Phosphorus(P)is an essential nutrient for crop growth,making it important for maintaining food security as the global population continues to increase.Plants acquire P primarily via the uptake of inorganic phosphate(P...Phosphorus(P)is an essential nutrient for crop growth,making it important for maintaining food security as the global population continues to increase.Plants acquire P primarily via the uptake of inorganic phosphate(Pi)in soil through their roots.Pi,which is usually sequestered in soils,is not easily absorbed by plants and represses plant growth.Plants have developed a series of mechanisms to cope with P deficiency.Moreover,P fertilizer applications are critical for maximizing crop yield.Maize is a major cereal crop cultivated worldwide.Increasing its P-use efficiency is important for optimizing maize production.Over the past two decades,considerable progresses have been achieved in studies aimed at adapting maize varieties to changes in environmental P supply.Here,we present an overview of the morphological,physiological,and molecular mechanisms involved in P acquisition,translocation,and redistribution in maize and combine the advances in Arabidopsis and rice,to better elucidate the progress of P nutrition.Additionally,we summarize the correlation between P and abiotic stress responses.Clarifying the mechanisms relevant to improving P absorption and use in maize can guide future research on sustainable agriculture.展开更多
Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of w...Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of wildfire pre-vention,monitoring,disaster response,and post-fire recovery.This review examines the potential utility of Digital Twin in wildfire management and aims to inspire further exploration and experimentation by researchers and practitioners in the fields of environment,forestry,fire ecology,and firefighting services.By creating virtual replicas of wildfire in the physical world,a Digital Twin platform facilitates data integration from multiple sources,such as remote sensing,weather forecast-ing,and ground-based sensors,providing a holistic view of emergency response and decision-making.Furthermore,Digital Twin can support simulation-based training and scenario testing for prescribed fire planning and firefighting to improve preparedness and response to evacuation and rescue.Successful applications of Digital Twin in wildfire management require horizontal collaboration among researchers,practitioners,and stakeholders,as well as enhanced resource sharing and data exchange.This review seeks a deeper understanding of future wildland fire management from a technological perspective and inspiration of future research and implementation.Further research should focus on refining and validating Digital Twin models and the integration into existing fire management operations,and then demonstrating them in real wildland fires.展开更多
Maize(Zea mays),which is a vital source of food,feed,and energy feedstock globally,has significant potential for higher yields.However,environmental stress conditions,including drought and salt stress,severely restric...Maize(Zea mays),which is a vital source of food,feed,and energy feedstock globally,has significant potential for higher yields.However,environmental stress conditions,including drought and salt stress,severely restrict maize plant growth and development,leading to great yield losses.Leucine-rich repeat receptor-like kinases(LRR-RLKs)function in biotic and abiotic stress responses in the model plant Arabidopsis(Arabidopsis thaliana),but their roles in abiotic stress responses in maize are not entirely understood.In this study,we determine that the LRR-RLK ZmMIK2,a homolog of the Arabidopsis LRR-RK MALE DISCOVERER 1(MDIS1)-INTERACTING RECEPTOR LIKE KINASE 2(MIK2),functions in resistance to both drought and salt stress in maize.Zmmik2 plants exhibit enhanced resistance to both stresses,whereas overexpressing ZmMIK2 confers the opposite phenotypes.Furthermore,we identify C2-DOMAIN-CONTAINING PROTEIN 1(ZmC2DP1),which interacts with the intracellular region of ZmMIK2.Notably,that region of ZmMIK2 mediates the phosphorylation of ZmC2DP1,likely by increasing its stability.Both ZmMIK2 and ZmC2DP1 are mainly expressed in roots.As with ZmMIK2,knockout of ZmC2DP1 enhances resistance to both drought and salt stress.We conclude that ZmMIK2-ZmC2DP1 acts as a negative regulatory module in maize drought-and salt-stress responses.展开更多
On September 5,2022,at least 10,855 landslides had been triggered by a magnitude Mw 6.7(Ms 6.8)earthquake on the eastern margin of the Tibetan Plateau.Unfortunately,a detailed analysis of the spatial patterns of lands...On September 5,2022,at least 10,855 landslides had been triggered by a magnitude Mw 6.7(Ms 6.8)earthquake on the eastern margin of the Tibetan Plateau.Unfortunately,a detailed analysis of the spatial patterns of landslides in the eastern margin of the Baryan Har block is lacking.The observations show that the highest landslide concentrations are distributed along the seismogenic fault(Moxi fault)and Dadu River valley,coinciding with the effects of the hanging wall and microepicenter.Seismogenic tectonics controlled the regional distribution of new landslides,and the local topography influenced the detailed positions on the slopes.The total landslide mass wasting volume was 223.1×10^(6)m^(3),and the maximum occurred in the Wandong Basin(value of 74×10^(6)m^(3)).Thirty landslide dams were temporarily existing.Although some local collapses occurred at the toe of the Hailuogou glacier,seismic shaking had no obvious influence on the overall stability of the glacier.A post debris flow assessment indicates that some large basins contained much loose material and that some steep small basins had high debris flow susceptibility.On the eastern margin of the Bayan Har block,the landslide-triggering thrust and strike-slip events both follow the distributions of the hanging wall.展开更多
Fusarium ear rot(FER),caused by Fusarium verticillioides,is a destructive fungal disease of maize.FER resistance is a complex,quantitatively inherited trait controlled by multiple minor-effect genes.In this study,we e...Fusarium ear rot(FER),caused by Fusarium verticillioides,is a destructive fungal disease of maize.FER resistance is a complex,quantitatively inherited trait controlled by multiple minor-effect genes.In this study,we employed two recombinant inbred line(RIL)populations with the common resistant parental line CML304 to identify FER-resistance loci.Initial QTL analysis identified 23 FER-resistance QTL,each explaining 5.21%-30.51%of the total phenotypic variation.Notably,one major QTL,qRfv2,on chromosome 2 was repeatedly detected,accounting for 11.92%-30.51%of the total phenotypic variation.qRfv2 was fine mapped to an interval of 1.01 Mb,flanked by the markers IDP8 and IDP10.qRfv2 is a semidominant resistance gene that could reduce the disease severity index(DSI)by 12.4%-20%,suggesting its potential for enhancing FER resistance in maize.Transcriptome analysis showed that 22 of the 28 annotated functional genes in the qRfv2 region displayed differential expression between parental lines in response to FER.One of the candidate genes,ZmLOX6,was validated to presumably provide a positive effect on FER resistance.Our study provides a basis for the potential cloning and application of FER resistance genes in maize breeding.展开更多
