates in the matrix are also broken and refined under the action of large rolling stress.In the process of cryogenic rolling,the tensile strength and hardness of SF-7055 Al alloy gradually increase,while the plasticity decreases.Moreover,the fracture morphology of cryogenic rolled SF-7055 Al alloy gradually transforms to the ductile and quasi-cleavage hybrid fracture characteristics with increased reduction.
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415 and 52205475)the Science Center for Gas Turbine Project(No.P2023-B-IV-003-001)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Huaqiao University Engineering Research Center of Brittle Materials Machining(MOE,2023IME-001)。
文摘The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and medical sectors.However,conventional machining of titanium alloys leads to elevated tool wear,development of surface defects,and reduced machining efficiency due to their low heat conductivity,and chemical affinity.These issues can be somewhat counteracted by integrating ultrasonic vibration in the conventional machining of titanium alloys and also enhance sustainability.This review article offers a holistic evaluation of the influence of ultrasonic vibration-assisted milling and turning on cutting forces,temperature,tool wear,and surface integrity,encompassing surface morphology,surface roughness,surface residual stress,surface hardness,and surface tribological properties during titanium alloys machining.Furthermore,it investigates the sustainability aspect that has not been previously examined.Studies on the performance of ultrasonic-assisted cutting revealed several advantages,including decreased cutting forces and cutting temperature,improved tool life,and a better-machined surface during machining.Consequently,the sustainability factor is improved due to minimized energy consumption and residual waste.In conclusion,the key challenges and future prospects in the ultrasonic-assisted cutting of titanium alloys are also discussed.This review article provides beneficial knowledge for manufactur-ers and researchers regarding ultrasonic vibration-assisted cutting of titanium alloy and will play an important role in achieving sustainability in the industry.
基金supported by the Key Laboratory Fund of National Key Laboratory of Science and Technology on High-strength Structural Materials(Nos.412130024,623020031)the Pre-research Fund(No.412130024).
文摘The strength improvement in the heat-treatable Al-Zn-Mg-Cu alloys is generally achieved by increasing the volume fraction of nanoprecipitates and reducing the grain size.However,utilizing one of them usu-ally leads to a drastic decrease in ductility.Herein,we architect a hierarchical microstructure integrating bimodal grain structures,nanoprecipitates,and hard-brittle coarse particles wrapped by ductility coarse grain(CG)bands via conventional cold rolling(CR)deformation and heat treatment methods to break the strength-ductility dilemma in the Al-8.89Zn-1.98Mg-2.06Cu-0.12Zr-0.05Sc-0.05Hf(wt.%)alloy.The results reveal that the coupling of high-volume fraction(∼1.2%)nanoprecipitates,∼52%narrow CG bands,and most coarse particles encapsulated by CG bands contribute to the 45%CR sample with outstanding over-all mechanical properties(a tensile strength of 655 MPa,a yield strength of 620 MPa,and an elongation of 15.5%).Microstructure-based strength analysis confirms that the high strength relates to a trade-offbetween the hierarchical features,namely high-volume fraction nanoprecipitates to counterbalance the strength loss caused by grain coarsening.The excellent ductility is due to the introduction of medium CG content with a narrow width that can trigger a cross-scale strain distribution during plastic deforma-tion,suppressing the catastrophic failure in the fine grain(FG)regions and facilitating the dimple fracture along the CG bands.This study proposes a feasible approach for tailoring hierarchical microstructures in Al-Zn-Mg-Cu alloys to achieve a superior strength-ductility combination.
基金supported by the Pre-research fund(No.412130024).
文摘The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the complex precipitation sequences.Here,a detailed investigation has been carried out on the atomic struc-tural evolution of T_(1) precipitate in an aged Al-Cu-Li-Mg-Ag alloy using state-of-the-art Cs-corrected high-angle annular dark field(HAADF)-coupled with integrated differential phase contrast(iDPC)-scanning transmission electron microscopy(STEM)and energy-dispersive X-ray spectroscopy(EDXS)techniques.An intermediate T_(1)’phase between T_(1p) and T_(1) phase,with a crystal structure and orientation rela-tionship consistent with T_(1),but exhibiting different atomic occupancy and chemical composition was found.We observed the atomic structural transformation from T_(1p) to T_(1)’phase(fcc→hcp),involving only 1/12<112>Al shear component.DFT calculation results validated our proposed structural models and the precipitation sequence.Besides,the distributions of minor solute elements(Ag,Mg,and Zn)in the pre-cipitates exhibited significant differences.These findings may contribute to a further understanding of the nucleation mechanism of T_(1) precipitate.
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415,and 52205475)the Science Center for Gas Turbine Project(Nos.P2022-AB-IV-002-001 and P2023-B-IV-003-001)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Superior Postdoctoral Project of Jiangsu Province(No.2022ZB215)the National Key Laboratory of Science and Technology on Helicopter Transmission in NUAA(No.HTL-A-22G12).
文摘Minimum quantity lubrication(MQL),as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining,utilizes a small amount of lubricant or coolant to reduce friction,tool wear,and heat during cutting processes.MQL technique has witnessed significant developments in recent years,such as combining MQL with other sustainable techniques to achieve optimum results,using biodegradable lubricants,and innovations in nozzle designs and delivery methods.This review presents an in-depth analysis of machining characteristics(e.g.,cutting forces,temperature,tool wear,chip morphology and surface integrity,etc.)and sustainability characteristics(e.g.,energy consumption,carbon emissions,processing time,machining cost,etc.)of conventional MQL and hybrid MQL techniques like cryogenic MQL,Ranque-Hilsch vortex tube MQL,nanofluids MQL,hybrid nanofluid MQL and ultrasonic vibration assisted MQL in machining of aeronautical materials.Subsequently,the latest research and developments are analyzed and summarized in the field of MQL,and provide a detailed comparison between each technique,considering advantages,challenges,and limitations in practical implementation.In addition,this review serves as a valuable source for researchers and engineers to optimize machining processes while minimizing environmental impact and operational costs.Ultimately,the potential future aspects of MQL for research and industrial execution are discussed.
