Wetlands are vital ecosystems that perform essential functions such as climate regulation,environmental purification,material circulation and energy flow.They play an essential role in global biogeochemical cycles,dri...Wetlands are vital ecosystems that perform essential functions such as climate regulation,environmental purification,material circulation and energy flow.They play an essential role in global biogeochemical cycles,driven primarily by microorganisms.Understanding the distribution of wetland microorganisms across different temperature zones is key to comprehending their ecological roles.A meta-analysis of 704 wetland soil samples on microbial communities was conducted,using statistical methods like analysis of variance,principal component analysis,non-metric nultidimensional scaling,and structural equation modeling to examine biogeography and diversity across temperature zones.Our findings revealed a clear latitudinal diversity gradient pattern,with the highest microbial abundance in the tropics and the lowest in the southern temperate zone,which differed significantly from other temperature zones.Proteobacteria(37.76%-51.04%),Acidobacteria(5.11%-30.70%)and Bacteroidetes(3.43%-16.16%)dominanted the bacterial communities.Notably,the southern temperate zone showed significant variations,with a higher prevalence of Acidobacteria(30.07%).To investigate the causes of this variability,we screened 177 core microbiome and identified latitude as the core environmental factor influencing microbial community composition.Moreover,soil microorganisms exhibited strong nitrogen cycling potentials(particularly nirD and nirB)and carbon cycling potentials(especially accA),with gene abundances showing little variation across temperature zones.Wetland bacterial communities also demonstrated high stability,with average variation degree index values ranging from 0.1 to 0.3.Our results improve the understanding of the diversity and biogeographic mechanisms of wetland bacterial communities and hold significant implications for the management and conservation of wetlands.展开更多
Ensuring national food security amidst rapid population growth and increasing extreme weather events remains a critical global challenge.However,the extent to which agricultural modernization in China enhances grain y...Ensuring national food security amidst rapid population growth and increasing extreme weather events remains a critical global challenge.However,the extent to which agricultural modernization in China enhances grain yield and contributes to food security remains unclear.Therefore,using panel data from 327 Chinese cities(2013–2021),this study employs spatial econometric models to analyze the spatial spillover effects of agricultural modernization level(AML)on grain yield and to reveal regional heterogeneity across nine major agricultural zones.The results showed a cumulative grain yield increase of 23.7 million tons,with peak productivity concentrated along the Hu Line and declining eastward and westward.AML also exhibited a steady increase but a clear spatial gradient,decreasing from coastal to inland regions,with the highest level observed in Southern China(SC).A key finding was that a 1%increase in AML directly raised local grain yield by an average of 4.185%,accompanied by significant positive spillover effects on neighboring regions.Regional variations revealed distinct patterns:the direct effects of AML were more pronounced in southern and eastern zones,while spillover effects dominated in northern and western zones.The largest positive direct impact of AML on grain yield was observed in the SC(8.499%),while Middle-Lower Yangtze Plain ranked second but exhibited the strongest positive spatial spillover effect(4.534%).These findings highlight the critical role of agricultural modernization in promoting grain production and provide a solid basis for optimizing regional agricultural systems,ensuring food security,and advancing sustainable agriculture.展开更多
Anaerobic ammonium oxidation(anammox)plays a vital role in the global nitrogen cycle by mitigating reactive nitrogen.In recent years,its ecological importance has drawn increasing attention.Despite its widespread occu...Anaerobic ammonium oxidation(anammox)plays a vital role in the global nitrogen cycle by mitigating reactive nitrogen.In recent years,its ecological importance has drawn increasing attention.Despite its widespread occurrence,the distribution and quantitative contribution of anammox to global nitrogen loss remain unclear.We collected 390 reported anammox activity measurements which were obtained using 15N isotope tracing techniques and analyzed anammox rate and environmental factors including soil/sediment and water property using generalized additive models(GAMs).Moreover,based on the division of the anammox activity region,we estimated anammox-driven nitrogen loss across different ecosystems including wetlands and oxygen minimum zones(OMZs)ecosystems.Our findings revealed that soil moisture content was the most significant predictor of anammox activity in wetlands ecosystems.Paddy fields contributed 51%of anammox-driven nitrogen loss(32.0 Tg N/yr),followed by rivers/lakes(29%)and wetlands(20%).Asia emerged as the dominant region for anammoxdriven nitrogen loss(30.7 Tg N/yr),with paddy fields making a substantial contribution.North America was the second-largest contributor(25.4 Tg N/yr),with rivers/lakes being the main sources of nitrogen loss.In OMZs ecosystems,nitrate and dissolved oxygen were key factors influencing anammox rates.OMZs were hotspots for anammox,with peak activity at 300 m depth and nitrogen loss totaling 68.6 Tg N/yr,mostly between 100 and 500 m depths.This study underscores the critical role of anammox in global nitrogen cycling and offers a basis for environmental nitrogen management through predictive anammox modeling.展开更多
Against the backdrop of accelerated development of new forms of trade,the question of whether rapid expansion of cross-border e-commerce(CBEC)can help to reduce carbon emissions among Chinese enterprises is of great s...Against the backdrop of accelerated development of new forms of trade,the question of whether rapid expansion of cross-border e-commerce(CBEC)can help to reduce carbon emissions among Chinese enterprises is of great significance for seizing new opportunities in foreign trade,and advancing firms’green and low-carbon transformation.This study treats the creation of CBEC pilot zones as a quasi-natural experiment,employing panel data from Chinese A-share listed companies matched with city-level information from 2006 to 2021.We construct a multi-period difference-in-differences model to identify the impact of CBEC pilot zone policy on corporate carbon emissions.Our findings indicate the construction of these pilot zones significantly reduces firms’carbon emissions intensity,and the results are robust across multiple tests.We show the pilot zone initiative contributes to emission reductions by enhancing the adoption of digital infrastructure,promoting green technological innovation,and increasing environmental awareness among enterprises.Quantile regressions reveal pilot zones exert a more pronounced carbon-reduction effect on firms characterized by high carbon emissions intensity and advanced levels of digital transformation.Moreover,the policy effect is especially significant in heavily polluting industries,and regions with weaker governmental environmental regulations or lower public environmental concerns.This study makes an innovative contribution to the literature by empirically verifying the environmental governance effect of establishing CBEC pilot zones,and offers practical guidance for governments in formulating cross-border e-commerce policies and for enterprises pursuing low carbon development.展开更多
