The isotope composition in precipitation has been widely considered as a tracer of monsoon activity.Compared with the coastal region,the monsoon margin usually has limited precipitation with large fluctuation and is u...The isotope composition in precipitation has been widely considered as a tracer of monsoon activity.Compared with the coastal region,the monsoon margin usually has limited precipitation with large fluctuation and is usually sensitive to climate change.The water resource management in the monsoon margin should be better planned by understanding the composition of precipitation isotope and its influencing factors.In this study,the precipitation samples were collected at five sampling sites(Baiyin City,Kongtong District,Maqu County,Wudu District,and Yinchuan City)of the monsoon margin in the northwest of China in 2022 to analyze the characteristics of stable hydrogen(δD)and oxygen(δ18O)isotopes.We analyzed the impact of meteorological factors(temperature,precipitation,and relative humidity)on the composition of precipitation isotope at daily level by regression analysis,utilized the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)-based backward trajectory model to simulate the air mass trajectory of precipitation events,and adopted the potential source contribution function(PSCF)and concentration weighted trajectory(CWT)to analyze the water vapor sources.The results showed that compared with the global meteoric water line(GMWL),the slope of the local meteoric water line(LMWL;δD=7.34δ^(18)O-1.16)was lower,indicating the existence of strong regional evaporation in the study area.Temperature significantly contributed toδ18O value,while relative humidity had a significant negative effect onδ18O value.Through the backward trajectory analysis,we found eight primary locations that were responsible for the water vapor sources of precipitation in the study area,of which moisture from the Indian Ocean to South China Sea(ITSC)and the western continental(CW)had the greatest influence on precipitation in the study area.The hydrogen and oxygen isotopes in precipitation are significantly influenced by the sources and transportation paths of air mass.In addition,the results of PSCF and CWT analysis showed that the water vapor source areas were primarily distributed in the south and northwest direction of the study area.展开更多
Based on meteorological data collected over nearly 60 years(1960-2017)from four national meteorological stations along the margins of the Badain Jaran Desert,this study analyzed the spatiotemporal variations in evapor...Based on meteorological data collected over nearly 60 years(1960-2017)from four national meteorological stations along the margins of the Badain Jaran Desert,this study analyzed the spatiotemporal variations in evaporation from water surfaces and identified the dominant controlling factors.Methods used included linear trend analysis,linear tendency estimation,the departure method,the rank correlation coefficient-based method,and Multiple Linear Regression(MLR).Results indicate notable spatiotemporal differences in evaporation distribution and evolution.Spatially,average annual evaporation exhibited a pronounced altitude effect,decreasing at a rate of about 8.23 mm/m from east to west with increasing altitude.Temporally,annual evaporation showed significant upward trends after 1996 at the northeastern(Guaizi Lake)and western(Dingxin)margins,with rates of 132 mm/10a and 105 mm/10a,respectively.Conversely,along the northwestern(Ejina Banner)and southern(Alxa Right Banner)margins of the desert,an evaporation paradox was observed,with annual evaporation trending downward at rates of 162 mm/10a and 187 mm/10a,respectively,especially after 1987.The dominant factors controlling evaporation varied spatially:Average annual temperature and relative humidity influended the western margin(Dingxin),average annual temperature was the key factor for the northeastern margin(Guaizi Lake),and average wind speed was crucial for the northern(Ejina Banner)and southern(Alxa Right Banner)margins.展开更多
Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by ...Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.展开更多
As a potential oil and gas reservoir, reef complexes have been a research focus from petroleum geologists for a long time. There are favorable conditions for the development of reef complexes in the South China Sea; h...As a potential oil and gas reservoir, reef complexes have been a research focus from petroleum geologists for a long time. There are favorable conditions for the development of reef complexes in the South China Sea; however, their internal structures, evolution and distribution are still poorly understood. Based on 2D and 3D seismic data, the internal structures and evolution patterns of the reef complexes on the carbonate platform margin in the deep water areas over the western South China Sea were studied in detail. The result shows that two types of reef complexes, i.e., fault controlling platform margin reef complexes and ramp reef complexes have been developed in the study area. The reef complexes have independent or continuous mound or lenticular seismic reflections, with three internal structures (i.e., aggrading, prograding and retrograding structures). There are different growth rates during the evolution of the reef complexes, resulting in the formation of catch-up reefs, keep-up reefs and quick step reefs. The study also reveals that different platform margin reef complexes have different internal structures and distributions, because of the different platform types. These results may be applied to the exploration and prediction of carbonate platform margin reef complexes in other areas that are similar to the study area.展开更多
The goal of the study was to model water quality impacts of growing perennial grasses on marginal soils. The GLEAMS-NAPRA and RUSLE models were used to simulate long-term surface runoff, percolation, erosion, total ph...The goal of the study was to model water quality impacts of growing perennial grasses on marginal soils. The GLEAMS-NAPRA and RUSLE models were used to simulate long-term surface runoff, percolation, erosion, total phosphorus (TP), and nitrate (NO3-N) losses associated with the production of corn-based bioenergy systems (i.e. conventional tillage corn and corn grain plus stover removal), switchgrass and Miscanthus on three marginal quality soils and one good quality soil in Indiana. Simulations showed that switchgrass and Miscanthus had no effect on annual runoff, but decreased percolation by at least 17%. Results also suggested a potential for reduction in erosion for Miscanthus across the soil types examined when compared to corn-based bioenergy production. The production of switchgrass and Miscanthus did not have significant effects on the simulated TP and NO3-N losses in runoff compared to corn production systems. Nitrates leached from fertilized Miscanthus production were approximately 90% lower than NO3-N leached from the production of fertilized switchgrass and corn systems. Additional studies are needed to better understand the hydrology, erosion and nutrient responses of Miscanthus and switchgrass production to meet bioenergy demands.展开更多