The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield...The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate.The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory,Mindlin solution and Euler-Bernoulli-Pasternak model,subsequently validated through both finite element simulation and field monitoring.It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling.The longitudinal settlement distribution can be categorized into five areas,with the area near the tunnel surface experiencing the most dramatic settlement changes.The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure,especially when the turning radius is less than 30 times the tunnel diameter.The tunnel crown exhibits larger displacement than the tunnel bottom,resulting in a distinctive‘vertical egg'shape.Furthermore,an optimized overcutting mode is proposed,involving precise control of the extension speed and angular velocity of the overcutting cutter,which effectively mitigates ground deformation,ensuring the protection of the existing tunnel during the construction.展开更多
1.Need for coordinated flyways conservation Flyways are migratory routes that encompass breeding,stopover,and non-breeding habitats essential for the annual life cycles of migratory birds(Bamford et al.,2008;Newton,20...1.Need for coordinated flyways conservation Flyways are migratory routes that encompass breeding,stopover,and non-breeding habitats essential for the annual life cycles of migratory birds(Bamford et al.,2008;Newton,2023).These routes are critical for maintaining global biodiversity by supporting seasonal movements across continents(Hua et al.,2015;Runge et al.,2015).Effective conservation of flyways,such as the East Asian-Australasian Flyway(EAAF)and Central Asian Flyway(CAF),requires international cooperation to protect key stopover sites(Yong et al.,2015;Kumar 2019;Schmaljohann et al.,2022).展开更多
This study presents a numerical simulation of large-scale shaking table tests on a superstructure supported by a pile group installed in an inclined liquefiable site,fo-cusing on nonlinear interactions between piles a...This study presents a numerical simulation of large-scale shaking table tests on a superstructure supported by a pile group installed in an inclined liquefiable site,fo-cusing on nonlinear interactions between piles and the soil.A three-dimensional finite element model of a soil-pile superstructure system is developed using OpenSeesMP.The temporal and spatial evolution of the radial soil pressure around the pile is evaluated in both liquefied and nonlique-fied sites.Results show that the soil pressure around the pile is significantly influenced by site inclination and soil lateral spreading.In liquefied sites,the soil pressure in the ex-truded zone of the upstream pile is significantly higher than that in the diffused zone.However,higher pressure occurs in the diffused zone for nonliquefied sites.Correspond-ingly,the liquefaction state significantly influences the force characteristics of the pile group system.Additionally,the group effect is more pronounced in liquefied sites.The results also indicate that the soil pressure distribution around the piles is closely related to the relative pile-soil displace-ment and reveals different on-pile force mechanisms under varying site conditions.These findings offer valuable in-sights into the seismic design of pile foundations in inclined liquefied sites.展开更多
Large-scale ice avalanches pose serious risks owing to their high speed and long travel distances,and their mobility is increased by ice melting owing to frictional heat.Most motion models for largescale ice avalanche...Large-scale ice avalanches pose serious risks owing to their high speed and long travel distances,and their mobility is increased by ice melting owing to frictional heat.Most motion models for largescale ice avalanches have been constructed for specific scenarios,neglecting the key effect of frictional ice melting on their mobility and having limited applicability.In this study,a two-dimensional model combining thermodynamic and dynamic properties was proposed.This model,based on depth-averaged and granular flow theories,considers the friction weakening process to simulate the dynamics of ice avalanches.The governing equations for motion and heat transfer were solved by employing the finite volume and the Crank-Nicolson methods.The numerical simulation results showed that the friction weakening caused by the thermal effect on the sliding surface significantly reduced the friction coefficient between the ice mass and its substrate,increasing the travel distance of ice avalanches.The initial ice content in the shear band affects the friction coefficient during the viscous and Coulomb friction stages.The higher the initial ice content in the shear band,the lower the viscous resistance during the frictional heatinginduced drag reduction stage,resulting in a longer sliding distance and larger coverage area.Notably,large-scale ice avalanches exhibit a"Volume Effect"similar to other mass movements such as landslides,debris flows,and rock avalanches.Ice avalanches with larger volumes exhibit greater mobility and coverage areas.The proposed model reveals the dynamic characteristics of large-scale ice avalanches under the effect of frictional heat and offers a valuable tool for dynamic analysis and supporting disaster risk reduction strategies.展开更多
Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experi...Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experiments under unidirectional flow, bidirectional flow, and wave-current interactions with different flow directions around the pile group foundation were first conducted to investigate the development of scour around the pile group foundation.Additionally, a three-dimensional scour numerical model was established via the open-source software REEF3D to simulate the flow field and scour around the prototype-scale foundation. The impact of flow on scour was discussed.Under unidirectional flow, scour equilibrium was reached more quickly, with the maximum scour depth reaching approximately 1.2 times the pile diameter and the extent of the scour hole spanning about 4.9 times the pile diameter.Compared with those under unidirectional flow, the scour depths under combinations of currents and waves, as well as bidirectional flow, were slightly smaller. However, the morphology of scour holes was more uniform and symmetrical. The numerical simulation results show good agreement with the experimental data, demonstrating the impact of varying flow directions on the velocity distribution around the foundation, the morphology of scour holes, and the location of the maximum scour depth.展开更多
CRISPR-Cas endonucleases mediate prokaryotic adaptive immunity by targeting foreign nucleic acids.CRISPR/Cas13b is a class 2 type VI-B ribonuclease that targets and cleaves single-stranded RNA.It exhibits higher RNA i...CRISPR-Cas endonucleases mediate prokaryotic adaptive immunity by targeting foreign nucleic acids.CRISPR/Cas13b is a class 2 type VI-B ribonuclease that targets and cleaves single-stranded RNA.It exhibits higher RNA interference activity than Cas13a and Cas13c and causes fewer collateral effects than RxCas13d in mammalian cells.However,a programmable CRISPR/Cas13b-mediated RNA interference system for endogenous transcripts in rice has not yet been established.Here,we developed a CRISPR/Cas13b-mediated system to target endogenous transcripts in rice.Our CRISPR/Cas13b system could inhibit multiple endogenous mRNAs simultaneously.In addition,this system efficiently repressed endogenous long noncoding RNAs with more than 50% inhibition in stable transgenic plants.Furthermore,we found only weak collateral effects of the CRISPR/Cas13b-mediated system at the transcriptome-wide level,and no difference in the agronomic traits of stable transgenic rice in the field.We present a programmable CRISPR/Cas13b-mediated knockdown system for rice,offering a potential biotechnological tool for functional genomics and crop improvement.展开更多
