Complex physical and chemical reactions during CO_(2)sequestration alter the microscopic pore structure of geological formations,impacting sequestration stability.To investigate CO_(2)sequestration dynamics,comprehens...Complex physical and chemical reactions during CO_(2)sequestration alter the microscopic pore structure of geological formations,impacting sequestration stability.To investigate CO_(2)sequestration dynamics,comprehensive physical simulation experiments were conducted under varied pressures,coupled with assessments of changes in mineral composition,ion concentrations,pore morphology,permeability,and sequestration capacity before and after experimentation.Simultaneously,a method using NMR T2spectra changes to measure pore volume shift and estimate CO_(2)sequestration is introduced.It quantifies CO_(2)needed for mineralization of soluble minerals.However,when CO_(2)dissolves in crude oil,the precipitation of asphaltene compounds impairs both seepage and storage capacities.Notably,the impact of dissolution and precipitation is closely associated with storage pressure,with a particularly pronounced influence on smaller pores.As pressure levels rise,the magnitude of pore alterations progressively increases.At a pressure threshold of 25 MPa,the rate of change in small pores due to dissolution reaches a maximum of 39.14%,while precipitation results in a change rate of-58.05%for small pores.The observed formation of dissolution pores and micro-cracks during dissolution,coupled with asphaltene precipitation,provides crucial insights for establishing CO_(2)sequestration parameters and optimizing strategies in low permeability reservoirs.展开更多
The commercial ZK 60 magnesium alloy with extruded state experienced aging heat treatment(T 6)was dynamically loaded at strain rate of 3000 s−1 by means of the split Hopkinson pressure bar(SHPB)in this paper.Transmiss...The commercial ZK 60 magnesium alloy with extruded state experienced aging heat treatment(T 6)was dynamically loaded at strain rate of 3000 s−1 by means of the split Hopkinson pressure bar(SHPB)in this paper.Transmission electron microscopy(TEM)observations showed that the precipitatedβ′_(1) phases partially dissolved(spheroidized)with blurred interfaces within 160μs at 3000 s^(−1).The average length and diameter of the rod-shapedβ′_(1) phase particles were 48.5 and 9.8 nm after the T 6 heat treatment;while the average diameter of the sphericalβ′_(1) phases changed to 8.8 nm after loading.The deformedβ′_(1) phase generated larger lattice distortion energy than Mg matrix under high strain rate loading.Therefore,the difference of free energy(the driving force of dissolution)between theβ′_(1) phase and the matrix increased,making the instantaneous dissolution of theβ′_(1) phase thermodynamically feasible.The dissolution(spheroidization)of theβ′_(1) phase particles was kinetically promoted because the diffusion rate of the solute Zn atoms was accelerated by combined actions of adiabatic temperature rise,high density of dislocations(vacancies)and high deviatoric stresses during high strain rate loading.The increase in hardness of ZK 60-T 6 alloy could be attributed to solid solution strengthening,dislocation strengthening and second phase particle strengthening.展开更多
Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temper...Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.展开更多
Hydrothermal ore zoning is a transport-reaction problem in which infiltration is the principal Prcness of transport and dissolution/Precipitation is the Principal process of chemical reactions.Neglecting diffusion an...Hydrothermal ore zoning is a transport-reaction problem in which infiltration is the principal Prcness of transport and dissolution/Precipitation is the Principal process of chemical reactions.Neglecting diffusion and ion exchange/adsorption would not affect the basic attributes of hydrothermal ore zoning. Hydrothermal ore zoning belongs essentially to infiltration metasomatic zoning, it results from the formation and propagation of dissolution/precipitation waves through Permeable media. The authors apply the theory of coupled infiltration and dissolution/precipitation reactions in Physicochemical hydrodynamics to studying the structural characteristics of dissolution/precipitation waves, and apply furthermore the coherence principle in dynamic theory of multicomponent coupled systems to revealing the dynamic mechanisms of their formation. The results of investigation verify and develop . C. 's theory of infiltration metasomatic zoning,on the one hand, raising it from the qualitative, equilibrium thermodynamic basis to the quantitative dynamic level;on the other hand, and more importantly, applying theories of Physicochemical hydrodynamics and dynamics of multicomponent coupled systems to bringing to light the dynamic mechanisms of formation of the structure of hydrothermal ore zoning, and advancing a theory of hydrothermal ore zoning, putting forward new ideas on the nature of the problem of hydrothermal ore zoning, the essence of hydrothermal ore zoning and the structural characteristics and mechanisms of formation of hydrothermal ore zoning.展开更多
The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(...The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was the diffusion in the molten slag.The dissolution rate of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was affected by the composition and size of inclusion.The functional relationship between the dimensionless inclusion capacity(Zh)and the dimensionless dissolution rate(Ry)of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was calculated as Ry=2.10×10^(-6)Zh^(0.160),while it was Ry=2.10×10^(-6)Zh^(0.0087)for Al_(2)O_(3)-CaO complex inclusions.On this basis,the complete dissolution time and rate of the complex inclusions were calculated by using the function relation between the Zh and Ry numbers.展开更多
The dominated contradiction in optimizing the performance of magnesium-air battery anode lies in the difficulty of achieving a good balance between activation and passivation during discharge process.To further reconci...The dominated contradiction in optimizing the performance of magnesium-air battery anode lies in the difficulty of achieving a good balance between activation and passivation during discharge process.To further reconcile this contradiction,two Mg-0.1Sc-0.1Y-0.1Ag anodes with different residual strain distribution through extrusion with/without annealing are fabricated.The results indicate that annealing can significantly lessen the“pseudo-anode”regions,thereby changing the dissolution mode of the matrix and achieving an effective dissolution during discharge.Additionally,p-type semiconductor characteristic of discharge productfilm could suppress the self-corrosion reaction without reducing the polarization of anode.The magnesium-air battery utilizing annealed Mg-0.1Sc-0.1Y-0.1Ag as anode achieves a synergistic improvement in specific capacity(1388.89 mA h g^(-1))and energy density(1960.42 mW h g^(-1)).This anode modification method accelerates the advancement of high efficiency and long lifespan magnesium-air batteries,offering renewable and cost-effective energy solutions for electronics and emergency equipment.展开更多