Stable oxygen and hydrogen isotopic compositions(δ^(18)O and δD) of plant xylem water and its potential water sources can provide new information for studying water sources, competitive interactions and water use pa...Stable oxygen and hydrogen isotopic compositions(δ^(18)O and δD) of plant xylem water and its potential water sources can provide new information for studying water sources, competitive interactions and water use patterns of plants. The contributions of different water sources to three plants, Hedysarum scoparium(HS), Caragana Korshinskii(CK) and Artemisia ordosica(AO), were investigated in the artificial sand-fixed vegetation of Shapotou, the southeastern margin of the Tengger Desert of northwestern China, based on meteorological data and δ^(18)O and δD values of precipitation, groundwater, soil water and xylem water of HS, CK and AO. Our results indicated that soil water infiltration through precipitation was the main water source of the artificial sand-fixed vegetation. Obvious differences in soil water content and in δ^(18)O of soil water and xylem water were found among different seasons. No relationship was found between the δ^(18)O in plant xylem water and in soil water in January. The same water use patterns were found in CK, HS and AO in May, suggesting they have the same water sources. The different water sources of CK, HS and AO in August indicate that water competition occurred. In addition, the main water sources of CK, HS and AO in August mainly come from shallow soil water, while they use relatively deep soil water in May. This phenomenon is related to the differences of soil water content throughout soil profile, precipitation, transpiration and water competition under different growth periods. The water use patterns of CK, HS and AO respond to soil water content throughout the soil profile and their competition balance for water uptake during different growth season. The results indicate that these sandfixed plants have developed into a relatively stable stage and they are able to regulate their water use behavior as a response to the environmental conditions, which reinforces the effectiveness of plantation of native shrubs without irrigation in degraded areas.展开更多
The relationships between crustal stretching and thinning,basin structure and petroleum geology in Baiyun deep-water area were analyzed using large area 3D seismic,gravity,magnetic,ocean bottom seismic(OBS),deep-water...The relationships between crustal stretching and thinning,basin structure and petroleum geology in Baiyun deep-water area were analyzed using large area 3D seismic,gravity,magnetic,ocean bottom seismic(OBS),deep-water exploration wells and integrated ocean drilling program(IODP).During the early syn-rifting period,deep-water area was a half-graben controlled by high angle faults influenced by the brittle extension of upper crust.In the mid syn-rifting period,this area was a broad-deep fault depression controlled by detachment faults undergone brittle-ductile deformation and differentiated extension in the crust.In the late syn-rifting period,this area experienced fault-sag transition due to saucer-shaped rheology change dominated by crustal ductile deformation.A broad-deep fault depression controlled by the large detachment faults penetrating through the crust is an important feature of deep-water basin.The study suggests that the broad-deep Baiyun sag provides great accommodation space for the development of massive deltaic-lacustrine deposition system and hydrocarbon source rocks.The differentiated lithospheric thinning also resulted in the different thermal subsidence during post-rifting period,and then controlled the development of continental shelf break and deep-water reservoir sedimentary environment.The high heat flow background caused by the strong thinning of lithosphere and the rise of mantle source resulted in particularities in the reservoir diagenesis,hydrocarbon generation process and accumulation of deep-water area in northern South China Sea.展开更多
Studied waters belong to warm (T=30-50℃), alkaline (pH=8.9-9.3), low mineralized (TDS〈235 mg/l) Na-HCO3 or Na-SO4-HCO3 thermal waters with high content of SiO2 (up to 81 mg/1) and F (up to 3.9 mg/l), occur...Studied waters belong to warm (T=30-50℃), alkaline (pH=8.9-9.3), low mineralized (TDS〈235 mg/l) Na-HCO3 or Na-SO4-HCO3 thermal waters with high content of SiO2 (up to 81 mg/1) and F (up to 3.9 mg/l), occur on modern volcano-tectonic rejuvenated areas of Eastern Sikhote-Alin orogenic belt. Low 3He concentration as well as N2/O2 and N2/Ar ratios exclude influence of deep mantle fluid. New rare earth element data constrain our understanding of water-rock interaction occurring in the water source region. Meteoric origin of waters is proved by stable isotope values varying from -71%o to -136.1‰ and from -10.8‰ to -18.8%o for δ^2H and δ^18O respectively. REE patterns reflect high pH, resultfing from water-rock interaction and oxidative conditions. Calculations of deep aquifer temperature using Na-K and quartz geothermometers show 116.8-131.1℃ and 82.2-125.8℃ respectively. Presence of deep faults both with abnormal thermal gradient (-45- 50 K/km) define unique geochemical shape of thermal waters of Sikhote-Alin, area, where no present volcanic activity is registered.展开更多
The water resource carrying capacity(WRCC)in river basin changes dynamically under climate change,economic development,and technological advancement.Climate change affects hydrological processes and spatial/temporal d...The water resource carrying capacity(WRCC)in river basin changes dynamically under climate change,economic development,and technological advancement.Climate change affects hydrological processes and spatial/temporal distribution of water resources;while economic develo-ment and technological advancement can also affect the balance of water resources systems.Under climate change,economic development,and technological advancement,itis of great significance to explore the dynamic behavior of WRCC in river basins.This will help to alleviate water resources security issues and build a sustainable water resources system.This study was carried out to evaluate the dynamic WRCC using the"climate,economics,and technology-control objective inversion mode",which used total water consumption,water-use efficiency,and restrained total pollutant control in the water functional area as boundary conditions.This study was conducted on the Keriya River Basin,a sub-catchment located in southem margin of the Taklimakan Desert.The WRCC in the Keriya River Basin in 2015 was calculated,and the trends in the short term(2020),middle tem(2030),and long term(2050)were predicted.The results revealed that climate change factors have a positive effect on WRCC in the Keriya River Basin,which leads to an increase in total water resources.Economic and technological development exhibits an overall positive effect,while increasing in water consumption and sewage discharge exhibit a negative effect.展开更多