The inheritance and development of cultural ecosystem conservation zones is an important way to promote comprehensive rural revitalization.This article studies the agricultural cultural resources of the three national...The inheritance and development of cultural ecosystem conservation zones is an important way to promote comprehensive rural revitalization.This article studies the agricultural cultural resources of the three national-level cultural ecosystem conservation zones in Wuling Mountain area from aspects such as the hometown of local specialties,geographical indications,time-honored brands,important agricultural cultural heritages,traditional villages,ethnic characteristic villages,and historical and cultural famous villages and towns.It also investigates their intangible cultural heritage resources from aspects such as representative projects,production-oriented protection demonstration bases,and the hometown of folk art and culture.This paper analyzes four major problems existing in national-level cultural ecosystem conservation zones and proposes strategies including taking the consolidation of the consciousness of the Chinese community as the main line and building a shared spiritual home for the Chinese nation.展开更多
EI Salvador is gradually consolidating its position as a strategic destination for foreign direct investment,especially for countries with extensive experience in industrial,technological,and logistics development,suc...EI Salvador is gradually consolidating its position as a strategic destination for foreign direct investment,especially for countries with extensive experience in industrial,technological,and logistics development,such as the People’s Republic of China.Thanks to ambitious economic policies based on sustainability,inclusivity,and global competitiveness,the country has clearly defined a development agenda focused on priority sectors with high potential for international cooperation.展开更多
The geological tectonic zone is closely related to outburst.Taking the outburst coal bodies in tectonic zones as the research object,combined with DIC and AE monitoring technologies and discrete element simulation,the...The geological tectonic zone is closely related to outburst.Taking the outburst coal bodies in tectonic zones as the research object,combined with DIC and AE monitoring technologies and discrete element simulation,the mechanical response,crack evolution and energy characteristics of coal bodies under different loading rates(impact disturbances)were studied.The results show that both the uniaxial compressive strength and elastic modulus are positively correlated with the loading rate,with a maximum increase in compressive strength of 25.15%.The uniaxial compressive strength is more sensitive to impact disturbances.The failure modes of coal bodies can be divided into the“slip-crack synchronization(S&C)type”and the“crack-first-then-slip(C&S)type”.The slip in tectonic zones is more severe at high loading rates.At low loading rates,shear cracks dominate(60.01%),while the proportion of tensile cracks increases significantly(70.52%)at high loading rates.Additionally,the rate of axial crack growth decreases as the loading rate increases.The peak values of total energy and dissipated energy increase significantly with the loading rate,and the peak energy of the C&S type is greater than that of the S&C type.Energy is preferentially released through the slip of tectonic zones and the propagation of radial cracks.展开更多
Subduction zones,linking the surface and deep carbon reservoirs,significantly affect the Earth’s long-term climate change and habitability.The subducting slabs undergo decarbonation with increasing pressure and tempe...Subduction zones,linking the surface and deep carbon reservoirs,significantly affect the Earth’s long-term climate change and habitability.The subducting slabs undergo decarbonation with increasing pressure and temperature,during which partial carbon mobilizes out of the slab and returns to the surface by arc volcanism or degassing,while the residual carbon continues to descend to greater depths in the mantle.The estimated carbon influx at subduction zones depends strongly on the calculation model,with contributions from sediments ranging from 15 to 60 Mt C/yr,altered ocean basalts from 18 to 61 Mt C/yr,and serpentinized perdotites from 1.3 to 36 Mt C/yr.The carbon influx varies in space and time.Carbon removal from subducting slab occurs through metamorphic reactions,carbonate dissolution,diapirism,hydrocarbon formation and melting.Among these decarbonation mechanisms,diapirism and slab meting play a decisive role in dictating the depth at which surface carbonates can subduct.Specifically,diapirism may restrict sedimentary carbonates at shallow depths(<200 km),while slab melting exhausts all carbonates from the altered ocean crust near transition zones(410–660 km).Consequently,a mechanism enabling surface carbonates to reach the lower mantle,i.e.,ultra-deep carbon cycle,is required to be in accordance with observations by natural samples.展开更多
Subduction zones are critical interfaces for lithospheric volatile fluxes,where complex tectonic and geochemical interactions facilitate the release of gases and fluids from deep-seated reservoirs within the Earth’s ...Subduction zones are critical interfaces for lithospheric volatile fluxes,where complex tectonic and geochemical interactions facilitate the release of gases and fluids from deep-seated reservoirs within the Earth’s crust.Mud volcanism,as a dynamic manifestation of these processes,contributes CH_(4)emissions that influence the global methane budget and impact marine ecosystems.Although∼2000 CH_(4)-rich mud extrusions have been documented in subduction zones globally,the geological origins and subduction-related geochemical and tectonic mechanisms driving these emissions remain poorly understood.This research examines the Makran subduction zone which hosts one of the world’s largest accretionary wedge and extensive CH_(4)-rich mud extrusions,as a model system.Integrated geochemical,geophysical,and geological observations reveal that thermogenic CH_(4)and clay-rich fluidized muds originate from deeply buried Himalayan turbidites(underthrusted sediments),driven by organic-rich sediment maturation and high fluid overpressure.Key tectonic features,including thrust faults,overburden pressure of wedge-top sediments,normal faults,brittle fractures,and seismicity,facilitate CH_(4)-rich mud extrusions into the hydrosphere and atmosphere.The extruded gases are predominantly CH_(4),with minor C_(2)H_(6),C_(3)H_(8),i-C_(4)H_(10),and n-C_(4)H_(10)while the mud breccia exhibits a chemical composition dominated by SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3),enriched with trace elements(Rb,Zr,and V)and clay minerals,quartz,and carbonates.Geochemical indicators suggest intense chemical weathering and mature sediments classifying the mud breccia as litharenite and sub-litharenite,indicative of deep burial and compaction.These findings model the evolution of CH_(4)-rich mud extrusions through three geological stages:(i)Eocene to Early Miocene pre-thermogenic formation of the CH_(4)-rich source,(ii)Middle Miocene to Pliocene syn-thermogenic CH_(4)and fluidized mud generation,and(iii)Pleistocene to Recent post-thermogenic CH_(4)-rich fluidized mud migration.These findings underscore the critical yet often overlooked role of subduction-related geochemical and tectonic processes in CH_(4)generation and emission,with significant implications for the global CH_(4)budget and marine ecosystems.展开更多
The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthqu...The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthquake risk zones. In this study, we leveraged a dense seismic array to investigate the high-resolution shallow crust shear wave velocity(Vs) structure beneath the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone, one of the most complex parts of the eastern boundary of the South Chuan–Dian Block. We analyzed the distribution of microseismic events detected between November 2022 and February 2023 based on the fine-scale Vs model obtained. The microseismicity in the study region was clustered into three groups, all spatially related to major faults in this region. These microseismic events indicate near-vertical fault planes, consistent with the fault geometry revealed by other researchers.Moreover, these microseismic events are influenced by the impoundment of the downstream Baihetan Reservoir and the complex tectonic stress near the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone. The depths of these microseismic events are shallower in the junction zone, whereas moving south along the Xiaojiang Fault Zone, the microseismic events become deeper.Additionally, we compared our fine-scale local Vs model with velocity models obtained by other researchers and found that our model offers greater detail in characterizing subsurface heterogeneity while demonstrating improved reliability in delineating fault systems.展开更多