Accurate seasonal precipitation forecasts,especially for extreme events,are crucial to preventing meteorological hazards and their potential impacts on national development,social activity,and security.However,the int...Accurate seasonal precipitation forecasts,especially for extreme events,are crucial to preventing meteorological hazards and their potential impacts on national development,social activity,and security.However,the intensity of summer precipitation is often largely underestimated in many current dynamic models.This study uses a deep learning method called Cycle-Consistent Generative Adversarial Networks(CycleGAN)to improve the seasonal forecasts for June-JulyAugust precipitation in southeastern China by the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS 1.0).The results suggest that the CycleGAN-based model significantly improves the accuracy in predicting the spatiotemporal distribution of summer precipitation compared to the traditional quantile mapping(QM)method.Using the unpaired bias-correction model,we can also obtain advanced forecasts of the frequency,intensity,and duration of extreme precipitation events over the dynamic model predictions.This study expands the potential applications of deep learning models toward improving seasonal precipitation forecasts.展开更多
This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has ...This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has seen a remarkable run of extreme precipitation events and resulting impacts. Here, we provide an overview of the most notable extreme events of the year, including extreme precipitation and floods, tropical cyclones, and droughts. The characteristics and impacts of these extreme events are summarized, followed by discussion on the physical drivers and the role of global warming.Finally, we also discuss the future prospects in extreme event studies, including impact-based perspectives, challenges in attribution of precipitation extremes, and the existing gap to minimize impacts from climate extremes.展开更多
Northern China is a prominent “hotspot” for land–atmosphere interactions, with substantial gradients in both moisture and thermal conditions. Previous studies have identified a link between land–atmosphere couplin...Northern China is a prominent “hotspot” for land–atmosphere interactions, with substantial gradients in both moisture and thermal conditions. Previous studies have identified a link between land–atmosphere coupling and the individual roles of each factor, but the synergistic effect of the two factors remains unclear. This study considers the covariation of evapotranspiration and precipitation to assess evapotranspiration–precipitation(ET–P) coupling across northern China,exploring its spatial variations and their linkage to water and heat factors. Our findings reveal a transition from strongly positive coupling in the northwest to weakly negative coupling in the southeast, peaking in spring. These spatial variations are attributable to water(soil moisture) and heat(air temperature), which explain 39% and 25% of the variability,respectively. The aridity index(AI), a water–heat synergy factor, is the dominant factor, explaining 66% of the spatial variation in ET–P coupling. As the AI increases, ET–P coupling shifts from strongly positive to weakly negative, with an AI around 0.7. This shift is determined by a shift in the evapotranspiration–lifting condensation level(LCL) coupling under an AI change. Regions with an AI below 0.7 experience water-limited evapotranspiration, where increased soil moisture enhances evapotranspiration, reduces sensible heat(H), and lowers the LCL, resulting in a negative ET–LCL coupling.Conversely, regions with an AI above 0.7 experience energy-limited evapotranspiration, where the positive ET–LCL coupling reflects a positive H–LCL coupling or a positive impact of the LCL on evapotranspiration. This analysis advances our understanding of the intricate influences of multifactor surface interactions on the spatial variations of land–atmosphere coupling.展开更多
Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this ...Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.展开更多
Martensite is an important microstructure in ultrahigh-strength steels,and enhancing the strength of martensitic steels often involves the introduction of precipitated phases within the martensitic matrix.Despite cons...Martensite is an important microstructure in ultrahigh-strength steels,and enhancing the strength of martensitic steels often involves the introduction of precipitated phases within the martensitic matrix.Despite considerable research efforts devoted to this area,a systematic summary of these advancements is lacking.This review focuses on the precipitates prevalent in ultrahigh-strength martensitic steel,primarily carbides(e.g.,MC,M_(2)C,and M_(3)C)and intermetallic compounds(e.g.,Ni Al,Ni_(3)X,and Fe_(2)Mo).The precipitation-strengthening effect of these precipitates on ultrahigh-strength martensitic steel is discussed from the aspects of heat treatment processes,microstructure of precipitate-strengthened martensite matrix,and mechanical performance.Finally,a perspective on the development of precipitation-strengthened martensitic steel is presented to contribute to the advancement of ultrahigh-strength martensitic steel.This review highlights significant findings,ongoing challenges,and opportunities in the development of ultrahigh-strength martensitic steel.展开更多
The effect of aging precipitation on the stress corrosion cracking(SCC)mechanism of Ni(Fe,Al)-maraging steel was studied through the comparative characterization and analyses of the microstructures and fracture featur...The effect of aging precipitation on the stress corrosion cracking(SCC)mechanism of Ni(Fe,Al)-maraging steel was studied through the comparative characterization and analyses of the microstructures and fracture features of solid–solution and peak-aged steels.Aging precipitation exerts a chain of impacts on the deformative compatibility and electrochemical difference between the matrix and oth-er phases or interfaces.The strength of the martensite matrix is enhanced by abundant and evenly dispersed Ni(Fe,Al)precipitates,thereby reducing the possibility of splitting across martensite laths.Meanwhile,the Volta potential difference(VPD)between the matrix and primary NbC particles increases from 11.43 to 18.60 mV.Given that most of the primary NbC particles tend to be distributed along high-angle grain boundaries(HAGBs),anodic dissolution along HAGBs accelerates.Therefore,mechanical and electrochemical factors triggered by aging precipitation are involved in the variation in SCC behavior and mechanism.The SCC susceptibility of the steel in-creases along with the increasing tendency for intergranular cracking.展开更多