The Triassic massive sandstone reservoir in the Tahe oilfield has a strong bottom-water drive and is characterized by great burial depth,high temperature and salinity,a thin pay zone,and strong heterogeneity.At presen...The Triassic massive sandstone reservoir in the Tahe oilfield has a strong bottom-water drive and is characterized by great burial depth,high temperature and salinity,a thin pay zone,and strong heterogeneity.At present,the water-cut is high in each block within the reservoir;some wells are at an ultrahigh water-cut stage.A lack of effective measures to control water-cut rise and stabilize oil production have necessitated the application of enhanced oil recovery(EOR)technology.This paper investigates the development and technological advances for oil reservoirs with strong edge/bottom-water drive globally,and compares their application to reservoirs with characteristics similar to the Tahe oilfield.Among the technological advances,gas injection from the top and along the direction of structural dip has been used to optimize the flow field in a typical bottom-water drive reservoir.Bottom-water coning is restrained by gas injection-assisted water control.In addition,increasing the lateral driving pressure differential improves the plane sweep efficiency which enhances oil recovery in turn.Gas injection technology in combination with technological measures like channeling prevention and blocking,and water plugging and profile control,can achieve better results in reservoir development.Gas flooding tests in the Tahe oilfield are of great significance to identifying which EOR technology is the most effective and has the potential of large-scale application for improving development of deep reservoirs with a strong bottomwater drive.展开更多
Conversion of solar energy into H_(2) by photoelectrochemical(PEC)water splitting is recognized as an ideal way to address the growing energy crisis and environmental issues.In a typical PEC cell,the construction of p...Conversion of solar energy into H_(2) by photoelectrochemical(PEC)water splitting is recognized as an ideal way to address the growing energy crisis and environmental issues.In a typical PEC cell,the construction of photoanodes is crucial to guarantee the high efficiency and stability of PEC reactions,which fundamentally rely on rationally designed semiconductors(as the active materials)and substrates(as the current collectors).In this review work,we start with a brief introduction of the roles of substrates in the PEC process.Then,we provide a systematic overview of representative strategies for the controlled fabrication of photoanodes on rationally designed substrates,including conductive glass,metal,sapphire,silicon,silicon carbide,and flexible substrates.Finally,some prospects concerning the challenges and research directions in this area are proposed.展开更多
Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen pro...Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process.However,for hydrogen produced via water electrolysis systems to be utilized in various fields in practice,the unit cost of hydrogen production must be reduced to$1/kg H_(2).To achieve this unit cost,technical targets for water electrolysis have been suggested regarding components in the system.In this paper,the types of water electrolysis systems and the limitations of water electrolysis system components are explained.We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.展开更多
The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.H...The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.展开更多
Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,t...Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,the anion exchange membrane(AEM) water electrolysis has gained intensive attention and is considered as the next-generation emerging technology due to its potential advantages,such as the use of low-cost non-noble metal catalysts,the relatively mature stack assembly process,etc.However,the AEM water electrolyzer is still in the early development stage of the kW-level stack,which is mainly attributed to severe performance decay caused by the core component,i.e.,AEM.Here,the review comprehensively presents the recent progress of advanced AEM from the view of the performance of water electrolysis cells.Herein,fundamental principles and critical components of AEM water electrolyzers are introduced,and work conditions of AEM water electrolyzers and AEM performance improvement strategies are discussed.The challenges and perspectives are also analyzed.展开更多
Due to the dissimilarity among different producing layers,the influences of inter-layer interference on the production performance of a multi-layer gas reservoir are possible.However,systematic studies of inter-layer ...Due to the dissimilarity among different producing layers,the influences of inter-layer interference on the production performance of a multi-layer gas reservoir are possible.However,systematic studies of inter-layer interference for tight gas reservoirs are really limited,especially for those reservoirs in the presence of water.In this work,five types of possible inter-layer interferences,including both absence and presence of water,are identified for commingled production of tight gas reservoirs.Subsequently,a series of reservoir-scale and pore-scale numerical simulations are conducted to quantify the degree of influence of each type of interference.Consistent field evidence from the Yan'an tight gas reservoir(Ordos Basin,China)is found to support the simulation results.Additionally,suggestions are proposed to mitigate the potential inter-layer interferences.The results indicate that,in the absence of water,commingled production is favorable in two situations:when there is a difference in physical properties and when there is a difference in the pressure system of each layer.For reservoirs with a multi-pressure system,the backflow phenomenon,which significantly influences the production performance,only occurs under extreme conditions(such as very low production rates or well shut-in periods).When water is introduced into the multi-layer system,inter-layer interference becomes nearly inevitable.Perforating both the gas-rich layer and water-rich layer for commingled production is not desirable,as it can trigger water invasion from the water-rich layer into the gas-rich layer.The gas-rich layer might also be interfered with by water from the neighboring unperforated water-rich layer,where the water might break the barrier(eg weak joint surface,cement in fractures)between the two layers and migrate into the gas-rich layer.Additionally,the gas-rich layer could possibly be interfered with by water that accumulates at the bottom of the wellbore due to gravitational differentiation during shut-in operations.展开更多