This work focuses on the influence of Al content on the precipitation of nanoprecipitates,growth of prior austenite grains(PAGs),and impact toughness in simulated coarse-grained heat-affected zones (CGHAZs) of two exp...This work focuses on the influence of Al content on the precipitation of nanoprecipitates,growth of prior austenite grains(PAGs),and impact toughness in simulated coarse-grained heat-affected zones (CGHAZs) of two experimental shipbuilding steels after being subjected to high-heat input welding at 400 kJ·cm^(-1).The base metals (BMs) of both steels contained three types of precipitates Type Ⅰ:cubic (Ti,Nb)(C,N),Type Ⅱ:precipitate with cubic (Ti,Nb)(C,N) core and Nb-rich cap,and Type Ⅲ:ellipsoidal Nb-rich precipitate.In the BM of 60Al and 160Al steels,the number densities of the precipitates were 11.37×10^(5) and 13.88×10^(5) mm^(-2),respectively The 60Al and 160Al steel contained 38.12% and 6.39% Type Ⅲ precipitates,respectively.The difference in the content of Type Ⅲ precipitates in the 60Al steel reduced the pinning effect at the elevated temperature of the CGHAZ,which facilitated the growth of PAGs The average PAG sizes in the CGHAZ of the 60Al and 160Al steels were 189.73 and 174.7μm,respectively.In the 60Al steel,the low lattice mismatch among Cu_(2)S,TiN,and γ-Al_(2)O_(3)facilitated the precipitation of Cu_(2)S and TiN onto γ-Al_(2)O_(3)during welding,which decreased the number density of independently precipitated (Ti,Nb)(C,N) particles but increased that of γ-Al_(2)O_(3)–Ti N–Cu_(2)S particles.Thus abnormally large PAGs formed in the CGHAZ of the 60Al steel,and they reached a maximum size of 1 mm.These PAGs greatly reduced the microstructural homogeneity and consequently decreased the impact toughness from 134 (0.016wt%Al) to 54 J (0.006wt%Al)at-40℃.展开更多
The self-organization mapping （SOM） neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem A...The self-organization mapping （SOM） neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem Assessment （ MA）, this paper develops an indicator system and conducts a spatial cluster analysis at the 1km by I km grid pixel scale with the SOM neural network algorithm to sort the core ecosystem services over the vertical and horizontal dimensions. A case study was carried out in Xilingol League. The ecosystem services in Xilingol League could be divided to six different ecological zones. The SOM neural network algorithm was capable of identifying the similarities among the input data automatically. The research provides both spatially and temporally valuable information targeted sustainable ecosystem management for decision-makers.展开更多
The faults and associated fracture zones in the tight sandstone reservoirs of the fifth member of the Triassic Xujiahe Formation(Xu-5 Member)in the Wubaochang area,northeastern Sichuan Basin,play a critical role in co...The faults and associated fracture zones in the tight sandstone reservoirs of the fifth member of the Triassic Xujiahe Formation(Xu-5 Member)in the Wubaochang area,northeastern Sichuan Basin,play a critical role in controlling gas well productivity.To delineate the distribution patterns of the faults and associated fracture zones in this area,a transfer-trained convolutional neural network(CNN)model and an XGBoost(eXtreme Gradient Boosting)-based intelligent seismic attribute fusion method were employed to identify faults and fracture zones,respectively,enabling precise characterization of their spatial distribution.The faults in the Wubaochang area are classified into first-to fourth-order structures,with the average fracture zone width on the hanging wall exceeding that of the footwall,demonstrating a strong positive correlation between fracture zone width and fault displacement.The study area is divided into three distinct deformation regions(southern,central and northern regions)featuring five fault structural styles(duplex,duplex-backthrust,imbricate thrust,synclinorium imbricate-backthrust,and anticlinorium imbricate-backthrust)and four corresponding fracture zone development patterns(duplex,duplex-backthrust,synclinorium imbricate-backthrust,and anticlinorium imbricate-backthrust).Based on the controlling effects of faults on gas enrichment,the dual-source hydrocarbon-supply zones are interpreted to be distributed in the northern and central regions,while the southern region is identified as gas-escape zones.By integrating the distribution of favorable reservoir development areas and fracture zones,two classes of gas enrichment zones(Class Ⅰ and Ⅱ)are delineated.Class Ⅰ zones are primarily distributed in the northern region and the transitional zone from the southern to central regions,whereas Class Ⅱ zones are concentrated in the central region.Class Ⅰ zones exhibit dual-source hydrocarbon-supply conditions,larger-scale fracture zone development,and higher favorability compared to Class Ⅱ zones.According to the defined gas accumulation effectiveness in different types of fracture zones,a high-productivity gas well model for the Wubaochang area is proposed,emphasizing“dual-source faults controlling enrichment,effective fracture zones controlling high production,and high matrix porosity ensuring sustained production”.Targeted drilling directions for different favorable zones are further optimized based on this model.展开更多
The study of natural hybridization facilitates our understanding of potential adaptive mechanisms in evolution and the process involved in speciation.In this study,we used multiple data types,including morphological t...The study of natural hybridization facilitates our understanding of potential adaptive mechanisms in evolution and the process involved in speciation.In this study,we used multiple data types,including morphological traits,ddRAD-seq and ecological niche data,to investigate the differences among Rhododendron×duclouxii hybrid zones and the mechanisms underlying natural hybridization and possible future evolutionary pathways.Our results show that the origins of each hybrid zone are independent,with variations in hybrid formation,structural characteristics,and patterns of genetic components and morphological trait differentiation.There were no significant differences in morphological traits or genetic variation between the F_(1)and F_(2)generations;however,the range of variation of the F_(2)generation was broader than that of the F_(1)generation.The distribution and ecological characteristics of R.×duclouxii did not significantly differ from those of the two parental species,indicating weak ecological niche preferences between the hybrid and parental taxa.These results imply that the hybrid zones of R.×duclouxii are characterized by considerable variability,with the magnitude of hybridization in each case likely influenced by unique combinations of biological and ecological factors specific to each hybrid zone.We predict that R.×duclouxii hybrid zones will persist and give rise to complex hybrid swarms,each potentially leading to different evolutionary outcomes.展开更多
Magnesium alloys,the lightest metallic materials for structural applications,have met the bottleneck in the applications at 300℃ due to limited creep resistance.The degradation of creep resistance closely depends on ...Magnesium alloys,the lightest metallic materials for structural applications,have met the bottleneck in the applications at 300℃ due to limited creep resistance.The degradation of creep resistance closely depends on the microstructural deterioration,especially the formation of precipitate-free zones(PFZs),but the detailed evolution process remains unclear in this regard.The present study adopted a quasi-in-situ methodology to track the evolution process of the PFZs in Mg-2.5Gd-0.1Zr(at.%)alloy during creep at 300℃ under 60 MPa.In the early creep stage,the widening of PFZs and phase transformation of intragranular precipitates are repressed by the applied stress.In the steady and accelerated creep stages,propagation of dislocations generates misorientation between PFZs and their parent grains,leading to the formation of Type-A PFZs.Meanwhile,vacancy diffusion leads to inverse migration of grain boundaries,and produces PFZs with serrated grain boundaries between split rows of grain boundary particles,causing the formation of Type-B PFZs.Secondary intergranular cracks tend to develop in Type-B PFZs in the accelerated creep stage,but the strain accumulation in Type-A PFZs is the key contributor to premature creep failure.展开更多