The effect of hot deformation onα-phase precipitation during the subsequent heat treatment,as well as the mechanical properties of TB18 Ti-alloy,was investigated.Results show that the round bar obtained by the dual-p...The effect of hot deformation onα-phase precipitation during the subsequent heat treatment,as well as the mechanical properties of TB18 Ti-alloy,was investigated.Results show that the round bar obtained by the dual-phase field forging of the cast ingot exhibits uniform composition distribution on its cross-section.However,various degrees of deformation are detected at different positions on the cross-section,which is attributed to the characteristics of the forging process.Under the forging condition,the microstructure is mainly composed ofβ-phase matrix and coarsened discontinuous primaryα-phases.After solution and following artificial aging treatment,the primaryα-phases disappear,while needle-like secondaryα-phases precipitate in the matrix.Additionally,dispersed white zones are observed in the samples after aging,which are analyzed to be the precipitation-free zones of secondaryα-phase.Despite a uniform compositional distribution among various regions,these dispersed white zones exhibit higher content and larger size in the positions that have undergone lower forging deformation.It indicates that the insufficient forging deformation inhibits the precipitation of the secondaryα-phase,ultimately resulting in the lower strengthening effect by heat treatment.Thus,consistent with the characteristics of the forging process,a periodic variation of sample in strength is detected along the circumferential direction of the forged round bar.展开更多
This study investigates trends in extreme precipitation events(EPEs)across Antarctica from 1979 to 2023,analyzing changes in EPE frequency,intensity,and the proportion of extreme to total precipitation.Using Self-Orga...This study investigates trends in extreme precipitation events(EPEs)across Antarctica from 1979 to 2023,analyzing changes in EPE frequency,intensity,and the proportion of extreme to total precipitation.Using Self-Organizing Map(SOM)techniques,the study distinguishes the contributions from thermodynamic,dynamic,and interaction components in explaining these trends.Positive EPE occurrence trends are observed across the Bellingshausen and Weddell Seas,Dronning Maud Land,and parts of the Southern Ocean,with declines limited to Queen Mary Land.Thermodynamic factors,responsible for 96.0%of the overall trend,are driven by increased water vapor content in polar air masses.Dynamic contributions,representing 10.8%,are linked to a strengthened Amundsen Sea Low(ASL)associated with the Southern Annular Mode(SAM)and Pacific South American(PSA)trends.Interaction effects make a slightly negative contribution(-6.8%)to the overall trend.Variations in water vapor transport and vertical velocity tied to annual 500-hPa geopotential height anomalies further explain EPE trends.These findings provide insight into the atmospheric processes that influence Antarctic EPEs,with implications for understanding the climatic impact on the polar environment.展开更多
Due to global warming, extreme weather and climate events are becoming more frequent, highlighting the need to explore the changing characteristics of precipitation in China, including extreme precipitation. A cluster...Due to global warming, extreme weather and climate events are becoming more frequent, highlighting the need to explore the changing characteristics of precipitation in China, including extreme precipitation. A clustering algorithm was developed to classify summer(June, July, and August) daily precipitation in China from 1961 to 2020, considering spatial distribution, standard deviations, and frequency of extreme precipitation events. The results reveal six distinct precipitation climate zones, a classification that differs from previous divisions. While overall precipitation has decreased in most regions, the frequency of extreme precipitation events has increased across all clusters, indicating a shift in precipitation distribution patterns. Analysis shows that the weakened Lake Baikal blocking high and strengthened Mongolian cyclone influence the arid region in northwest China(Cluster 1), which is characterized by the lowest precipitation.The transition zone between the monsoon and arid region(Cluster 2) is affected by the Mongolian cyclone, water vapor transport from the Indian Ocean, and shifts in the monsoon boundary. Clusters 3 and 4 represent areas associated with advancement and retreat of the summer monsoon. In the Meiyu region, two distinct subregions have been identified exist.Cluster 4 is primarily influenced by the East Asia-Pacific wave train. Despite sharing similar climate drivers and proximity,Clusters 4 and 5 differ significantly due to topographic variations and disparate levels of urbanization. Cluster 5 exhibits a higher average precipitation, greater variability, and more frequent extreme events. Cluster 6 exhibits the highest overall precipitation in the coastal areas of Guangdong and Guangxi, where abundant water vapor contributes to a higher frequency of extreme precipitation. In addition, anthropogenic activities and urbanization significantly influence precipitation in Beijing-Tianjin-Hebei and Yangtze River Delta regions. This research proposes a precipitation classification scheme integrating multiple precipitation parameters, providing support for risk management and mitigation strategies in the face of increasing extreme precipitation events.展开更多
Cloud type profoundly affects precipitation,but few studies have explored its impact on precipitation scale height.The authors calculated the ratio of the volume of each cloud type to the total cloud volume and partit...Cloud type profoundly affects precipitation,but few studies have explored its impact on precipitation scale height.The authors calculated the ratio of the volume of each cloud type to the total cloud volume and partitioned the tropical region based on the dominant cloud types.Based on this,tropical regions were categorized into altocumulus control regions,stratocumulus control regions,deep convective cloud control regions,and transition regions.These regions exhibit unique characteristics:high precipitation scale heights and low surface precipitation rates in altocumulus control regions;low precipitation scale heights and low surface precipitation rates in stratocumulus control regions;and moderate precipitation scale heights with high surface precipitation rates in deep convective cloud regions.These features arise from differences in cloud characteristics,precipitation probability,and intensity,influenced by varying water vapor structures.In terms of physical mechanisms,altocumulus,stratocumulus,and deep convective cloud regions are characterized by total dryness,upper-level dryness with lower-level wetness,and total wetness,respectively.Upper-layer dryness leads to low cloud and precipitation structures,reducing the precipitation scale height,while lower-layer dryness increases it.Different humidity conditions in the upper and lower layers lead to variations in cloud type and volume distribution,ultimately affecting precipitation scale heights.This finding aids the mechanistic study of cloud precipitation physics in the tropics,providing valuable insights for developing numerical models and parameterizations.展开更多