The alpine meadow ecosystem accounts for 27%of the total area of the Tibetan Plateau and is also one of the most important vegetation types.The Dangxiong alpine meadow ecosystem,located in the south-central part of th...The alpine meadow ecosystem accounts for 27%of the total area of the Tibetan Plateau and is also one of the most important vegetation types.The Dangxiong alpine meadow ecosystem,located in the south-central part of the Tibetan Plateau,is a typical example.To understand the carbon and water fluxes,water use efficiency(WUE),and their responses to future climate change for the alpine meadow ecosystem in the Dangxiong area,two parameter estimation methods,the Model-independent Parameter Estimation(PEST)and the Dynamic Dimensions Search(DDS),were used to optimize the Biome-BGC model.Then,the gross primary productivity(GPP)and evapotranspiration(ET)were simulated.The results show that the DDS parameter calibration method has a better performance.The annual GPP and ET show an increasing trend,while the WUE shows a decreasing trend.Meanwhile,ET and GPP reach their peaks in July and August,respectively,and WUE shows a“dual-peak”pattern,reaching peaks in May and November.Furthermore,according to the simulation results for the next nearly 100 years,the ensemble average GPP and ET exhibit a significant increasing trend,and the growth rate under the SSP5–8.5 scenario is greater than that under the SSP2–4.5 scenario.WUE shows an increasing trend under the SSP2–4.5 scenario and a significant increasing trend under the SSP5–8.5 scenario.This study has important scientific significance for carbon and water cycle prediction and vegetation ecological protection on the Tibetan Plateau.展开更多
This study investigates the impact of different water coupling coefficients on the blasting effect of red sandstone.The analysis is based on the theories of detonation wave and elastic wave,focusing on the variation i...This study investigates the impact of different water coupling coefficients on the blasting effect of red sandstone.The analysis is based on the theories of detonation wave and elastic wave,focusing on the variation in wall pressure of the blasting holes.Using DDNP explosive as the explosive load,blasting tests were conducted on red sandstone specimens with four different water coupling coefficients:1.20,1.33,1.50,and 2.00.The study examines the morphologies of the rock specimens after blasting under these different water coupling coefficients.Additionally,the fractal dimensions of the surface cracks resulting from the blasting were calculated to provide a quantitative evaluation of the extent of rock damage.CT scanning and 3D reconstruction were performed on the post-blasting specimens to visually depict the extent of damage and fractures within the rock.Additionally,the volume fractal dimension and damage degree of the post-blasting specimens are calculated.The findings are then combined with numerical simulation to facilitate auxiliary analysis.The results demonstrate that an increase in the water coupling coefficient leads to a reduction in the peak pressure on the hole wall and the crushing zone,enabling more of the explosion energy to be utilized for crack propagation following the explosion.The specimens exhibited distinct failure patterns,resulting in corresponding changes in fractal dimensions.The simulated pore wall pressure–time curve validated the derived theoretical results,whereas the stress cloud map and explosion energy-time curve demonstrated the buffering effect of the water medium.As the water coupling coefficient increases,the buffering effect of the water medium becomes increasingly prominent.展开更多
To investigate the mechanism of rockburst prevention by spraying water onto the surrounding rocks,15 experiments are performed considering different water absorption levels on a single face.High-speed photography and ...To investigate the mechanism of rockburst prevention by spraying water onto the surrounding rocks,15 experiments are performed considering different water absorption levels on a single face.High-speed photography and acoustic emission(AE)system are used to monitor the rockburst process.The effect of water on sandstone rockburst and the prevention mechanism of water on sandstone rockburst are analyzed from the perspective of energy and failure mode.The results show that the higher the ab-sorption degree,the lower the intensity of the rockburst after absorbing water on single side of sand-stone.This is reflected in the fact that with the increase in the water absorption level,the ejection velocity of rockburst fragments is smaller,the depth of the rockburst pit is shallower,and the AE energy is smaller.Under the water absorption level of 100%,the magnitude of rockburst intensity changes from medium to slight.The prevention mechanism of water on sandstone rockburst is that water reduces the capacity of sandstone to store strain energy and accelerates the expansion of shear cracks,which is not conducive to the occurrence of plate cracking before rockburst,and destroys the conditions for rockburst incubation.展开更多
Folklore is an important carrier to show local culture and express people’s emotions in the way of oral transmission.Tradition holds that folklore loses its vitality without oral narration.However,it is difficult to ...Folklore is an important carrier to show local culture and express people’s emotions in the way of oral transmission.Tradition holds that folklore loses its vitality without oral narration.However,it is difficult to find the traditional context of telling and disseminating folklore only by word of mouth.More often,under the impetus of multiple contexts and different forces,folklore in multiple media is widely spread through mutual reference and integration.The current situation of the water Margin theory circulating in Liangshan area is enough to illustrate this point.Water Margin has a very long history of inheritance,from government officials to ordinary people,under the influence of different media,dissemination and inheritance,become a rich local cultural capital.In the current social development context,the spread of the outlaws of the Marsh is no longer a simple word of mouth.The emergence of high-tech means such as Television and the Internet,as well as the promotion of cultural tourism,has reconstructed the legend of the contemporary water Margin figures.In the process of the reconstruction of the local legend of the water margin in Liangshan,the joint efforts of national forces and market factors have promoted the blending and exchange of three different levels of literature,such as elite literature dominated by the legend of the water margin,popular literature represented by folk quyi and folk literature spread orally by the general public,forming a communication situation of mutual learning,mutual tolerance and interaction between elegance and customs.展开更多
Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic...Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water electrolysis.Ni_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal network.Here,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water electrocatalysis.Herein,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are discussed.The challenges and perspectives are also analyzed.展开更多
基金supported by the National Natural Science Foundation of China(42161007)the Scientific Research Program for Higher Education Institutions of Gansu Province(2021B-081)the Natural Science Foundation of Gansu Province(22JR5RA074).