Based on the waterflooding development in carbonate reservoirs in the Middle East,this study analyzes the geological characteristics and waterflooding behaviors/patterns of different types of high permeability zones(H...Based on the waterflooding development in carbonate reservoirs in the Middle East,this study analyzes the geological characteristics and waterflooding behaviors/patterns of different types of high permeability zones(HPZs),and proposes rational waterflooding strategies and modes.Four types of HPZs,i.e.sedimentation-dominated,sedimentation-diagenesis coupling,biogenic and composite,are identified in the carbonate reservoirs in the Middle East.Based on their distribution patterns,flow mechanisms,and waterflooding behaviors/patterns,five waterflooding modes are established:(1)the mode with stepwise-infilled areal vertical well pattern,for composite HFZs in patchy distribution;(2)the mode with regular row vertical well pattern for TypeⅠchannel“network”HFZs(with dominant water flow pathways at the base),and the mode with irregular differentiated vertical well pattern for TypeⅡchannel“network”HFZs(where multi-stage superimposition leads to“layered flooding”),for sedimentation-diagenesis coupling HFZs;(3)the mode with row horizontal wells through bottom injection and top production,for biogenic HFZs characterized by thin,contiguous distribution and rapid advancing of injected water along a工-shaped path;and(4)the mode with progressive waterflooding through edge water injection via vertical well and oil production via horizontal well,for sedimentation-dominated HFZs characterized by thick,contiguous distribution and flood first in upper anti-rhythmic reservoirs.Development practices demonstrate that the proposed waterflooding modes are efficient in the highly heterogeneous carbonate reservoirs in the Middle East,with balanced employment of reserves in the adjacent reservoirs and enhanced oil recovery.展开更多
Micro(nano)plastics,as an emerging environmental pollutant,are gradually discovered in hyporheic zones and groundwaterworldwide.Recent studies have focused on the origin and spatial/temporal distribution of micro(nano...Micro(nano)plastics,as an emerging environmental pollutant,are gradually discovered in hyporheic zones and groundwaterworldwide.Recent studies have focused on the origin and spatial/temporal distribution of micro(nano)plastics in regional groundwater,together with the influence of their properties and effects of environmental factors on their transport.However,the transport of micro(nano)plastics in the whole hyporheic zone-groundwater system and the behavior of co-existing substances still lack a complete theoretical interpretation.To provide systematic theoretical support for that,this review summarizes the current pollution status of micro(nano)plastics in the hyporheic zone-groundwater system,provides a comprehensive introduction of their sources and fate,and classifies the transport mechanisms into mechanical transport,physicochemical transport and biological processes assisted transport fromthe perspectives ofmechanical stress,physicochemical reactions,and bioturbation,respectively.Ultimately,this review proposes to advance the understanding of the multi-dimensional hydrosphere transport of micro(nano)plastics centered on groundwater,themicroorganisms-mediated synergistic transformation and co-transport involving the intertidal circulation.Overall,this review systematically dissects the presence and transport cycles of micro(nano)plastics within the hyporheic zone-groundwater system and proposes prospects for future studies based on the limitations of current studies.展开更多
Over 90%of Earth’s carbon is stored in the mantle and core.The deep carbon cycle plays a critical role in regulating surface carbon fluxes,global climate,and the habitability of Earth.Carbon mainly residing within th...Over 90%of Earth’s carbon is stored in the mantle and core.The deep carbon cycle plays a critical role in regulating surface carbon fluxes,global climate,and the habitability of Earth.Carbon mainly residing within the sediments,altered oceanic crust,and mantle peridotite as carbonate minerals and organic carbon is transported to the deep Earth via plate subduction.A series of reactions(e.g.,metamorphism,dissolution,and melting)occurring in the subducting slab drive the carbon removal.Some of the car-bon is recycled to the surface via arc volcanism,while the rest is carried into the deeper Earth.More than two-thirds of the global subduction carbon input comes from sedimen-tary carbon,whose fate during subduction directly affects the flux in the global carbon cycle.Over the past two dec-ades,the sedimentary carbon cycle in subduction zones has been extensively studied by experiments and computational approaches.Here,we provide a comprehensive review of the sources,species,decarbonation reactions,carbon cycle trac-ing,and fluxes of sedimentary carbon in subduction zones,and the role of sedimentary carbon subduction in climate evolution and mantle chemistry.Further research is required for our understanding of deep carbon cycle processes and their role in Earth’s climate.展开更多
Cross-border e-commerce has emerged as a new growth point in foreign trade.While the Dalian comprehensive pilot zone has made some progress,its development is constrained by issues such as the global economic slowdown...Cross-border e-commerce has emerged as a new growth point in foreign trade.While the Dalian comprehensive pilot zone has made some progress,its development is constrained by issues such as the global economic slowdown,the relatively small scale of cross-border e-commerce,a high concentration of export commodities,imperfect information mechanisms,and high overall costs.To address these challenges,this paper explores the importance of the construction of the Dalian comprehensive pilot zone for cross-border e-commerce to the transformation and upgrading of exports.Based on my research project,“Research on Path Optimization of Financial Support for the Development of Advanced Manufacturing Clusters in Dalian,”this paper analyzes the current challenges and limiting factors and proposes corresponding countermeasures and suggestions.展开更多
This study reconstructed the paleo-uplift and depression pattern within the sequence stratigraphic framework of the Mid-Permian Maokou Formation,Sichuan Basin,investigated its tectono-sedimentary mechanisms and its co...This study reconstructed the paleo-uplift and depression pattern within the sequence stratigraphic framework of the Mid-Permian Maokou Formation,Sichuan Basin,investigated its tectono-sedimentary mechanisms and its control on paleogeomorphology and large-sale shoals based on analysis of outcrops,loggings and seismic data.The results show that the Maokou Formation comprises two third-order sequences,six fourth-order sequences(SSQ1-SSQ6),and four distinct slope-break zones developing progressively from north to south.Slope-break zones I-III in the northern basin,controlled by synsedimentary extensional faults,exhibited a NE-trending linear distribution with gradual southeastward migration.In contrast,slope-break zone IV in the southern basin displayed an arcuate distribution along the Emeishan Large Igneous Province(ELIP).The evolutions of these multistage slope-break zones governed the Mid-Permian paleogeomorphy in the Sichuan Basin transformations from a giant,north-dipping gentle slope(higher in the southwest than in the northeast)in the early-stage(SSQ1-SSQ2)to a platform(south)-basin(north)pattern in the middle-stage(SSQ3-SSQ5).Ultimately,a further depression zone developed in the southwestern basin during the late-stage(SSQ6),forming a paleo-uplift bounded by two depressions.The developments of the Mid-Permian paleogeomorphic configuration reflected the combined control by the rapid subduction of the Mianlüe Ocean and the episodic eruptions of the Emeishan mantle plume(or hot spots),which jointly facilitated the formation of extensive high-energy shoal facies belts along slope-break zones and around paleo-volcanic uplifts.展开更多
基金supported by the National Natural Science Foundation of China(No.52070019).