A three-dimensional numerical model of sand wave dynamics,incorporating the interaction of currents and waves at various angles,has been developed using the Regional Ocean Modeling System(ROMS).This model accounts for...A three-dimensional numerical model of sand wave dynamics,incorporating the interaction of currents and waves at various angles,has been developed using the Regional Ocean Modeling System(ROMS).This model accounts for both bedload and suspended load sediment transport under combined waves and current conditions.The investigation examines the influence of several key parameters,including the rotation angle of sand waves relative to the main current,tidal current velocity amplitude,residual current,water depth,wave height,wave period,and wave direction,on sand wave evolution.The growth rate and migration rate of sand waves decrease as their rotation angle increases.For rotation angles smaller than 15°,sand wave evolution can be effectively simulated by a vertical 2D model with an error within 10%.The numerical results demonstrate that variations in tidal current velocity amplitude or residual current affect both vertical growth and horizontal migration of sand waves.As tidal current velocity amplitude and residual current increase,the growth rate initially rises to a maximum before decreasing.The migration rate shows a consistent increase with increasing tidal current amplitude and residual current.Under combined waves and current,both growth and migration rates decrease as water depth increases.With increasing wave height and period,the growth rate and migration rate initially rise to maximum values before declining,while showing a consistent increase with wave height and period.The change rate of sand waves reaches its maximum when wave propagation aligns parallel to tidal currents,and reaches its minimum when wave propagation is perpendicular to the currents.This phenomenon can be explained by the fluctuation of total bed shear stress relative to the angle of interaction between waves and current.展开更多
A novel bidirectional tuned rolling mass damper(Bi-TRMD)device is proposed,and its dynamic character-istics and vibration reduction performance are investigated.The device achieves the performance goal of bidirectiona...A novel bidirectional tuned rolling mass damper(Bi-TRMD)device is proposed,and its dynamic character-istics and vibration reduction performance are investigated.The device achieves the performance goal of bidirectional vibration reduction for a tuned rolling mass damper with a single concave structure.First,the Bi-TRMD device is introduced,and its three-dimensional(3D)mechanical model is established.The motion equations of the model are de-rived using the Gibbs-Appell equation,and a trajectory pre-diction method for the sphere and structure within the model is developed.This method demonstrates that the rolling motion of the sphere around orthogonal axes is nearly indepen-dent within a limited range,enabling the simplification of the 3D model into a two-dimensional(2D)model.The accuracy of this simplification is validated through case analysis.The vibration reduction parameters are optimized using the 2D model and Den Hartog theory,leading to the derivation of mathematical expressions for the optimal frequency ratio and damping ratio.Subsequently,the bidirectional vi-bration reduction performance of the Bi-TRMD is analyzed.The results show that under white noise excitation,the Bi-TRMD achieves a bidirectional peak acceleration reduction rate that is 9.92%and 7.79%higher than that of translational tuned mass dampers(TMD)with the same mass.These findings demonstrate that the proposed Bi-TRMD ef-fectively achieves two-directional vibration reduction with a single concave structure,offering superior vibration reduction performance.展开更多
The Yarlung Tsangpo River(YTR),located in the Himalayan orogenic belt,is renowned for its deep gorges and complex tectonic features,as well as its reputation as a landslide-prone region.However,less is known about the...The Yarlung Tsangpo River(YTR),located in the Himalayan orogenic belt,is renowned for its deep gorges and complex tectonic features,as well as its reputation as a landslide-prone region.However,less is known about the distribution of landslides across the entire river basin.To address this gap in knowledge,this study first established a comprehensive landslide inventory across the entire basin using remote sensing mapping and multiple field investigations.Then,a systematic analysis of the spatial and size distributions was conducted.The results indicated that the YTR basin features at least 2390 landslides with areas exceeding 104 m2,spanning a total area and volume of 1087.6 km^(2) and 48.4 km^(3),respectively.These landslides can be classified into eight types,and rockslides are the most common(53.1%).Their distributions are highly asymmetric,with the following notable patterns:(1)the Tsangpo suture zone(53.4%)contains a greater number of landslides than other tectonic units;(2)the landslide size is influenced by the relief and elevation conditions,with positive relationships observed between the local relief and landslide area,as well as between the elevation range and landslide area;and(3)the landslide distribution is not significantly correlated with rainfall,and seasonally frozen ground is associated with a greater concentration of landslides.Alternating slate and shale groups in the Tsangpo suture zone may be the factors responding to landslide concentration.A total of 20.6%of landslide-blocked rivers were observed,with some forming river knickpoints.Due to the limited data,spatial and size analyses are perhaps immature,and further systematic analysis remains necessary.展开更多
Understanding the relationship between sediment and discharge is crucial for effective river management and water-sediment modeling,especially in the Brahmaputra River,one of the large transboundary rivers with high s...Understanding the relationship between sediment and discharge is crucial for effective river management and water-sediment modeling,especially in the Brahmaputra River,one of the large transboundary rivers with high sediment and discharge variability in South Asia.Current knowledge of sediment-water relations is constrained by limited data,hindering effective transboundary river management.Using multivariate linear regression,climate elasticity coefficient,and traditional sediment rating curve,this study is designed to compare the sediment-water relations of the upstream(Nuxia)and the downstream(Bahadurabad).The results reveal significant variability between the two stations.In the upstream Nuxia,the simulation strongly correlates with observed suspended sediment load(SSL)and discharge(Q)(Pearson's r of 0.62 and 0.68,respectively).Conversely,at downstream Bahadurabad,weaker correlations(r=0.31 for sediment and r=0.51 for discharge simulation)indicate a reduced relation.This contrast reflects the non-linear nature of sediment-discharge coupling along the river continuum,shaped by both climatic and anthropogenic influences.Elasticity(ε)analysis highlights the dominant role of precipitation in shaping sediment-water dynamics(εP-SSL=2.53,εP-Q=1.01)at Nuxia,while Bahadurabad(εP-SSL=0.41,εP-Q=0.82)reflects a reduced sensitivity,possibly due to sediment retention along the floodplain.Air temperature elasticity(εT-SSL,-0.15&-3.06 at Nuxia and Bahadurabad,respectively)reveals contrasting impacts,strongly negatively influencing sediment transport at Bahadurabad.These findings highlight the significance of spatial variability and climatic influences on sediment dynamics,underscoring the necessity for site-specific management strategies.The sediment rating curve(SRC)analysis reveals a strong relationship between sediment and discharge(R^(2)=0.88)at Nuxia and a relatively weaker relationship(R^(2)=0.14)at Bahadurabad,which demonstrates a lower sedimentdischarge coupling that could be affected by downstream factors such as sediment deposition,channel morphology,and anthropogenic activities.This study offers valuable insights into sediment-water dynamics,highlighting the importance of understanding nonlinear relationships in the Brahmaputra River.展开更多