文摘The isotope composition in precipitation has been widely considered as a tracer of monsoon activity.Compared with the coastal region,the monsoon margin usually has limited precipitation with large fluctuation and is usually sensitive to climate change.The water resource management in the monsoon margin should be better planned by understanding the composition of precipitation isotope and its influencing factors.In this study,the precipitation samples were collected at five sampling sites(Baiyin City,Kongtong District,Maqu County,Wudu District,and Yinchuan City)of the monsoon margin in the northwest of China in 2022 to analyze the characteristics of stable hydrogen(δD)and oxygen(δ18O)isotopes.We analyzed the impact of meteorological factors(temperature,precipitation,and relative humidity)on the composition of precipitation isotope at daily level by regression analysis,utilized the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)-based backward trajectory model to simulate the air mass trajectory of precipitation events,and adopted the potential source contribution function(PSCF)and concentration weighted trajectory(CWT)to analyze the water vapor sources.The results showed that compared with the global meteoric water line(GMWL),the slope of the local meteoric water line(LMWL;δD=7.34δ^(18)O-1.16)was lower,indicating the existence of strong regional evaporation in the study area.Temperature significantly contributed toδ18O value,while relative humidity had a significant negative effect onδ18O value.Through the backward trajectory analysis,we found eight primary locations that were responsible for the water vapor sources of precipitation in the study area,of which moisture from the Indian Ocean to South China Sea(ITSC)and the western continental(CW)had the greatest influence on precipitation in the study area.The hydrogen and oxygen isotopes in precipitation are significantly influenced by the sources and transportation paths of air mass.In addition,the results of PSCF and CWT analysis showed that the water vapor source areas were primarily distributed in the south and northwest direction of the study area.
基金supported by the Natural Science Foundation of Hebei Province(D202450411)the Basic Research Programme of Chinese Academy of Geological Sciences(CAGS)(YK202302).
文摘Based on meteorological data collected over nearly 60 years(1960-2017)from four national meteorological stations along the margins of the Badain Jaran Desert,this study analyzed the spatiotemporal variations in evaporation from water surfaces and identified the dominant controlling factors.Methods used included linear trend analysis,linear tendency estimation,the departure method,the rank correlation coefficient-based method,and Multiple Linear Regression(MLR).Results indicate notable spatiotemporal differences in evaporation distribution and evolution.Spatially,average annual evaporation exhibited a pronounced altitude effect,decreasing at a rate of about 8.23 mm/m from east to west with increasing altitude.Temporally,annual evaporation showed significant upward trends after 1996 at the northeastern(Guaizi Lake)and western(Dingxin)margins,with rates of 132 mm/10a and 105 mm/10a,respectively.Conversely,along the northwestern(Ejina Banner)and southern(Alxa Right Banner)margins of the desert,an evaporation paradox was observed,with annual evaporation trending downward at rates of 162 mm/10a and 187 mm/10a,respectively,especially after 1987.The dominant factors controlling evaporation varied spatially:Average annual temperature and relative humidity influended the western margin(Dingxin),average annual temperature was the key factor for the northeastern margin(Guaizi Lake),and average wind speed was crucial for the northern(Ejina Banner)and southern(Alxa Right Banner)margins.
基金support from the Czech Science Foundation,project EXPRO,No 19-27454Xsupport by the European Union under the REFRESH—Research Excellence For Region Sustainability and High-tech Industries project number CZ.10.03.01/00/22_003/0000048 via the Operational Programme Just Transition from the Ministry of the Environment of the Czech Republic+1 种基金Horizon Europe project EIC Pathfinder Open 2023,“GlaS-A-Fuels”(No.101130717)supported from ERDF/ESF,project TECHSCALE No.CZ.02.01.01/00/22_008/0004587).
文摘Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.
基金The National Science and Technology Major Project of China under contract No.2011ZX05025-002-02the National Natural Science Foundation of China under contract No.41202086+3 种基金the National Natural Science Foundation of China under contract No.41102068China Postdoctoral Science Special Fund under contract No.201003654the Special Fund for Basic Scientific Research of Central Colleges,China University of Geosciences(Wuhan)under contract No.CUGL100252the Young Scholars Development Fund of SWPU under contract No.201599010078
文摘As a potential oil and gas reservoir, reef complexes have been a research focus from petroleum geologists for a long time. There are favorable conditions for the development of reef complexes in the South China Sea; however, their internal structures, evolution and distribution are still poorly understood. Based on 2D and 3D seismic data, the internal structures and evolution patterns of the reef complexes on the carbonate platform margin in the deep water areas over the western South China Sea were studied in detail. The result shows that two types of reef complexes, i.e., fault controlling platform margin reef complexes and ramp reef complexes have been developed in the study area. The reef complexes have independent or continuous mound or lenticular seismic reflections, with three internal structures (i.e., aggrading, prograding and retrograding structures). There are different growth rates during the evolution of the reef complexes, resulting in the formation of catch-up reefs, keep-up reefs and quick step reefs. The study also reveals that different platform margin reef complexes have different internal structures and distributions, because of the different platform types. These results may be applied to the exploration and prediction of carbonate platform margin reef complexes in other areas that are similar to the study area.
文摘The goal of the study was to model water quality impacts of growing perennial grasses on marginal soils. The GLEAMS-NAPRA and RUSLE models were used to simulate long-term surface runoff, percolation, erosion, total phosphorus (TP), and nitrate (NO3-N) losses associated with the production of corn-based bioenergy systems (i.e. conventional tillage corn and corn grain plus stover removal), switchgrass and Miscanthus on three marginal quality soils and one good quality soil in Indiana. Simulations showed that switchgrass and Miscanthus had no effect on annual runoff, but decreased percolation by at least 17%. Results also suggested a potential for reduction in erosion for Miscanthus across the soil types examined when compared to corn-based bioenergy production. The production of switchgrass and Miscanthus did not have significant effects on the simulated TP and NO3-N losses in runoff compared to corn production systems. Nitrates leached from fertilized Miscanthus production were approximately 90% lower than NO3-N leached from the production of fertilized switchgrass and corn systems. Additional studies are needed to better understand the hydrology, erosion and nutrient responses of Miscanthus and switchgrass production to meet bioenergy demands.