文摘Wetlands are vital ecosystems that perform essential functions such as climate regulation,environmental purification,material circulation and energy flow.They play an essential role in global biogeochemical cycles,driven primarily by microorganisms.Understanding the distribution of wetland microorganisms across different temperature zones is key to comprehending their ecological roles.A meta-analysis of 704 wetland soil samples on microbial communities was conducted,using statistical methods like analysis of variance,principal component analysis,non-metric nultidimensional scaling,and structural equation modeling to examine biogeography and diversity across temperature zones.Our findings revealed a clear latitudinal diversity gradient pattern,with the highest microbial abundance in the tropics and the lowest in the southern temperate zone,which differed significantly from other temperature zones.Proteobacteria(37.76%-51.04%),Acidobacteria(5.11%-30.70%)and Bacteroidetes(3.43%-16.16%)dominanted the bacterial communities.Notably,the southern temperate zone showed significant variations,with a higher prevalence of Acidobacteria(30.07%).To investigate the causes of this variability,we screened 177 core microbiome and identified latitude as the core environmental factor influencing microbial community composition.Moreover,soil microorganisms exhibited strong nitrogen cycling potentials(particularly nirD and nirB)and carbon cycling potentials(especially accA),with gene abundances showing little variation across temperature zones.Wetland bacterial communities also demonstrated high stability,with average variation degree index values ranging from 0.1 to 0.3.Our results improve the understanding of the diversity and biogeographic mechanisms of wetland bacterial communities and hold significant implications for the management and conservation of wetlands.
基金National Natural Science Foundation of China,No.42471455,No.42230113National Key Research and Development Program of China,No.2022YFC3800804-01。
文摘Ensuring national food security amidst rapid population growth and increasing extreme weather events remains a critical global challenge.However,the extent to which agricultural modernization in China enhances grain yield and contributes to food security remains unclear.Therefore,using panel data from 327 Chinese cities(2013–2021),this study employs spatial econometric models to analyze the spatial spillover effects of agricultural modernization level(AML)on grain yield and to reveal regional heterogeneity across nine major agricultural zones.The results showed a cumulative grain yield increase of 23.7 million tons,with peak productivity concentrated along the Hu Line and declining eastward and westward.AML also exhibited a steady increase but a clear spatial gradient,decreasing from coastal to inland regions,with the highest level observed in Southern China(SC).A key finding was that a 1%increase in AML directly raised local grain yield by an average of 4.185%,accompanied by significant positive spillover effects on neighboring regions.Regional variations revealed distinct patterns:the direct effects of AML were more pronounced in southern and eastern zones,while spillover effects dominated in northern and western zones.The largest positive direct impact of AML on grain yield was observed in the SC(8.499%),while Middle-Lower Yangtze Plain ranked second but exhibited the strongest positive spatial spillover effect(4.534%).These findings highlight the critical role of agricultural modernization in promoting grain production and provide a solid basis for optimizing regional agricultural systems,ensuring food security,and advancing sustainable agriculture.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0750400)the National Natural Science Foundation of China(Nos.91851204,42177063,and 52370185)+1 种基金the Special project of eco-environmental technology for peak carbon dioxide emissions and carbon neutrality(No.RCEES-TDZ-2021-20)the State Key Joint Laboratory of Environmental Simulation and Pollution Control(Research Center for Eco-environmental Sciences,Chinese Academy of Sciences)(No.24Z01ESPCR).
文摘Anaerobic ammonium oxidation(anammox)plays a vital role in the global nitrogen cycle by mitigating reactive nitrogen.In recent years,its ecological importance has drawn increasing attention.Despite its widespread occurrence,the distribution and quantitative contribution of anammox to global nitrogen loss remain unclear.We collected 390 reported anammox activity measurements which were obtained using 15N isotope tracing techniques and analyzed anammox rate and environmental factors including soil/sediment and water property using generalized additive models(GAMs).Moreover,based on the division of the anammox activity region,we estimated anammox-driven nitrogen loss across different ecosystems including wetlands and oxygen minimum zones(OMZs)ecosystems.Our findings revealed that soil moisture content was the most significant predictor of anammox activity in wetlands ecosystems.Paddy fields contributed 51%of anammox-driven nitrogen loss(32.0 Tg N/yr),followed by rivers/lakes(29%)and wetlands(20%).Asia emerged as the dominant region for anammoxdriven nitrogen loss(30.7 Tg N/yr),with paddy fields making a substantial contribution.North America was the second-largest contributor(25.4 Tg N/yr),with rivers/lakes being the main sources of nitrogen loss.In OMZs ecosystems,nitrate and dissolved oxygen were key factors influencing anammox rates.OMZs were hotspots for anammox,with peak activity at 300 m depth and nitrogen loss totaling 68.6 Tg N/yr,mostly between 100 and 500 m depths.This study underscores the critical role of anammox in global nitrogen cycling and offers a basis for environmental nitrogen management through predictive anammox modeling.
基金support provided by the National Natural Science Foundation of China[Grant No.72204202]2025 Annual Research Program of the China Society for Commercial Statistics[Grant No.2025STY10]General Project of Philosophy Society in Jiangsu Province Universities[Grant Nos.2023SJYB0923 and 2025SJYB0708].
文摘Against the backdrop of accelerated development of new forms of trade,the question of whether rapid expansion of cross-border e-commerce(CBEC)can help to reduce carbon emissions among Chinese enterprises is of great significance for seizing new opportunities in foreign trade,and advancing firms’green and low-carbon transformation.This study treats the creation of CBEC pilot zones as a quasi-natural experiment,employing panel data from Chinese A-share listed companies matched with city-level information from 2006 to 2021.We construct a multi-period difference-in-differences model to identify the impact of CBEC pilot zone policy on corporate carbon emissions.Our findings indicate the construction of these pilot zones significantly reduces firms’carbon emissions intensity,and the results are robust across multiple tests.We show the pilot zone initiative contributes to emission reductions by enhancing the adoption of digital infrastructure,promoting green technological innovation,and increasing environmental awareness among enterprises.Quantile regressions reveal pilot zones exert a more pronounced carbon-reduction effect on firms characterized by high carbon emissions intensity and advanced levels of digital transformation.Moreover,the policy effect is especially significant in heavily polluting industries,and regions with weaker governmental environmental regulations or lower public environmental concerns.This study makes an innovative contribution to the literature by empirically verifying the environmental governance effect of establishing CBEC pilot zones,and offers practical guidance for governments in formulating cross-border e-commerce policies and for enterprises pursuing low carbon development.
基金Supported by Humanities and Social Sciences Research Project of the Ministry of Education of China(24YJA850006).
文摘The inheritance and development of cultural ecosystem conservation zones is an important way to promote comprehensive rural revitalization.This article studies the agricultural cultural resources of the three national-level cultural ecosystem conservation zones in Wuling Mountain area from aspects such as the hometown of local specialties,geographical indications,time-honored brands,important agricultural cultural heritages,traditional villages,ethnic characteristic villages,and historical and cultural famous villages and towns.It also investigates their intangible cultural heritage resources from aspects such as representative projects,production-oriented protection demonstration bases,and the hometown of folk art and culture.This paper analyzes four major problems existing in national-level cultural ecosystem conservation zones and proposes strategies including taking the consolidation of the consciousness of the Chinese community as the main line and building a shared spiritual home for the Chinese nation.