Although the increase in the frequency of mass wasting events in the Sedongpu gully in recent years indicates that the Sedongpu gully has entered an intense mass wasting period,the current literature focuses only on i...Although the increase in the frequency of mass wasting events in the Sedongpu gully in recent years indicates that the Sedongpu gully has entered an intense mass wasting period,the current literature focuses only on ice‒rock avalanche events and lacks comprehensive knowledge of Sedongpu gully activity.To clarify the spatiotemporal distribution and scales of mass wasting events,we analysed multiple images from 1969 to present(including optical images and synthetic aperture radar(SAR)images)and topography data from 2013 to present.Since 1969,there have been at least 19 obvious mass wasting events that can be divided into 3 subpatterns:ice‒rock avalanches(IRAs,8 events),ice‒moraine avalanches(IMAs,2 events),and glacier debris flows(GDFs,9 events).Since 2017,the Sedongpu gully has entered the most active period,i.e.more than 68%of events occurred after 2017,and approximately 530 Mm^(3)and 185 Mm^(3)of materials were removed from mixtures of glacial and moraine(MGM)and glacial source areas(GSAs).Recent continuous warning states that the temperature of the Sedongpu gully area exceeded 0℃ from April to July 2012,and the 2017 Mw 6.4 Nyingchi earthquake was critical in the current intense erosion state.展开更多
Red clay,widely used as a subgrade material in southern China,requires a reliable evaluation of its dynamic behavior to ensure infrastructure safety.Long-term cyclic triaxial tests were conducted on red clay from typi...Red clay,widely used as a subgrade material in southern China,requires a reliable evaluation of its dynamic behavior to ensure infrastructure safety.Long-term cyclic triaxial tests were conducted on red clay from typical,complex subway subgrades to investigate its dynamic properties and shakedown behavior under intermittent cyclic loading.Results show that intermittent cyclic loading,especially with multiple amplitudes,causes greater axial plastic strain and lower post-cyclic strength than continuous loading.These effects diminish with increasing confining pressure.Notably,axial strain partially recovers during loading intervals,with recovery ratios depending on the number and sequence of pauses.Based on the rules of cumulative plastic strain rates and cumulative plastic strain increments,shakedown behavior for red clay under intermittent cyclic loading is divided into three categories:plastic shakedown,critical shakedown,and plastic creep.A quantitative shakedown limit criterion is proposed using the Boltzmann function.Shakedown behavior significantly influences the post-cyclic strengths,and the influence diminishes as confining pressure increases.Samples exhibiting plastic creep and plastic shakedown behavior have the lowest and highest strengths,and those with critical shakedown behaviors have medium strengths.Cyclic loading with relatively low-stress amplitude causes a hardening effect,while cyclic loading intermittence or cyclic loading with relatively high-stress amplitude causes a degradation effect,and both effects are mitigated by higher confining pressures.展开更多
Salt stress significantly inhibits crop growth and development,and mitigating this can enhance salt tolerance in various crops.Previous studies have shown that regulating saccharide biosynthesis is a key aspect of pla...Salt stress significantly inhibits crop growth and development,and mitigating this can enhance salt tolerance in various crops.Previous studies have shown that regulating saccharide biosynthesis is a key aspect of plant salt tolerance;however,the underlying molecular mechanisms remain largely unexplored.In this study,we demonstrate that overexpression of a salt-inducible galactinol synthase gene,ZmGolS1,alleviates salt-induced growth inhibition,likely by promoting raffinose synthesis.Additionally,we show that natural variation in ZmGolS1 transcript levels contributes to the diversity of raffinose content and salt tolerance in maize.We further reveal that ZmRR18,a type-B response regulator transcription factor,binds to the AATC element in the promoter of ZmGolS1,with this binding increases the transcript levels of ZmGolS1 under salt conditions.Moreover,a single nucleotide polymorphism(termed SNP-302T)within the ZmGolS1 promoter significantly reduces its binding affinity for ZmRR18,resulting in decreased ZmGolS1 expression and diminished raffinose content,ultimately leading to a salt-hypersensitive phenotype.Collectively,our findings reveal the molecular mechanisms by which the ZmRR18-ZmGolS1 module enhances raffinose biosynthesis,thereby promoting maize growth under salt conditions.This research provides important insights into salt tolerance mechanisms associated with saccharide biosynthesis and identifies valuable genetic loci for breeding salt-tolerant maize varieties.展开更多
Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unex...Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unexplored.To address this gap,we designed a topological seismic metamaterial,where the topological interface is formed by joining the ends of two distinct one-dimensional periodic lattices.The first full-scale field experiment confirms the existence of topological interface states,which exhibit pronounced localization characteristics and induce a resonant amplification effect of 7.2 dB on the total energy of seismic surface waves.This study provides the first experimental validation for the implementation of topological principles in the design of seismic metamaterials,enabling novel approaches to high-sensitivity seismic detection and efficient energy localization for wave control.展开更多
Earthquakes may inflict varied levels of damage on mountains.Understanding the deformation properties of earthquake-damaged rock masses is critical for evaluating rocky slope stability over time.Taking the phyllite of...Earthquakes may inflict varied levels of damage on mountains.Understanding the deformation properties of earthquake-damaged rock masses is critical for evaluating rocky slope stability over time.Taking the phyllite of the Xinmo Village rockslide as the research object,the degradation features of the phyllite are investigated through laboratory tests,and a discrete-element numerical approach that fully accounts for the progressive rock deterioration is presented.The approach is then used to investigate the evolution characteristics of phyllite under various dynamic and static loading circumstances.Results show that the remaining strength of rock decreases with increasing dynamic cyclic loading(DCL)amplitude and times but increases with increasing frequency.As the dynamic damage degree increases,rock failure modes become more complex,and microcracks expand in a more preferential orientation,as well as a denser spatial distribution.Dynamic damage cracks act as the dominant paths for the macroscopic failure surface of the rock.The results indicate that the input energy and dissipated energy increase with fluctuating and linear trends with the advance of the DCL,respectively.The peak strain energy and acoustic emission(AE)magnitude decrease with increasing dynamic damage degrees,and the distribution of AE events displays temporal dispersion and spatial clustering characteristics,which is attributed to a decrease in the rock's potential for storing energy.展开更多
基金supported by grants from the National Key Research and Development Program of China(2021YFF1000500)the National Natural Science Foundation of China(32370272,31970273,and 31921001).