Deforestation has a significant influence on the hydrological cycle.Understanding the impact of deforestation on precipitation extremes is crucial for addressing global environmental challenges.This study investigates...Deforestation has a significant influence on the hydrological cycle.Understanding the impact of deforestation on precipitation extremes is crucial for addressing global environmental challenges.This study investigates the impact of deforestation on precipitation extremes(R95p index,which represents the total amount of precipitation exceeding the 95th percentile of the reference period)in China,using outputs from three earth system models(CanESM5,IPSL-CM6A-LR,and MIROC-ES2L).All models,along with their multimodel mean,indicate a general decrease in R95p in Northeast China and southern China,and changes in Northwest China and the Tibetan Plateau are minimal.In contrast,the responses are model-dependent in the Huanghuai and Jianghuai regions.The overall nationwide multimodel mean suggests an annual R95p decrease of 10.7 mm,with individual model variations ranging from-28.0 to 2.0 mm.Further analysis using precipitation extremes scaling reveals a high spatial correlation with direct precipitation extremes changes on both annual and seasonal scales,albeit with slightly smaller magnitudes.Decomposing the response into dynamic and thermodynamic scaling,the authors find that dynamic contributions predominantly drive the changes in precipitation extremes on both annual and seasonal scales.The authors findings highlight the substantial role of dynamic processes in modulating the response of precipitation extremes to deforestation in China.展开更多
Global coral reef ecosystems have been severely degraded due to the combined effects of climate change and human activities.Changes in the seawater carbonate system of coral reef ecosystems can reflect their status an...Global coral reef ecosystems have been severely degraded due to the combined effects of climate change and human activities.Changes in the seawater carbonate system of coral reef ecosystems can reflect their status and their responses to the impacts of climate change and human activities.Winter and summer surveys in 2019 found that the ecological community of the Luhuitou coral reef flat was dominated by macroalgae and corals,respectively,contrasting with the conditions 10 years ago.The Luhuitou fringing reefs were sources of atmospheric CO_(2) in both seasons.In winter,the daily variation range of dissolved inorganic carbon(DIC)in Luhuitou coral reefs was up to 450μmol/kg,while that of total alkalinity(TA)was only 68μmol/kg.This indicated that the organic production was significantly higher than the calcification process during this period.The TA/DIC was approximately 0.15,which was less than half of that in healthy coral reefs;hence,photosynthesis-respiration processes were the most important factors controlling daily changes in the seawater carbonate system.The net community production(NCP)of the Luhuitou coral reef ecosystem in winter was as high as 47.65 mmol C/(m^(2)·h).While the net community calcification(NCC)was approximately 3.35 and-4.15 mmol CaCO_(3)/(m^(2)·h)during the daytime and nighttime respectively.Therefore,the NCC for the entire day was-21.9 mmol CaCO_(3)/(m^(2)·d),indicating a net autotrophic dissolved state.In summer,the acidification was enhanced by thunderstorms and heavy rain with the highest seawater partial pressure of CO_(2)(p CO_(2))and lowest pH T.Over the past 10 years,the increase rate of seawater p CO_(2) in Luhuitou reef was approximately 13.3μatm/a***,six times that of the open ocean,while the decrease rate of pH was approximately 0.0083/a,being five times that of the global ocean.These findings underscore the importance of protecting and restoring Luhuitou fringing reef,as well as similar reefs worldwide.展开更多
The intensification of extreme precipitation(EP)under global warming presents a substantial risk to human safety and societal progress.Studying the specific impacts of global warming on rare EP events in China not onl...The intensification of extreme precipitation(EP)under global warming presents a substantial risk to human safety and societal progress.Studying the specific impacts of global warming on rare EP events in China not only enhances the comprehension of these shifts,but also paves the way for the development of proactive strategies to alleviate associated damages.Results from large-ensemble simulation data demonstrate that global warming has led to an enhancement in once-in-a-decade EP events in parts of western and central China over the past few decades,with the strengthening of the South Asia high(SAH)caused by global warming playing a dominant role.The strengthening of the SAH corresponds to an intensification and westward extension of the western Pacific subtropical high in the lower troposphere.The region between these two systems experiences enhanced upward motion and increased southwesterly water vapor transport,leading to a rise in climatological precipitation in western and central China,thereby raising the threshold for once-in-a-decade EP events.展开更多
1.Introduction.Ni-Mn-X(X=Ga,In,Sn,or Sb)Heusler alloys have versatile properties[1-4],such as shape memory effect[1],superelastic-ity[5],magnetocaloric effect[3],elastocaloric effect[6],and even multicaloric effect[7]...1.Introduction.Ni-Mn-X(X=Ga,In,Sn,or Sb)Heusler alloys have versatile properties[1-4],such as shape memory effect[1],superelastic-ity[5],magnetocaloric effect[3],elastocaloric effect[6],and even multicaloric effect[7],that indicate their potential for use in actu-ators,sensors,micropumps,energy harvesters,and solid-state re-frigeration[8-10].Among the alloys,Ni-Mn-Sn-based alloys are environment-friendly and cost-effective[6,7,11],and hence,they have received widespread attention.展开更多
基金support of the National Natural Science Foundation of China(Grant Nos.52174030,52474042 and 52374041)the Postgraduate Innovation Fund Project of Xi'an Shiyou University(No.YCX2411001)the Natural Science Basic Research Program of Shaanxi(Program Nos.2024JCYBMS-256 and 2022JQ-528)。
文摘Complex physical and chemical reactions during CO_(2)sequestration alter the microscopic pore structure of geological formations,impacting sequestration stability.To investigate CO_(2)sequestration dynamics,comprehensive physical simulation experiments were conducted under varied pressures,coupled with assessments of changes in mineral composition,ion concentrations,pore morphology,permeability,and sequestration capacity before and after experimentation.Simultaneously,a method using NMR T2spectra changes to measure pore volume shift and estimate CO_(2)sequestration is introduced.It quantifies CO_(2)needed for mineralization of soluble minerals.However,when CO_(2)dissolves in crude oil,the precipitation of asphaltene compounds impairs both seepage and storage capacities.Notably,the impact of dissolution and precipitation is closely associated with storage pressure,with a particularly pronounced influence on smaller pores.As pressure levels rise,the magnitude of pore alterations progressively increases.At a pressure threshold of 25 MPa,the rate of change in small pores due to dissolution reaches a maximum of 39.14%,while precipitation results in a change rate of-58.05%for small pores.The observed formation of dissolution pores and micro-cracks during dissolution,coupled with asphaltene precipitation,provides crucial insights for establishing CO_(2)sequestration parameters and optimizing strategies in low permeability reservoirs.