文摘EI Salvador is gradually consolidating its position as a strategic destination for foreign direct investment,especially for countries with extensive experience in industrial,technological,and logistics development,such as the People’s Republic of China.Thanks to ambitious economic policies based on sustainability,inclusivity,and global competitiveness,the country has clearly defined a development agenda focused on priority sectors with high potential for international cooperation.
基金supported by the National Natural Science Foundation of China(Nos.52374122 and 51874165)the Liaoning Revitalization Talents Program(No.XLYC1902106).
文摘The geological tectonic zone is closely related to outburst.Taking the outburst coal bodies in tectonic zones as the research object,combined with DIC and AE monitoring technologies and discrete element simulation,the mechanical response,crack evolution and energy characteristics of coal bodies under different loading rates(impact disturbances)were studied.The results show that both the uniaxial compressive strength and elastic modulus are positively correlated with the loading rate,with a maximum increase in compressive strength of 25.15%.The uniaxial compressive strength is more sensitive to impact disturbances.The failure modes of coal bodies can be divided into the“slip-crack synchronization(S&C)type”and the“crack-first-then-slip(C&S)type”.The slip in tectonic zones is more severe at high loading rates.At low loading rates,shear cracks dominate(60.01%),while the proportion of tensile cracks increases significantly(70.52%)at high loading rates.Additionally,the rate of axial crack growth decreases as the loading rate increases.The peak values of total energy and dissipated energy increase significantly with the loading rate,and the peak energy of the C&S type is greater than that of the S&C type.Energy is preferentially released through the slip of tectonic zones and the propagation of radial cracks.
基金supported by the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2022QNLM050201-3)the National Key R&D Program of China(No.2022YFF0801000)the National Natural Science Foundation of China(Nos.92158206,42003049).
文摘Subduction zones,linking the surface and deep carbon reservoirs,significantly affect the Earth’s long-term climate change and habitability.The subducting slabs undergo decarbonation with increasing pressure and temperature,during which partial carbon mobilizes out of the slab and returns to the surface by arc volcanism or degassing,while the residual carbon continues to descend to greater depths in the mantle.The estimated carbon influx at subduction zones depends strongly on the calculation model,with contributions from sediments ranging from 15 to 60 Mt C/yr,altered ocean basalts from 18 to 61 Mt C/yr,and serpentinized perdotites from 1.3 to 36 Mt C/yr.The carbon influx varies in space and time.Carbon removal from subducting slab occurs through metamorphic reactions,carbonate dissolution,diapirism,hydrocarbon formation and melting.Among these decarbonation mechanisms,diapirism and slab meting play a decisive role in dictating the depth at which surface carbonates can subduct.Specifically,diapirism may restrict sedimentary carbonates at shallow depths(<200 km),while slab melting exhausts all carbonates from the altered ocean crust near transition zones(410–660 km).Consequently,a mechanism enabling surface carbonates to reach the lower mantle,i.e.,ultra-deep carbon cycle,is required to be in accordance with observations by natural samples.
基金funded by the National Natural Science Foundation of China(Grants No.92058213 and No.U22A20581)the Specific Research Fund of the Innovation Platform for Academicians of Hainan Province(Grant No.YSPTZX202204)key R&D projects of Hainan Province(ZDYF2024GXJS022).
文摘Subduction zones are critical interfaces for lithospheric volatile fluxes,where complex tectonic and geochemical interactions facilitate the release of gases and fluids from deep-seated reservoirs within the Earth’s crust.Mud volcanism,as a dynamic manifestation of these processes,contributes CH_(4)emissions that influence the global methane budget and impact marine ecosystems.Although∼2000 CH_(4)-rich mud extrusions have been documented in subduction zones globally,the geological origins and subduction-related geochemical and tectonic mechanisms driving these emissions remain poorly understood.This research examines the Makran subduction zone which hosts one of the world’s largest accretionary wedge and extensive CH_(4)-rich mud extrusions,as a model system.Integrated geochemical,geophysical,and geological observations reveal that thermogenic CH_(4)and clay-rich fluidized muds originate from deeply buried Himalayan turbidites(underthrusted sediments),driven by organic-rich sediment maturation and high fluid overpressure.Key tectonic features,including thrust faults,overburden pressure of wedge-top sediments,normal faults,brittle fractures,and seismicity,facilitate CH_(4)-rich mud extrusions into the hydrosphere and atmosphere.The extruded gases are predominantly CH_(4),with minor C_(2)H_(6),C_(3)H_(8),i-C_(4)H_(10),and n-C_(4)H_(10)while the mud breccia exhibits a chemical composition dominated by SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3),enriched with trace elements(Rb,Zr,and V)and clay minerals,quartz,and carbonates.Geochemical indicators suggest intense chemical weathering and mature sediments classifying the mud breccia as litharenite and sub-litharenite,indicative of deep burial and compaction.These findings model the evolution of CH_(4)-rich mud extrusions through three geological stages:(i)Eocene to Early Miocene pre-thermogenic formation of the CH_(4)-rich source,(ii)Middle Miocene to Pliocene syn-thermogenic CH_(4)and fluidized mud generation,and(iii)Pleistocene to Recent post-thermogenic CH_(4)-rich fluidized mud migration.These findings underscore the critical yet often overlooked role of subduction-related geochemical and tectonic processes in CH_(4)generation and emission,with significant implications for the global CH_(4)budget and marine ecosystems.
基金funded by the National Key R&D Program of China (Grant No. 2021YFC3000704)the National Natural Science Foundation of China (Grant No. 42125401)the Central Public-interest Scientific Institution Basal Research Fund (Grant No. CEAIEF20240401)。
文摘The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthquake risk zones. In this study, we leveraged a dense seismic array to investigate the high-resolution shallow crust shear wave velocity(Vs) structure beneath the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone, one of the most complex parts of the eastern boundary of the South Chuan–Dian Block. We analyzed the distribution of microseismic events detected between November 2022 and February 2023 based on the fine-scale Vs model obtained. The microseismicity in the study region was clustered into three groups, all spatially related to major faults in this region. These microseismic events indicate near-vertical fault planes, consistent with the fault geometry revealed by other researchers.Moreover, these microseismic events are influenced by the impoundment of the downstream Baihetan Reservoir and the complex tectonic stress near the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone. The depths of these microseismic events are shallower in the junction zone, whereas moving south along the Xiaojiang Fault Zone, the microseismic events become deeper.Additionally, we compared our fine-scale local Vs model with velocity models obtained by other researchers and found that our model offers greater detail in characterizing subsurface heterogeneity while demonstrating improved reliability in delineating fault systems.