文摘Phosphorus(P)is an essential nutrient for crop growth,making it important for maintaining food security as the global population continues to increase.Plants acquire P primarily via the uptake of inorganic phosphate(Pi)in soil through their roots.Pi,which is usually sequestered in soils,is not easily absorbed by plants and represses plant growth.Plants have developed a series of mechanisms to cope with P deficiency.Moreover,P fertilizer applications are critical for maximizing crop yield.Maize is a major cereal crop cultivated worldwide.Increasing its P-use efficiency is important for optimizing maize production.Over the past two decades,considerable progresses have been achieved in studies aimed at adapting maize varieties to changes in environmental P supply.Here,we present an overview of the morphological,physiological,and molecular mechanisms involved in P acquisition,translocation,and redistribution in maize and combine the advances in Arabidopsis and rice,to better elucidate the progress of P nutrition.Additionally,we summarize the correlation between P and abiotic stress responses.Clarifying the mechanisms relevant to improving P absorption and use in maize can guide future research on sustainable agriculture.
基金funded by the National Natural Science Foundation of China(NSFC No.52322610)Hong Kong Research Grants Council Theme-based Research Scheme(T22-505/19-N).
文摘Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of wildfire pre-vention,monitoring,disaster response,and post-fire recovery.This review examines the potential utility of Digital Twin in wildfire management and aims to inspire further exploration and experimentation by researchers and practitioners in the fields of environment,forestry,fire ecology,and firefighting services.By creating virtual replicas of wildfire in the physical world,a Digital Twin platform facilitates data integration from multiple sources,such as remote sensing,weather forecast-ing,and ground-based sensors,providing a holistic view of emergency response and decision-making.Furthermore,Digital Twin can support simulation-based training and scenario testing for prescribed fire planning and firefighting to improve preparedness and response to evacuation and rescue.Successful applications of Digital Twin in wildfire management require horizontal collaboration among researchers,practitioners,and stakeholders,as well as enhanced resource sharing and data exchange.This review seeks a deeper understanding of future wildland fire management from a technological perspective and inspiration of future research and implementation.Further research should focus on refining and validating Digital Twin models and the integration into existing fire management operations,and then demonstrating them in real wildland fires.
基金supported by the National Key Research and Development Program of China(2021YFD1200703 and 2022YFF1001602)the National Science Foundation of China(32272024 and 32171940)+2 种基金the Pinduoduo-China Agricultural University Research Fund(PC2023B01001)the Chinese Universities Scientific Fund(2022TC142)the 2115 Talent Development Program of China Agricultural University。
文摘Maize(Zea mays),which is a vital source of food,feed,and energy feedstock globally,has significant potential for higher yields.However,environmental stress conditions,including drought and salt stress,severely restrict maize plant growth and development,leading to great yield losses.Leucine-rich repeat receptor-like kinases(LRR-RLKs)function in biotic and abiotic stress responses in the model plant Arabidopsis(Arabidopsis thaliana),but their roles in abiotic stress responses in maize are not entirely understood.In this study,we determine that the LRR-RLK ZmMIK2,a homolog of the Arabidopsis LRR-RK MALE DISCOVERER 1(MDIS1)-INTERACTING RECEPTOR LIKE KINASE 2(MIK2),functions in resistance to both drought and salt stress in maize.Zmmik2 plants exhibit enhanced resistance to both stresses,whereas overexpressing ZmMIK2 confers the opposite phenotypes.Furthermore,we identify C2-DOMAIN-CONTAINING PROTEIN 1(ZmC2DP1),which interacts with the intracellular region of ZmMIK2.Notably,that region of ZmMIK2 mediates the phosphorylation of ZmC2DP1,likely by increasing its stability.Both ZmMIK2 and ZmC2DP1 are mainly expressed in roots.As with ZmMIK2,knockout of ZmC2DP1 enhances resistance to both drought and salt stress.We conclude that ZmMIK2-ZmC2DP1 acts as a negative regulatory module in maize drought-and salt-stress responses.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20603 and U21A2008)the Science Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZYTS-03).
文摘On September 5,2022,at least 10,855 landslides had been triggered by a magnitude Mw 6.7(Ms 6.8)earthquake on the eastern margin of the Tibetan Plateau.Unfortunately,a detailed analysis of the spatial patterns of landslides in the eastern margin of the Baryan Har block is lacking.The observations show that the highest landslide concentrations are distributed along the seismogenic fault(Moxi fault)and Dadu River valley,coinciding with the effects of the hanging wall and microepicenter.Seismogenic tectonics controlled the regional distribution of new landslides,and the local topography influenced the detailed positions on the slopes.The total landslide mass wasting volume was 223.1×10^(6)m^(3),and the maximum occurred in the Wandong Basin(value of 74×10^(6)m^(3)).Thirty landslide dams were temporarily existing.Although some local collapses occurred at the toe of the Hailuogou glacier,seismic shaking had no obvious influence on the overall stability of the glacier.A post debris flow assessment indicates that some large basins contained much loose material and that some steep small basins had high debris flow susceptibility.On the eastern margin of the Bayan Har block,the landslide-triggering thrust and strike-slip events both follow the distributions of the hanging wall.
基金financially funded by the National Natural Science Foundation of China(U2004205)the China Agricultural University-Syngenta Project.
文摘Fusarium ear rot(FER),caused by Fusarium verticillioides,is a destructive fungal disease of maize.FER resistance is a complex,quantitatively inherited trait controlled by multiple minor-effect genes.In this study,we employed two recombinant inbred line(RIL)populations with the common resistant parental line CML304 to identify FER-resistance loci.Initial QTL analysis identified 23 FER-resistance QTL,each explaining 5.21%-30.51%of the total phenotypic variation.Notably,one major QTL,qRfv2,on chromosome 2 was repeatedly detected,accounting for 11.92%-30.51%of the total phenotypic variation.qRfv2 was fine mapped to an interval of 1.01 Mb,flanked by the markers IDP8 and IDP10.qRfv2 is a semidominant resistance gene that could reduce the disease severity index(DSI)by 12.4%-20%,suggesting its potential for enhancing FER resistance in maize.Transcriptome analysis showed that 22 of the 28 annotated functional genes in the qRfv2 region displayed differential expression between parental lines in response to FER.One of the candidate genes,ZmLOX6,was validated to presumably provide a positive effect on FER resistance.Our study provides a basis for the potential cloning and application of FER resistance genes in maize breeding.
基金financially supported by the National Natural Science Foundation of China(Grant No.52078334)the National Key Research and Development Program of China(Grant No.2017YFC0805402)the Tianjin Research Innovation Project for Postgraduate Students(Grant No.2021YJSB141).