基金Projects(51871243,51574290)supported by the National Natural Science Foundation of ChinaProject(ASSIKFJJ202304001)supported by the Open Fund of the National Key Laboratory of Strength and Structural Integrity,China+3 种基金Project(HT-CSNS-DG-CD-0092/2021)supported by the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology,ChinaProject(2022KF-08)supported by the Hubei Longzhong Laboratory,ChinaProject(22kfgk06)supported by the Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province,ChinaProject(PBSKL2022C01)supported by the State Key Laboratory of Precision Blasting and Hubei Key Laboratory of Blasting Engineering,China。
文摘The commercial ZK 60 magnesium alloy with extruded state experienced aging heat treatment(T 6)was dynamically loaded at strain rate of 3000 s−1 by means of the split Hopkinson pressure bar(SHPB)in this paper.Transmission electron microscopy(TEM)observations showed that the precipitatedβ′_(1) phases partially dissolved(spheroidized)with blurred interfaces within 160μs at 3000 s^(−1).The average length and diameter of the rod-shapedβ′_(1) phase particles were 48.5 and 9.8 nm after the T 6 heat treatment;while the average diameter of the sphericalβ′_(1) phases changed to 8.8 nm after loading.The deformedβ′_(1) phase generated larger lattice distortion energy than Mg matrix under high strain rate loading.Therefore,the difference of free energy(the driving force of dissolution)between theβ′_(1) phase and the matrix increased,making the instantaneous dissolution of theβ′_(1) phase thermodynamically feasible.The dissolution(spheroidization)of theβ′_(1) phase particles was kinetically promoted because the diffusion rate of the solute Zn atoms was accelerated by combined actions of adiabatic temperature rise,high density of dislocations(vacancies)and high deviatoric stresses during high strain rate loading.The increase in hardness of ZK 60-T 6 alloy could be attributed to solid solution strengthening,dislocation strengthening and second phase particle strengthening.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2062)supported by the Key Laboratory for Carbonate Reservoirs of China National Petroleum Corporation。
文摘Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.
文摘Hydrothermal ore zoning is a transport-reaction problem in which infiltration is the principal Prcness of transport and dissolution/Precipitation is the Principal process of chemical reactions.Neglecting diffusion and ion exchange/adsorption would not affect the basic attributes of hydrothermal ore zoning. Hydrothermal ore zoning belongs essentially to infiltration metasomatic zoning, it results from the formation and propagation of dissolution/precipitation waves through Permeable media. The authors apply the theory of coupled infiltration and dissolution/precipitation reactions in Physicochemical hydrodynamics to studying the structural characteristics of dissolution/precipitation waves, and apply furthermore the coherence principle in dynamic theory of multicomponent coupled systems to revealing the dynamic mechanisms of their formation. The results of investigation verify and develop . C. 's theory of infiltration metasomatic zoning,on the one hand, raising it from the qualitative, equilibrium thermodynamic basis to the quantitative dynamic level;on the other hand, and more importantly, applying theories of Physicochemical hydrodynamics and dynamics of multicomponent coupled systems to bringing to light the dynamic mechanisms of formation of the structure of hydrothermal ore zoning, and advancing a theory of hydrothermal ore zoning, putting forward new ideas on the nature of the problem of hydrothermal ore zoning, the essence of hydrothermal ore zoning and the structural characteristics and mechanisms of formation of hydrothermal ore zoning.
基金support from the National Key R&D Program(No.2023YFB3709900)the National Natural Science Foundation of China(Grant No.U22A20171)+1 种基金the High Steel Center at the North China University of Technologythe University of Science and Technology Beijing,China.
文摘The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was the diffusion in the molten slag.The dissolution rate of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was affected by the composition and size of inclusion.The functional relationship between the dimensionless inclusion capacity(Zh)and the dimensionless dissolution rate(Ry)of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was calculated as Ry=2.10×10^(-6)Zh^(0.160),while it was Ry=2.10×10^(-6)Zh^(0.0087)for Al_(2)O_(3)-CaO complex inclusions.On this basis,the complete dissolution time and rate of the complex inclusions were calculated by using the function relation between the Zh and Ry numbers.
基金the National Natural Science:Foundation of China(52375370)the Open Project of Salt Lake Chemical Engineering Research Complex,Qinghai University(2023-DXSSKF-Z02)+2 种基金the Nat-ural Science Foundation of Shanxi(202103021224049)GDAS Projects of International cooperation platform of Sci-ence and Technology(2022GDASZH-2022010203-003)Guangdong province Science and Technology Plan Projects(2023B1212060045).
文摘The dominated contradiction in optimizing the performance of magnesium-air battery anode lies in the difficulty of achieving a good balance between activation and passivation during discharge process.To further reconcile this contradiction,two Mg-0.1Sc-0.1Y-0.1Ag anodes with different residual strain distribution through extrusion with/without annealing are fabricated.The results indicate that annealing can significantly lessen the“pseudo-anode”regions,thereby changing the dissolution mode of the matrix and achieving an effective dissolution during discharge.Additionally,p-type semiconductor characteristic of discharge productfilm could suppress the self-corrosion reaction without reducing the polarization of anode.The magnesium-air battery utilizing annealed Mg-0.1Sc-0.1Y-0.1Ag as anode achieves a synergistic improvement in specific capacity(1388.89 mA h g^(-1))and energy density(1960.42 mW h g^(-1)).This anode modification method accelerates the advancement of high efficiency and long lifespan magnesium-air batteries,offering renewable and cost-effective energy solutions for electronics and emergency equipment.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFA0608000)the National Natural Science Foundation of China(Grant No.42030605)+1 种基金CAAI-MindSpore Academic Fund Research Projects(CAAIXSJLJJ2023MindSpore11)the program of China Scholarships Council(No.CXXM2101180001)。
文摘Accurate seasonal precipitation forecasts,especially for extreme events,are crucial to preventing meteorological hazards and their potential impacts on national development,social activity,and security.However,the intensity of summer precipitation is often largely underestimated in many current dynamic models.This study uses a deep learning method called Cycle-Consistent Generative Adversarial Networks(CycleGAN)to improve the seasonal forecasts for June-JulyAugust precipitation in southeastern China by the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS 1.0).The results suggest that the CycleGAN-based model significantly improves the accuracy in predicting the spatiotemporal distribution of summer precipitation compared to the traditional quantile mapping(QM)method.Using the unpaired bias-correction model,we can also obtain advanced forecasts of the frequency,intensity,and duration of extreme precipitation events over the dynamic model predictions.This study expands the potential applications of deep learning models toward improving seasonal precipitation forecasts.