基金support from the National Natural Science Foundation of China (No. U1960202)the Opening Foundation from Shanghai Engineering Research Center of Hot Manufacturing, China (No. 18DZ2253400)。
文摘This work focuses on the influence of Al content on the precipitation of nanoprecipitates,growth of prior austenite grains(PAGs),and impact toughness in simulated coarse-grained heat-affected zones (CGHAZs) of two experimental shipbuilding steels after being subjected to high-heat input welding at 400 kJ·cm^(-1).The base metals (BMs) of both steels contained three types of precipitates Type Ⅰ:cubic (Ti,Nb)(C,N),Type Ⅱ:precipitate with cubic (Ti,Nb)(C,N) core and Nb-rich cap,and Type Ⅲ:ellipsoidal Nb-rich precipitate.In the BM of 60Al and 160Al steels,the number densities of the precipitates were 11.37×10^(5) and 13.88×10^(5) mm^(-2),respectively The 60Al and 160Al steel contained 38.12% and 6.39% Type Ⅲ precipitates,respectively.The difference in the content of Type Ⅲ precipitates in the 60Al steel reduced the pinning effect at the elevated temperature of the CGHAZ,which facilitated the growth of PAGs The average PAG sizes in the CGHAZ of the 60Al and 160Al steels were 189.73 and 174.7μm,respectively.In the 60Al steel,the low lattice mismatch among Cu_(2)S,TiN,and γ-Al_(2)O_(3)facilitated the precipitation of Cu_(2)S and TiN onto γ-Al_(2)O_(3)during welding,which decreased the number density of independently precipitated (Ti,Nb)(C,N) particles but increased that of γ-Al_(2)O_(3)–Ti N–Cu_(2)S particles.Thus abnormally large PAGs formed in the CGHAZ of the 60Al steel,and they reached a maximum size of 1 mm.These PAGs greatly reduced the microstructural homogeneity and consequently decreased the impact toughness from 134 (0.016wt%Al) to 54 J (0.006wt%Al)at-40℃.
基金Supported by the National Scientific Foundation of China(4080123170873118)+6 种基金the Chinese Academy of Sciences(KZCX2-YW-305-2KSCX2-YW-N-039KZCX2-YW-326-1)the Ministry of Science and Technology of China(2006DFB91912012006BAC08B032006BAC08B062008BAK47B02)~~
文摘The self-organization mapping （SOM） neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem Assessment （ MA）, this paper develops an indicator system and conducts a spatial cluster analysis at the 1km by I km grid pixel scale with the SOM neural network algorithm to sort the core ecosystem services over the vertical and horizontal dimensions. A case study was carried out in Xilingol League. The ecosystem services in Xilingol League could be divided to six different ecological zones. The SOM neural network algorithm was capable of identifying the similarities among the input data automatically. The research provides both spatially and temporally valuable information targeted sustainable ecosystem management for decision-makers.
基金Supported by National Natural Science Foundation of China and Enterprise Innovation and Development Joint Fund(U21B2062).
文摘The faults and associated fracture zones in the tight sandstone reservoirs of the fifth member of the Triassic Xujiahe Formation(Xu-5 Member)in the Wubaochang area,northeastern Sichuan Basin,play a critical role in controlling gas well productivity.To delineate the distribution patterns of the faults and associated fracture zones in this area,a transfer-trained convolutional neural network(CNN)model and an XGBoost(eXtreme Gradient Boosting)-based intelligent seismic attribute fusion method were employed to identify faults and fracture zones,respectively,enabling precise characterization of their spatial distribution.The faults in the Wubaochang area are classified into first-to fourth-order structures,with the average fracture zone width on the hanging wall exceeding that of the footwall,demonstrating a strong positive correlation between fracture zone width and fault displacement.The study area is divided into three distinct deformation regions(southern,central and northern regions)featuring five fault structural styles(duplex,duplex-backthrust,imbricate thrust,synclinorium imbricate-backthrust,and anticlinorium imbricate-backthrust)and four corresponding fracture zone development patterns(duplex,duplex-backthrust,synclinorium imbricate-backthrust,and anticlinorium imbricate-backthrust).Based on the controlling effects of faults on gas enrichment,the dual-source hydrocarbon-supply zones are interpreted to be distributed in the northern and central regions,while the southern region is identified as gas-escape zones.By integrating the distribution of favorable reservoir development areas and fracture zones,two classes of gas enrichment zones(Class Ⅰ and Ⅱ)are delineated.Class Ⅰ zones are primarily distributed in the northern region and the transitional zone from the southern to central regions,whereas Class Ⅱ zones are concentrated in the central region.Class Ⅰ zones exhibit dual-source hydrocarbon-supply conditions,larger-scale fracture zone development,and higher favorability compared to Class Ⅱ zones.According to the defined gas accumulation effectiveness in different types of fracture zones,a high-productivity gas well model for the Wubaochang area is proposed,emphasizing“dual-source faults controlling enrichment,effective fracture zones controlling high production,and high matrix porosity ensuring sustained production”.Targeted drilling directions for different favorable zones are further optimized based on this model.
基金supported by the National Natural Science Foundation of China,China(32300200,31670213,32160240)Postdoctoral Directional Training Foundation of Yunnan Province,China(E33O31C261)+2 种基金the Key Basic Research Program of Yunnan Province,China(202101BC070003)the CAS President’s International Fellowship Initiative,China(2024PVA0087)supported by the Rural and Environment Science and Analytical Services Division of the Scottish Government,United Kingdom.
文摘The study of natural hybridization facilitates our understanding of potential adaptive mechanisms in evolution and the process involved in speciation.In this study,we used multiple data types,including morphological traits,ddRAD-seq and ecological niche data,to investigate the differences among Rhododendron×duclouxii hybrid zones and the mechanisms underlying natural hybridization and possible future evolutionary pathways.Our results show that the origins of each hybrid zone are independent,with variations in hybrid formation,structural characteristics,and patterns of genetic components and morphological trait differentiation.There were no significant differences in morphological traits or genetic variation between the F_(1)and F_(2)generations;however,the range of variation of the F_(2)generation was broader than that of the F_(1)generation.The distribution and ecological characteristics of R.×duclouxii did not significantly differ from those of the two parental species,indicating weak ecological niche preferences between the hybrid and parental taxa.These results imply that the hybrid zones of R.×duclouxii are characterized by considerable variability,with the magnitude of hybridization in each case likely influenced by unique combinations of biological and ecological factors specific to each hybrid zone.We predict that R.×duclouxii hybrid zones will persist and give rise to complex hybrid swarms,each potentially leading to different evolutionary outcomes.
基金funded by the Key-Area Research and Develop-ment Program of Guangdong Province No.2020B010186001)the National Natural Science Foundation of China(Nos.51671128 and U2037601)+1 种基金support from the Na-tional Natural Science Foundation of China(No.52101018)the Shanghai Pujiang Program(No.21PJ1405800).
文摘Magnesium alloys,the lightest metallic materials for structural applications,have met the bottleneck in the applications at 300℃ due to limited creep resistance.The degradation of creep resistance closely depends on the microstructural deterioration,especially the formation of precipitate-free zones(PFZs),but the detailed evolution process remains unclear in this regard.The present study adopted a quasi-in-situ methodology to track the evolution process of the PFZs in Mg-2.5Gd-0.1Zr(at.%)alloy during creep at 300℃ under 60 MPa.In the early creep stage,the widening of PFZs and phase transformation of intragranular precipitates are repressed by the applied stress.In the steady and accelerated creep stages,propagation of dislocations generates misorientation between PFZs and their parent grains,leading to the formation of Type-A PFZs.Meanwhile,vacancy diffusion leads to inverse migration of grain boundaries,and produces PFZs with serrated grain boundaries between split rows of grain boundary particles,causing the formation of Type-B PFZs.Secondary intergranular cracks tend to develop in Type-B PFZs in the accelerated creep stage,but the strain accumulation in Type-A PFZs is the key contributor to premature creep failure.