文摘The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate.The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory,Mindlin solution and Euler-Bernoulli-Pasternak model,subsequently validated through both finite element simulation and field monitoring.It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling.The longitudinal settlement distribution can be categorized into five areas,with the area near the tunnel surface experiencing the most dramatic settlement changes.The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure,especially when the turning radius is less than 30 times the tunnel diameter.The tunnel crown exhibits larger displacement than the tunnel bottom,resulting in a distinctive‘vertical egg'shape.Furthermore,an optimized overcutting mode is proposed,involving precise control of the extension speed and angular velocity of the overcutting cutter,which effectively mitigates ground deformation,ensuring the protection of the existing tunnel during the construction.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(RS-2021-NR060142)HSF's GMACC Project。
文摘1.Need for coordinated flyways conservation Flyways are migratory routes that encompass breeding,stopover,and non-breeding habitats essential for the annual life cycles of migratory birds(Bamford et al.,2008;Newton,2023).These routes are critical for maintaining global biodiversity by supporting seasonal movements across continents(Hua et al.,2015;Runge et al.,2015).Effective conservation of flyways,such as the East Asian-Australasian Flyway(EAAF)and Central Asian Flyway(CAF),requires international cooperation to protect key stopover sites(Yong et al.,2015;Kumar 2019;Schmaljohann et al.,2022).
基金The National Science Fund for Distinguished Young Scholars (No. 52225807)。
文摘This study presents a numerical simulation of large-scale shaking table tests on a superstructure supported by a pile group installed in an inclined liquefiable site,fo-cusing on nonlinear interactions between piles and the soil.A three-dimensional finite element model of a soil-pile superstructure system is developed using OpenSeesMP.The temporal and spatial evolution of the radial soil pressure around the pile is evaluated in both liquefied and nonlique-fied sites.Results show that the soil pressure around the pile is significantly influenced by site inclination and soil lateral spreading.In liquefied sites,the soil pressure in the ex-truded zone of the upstream pile is significantly higher than that in the diffused zone.However,higher pressure occurs in the diffused zone for nonliquefied sites.Correspond-ingly,the liquefaction state significantly influences the force characteristics of the pile group system.Additionally,the group effect is more pronounced in liquefied sites.The results also indicate that the soil pressure distribution around the piles is closely related to the relative pile-soil displace-ment and reveals different on-pile force mechanisms under varying site conditions.These findings offer valuable in-sights into the seismic design of pile foundations in inclined liquefied sites.
基金supported by Chinese Academy of Sciences(CAS)program of"Western Youth Scholar"(E2R2050050)。
文摘Large-scale ice avalanches pose serious risks owing to their high speed and long travel distances,and their mobility is increased by ice melting owing to frictional heat.Most motion models for largescale ice avalanches have been constructed for specific scenarios,neglecting the key effect of frictional ice melting on their mobility and having limited applicability.In this study,a two-dimensional model combining thermodynamic and dynamic properties was proposed.This model,based on depth-averaged and granular flow theories,considers the friction weakening process to simulate the dynamics of ice avalanches.The governing equations for motion and heat transfer were solved by employing the finite volume and the Crank-Nicolson methods.The numerical simulation results showed that the friction weakening caused by the thermal effect on the sliding surface significantly reduced the friction coefficient between the ice mass and its substrate,increasing the travel distance of ice avalanches.The initial ice content in the shear band affects the friction coefficient during the viscous and Coulomb friction stages.The higher the initial ice content in the shear band,the lower the viscous resistance during the frictional heatinginduced drag reduction stage,resulting in a longer sliding distance and larger coverage area.Notably,large-scale ice avalanches exhibit a"Volume Effect"similar to other mass movements such as landslides,debris flows,and rock avalanches.Ice avalanches with larger volumes exhibit greater mobility and coverage areas.The proposed model reveals the dynamic characteristics of large-scale ice avalanches under the effect of frictional heat and offers a valuable tool for dynamic analysis and supporting disaster risk reduction strategies.
基金financially supported by the National Key Research and Development Program of China (Grant No. 2021YFB2601100)the National Natural Science Foundation of China (Grant No. 51979190)。
文摘Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experiments under unidirectional flow, bidirectional flow, and wave-current interactions with different flow directions around the pile group foundation were first conducted to investigate the development of scour around the pile group foundation.Additionally, a three-dimensional scour numerical model was established via the open-source software REEF3D to simulate the flow field and scour around the prototype-scale foundation. The impact of flow on scour was discussed.Under unidirectional flow, scour equilibrium was reached more quickly, with the maximum scour depth reaching approximately 1.2 times the pile diameter and the extent of the scour hole spanning about 4.9 times the pile diameter.Compared with those under unidirectional flow, the scour depths under combinations of currents and waves, as well as bidirectional flow, were slightly smaller. However, the morphology of scour holes was more uniform and symmetrical. The numerical simulation results show good agreement with the experimental data, demonstrating the impact of varying flow directions on the velocity distribution around the foundation, the morphology of scour holes, and the location of the maximum scour depth.
基金supported by the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LZ22C150002 and LR24C150001)the National Key Research and Development Program of China(Grant Nos.2021YFF1000402 and 2022YFD1401600)+1 种基金the National Natural Science Foundation of China(Grant No.32170262)the Fundamental Research Funds for the Central Universities,China(Grant No.K20240124).
文摘CRISPR-Cas endonucleases mediate prokaryotic adaptive immunity by targeting foreign nucleic acids.CRISPR/Cas13b is a class 2 type VI-B ribonuclease that targets and cleaves single-stranded RNA.It exhibits higher RNA interference activity than Cas13a and Cas13c and causes fewer collateral effects than RxCas13d in mammalian cells.However,a programmable CRISPR/Cas13b-mediated RNA interference system for endogenous transcripts in rice has not yet been established.Here,we developed a CRISPR/Cas13b-mediated system to target endogenous transcripts in rice.Our CRISPR/Cas13b system could inhibit multiple endogenous mRNAs simultaneously.In addition,this system efficiently repressed endogenous long noncoding RNAs with more than 50% inhibition in stable transgenic plants.Furthermore,we found only weak collateral effects of the CRISPR/Cas13b-mediated system at the transcriptome-wide level,and no difference in the agronomic traits of stable transgenic rice in the field.We present a programmable CRISPR/Cas13b-mediated knockdown system for rice,offering a potential biotechnological tool for functional genomics and crop improvement.
基金the National Natural Science Foundation of China(Grant Nos.52371289 and 51979192).