基金jointly supported by the National Natural Science Foundation of China (Grant Nos.42422502 and 42275038)the China Meteorological Administration Climate Change Special Program (Grant No.QBZ202306)funded by the Met Office Climate Science for Service Partnership (CSSP) China project under the International Science Partnerships Fund (ISPF)。
文摘This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has seen a remarkable run of extreme precipitation events and resulting impacts. Here, we provide an overview of the most notable extreme events of the year, including extreme precipitation and floods, tropical cyclones, and droughts. The characteristics and impacts of these extreme events are summarized, followed by discussion on the physical drivers and the role of global warming.Finally, we also discuss the future prospects in extreme event studies, including impact-based perspectives, challenges in attribution of precipitation extremes, and the existing gap to minimize impacts from climate extremes.
基金jointly supported by the National Science Foundation of China (Grant No.42230611)the Meteorological Joint Fund (Grant No.U2142208)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (grant no.2019QZKK0102)the National Science Foundation of China (Grant No.42005071)the Gansu Province Key Talent Project (Grant No.2023RCXM37)。
文摘Northern China is a prominent “hotspot” for land–atmosphere interactions, with substantial gradients in both moisture and thermal conditions. Previous studies have identified a link between land–atmosphere coupling and the individual roles of each factor, but the synergistic effect of the two factors remains unclear. This study considers the covariation of evapotranspiration and precipitation to assess evapotranspiration–precipitation(ET–P) coupling across northern China,exploring its spatial variations and their linkage to water and heat factors. Our findings reveal a transition from strongly positive coupling in the northwest to weakly negative coupling in the southeast, peaking in spring. These spatial variations are attributable to water(soil moisture) and heat(air temperature), which explain 39% and 25% of the variability,respectively. The aridity index(AI), a water–heat synergy factor, is the dominant factor, explaining 66% of the spatial variation in ET–P coupling. As the AI increases, ET–P coupling shifts from strongly positive to weakly negative, with an AI around 0.7. This shift is determined by a shift in the evapotranspiration–lifting condensation level(LCL) coupling under an AI change. Regions with an AI below 0.7 experience water-limited evapotranspiration, where increased soil moisture enhances evapotranspiration, reduces sensible heat(H), and lowers the LCL, resulting in a negative ET–LCL coupling.Conversely, regions with an AI above 0.7 experience energy-limited evapotranspiration, where the positive ET–LCL coupling reflects a positive H–LCL coupling or a positive impact of the LCL on evapotranspiration. This analysis advances our understanding of the intricate influences of multifactor surface interactions on the spatial variations of land–atmosphere coupling.
基金financially supported by the National Natural Science Foundation of China(No.52071040 and 51871036)Natural Science Foundation of Shandong Province,China(No.ZR2022QE008)China Postdoctoral Science Foundation(No.2022M712984)。
文摘Although magnesium-aluminum alloys,such as AZ80 and AZ91 have promising application potential in automotive,high-speed train and aerospace fields,their age-hardening response is generally not very appreciable.In this work,the aging-hardening response of AZ80 alloy was effectively enhanced by applying cold-rolling deformation before conducting conventional aging treatment at 200°C.Compared to the directly aged sample,the yield strength of the pre-rolling and aged sample was increased by 35 MPa.Electron microscope examination confirmed that profuse{10¯11}and{10¯11}-{10¯12}twins,consisting of high density of dislocations and stacking faults,were generated by cold rolling.Blocky or ellipsoidal Mg_(17)Al_(12)precipitates formed at the twin boundaries(TBs)during subsequent aging treatment.Crystallographic analysis indicated that the precipitates at{10¯11}TBs always held an identical Potter OR with both the matrix and twin,while the precipitates at{10¯11}-{10¯12}TBs exhibited three different ORs:Burgers OR,Potter OR and P-S OR with either the matrix or the twin.Moreover,recrystallized grains were found inside{10¯11}-{10¯12}double twins after peak-aging at 200°C,implying that precipitation and recrystallization might occur concurrently along TBs at a relatively low temperature.It was speculated that the highly stored energy inside twins and the high elastic energy between the precipitates and twins were driving factors for the occurrence of recrystallization.
基金supported by the National Natural Science Foundation of China(Nos.52122408 and 52071023)financial support from the Fundamental Research Funds for the Central Universities(University of Science and Technology Beijing,No.FRF-TP-2021-04C1,and 06500135)。
文摘Martensite is an important microstructure in ultrahigh-strength steels,and enhancing the strength of martensitic steels often involves the introduction of precipitated phases within the martensitic matrix.Despite considerable research efforts devoted to this area,a systematic summary of these advancements is lacking.This review focuses on the precipitates prevalent in ultrahigh-strength martensitic steel,primarily carbides(e.g.,MC,M_(2)C,and M_(3)C)and intermetallic compounds(e.g.,Ni Al,Ni_(3)X,and Fe_(2)Mo).The precipitation-strengthening effect of these precipitates on ultrahigh-strength martensitic steel is discussed from the aspects of heat treatment processes,microstructure of precipitate-strengthened martensite matrix,and mechanical performance.Finally,a perspective on the development of precipitation-strengthened martensitic steel is presented to contribute to the advancement of ultrahigh-strength martensitic steel.This review highlights significant findings,ongoing challenges,and opportunities in the development of ultrahigh-strength martensitic steel.
基金support from the National Key Research and Development Program of China(No.2023YFB3710300)National Natural Science Foundation of China(Nos.12174296 and 52101088)+1 种基金Major Program(JD)of Hubei Province,China(No.2023BAA019-5)Numerical calculation is supported by the High-Performance Computing Center of Wuhan University of Science and Technology,China.