基金Supported by the China National Petroleum Corporation Major Science and Technology Project(2023ZZ19-01,2023ZZ19-07).
文摘Based on the waterflooding development in carbonate reservoirs in the Middle East,this study analyzes the geological characteristics and waterflooding behaviors/patterns of different types of high permeability zones(HPZs),and proposes rational waterflooding strategies and modes.Four types of HPZs,i.e.sedimentation-dominated,sedimentation-diagenesis coupling,biogenic and composite,are identified in the carbonate reservoirs in the Middle East.Based on their distribution patterns,flow mechanisms,and waterflooding behaviors/patterns,five waterflooding modes are established:(1)the mode with stepwise-infilled areal vertical well pattern,for composite HFZs in patchy distribution;(2)the mode with regular row vertical well pattern for TypeⅠchannel“network”HFZs(with dominant water flow pathways at the base),and the mode with irregular differentiated vertical well pattern for TypeⅡchannel“network”HFZs(where multi-stage superimposition leads to“layered flooding”),for sedimentation-diagenesis coupling HFZs;(3)the mode with row horizontal wells through bottom injection and top production,for biogenic HFZs characterized by thin,contiguous distribution and rapid advancing of injected water along a工-shaped path;and(4)the mode with progressive waterflooding through edge water injection via vertical well and oil production via horizontal well,for sedimentation-dominated HFZs characterized by thick,contiguous distribution and flood first in upper anti-rhythmic reservoirs.Development practices demonstrate that the proposed waterflooding modes are efficient in the highly heterogeneous carbonate reservoirs in the Middle East,with balanced employment of reserves in the adjacent reservoirs and enhanced oil recovery.
基金supported by the National Natural Science Foundation of China(Nos.22036001,42342057,and 22236006).
文摘Micro(nano)plastics,as an emerging environmental pollutant,are gradually discovered in hyporheic zones and groundwaterworldwide.Recent studies have focused on the origin and spatial/temporal distribution of micro(nano)plastics in regional groundwater,together with the influence of their properties and effects of environmental factors on their transport.However,the transport of micro(nano)plastics in the whole hyporheic zone-groundwater system and the behavior of co-existing substances still lack a complete theoretical interpretation.To provide systematic theoretical support for that,this review summarizes the current pollution status of micro(nano)plastics in the hyporheic zone-groundwater system,provides a comprehensive introduction of their sources and fate,and classifies the transport mechanisms into mechanical transport,physicochemical transport and biological processes assisted transport fromthe perspectives ofmechanical stress,physicochemical reactions,and bioturbation,respectively.Ultimately,this review proposes to advance the understanding of the multi-dimensional hydrosphere transport of micro(nano)plastics centered on groundwater,themicroorganisms-mediated synergistic transformation and co-transport involving the intertidal circulation.Overall,this review systematically dissects the presence and transport cycles of micro(nano)plastics within the hyporheic zone-groundwater system and proposes prospects for future studies based on the limitations of current studies.
基金supported by the National Natural Science Foundation of China(No.42274137).
文摘Over 90%of Earth’s carbon is stored in the mantle and core.The deep carbon cycle plays a critical role in regulating surface carbon fluxes,global climate,and the habitability of Earth.Carbon mainly residing within the sediments,altered oceanic crust,and mantle peridotite as carbonate minerals and organic carbon is transported to the deep Earth via plate subduction.A series of reactions(e.g.,metamorphism,dissolution,and melting)occurring in the subducting slab drive the carbon removal.Some of the car-bon is recycled to the surface via arc volcanism,while the rest is carried into the deeper Earth.More than two-thirds of the global subduction carbon input comes from sedimen-tary carbon,whose fate during subduction directly affects the flux in the global carbon cycle.Over the past two dec-ades,the sedimentary carbon cycle in subduction zones has been extensively studied by experiments and computational approaches.Here,we provide a comprehensive review of the sources,species,decarbonation reactions,carbon cycle trac-ing,and fluxes of sedimentary carbon in subduction zones,and the role of sedimentary carbon subduction in climate evolution and mantle chemistry.Further research is required for our understanding of deep carbon cycle processes and their role in Earth’s climate.
文摘Cross-border e-commerce has emerged as a new growth point in foreign trade.While the Dalian comprehensive pilot zone has made some progress,its development is constrained by issues such as the global economic slowdown,the relatively small scale of cross-border e-commerce,a high concentration of export commodities,imperfect information mechanisms,and high overall costs.To address these challenges,this paper explores the importance of the construction of the Dalian comprehensive pilot zone for cross-border e-commerce to the transformation and upgrading of exports.Based on my research project,“Research on Path Optimization of Financial Support for the Development of Advanced Manufacturing Clusters in Dalian,”this paper analyzes the current challenges and limiting factors and proposes corresponding countermeasures and suggestions.
基金Supported by the Key projects of the PetroChina Joint Fund Under the National Natural Science Foundation of China(U23B20154,92255302)Science and Technology Cooperation Project of the Innovation Consortium between PetroChina and Southwest Petroleum University(2020CX010000)Open Fund of the Key Laboratory of Carbonate Reservoirs,China National Petroleum Corporation(RIPED-2024-JS-1804).
文摘This study reconstructed the paleo-uplift and depression pattern within the sequence stratigraphic framework of the Mid-Permian Maokou Formation,Sichuan Basin,investigated its tectono-sedimentary mechanisms and its control on paleogeomorphology and large-sale shoals based on analysis of outcrops,loggings and seismic data.The results show that the Maokou Formation comprises two third-order sequences,six fourth-order sequences(SSQ1-SSQ6),and four distinct slope-break zones developing progressively from north to south.Slope-break zones I-III in the northern basin,controlled by synsedimentary extensional faults,exhibited a NE-trending linear distribution with gradual southeastward migration.In contrast,slope-break zone IV in the southern basin displayed an arcuate distribution along the Emeishan Large Igneous Province(ELIP).The evolutions of these multistage slope-break zones governed the Mid-Permian paleogeomorphy in the Sichuan Basin transformations from a giant,north-dipping gentle slope(higher in the southwest than in the northeast)in the early-stage(SSQ1-SSQ2)to a platform(south)-basin(north)pattern in the middle-stage(SSQ3-SSQ5).Ultimately,a further depression zone developed in the southwestern basin during the late-stage(SSQ6),forming a paleo-uplift bounded by two depressions.The developments of the Mid-Permian paleogeomorphic configuration reflected the combined control by the rapid subduction of the Mianlüe Ocean and the episodic eruptions of the Emeishan mantle plume(or hot spots),which jointly facilitated the formation of extensive high-energy shoal facies belts along slope-break zones and around paleo-volcanic uplifts.