文摘A three-dimensional numerical model of sand wave dynamics,incorporating the interaction of currents and waves at various angles,has been developed using the Regional Ocean Modeling System(ROMS).This model accounts for both bedload and suspended load sediment transport under combined waves and current conditions.The investigation examines the influence of several key parameters,including the rotation angle of sand waves relative to the main current,tidal current velocity amplitude,residual current,water depth,wave height,wave period,and wave direction,on sand wave evolution.The growth rate and migration rate of sand waves decrease as their rotation angle increases.For rotation angles smaller than 15°,sand wave evolution can be effectively simulated by a vertical 2D model with an error within 10%.The numerical results demonstrate that variations in tidal current velocity amplitude or residual current affect both vertical growth and horizontal migration of sand waves.As tidal current velocity amplitude and residual current increase,the growth rate initially rises to a maximum before decreasing.The migration rate shows a consistent increase with increasing tidal current amplitude and residual current.Under combined waves and current,both growth and migration rates decrease as water depth increases.With increasing wave height and period,the growth rate and migration rate initially rise to maximum values before declining,while showing a consistent increase with wave height and period.The change rate of sand waves reaches its maximum when wave propagation aligns parallel to tidal currents,and reaches its minimum when wave propagation is perpendicular to the currents.This phenomenon can be explained by the fluctuation of total bed shear stress relative to the angle of interaction between waves and current.
基金The National Key Research and Development Pro-gram of China(No.2022YFC3801201)the National Natural Science Foundation of China(No.51921006,52478505)+1 种基金the Natural Science Foundation of Guangdong Province(No.2022A1515010403)Shenzhen Collaborative Innovation Project(No.CJGJZD20220517142401002).
文摘A novel bidirectional tuned rolling mass damper(Bi-TRMD)device is proposed,and its dynamic character-istics and vibration reduction performance are investigated.The device achieves the performance goal of bidirectional vibration reduction for a tuned rolling mass damper with a single concave structure.First,the Bi-TRMD device is introduced,and its three-dimensional(3D)mechanical model is established.The motion equations of the model are de-rived using the Gibbs-Appell equation,and a trajectory pre-diction method for the sphere and structure within the model is developed.This method demonstrates that the rolling motion of the sphere around orthogonal axes is nearly indepen-dent within a limited range,enabling the simplification of the 3D model into a two-dimensional(2D)model.The accuracy of this simplification is validated through case analysis.The vibration reduction parameters are optimized using the 2D model and Den Hartog theory,leading to the derivation of mathematical expressions for the optimal frequency ratio and damping ratio.Subsequently,the bidirectional vi-bration reduction performance of the Bi-TRMD is analyzed.The results show that under white noise excitation,the Bi-TRMD achieves a bidirectional peak acceleration reduction rate that is 9.92%and 7.79%higher than that of translational tuned mass dampers(TMD)with the same mass.These findings demonstrate that the proposed Bi-TRMD ef-fectively achieves two-directional vibration reduction with a single concave structure,offering superior vibration reduction performance.
基金supported by the National Key R&D Program of China(Grant No.2023YFC3008300)the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chinese Academy of Sciences(Grant No.IMHE-ZYTS-03 and IMHE-ZDRW-03).
文摘The Yarlung Tsangpo River(YTR),located in the Himalayan orogenic belt,is renowned for its deep gorges and complex tectonic features,as well as its reputation as a landslide-prone region.However,less is known about the distribution of landslides across the entire river basin.To address this gap in knowledge,this study first established a comprehensive landslide inventory across the entire basin using remote sensing mapping and multiple field investigations.Then,a systematic analysis of the spatial and size distributions was conducted.The results indicated that the YTR basin features at least 2390 landslides with areas exceeding 104 m2,spanning a total area and volume of 1087.6 km^(2) and 48.4 km^(3),respectively.These landslides can be classified into eight types,and rockslides are the most common(53.1%).Their distributions are highly asymmetric,with the following notable patterns:(1)the Tsangpo suture zone(53.4%)contains a greater number of landslides than other tectonic units;(2)the landslide size is influenced by the relief and elevation conditions,with positive relationships observed between the local relief and landslide area,as well as between the elevation range and landslide area;and(3)the landslide distribution is not significantly correlated with rainfall,and seasonally frozen ground is associated with a greater concentration of landslides.Alternating slate and shale groups in the Tsangpo suture zone may be the factors responding to landslide concentration.A total of 20.6%of landslide-blocked rivers were observed,with some forming river knickpoints.Due to the limited data,spatial and size analyses are perhaps immature,and further systematic analysis remains necessary.
基金jointly supported by the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0902)National Natural Science Foundation of China(NSFC)project(Grant No.42305178)+1 种基金the Key R&D Program of Tibet Autonomous Region(Grant No.XZ202301ZY0039G)the Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHEZDRW-01)。
文摘Understanding the relationship between sediment and discharge is crucial for effective river management and water-sediment modeling,especially in the Brahmaputra River,one of the large transboundary rivers with high sediment and discharge variability in South Asia.Current knowledge of sediment-water relations is constrained by limited data,hindering effective transboundary river management.Using multivariate linear regression,climate elasticity coefficient,and traditional sediment rating curve,this study is designed to compare the sediment-water relations of the upstream(Nuxia)and the downstream(Bahadurabad).The results reveal significant variability between the two stations.In the upstream Nuxia,the simulation strongly correlates with observed suspended sediment load(SSL)and discharge(Q)(Pearson's r of 0.62 and 0.68,respectively).Conversely,at downstream Bahadurabad,weaker correlations(r=0.31 for sediment and r=0.51 for discharge simulation)indicate a reduced relation.This contrast reflects the non-linear nature of sediment-discharge coupling along the river continuum,shaped by both climatic and anthropogenic influences.Elasticity(ε)analysis highlights the dominant role of precipitation in shaping sediment-water dynamics(εP-SSL=2.53,εP-Q=1.01)at Nuxia,while Bahadurabad(εP-SSL=0.41,εP-Q=0.82)reflects a reduced sensitivity,possibly due to sediment retention along the floodplain.Air temperature elasticity(εT-SSL,-0.15&-3.06 at Nuxia and Bahadurabad,respectively)reveals contrasting impacts,strongly negatively influencing sediment transport at Bahadurabad.These findings highlight the significance of spatial variability and climatic influences on sediment dynamics,underscoring the necessity for site-specific management strategies.The sediment rating curve(SRC)analysis reveals a strong relationship between sediment and discharge(R^(2)=0.88)at Nuxia and a relatively weaker relationship(R^(2)=0.14)at Bahadurabad,which demonstrates a lower sedimentdischarge coupling that could be affected by downstream factors such as sediment deposition,channel morphology,and anthropogenic activities.This study offers valuable insights into sediment-water dynamics,highlighting the importance of understanding nonlinear relationships in the Brahmaputra River.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFC3000401 and 2023YFS0435)the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZYTS-03)。
文摘Although the increase in the frequency of mass wasting events in the Sedongpu gully in recent years indicates that the Sedongpu gully has entered an intense mass wasting period,the current literature focuses only on ice‒rock avalanche events and lacks comprehensive knowledge of Sedongpu gully activity.To clarify the spatiotemporal distribution and scales of mass wasting events,we analysed multiple images from 1969 to present(including optical images and synthetic aperture radar(SAR)images)and topography data from 2013 to present.Since 1969,there have been at least 19 obvious mass wasting events that can be divided into 3 subpatterns:ice‒rock avalanches(IRAs,8 events),ice‒moraine avalanches(IMAs,2 events),and glacier debris flows(GDFs,9 events).Since 2017,the Sedongpu gully has entered the most active period,i.e.more than 68%of events occurred after 2017,and approximately 530 Mm^(3)and 185 Mm^(3)of materials were removed from mixtures of glacial and moraine(MGM)and glacial source areas(GSAs).Recent continuous warning states that the temperature of the Sedongpu gully area exceeded 0℃ from April to July 2012,and the 2017 Mw 6.4 Nyingchi earthquake was critical in the current intense erosion state.