文摘The effect of aging precipitation on the stress corrosion cracking(SCC)mechanism of Ni(Fe,Al)-maraging steel was studied through the comparative characterization and analyses of the microstructures and fracture features of solid–solution and peak-aged steels.Aging precipitation exerts a chain of impacts on the deformative compatibility and electrochemical difference between the matrix and oth-er phases or interfaces.The strength of the martensite matrix is enhanced by abundant and evenly dispersed Ni(Fe,Al)precipitates,thereby reducing the possibility of splitting across martensite laths.Meanwhile,the Volta potential difference(VPD)between the matrix and primary NbC particles increases from 11.43 to 18.60 mV.Given that most of the primary NbC particles tend to be distributed along high-angle grain boundaries(HAGBs),anodic dissolution along HAGBs accelerates.Therefore,mechanical and electrochemical factors triggered by aging precipitation are involved in the variation in SCC behavior and mechanism.The SCC susceptibility of the steel in-creases along with the increasing tendency for intergranular cracking.
基金Qin Chuangyuan Cites High-Level Innovation,Entrepreneurship Talent Project(QCYRCXM-2023-003)Innovation Capability Support Program of Shaanxi(2022KJXX-84)。
文摘The effect of hot deformation onα-phase precipitation during the subsequent heat treatment,as well as the mechanical properties of TB18 Ti-alloy,was investigated.Results show that the round bar obtained by the dual-phase field forging of the cast ingot exhibits uniform composition distribution on its cross-section.However,various degrees of deformation are detected at different positions on the cross-section,which is attributed to the characteristics of the forging process.Under the forging condition,the microstructure is mainly composed ofβ-phase matrix and coarsened discontinuous primaryα-phases.After solution and following artificial aging treatment,the primaryα-phases disappear,while needle-like secondaryα-phases precipitate in the matrix.Additionally,dispersed white zones are observed in the samples after aging,which are analyzed to be the precipitation-free zones of secondaryα-phase.Despite a uniform compositional distribution among various regions,these dispersed white zones exhibit higher content and larger size in the positions that have undergone lower forging deformation.It indicates that the insufficient forging deformation inhibits the precipitation of the secondaryα-phase,ultimately resulting in the lower strengthening effect by heat treatment.Thus,consistent with the characteristics of the forging process,a periodic variation of sample in strength is detected along the circumferential direction of the forged round bar.
基金supported by the National Key R&D Program of China(2022YFE0106300)Norges Forskningsråd(328886).
文摘This study investigates trends in extreme precipitation events(EPEs)across Antarctica from 1979 to 2023,analyzing changes in EPE frequency,intensity,and the proportion of extreme to total precipitation.Using Self-Organizing Map(SOM)techniques,the study distinguishes the contributions from thermodynamic,dynamic,and interaction components in explaining these trends.Positive EPE occurrence trends are observed across the Bellingshausen and Weddell Seas,Dronning Maud Land,and parts of the Southern Ocean,with declines limited to Queen Mary Land.Thermodynamic factors,responsible for 96.0%of the overall trend,are driven by increased water vapor content in polar air masses.Dynamic contributions,representing 10.8%,are linked to a strengthened Amundsen Sea Low(ASL)associated with the Southern Annular Mode(SAM)and Pacific South American(PSA)trends.Interaction effects make a slightly negative contribution(-6.8%)to the overall trend.Variations in water vapor transport and vertical velocity tied to annual 500-hPa geopotential height anomalies further explain EPE trends.These findings provide insight into the atmospheric processes that influence Antarctic EPEs,with implications for understanding the climatic impact on the polar environment.
基金National Natural Science Foundation of China(U2442202, 42274217, 62441501)Key Innovation Team of China Meteorological Administration (CMA2024ZD01)Scientific Research Foundation of CUIT (376278, KYTZ202158)。
文摘Due to global warming, extreme weather and climate events are becoming more frequent, highlighting the need to explore the changing characteristics of precipitation in China, including extreme precipitation. A clustering algorithm was developed to classify summer(June, July, and August) daily precipitation in China from 1961 to 2020, considering spatial distribution, standard deviations, and frequency of extreme precipitation events. The results reveal six distinct precipitation climate zones, a classification that differs from previous divisions. While overall precipitation has decreased in most regions, the frequency of extreme precipitation events has increased across all clusters, indicating a shift in precipitation distribution patterns. Analysis shows that the weakened Lake Baikal blocking high and strengthened Mongolian cyclone influence the arid region in northwest China(Cluster 1), which is characterized by the lowest precipitation.The transition zone between the monsoon and arid region(Cluster 2) is affected by the Mongolian cyclone, water vapor transport from the Indian Ocean, and shifts in the monsoon boundary. Clusters 3 and 4 represent areas associated with advancement and retreat of the summer monsoon. In the Meiyu region, two distinct subregions have been identified exist.Cluster 4 is primarily influenced by the East Asia-Pacific wave train. Despite sharing similar climate drivers and proximity,Clusters 4 and 5 differ significantly due to topographic variations and disparate levels of urbanization. Cluster 5 exhibits a higher average precipitation, greater variability, and more frequent extreme events. Cluster 6 exhibits the highest overall precipitation in the coastal areas of Guangdong and Guangxi, where abundant water vapor contributes to a higher frequency of extreme precipitation. In addition, anthropogenic activities and urbanization significantly influence precipitation in Beijing-Tianjin-Hebei and Yangtze River Delta regions. This research proposes a precipitation classification scheme integrating multiple precipitation parameters, providing support for risk management and mitigation strategies in the face of increasing extreme precipitation events.
基金supported by the National Natural Science Foundation of China[grant numbers 42175099 and 42027804]The appointment of Chunsong Lu at Nanjing University of Information Science&Technology was partially supported by the Jiangsu Specially-Appointed Professor[grant number R2024T01].