基金supported by the National Science Foundation China (Grants No. 41771028 and 41571025)the Key Laboratory of Agricultural Water Resources, the Chinese Academy of Sciences (Grants No. KFKT201606)the Shaanxi province natural science foundation research project (Grants No. 2016JM4006)
文摘Stable oxygen and hydrogen isotopic compositions(δ^(18)O and δD) of plant xylem water and its potential water sources can provide new information for studying water sources, competitive interactions and water use patterns of plants. The contributions of different water sources to three plants, Hedysarum scoparium(HS), Caragana Korshinskii(CK) and Artemisia ordosica(AO), were investigated in the artificial sand-fixed vegetation of Shapotou, the southeastern margin of the Tengger Desert of northwestern China, based on meteorological data and δ^(18)O and δD values of precipitation, groundwater, soil water and xylem water of HS, CK and AO. Our results indicated that soil water infiltration through precipitation was the main water source of the artificial sand-fixed vegetation. Obvious differences in soil water content and in δ^(18)O of soil water and xylem water were found among different seasons. No relationship was found between the δ^(18)O in plant xylem water and in soil water in January. The same water use patterns were found in CK, HS and AO in May, suggesting they have the same water sources. The different water sources of CK, HS and AO in August indicate that water competition occurred. In addition, the main water sources of CK, HS and AO in August mainly come from shallow soil water, while they use relatively deep soil water in May. This phenomenon is related to the differences of soil water content throughout soil profile, precipitation, transpiration and water competition under different growth periods. The water use patterns of CK, HS and AO respond to soil water content throughout the soil profile and their competition balance for water uptake during different growth season. The results indicate that these sandfixed plants have developed into a relatively stable stage and they are able to regulate their water use behavior as a response to the environmental conditions, which reinforces the effectiveness of plantation of native shrubs without irrigation in degraded areas.
基金Supported by the Science and Technology Project of CNOOC Ltd.(YXKY-2012-SHENHAI-01)China National Science and Technology Major Project(2011ZX05025-003+1 种基金 2016ZX05026-003)the National Natural Science Foundation of China(91128207)
文摘The relationships between crustal stretching and thinning,basin structure and petroleum geology in Baiyun deep-water area were analyzed using large area 3D seismic,gravity,magnetic,ocean bottom seismic(OBS),deep-water exploration wells and integrated ocean drilling program(IODP).During the early syn-rifting period,deep-water area was a half-graben controlled by high angle faults influenced by the brittle extension of upper crust.In the mid syn-rifting period,this area was a broad-deep fault depression controlled by detachment faults undergone brittle-ductile deformation and differentiated extension in the crust.In the late syn-rifting period,this area experienced fault-sag transition due to saucer-shaped rheology change dominated by crustal ductile deformation.A broad-deep fault depression controlled by the large detachment faults penetrating through the crust is an important feature of deep-water basin.The study suggests that the broad-deep Baiyun sag provides great accommodation space for the development of massive deltaic-lacustrine deposition system and hydrocarbon source rocks.The differentiated lithospheric thinning also resulted in the different thermal subsidence during post-rifting period,and then controlled the development of continental shelf break and deep-water reservoir sedimentary environment.The high heat flow background caused by the strong thinning of lithosphere and the rise of mantle source resulted in particularities in the reservoir diagenesis,hydrocarbon generation process and accumulation of deep-water area in northern South China Sea.
文摘Studied waters belong to warm (T=30-50℃), alkaline (pH=8.9-9.3), low mineralized (TDS〈235 mg/l) Na-HCO3 or Na-SO4-HCO3 thermal waters with high content of SiO2 (up to 81 mg/1) and F (up to 3.9 mg/l), occur on modern volcano-tectonic rejuvenated areas of Eastern Sikhote-Alin orogenic belt. Low 3He concentration as well as N2/O2 and N2/Ar ratios exclude influence of deep mantle fluid. New rare earth element data constrain our understanding of water-rock interaction occurring in the water source region. Meteoric origin of waters is proved by stable isotope values varying from -71%o to -136.1‰ and from -10.8‰ to -18.8%o for δ^2H and δ^18O respectively. REE patterns reflect high pH, resultfing from water-rock interaction and oxidative conditions. Calculations of deep aquifer temperature using Na-K and quartz geothermometers show 116.8-131.1℃ and 82.2-125.8℃ respectively. Presence of deep faults both with abnormal thermal gradient (-45- 50 K/km) define unique geochemical shape of thermal waters of Sikhote-Alin, area, where no present volcanic activity is registered.
文摘The water resource carrying capacity(WRCC)in river basin changes dynamically under climate change,economic development,and technological advancement.Climate change affects hydrological processes and spatial/temporal distribution of water resources;while economic develo-ment and technological advancement can also affect the balance of water resources systems.Under climate change,economic development,and technological advancement,itis of great significance to explore the dynamic behavior of WRCC in river basins.This will help to alleviate water resources security issues and build a sustainable water resources system.This study was carried out to evaluate the dynamic WRCC using the"climate,economics,and technology-control objective inversion mode",which used total water consumption,water-use efficiency,and restrained total pollutant control in the water functional area as boundary conditions.This study was conducted on the Keriya River Basin,a sub-catchment located in southem margin of the Taklimakan Desert.The WRCC in the Keriya River Basin in 2015 was calculated,and the trends in the short term(2020),middle tem(2030),and long term(2050)were predicted.The results revealed that climate change factors have a positive effect on WRCC in the Keriya River Basin,which leads to an increase in total water resources.Economic and technological development exhibits an overall positive effect,while increasing in water consumption and sewage discharge exhibit a negative effect.