基金the support of the National Natural Science Foundation of China(Grant No.52108319)the Natural Science Foundation of Jiangxi Province(20224BAB214069)。
文摘Red clay,widely used as a subgrade material in southern China,requires a reliable evaluation of its dynamic behavior to ensure infrastructure safety.Long-term cyclic triaxial tests were conducted on red clay from typical,complex subway subgrades to investigate its dynamic properties and shakedown behavior under intermittent cyclic loading.Results show that intermittent cyclic loading,especially with multiple amplitudes,causes greater axial plastic strain and lower post-cyclic strength than continuous loading.These effects diminish with increasing confining pressure.Notably,axial strain partially recovers during loading intervals,with recovery ratios depending on the number and sequence of pauses.Based on the rules of cumulative plastic strain rates and cumulative plastic strain increments,shakedown behavior for red clay under intermittent cyclic loading is divided into three categories:plastic shakedown,critical shakedown,and plastic creep.A quantitative shakedown limit criterion is proposed using the Boltzmann function.Shakedown behavior significantly influences the post-cyclic strengths,and the influence diminishes as confining pressure increases.Samples exhibiting plastic creep and plastic shakedown behavior have the lowest and highest strengths,and those with critical shakedown behaviors have medium strengths.Cyclic loading with relatively low-stress amplitude causes a hardening effect,while cyclic loading intermittence or cyclic loading with relatively high-stress amplitude causes a degradation effect,and both effects are mitigated by higher confining pressures.
基金support from the National Key R&D Program of China(2022YFF1001601)the National Science Fund for Distinguished Young Scholars(32325037)+2 种基金the National Natural Science Foundation of China(32201718 and 32401756)the Postdoctoral Innovation Talents Support Program(BX20240420)the China Postdoctoral Science Foundation(2024T171011 and 2023M743817).
文摘Salt stress significantly inhibits crop growth and development,and mitigating this can enhance salt tolerance in various crops.Previous studies have shown that regulating saccharide biosynthesis is a key aspect of plant salt tolerance;however,the underlying molecular mechanisms remain largely unexplored.In this study,we demonstrate that overexpression of a salt-inducible galactinol synthase gene,ZmGolS1,alleviates salt-induced growth inhibition,likely by promoting raffinose synthesis.Additionally,we show that natural variation in ZmGolS1 transcript levels contributes to the diversity of raffinose content and salt tolerance in maize.We further reveal that ZmRR18,a type-B response regulator transcription factor,binds to the AATC element in the promoter of ZmGolS1,with this binding increases the transcript levels of ZmGolS1 under salt conditions.Moreover,a single nucleotide polymorphism(termed SNP-302T)within the ZmGolS1 promoter significantly reduces its binding affinity for ZmRR18,resulting in decreased ZmGolS1 expression and diminished raffinose content,ultimately leading to a salt-hypersensitive phenotype.Collectively,our findings reveal the molecular mechanisms by which the ZmRR18-ZmGolS1 module enhances raffinose biosynthesis,thereby promoting maize growth under salt conditions.This research provides important insights into salt tolerance mechanisms associated with saccharide biosynthesis and identifies valuable genetic loci for breeding salt-tolerant maize varieties.
基金supported by the National Natural Science Foundation of China(Grant No.11974044)。
文摘Topological insulators with localized edge or interface states have been extensively studied,particularly in phononic crystals and related fields;however,their application in seismic metamaterials remains largely unexplored.To address this gap,we designed a topological seismic metamaterial,where the topological interface is formed by joining the ends of two distinct one-dimensional periodic lattices.The first full-scale field experiment confirms the existence of topological interface states,which exhibit pronounced localization characteristics and induce a resonant amplification effect of 7.2 dB on the total energy of seismic surface waves.This study provides the first experimental validation for the implementation of topological principles in the design of seismic metamaterials,enabling novel approaches to high-sensitivity seismic detection and efficient energy localization for wave control.
基金the financial support from the National Natural Science Foundation of China(Grant No.U22A20603)the National Key Research and Development Program of China(Grant No.2023YFC3008300).
文摘Earthquakes may inflict varied levels of damage on mountains.Understanding the deformation properties of earthquake-damaged rock masses is critical for evaluating rocky slope stability over time.Taking the phyllite of the Xinmo Village rockslide as the research object,the degradation features of the phyllite are investigated through laboratory tests,and a discrete-element numerical approach that fully accounts for the progressive rock deterioration is presented.The approach is then used to investigate the evolution characteristics of phyllite under various dynamic and static loading circumstances.Results show that the remaining strength of rock decreases with increasing dynamic cyclic loading(DCL)amplitude and times but increases with increasing frequency.As the dynamic damage degree increases,rock failure modes become more complex,and microcracks expand in a more preferential orientation,as well as a denser spatial distribution.Dynamic damage cracks act as the dominant paths for the macroscopic failure surface of the rock.The results indicate that the input energy and dissipated energy increase with fluctuating and linear trends with the advance of the DCL,respectively.The peak strain energy and acoustic emission(AE)magnitude decrease with increasing dynamic damage degrees,and the distribution of AE events displays temporal dispersion and spatial clustering characteristics,which is attributed to a decrease in the rock's potential for storing energy.