文摘Cloud type profoundly affects precipitation,but few studies have explored its impact on precipitation scale height.The authors calculated the ratio of the volume of each cloud type to the total cloud volume and partitioned the tropical region based on the dominant cloud types.Based on this,tropical regions were categorized into altocumulus control regions,stratocumulus control regions,deep convective cloud control regions,and transition regions.These regions exhibit unique characteristics:high precipitation scale heights and low surface precipitation rates in altocumulus control regions;low precipitation scale heights and low surface precipitation rates in stratocumulus control regions;and moderate precipitation scale heights with high surface precipitation rates in deep convective cloud regions.These features arise from differences in cloud characteristics,precipitation probability,and intensity,influenced by varying water vapor structures.In terms of physical mechanisms,altocumulus,stratocumulus,and deep convective cloud regions are characterized by total dryness,upper-level dryness with lower-level wetness,and total wetness,respectively.Upper-layer dryness leads to low cloud and precipitation structures,reducing the precipitation scale height,while lower-layer dryness increases it.Different humidity conditions in the upper and lower layers lead to variations in cloud type and volume distribution,ultimately affecting precipitation scale heights.This finding aids the mechanistic study of cloud precipitation physics in the tropics,providing valuable insights for developing numerical models and parameterizations.
基金supported by National Natural Science Foundation of China[grant number 42305041].
文摘Deforestation has a significant influence on the hydrological cycle.Understanding the impact of deforestation on precipitation extremes is crucial for addressing global environmental challenges.This study investigates the impact of deforestation on precipitation extremes(R95p index,which represents the total amount of precipitation exceeding the 95th percentile of the reference period)in China,using outputs from three earth system models(CanESM5,IPSL-CM6A-LR,and MIROC-ES2L).All models,along with their multimodel mean,indicate a general decrease in R95p in Northeast China and southern China,and changes in Northwest China and the Tibetan Plateau are minimal.In contrast,the responses are model-dependent in the Huanghuai and Jianghuai regions.The overall nationwide multimodel mean suggests an annual R95p decrease of 10.7 mm,with individual model variations ranging from-28.0 to 2.0 mm.Further analysis using precipitation extremes scaling reveals a high spatial correlation with direct precipitation extremes changes on both annual and seasonal scales,albeit with slightly smaller magnitudes.Decomposing the response into dynamic and thermodynamic scaling,the authors find that dynamic contributions predominantly drive the changes in precipitation extremes on both annual and seasonal scales.The authors findings highlight the substantial role of dynamic processes in modulating the response of precipitation extremes to deforestation in China.
基金Supported by the National Key Research and Development Program of China(Nos.2021YFC3100500,2022YFC3103602,2021YFF0502800)the National Natural Science Foundation of China(No.U23A2035)+3 种基金the Science and Technology Planning Project of Guangdong Province,China(No.2023B1212060047)the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences(No.LTO1919)the Visiting Fellowship Program of the State Key Laboratory of Marine Environmental Science,Xiamen University(No.MELRS1914)the Hainan Province Key R&D Program(No.ZDYF2023SHFZ131)。
文摘Global coral reef ecosystems have been severely degraded due to the combined effects of climate change and human activities.Changes in the seawater carbonate system of coral reef ecosystems can reflect their status and their responses to the impacts of climate change and human activities.Winter and summer surveys in 2019 found that the ecological community of the Luhuitou coral reef flat was dominated by macroalgae and corals,respectively,contrasting with the conditions 10 years ago.The Luhuitou fringing reefs were sources of atmospheric CO_(2) in both seasons.In winter,the daily variation range of dissolved inorganic carbon(DIC)in Luhuitou coral reefs was up to 450μmol/kg,while that of total alkalinity(TA)was only 68μmol/kg.This indicated that the organic production was significantly higher than the calcification process during this period.The TA/DIC was approximately 0.15,which was less than half of that in healthy coral reefs;hence,photosynthesis-respiration processes were the most important factors controlling daily changes in the seawater carbonate system.The net community production(NCP)of the Luhuitou coral reef ecosystem in winter was as high as 47.65 mmol C/(m^(2)·h).While the net community calcification(NCC)was approximately 3.35 and-4.15 mmol CaCO_(3)/(m^(2)·h)during the daytime and nighttime respectively.Therefore,the NCC for the entire day was-21.9 mmol CaCO_(3)/(m^(2)·d),indicating a net autotrophic dissolved state.In summer,the acidification was enhanced by thunderstorms and heavy rain with the highest seawater partial pressure of CO_(2)(p CO_(2))and lowest pH T.Over the past 10 years,the increase rate of seawater p CO_(2) in Luhuitou reef was approximately 13.3μatm/a***,six times that of the open ocean,while the decrease rate of pH was approximately 0.0083/a,being five times that of the global ocean.These findings underscore the importance of protecting and restoring Luhuitou fringing reef,as well as similar reefs worldwide.
基金supported by the National Natural Science Foundation of China[grant number 42088101]the National Key Research and Development Program of China[grant number 2022YFF0801702]。
文摘The intensification of extreme precipitation(EP)under global warming presents a substantial risk to human safety and societal progress.Studying the specific impacts of global warming on rare EP events in China not only enhances the comprehension of these shifts,but also paves the way for the development of proactive strategies to alleviate associated damages.Results from large-ensemble simulation data demonstrate that global warming has led to an enhancement in once-in-a-decade EP events in parts of western and central China over the past few decades,with the strengthening of the South Asia high(SAH)caused by global warming playing a dominant role.The strengthening of the SAH corresponds to an intensification and westward extension of the western Pacific subtropical high in the lower troposphere.The region between these two systems experiences enhanced upward motion and increased southwesterly water vapor transport,leading to a rise in climatological precipitation in western and central China,thereby raising the threshold for once-in-a-decade EP events.
基金supported by the National Key R&D Pro-gram of China(No.2022YFB3805701)National Natural Science Foundation of China(NSFC)(No.52371182,51701052,52192592,52192593)+1 种基金Young Elite Scientists Sponsorship Program by CAST(No.2019QNRC001)the Heilongjiang Touyan Innovation Team Program.
文摘1.Introduction.Ni-Mn-X(X=Ga,In,Sn,or Sb)Heusler alloys have versatile properties[1-4],such as shape memory effect[1],superelastic-ity[5],magnetocaloric effect[3],elastocaloric effect[6],and even multicaloric effect[7],that indicate their potential for use in actu-ators,sensors,micropumps,energy harvesters,and solid-state re-frigeration[8-10].Among the alloys,Ni-Mn-Sn-based alloys are environment-friendly and cost-effective[6,7,11],and hence,they have received widespread attention.