文摘The Triassic massive sandstone reservoir in the Tahe oilfield has a strong bottom-water drive and is characterized by great burial depth,high temperature and salinity,a thin pay zone,and strong heterogeneity.At present,the water-cut is high in each block within the reservoir;some wells are at an ultrahigh water-cut stage.A lack of effective measures to control water-cut rise and stabilize oil production have necessitated the application of enhanced oil recovery(EOR)technology.This paper investigates the development and technological advances for oil reservoirs with strong edge/bottom-water drive globally,and compares their application to reservoirs with characteristics similar to the Tahe oilfield.Among the technological advances,gas injection from the top and along the direction of structural dip has been used to optimize the flow field in a typical bottom-water drive reservoir.Bottom-water coning is restrained by gas injection-assisted water control.In addition,increasing the lateral driving pressure differential improves the plane sweep efficiency which enhances oil recovery in turn.Gas injection technology in combination with technological measures like channeling prevention and blocking,and water plugging and profile control,can achieve better results in reservoir development.Gas flooding tests in the Tahe oilfield are of great significance to identifying which EOR technology is the most effective and has the potential of large-scale application for improving development of deep reservoirs with a strong bottomwater drive.
基金Natural Science Foundation of Zhejiang Province,Grant/Award Number:LY23E020002National Natural Science Foundation of China,Grant/Award Number:52272085 and 51972178+1 种基金Natural Science Foundation of Ningbo,Grant/Award Number:2021J145China Postdoctoral Science Foundation,Grant/Award Number:2020M681966。
文摘Conversion of solar energy into H_(2) by photoelectrochemical(PEC)water splitting is recognized as an ideal way to address the growing energy crisis and environmental issues.In a typical PEC cell,the construction of photoanodes is crucial to guarantee the high efficiency and stability of PEC reactions,which fundamentally rely on rationally designed semiconductors(as the active materials)and substrates(as the current collectors).In this review work,we start with a brief introduction of the roles of substrates in the PEC process.Then,we provide a systematic overview of representative strategies for the controlled fabrication of photoanodes on rationally designed substrates,including conductive glass,metal,sapphire,silicon,silicon carbide,and flexible substrates.Finally,some prospects concerning the challenges and research directions in this area are proposed.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20213030040590)the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(NRF-2021K1A4A8A01079455)。
文摘Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process.However,for hydrogen produced via water electrolysis systems to be utilized in various fields in practice,the unit cost of hydrogen production must be reduced to$1/kg H_(2).To achieve this unit cost,technical targets for water electrolysis have been suggested regarding components in the system.In this paper,the types of water electrolysis systems and the limitations of water electrolysis system components are explained.We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.
基金financial support of the National Natural Science Foundation of China(U21A20218 and 32101857)the‘Double First-Class’Key Scientific Research Project of Education Department in Gansu Province,China(GSSYLXM-02)+1 种基金the Fuxi Young Talents Fund of Gansu Agricultural University,China(Gaufx03Y10)the“Innovation Star”Program of Graduate Students in 2023 of Gansu Province,China(2023CXZX681)。
文摘The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.
基金supported by the National Key Research and Development Program(2022YFB4202200)the Fundamental Research Funds for the Central Universities and sponsored by Shanghai Pujiang Program(22PJ1413100)。
文摘Green hydrogen produced by water electrolysis combined with renewable energy is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.Among water electrolysis technologies,the anion exchange membrane(AEM) water electrolysis has gained intensive attention and is considered as the next-generation emerging technology due to its potential advantages,such as the use of low-cost non-noble metal catalysts,the relatively mature stack assembly process,etc.However,the AEM water electrolyzer is still in the early development stage of the kW-level stack,which is mainly attributed to severe performance decay caused by the core component,i.e.,AEM.Here,the review comprehensively presents the recent progress of advanced AEM from the view of the performance of water electrolysis cells.Herein,fundamental principles and critical components of AEM water electrolyzers are introduced,and work conditions of AEM water electrolyzers and AEM performance improvement strategies are discussed.The challenges and perspectives are also analyzed.
基金supported by the National Natural Science Foundation of China(Grant Nos.52304044,52222402,52234003,52174036)Sichuan Science and Technology Program(Nos.2022JDJQ0009,2023NSFSC0934)+2 种基金Key Technology R&D Program of Shaanxi Province(2023-YBGY-30)the Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(Grant No.2020CX030202)the China Postdoctoral Science Foundation(Grant No.2022M722638)。
文摘Due to the dissimilarity among different producing layers,the influences of inter-layer interference on the production performance of a multi-layer gas reservoir are possible.However,systematic studies of inter-layer interference for tight gas reservoirs are really limited,especially for those reservoirs in the presence of water.In this work,five types of possible inter-layer interferences,including both absence and presence of water,are identified for commingled production of tight gas reservoirs.Subsequently,a series of reservoir-scale and pore-scale numerical simulations are conducted to quantify the degree of influence of each type of interference.Consistent field evidence from the Yan'an tight gas reservoir(Ordos Basin,China)is found to support the simulation results.Additionally,suggestions are proposed to mitigate the potential inter-layer interferences.The results indicate that,in the absence of water,commingled production is favorable in two situations:when there is a difference in physical properties and when there is a difference in the pressure system of each layer.For reservoirs with a multi-pressure system,the backflow phenomenon,which significantly influences the production performance,only occurs under extreme conditions(such as very low production rates or well shut-in periods).When water is introduced into the multi-layer system,inter-layer interference becomes nearly inevitable.Perforating both the gas-rich layer and water-rich layer for commingled production is not desirable,as it can trigger water invasion from the water-rich layer into the gas-rich layer.The gas-rich layer might also be interfered with by water from the neighboring unperforated water-rich layer,where the water might break the barrier(eg weak joint surface,cement in fractures)between the two layers and migrate into the gas-rich layer.Additionally,the gas-rich layer could possibly be interfered with by water that accumulates at the bottom of the wellbore due to gravitational differentiation during shut-in operations.
基金supported by the Second Comprehensive Scientific Research Survey on the Tibetan Plateau[grant number 2019QZKK0103]the National Natural Science Foundation of China[grant numbers 42375071 and 42230610].
文摘The alpine meadow ecosystem accounts for 27%of the total area of the Tibetan Plateau and is also one of the most important vegetation types.The Dangxiong alpine meadow ecosystem,located in the south-central part of the Tibetan Plateau,is a typical example.To understand the carbon and water fluxes,water use efficiency(WUE),and their responses to future climate change for the alpine meadow ecosystem in the Dangxiong area,two parameter estimation methods,the Model-independent Parameter Estimation(PEST)and the Dynamic Dimensions Search(DDS),were used to optimize the Biome-BGC model.Then,the gross primary productivity(GPP)and evapotranspiration(ET)were simulated.The results show that the DDS parameter calibration method has a better performance.The annual GPP and ET show an increasing trend,while the WUE shows a decreasing trend.Meanwhile,ET and GPP reach their peaks in July and August,respectively,and WUE shows a“dual-peak”pattern,reaching peaks in May and November.Furthermore,according to the simulation results for the next nearly 100 years,the ensemble average GPP and ET exhibit a significant increasing trend,and the growth rate under the SSP5–8.5 scenario is greater than that under the SSP2–4.5 scenario.WUE shows an increasing trend under the SSP2–4.5 scenario and a significant increasing trend under the SSP5–8.5 scenario.This study has important scientific significance for carbon and water cycle prediction and vegetation ecological protection on the Tibetan Plateau.
基金National Key Research and Development Program of China(2021YFC2902103)National Natural Science Foundation of China(51934001)Fundamental Research Funds for the Central Universities(2023JCCXLJ02).
文摘This study investigates the impact of different water coupling coefficients on the blasting effect of red sandstone.The analysis is based on the theories of detonation wave and elastic wave,focusing on the variation in wall pressure of the blasting holes.Using DDNP explosive as the explosive load,blasting tests were conducted on red sandstone specimens with four different water coupling coefficients:1.20,1.33,1.50,and 2.00.The study examines the morphologies of the rock specimens after blasting under these different water coupling coefficients.Additionally,the fractal dimensions of the surface cracks resulting from the blasting were calculated to provide a quantitative evaluation of the extent of rock damage.CT scanning and 3D reconstruction were performed on the post-blasting specimens to visually depict the extent of damage and fractures within the rock.Additionally,the volume fractal dimension and damage degree of the post-blasting specimens are calculated.The findings are then combined with numerical simulation to facilitate auxiliary analysis.The results demonstrate that an increase in the water coupling coefficient leads to a reduction in the peak pressure on the hole wall and the crushing zone,enabling more of the explosion energy to be utilized for crack propagation following the explosion.The specimens exhibited distinct failure patterns,resulting in corresponding changes in fractal dimensions.The simulated pore wall pressure–time curve validated the derived theoretical results,whereas the stress cloud map and explosion energy-time curve demonstrated the buffering effect of the water medium.As the water coupling coefficient increases,the buffering effect of the water medium becomes increasingly prominent.
基金The financial support from the National Natural Science Foun-dation of China(Grant Nos.52074299 and 41941018)the Fundamental Research Funds for the Central Universities of China(Grant No.2023JCCXSB02)are gratefully acknowledged.
文摘To investigate the mechanism of rockburst prevention by spraying water onto the surrounding rocks,15 experiments are performed considering different water absorption levels on a single face.High-speed photography and acoustic emission(AE)system are used to monitor the rockburst process.The effect of water on sandstone rockburst and the prevention mechanism of water on sandstone rockburst are analyzed from the perspective of energy and failure mode.The results show that the higher the ab-sorption degree,the lower the intensity of the rockburst after absorbing water on single side of sand-stone.This is reflected in the fact that with the increase in the water absorption level,the ejection velocity of rockburst fragments is smaller,the depth of the rockburst pit is shallower,and the AE energy is smaller.Under the water absorption level of 100%,the magnitude of rockburst intensity changes from medium to slight.The prevention mechanism of water on sandstone rockburst is that water reduces the capacity of sandstone to store strain energy and accelerates the expansion of shear cracks,which is not conducive to the occurrence of plate cracking before rockburst,and destroys the conditions for rockburst incubation.
文摘Folklore is an important carrier to show local culture and express people’s emotions in the way of oral transmission.Tradition holds that folklore loses its vitality without oral narration.However,it is difficult to find the traditional context of telling and disseminating folklore only by word of mouth.More often,under the impetus of multiple contexts and different forces,folklore in multiple media is widely spread through mutual reference and integration.The current situation of the water Margin theory circulating in Liangshan area is enough to illustrate this point.Water Margin has a very long history of inheritance,from government officials to ordinary people,under the influence of different media,dissemination and inheritance,become a rich local cultural capital.In the current social development context,the spread of the outlaws of the Marsh is no longer a simple word of mouth.The emergence of high-tech means such as Television and the Internet,as well as the promotion of cultural tourism,has reconstructed the legend of the contemporary water Margin figures.In the process of the reconstruction of the local legend of the water margin in Liangshan,the joint efforts of national forces and market factors have promoted the blending and exchange of three different levels of literature,such as elite literature dominated by the legend of the water margin,popular literature represented by folk quyi and folk literature spread orally by the general public,forming a communication situation of mutual learning,mutual tolerance and interaction between elegance and customs.
基金supported by the National Key Research and Development Program(No.2022YFB4202200)the Fundamental Research Funds for the Central Universities.
文摘Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water electrolysis.Ni_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal network.Here,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water electrocatalysis.Herein,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are discussed.The challenges and perspectives are also analyzed.