Changes in metal concentrations in the litter of Potamogeton crispus were monitored during a consecutive 40-day in situ decomposition experiment using the litterbag method.The accumulation index was calculated and use...Changes in metal concentrations in the litter of Potamogeton crispus were monitored during a consecutive 40-day in situ decomposition experiment using the litterbag method.The accumulation index was calculated and used to indicate the changes in the metals in litter.The results showed that the concentrations of Al,Cd,Cr,Fe,Mn,and Pb in litter increased significantly during the decomposition,while Cu and Zn concentrations decreased dramatically.Significant positive correlations were found between the concentrations of Al,Cr,Fe,and Mn and between Cu and Zn.Moreover,Cu and Zn both negatively correlated with Al and Fe.The remaining dry mass was negatively correlated with Al and Fe concentrations but positively correlated with Cu and Zn concentrations.Generally the accumulation index values of metals other than Al were less than one,indicating that the litter of P.crispus acted as a source of metals to the surrounding water body.Al was the only metal that showed continuous net accumulation in litter.The net accumulation of Fe and Mn in litter during the last 10 days of the experiment may indicate the precipitation of Feand Mn-oxides.It was estimated that 160 g/m^2（dry weight）P.crispus was decomposed in40 days.This was equivalent to releasing the following amounts of metals：0.01 mg Cd,0.03 mg Cr,0.71 mg Cu,0.55 mg Mn,0.02 mg Pb and 13.8 mg Zn into surrounding water,and accumulating 149 mg Al and 11 mg Fe,in a 1 m^2 area.展开更多
Encapsulation of water-soluble cargoes in millimeter-sized capsules has enabled major advances in various fields,including pharmaceuticals,food,cosmetics,packaging,and materials.However,because of the lack of fabricat...Encapsulation of water-soluble cargoes in millimeter-sized capsules has enabled major advances in various fields,including pharmaceuticals,food,cosmetics,packaging,and materials.However,because of the lack of fabrication precision,low cargo retention,suboptimal mechanical properties,and difficulty in preventing water evaporation,this technique is more challenging than microencapsulation techniques.In this study,we developed a surfactant-free and organic solvent-free water-in-oil in-air emulsification approach for synthesizing double-layered“milli-capsules”for the precise encapsulation,enhanced retention,and force-triggered burst release of water-soluble bioactive cargoes.In particular,we synthesized milli-capsules with a first shell of poly(ethylene glycol dimethacrylate)for the efficient encapsulation of bioactive cargoes and a second shell of beeswax to prolong the retention of the entrapped bioactive compounds.Unlike traditional milli-capsules,which exhibit poor shape uniformity and mechanical stability,we introduced metallic ions to stabilize the interfacial tension and employed constant rotation to balance the gravity,buoyancy,inertial,and viscous forces imposed on the droplets,resulting in uniform and rigid milli-capsules with narrow rupture forces.Furthermore,additional hydrophobic beeswax coating prevented water volatilization and substantially prolonged the shelf life of the encapsulated compounds from a few days to a few months while maintaining their bioactivities.The proposed milli-capsule system addresses the challenge of precise fabrication of large carriers for water-soluble cargoes,representing a significant step toward the long-term storage and controlled release of bioactive cargoes for various industrial applications.展开更多
The establishment of plantations has become a critical approach for reducing greenhouse gas emissions,particularly in fragile environments with carbon sequestration potential.In karst areas,plantations based on fastgr...The establishment of plantations has become a critical approach for reducing greenhouse gas emissions,particularly in fragile environments with carbon sequestration potential.In karst areas,plantations based on fastgrowing afforestation species made significant contributions to enhancing carbon sequestration.However,the impact of understory vegetation on carbon accumulation remains unclear.Especially,the carbon accumulation associated with litter produced during the replacement of understory species receives insufficient attention,which leads to the neglect of the carbon sequestration potential in plantations of karst areas.Leaf is a crucial organ that links the litter production.To explore how leaf traits adapt to competitive environments and drive litter carbon accumulation during understory species replacement,this study observed leaf traits and litter carbon content changes in three types of plantations in the Liujiang River Basin,a typical karst area.A total of 37 sampling plots were selected for field investigation over a twoyear period.Leaf traits,species diversity,vegetation coverage,and litter carbon characteristics in understory vegetation were measured.Variance analysis,allometric equations,and path analysis were used for data analysis.The results showed that most understory species adopted a biomass conservation strategy under high-coverage conditions(>44.27%)and expanded competitive leaf area under low-coverage conditions(<44.27%).However,Bidens pilosa and Miscanthus floridulus exhibited strong competitiveness during understory species replacement.They showed an expansion of competitive leaf area under high-coverage conditions.This competitive strategy reduced species diversity and community specific leaf area.But the rapid expansion of Bidens pilosa and Miscanthus floridulus increased understory vegetation coverage,and their increased specific leaf area facilitated leaf shedding,resulting in significant litter weight accumulation(P<0.05),thereby enhancing litter carbon content per unit area.These competitive strategies were key driving factors for the increase in litter carbon content per square meter,which reached a maximum of 49.6% higher than that in natural grasslands.And the maximum increase in litter carbon accumulation derived from understory vegetation reached 3.37 times from 2023 to 2024 in plantations.In the understory vegetation of plantations,the competitive strategies reflected by leaf adaptation of key competitive species are critical factors influencing litter carbon accumulation.Future research could deeply explore the carbon sequestration effects resulting from the dynamic changes in competition within the understory vegetation of plantations.展开更多
Highlights OsCAX2 is localized to tonoplast,and cadmium induces its expression.OsCAX2 overexpression reduces cadmium concentration in indica rice grains by 49.1%.Cadmium(Cd)exposure poses significant health risks to h...Highlights OsCAX2 is localized to tonoplast,and cadmium induces its expression.OsCAX2 overexpression reduces cadmium concentration in indica rice grains by 49.1%.Cadmium(Cd)exposure poses significant health risks to humans,and the International Agency for Research on Cancer has classified it as a Group I carcinogen.Cadmium undergoes minimal metabolism in the human body;consequently,prolonged Cd^(2+)exposure can cause severe damage to multiple organs including the liver,kidneys,lungs,bones,and immune system(Shao et al.2024).Rice,one of the three global staple crops,and Cd exposure in humans primarily occurs the consumption of contaminated rice grains.The contribution of rice to the total dietary Cd intake is over 50% for non-smoking Asian populations(Chen et al.2018;Shi et al.2020).展开更多
Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or ...Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.展开更多
Rapidly improving infertile croplands and enhancing their soil organic carbon(SOC)pool necessitate substantial organic materials incorporation.Converting loose crop straw into granulated form facilitates uniform incor...Rapidly improving infertile croplands and enhancing their soil organic carbon(SOC)pool necessitate substantial organic materials incorporation.Converting loose crop straw into granulated form facilitates uniform incorporation within the plough soil layer.As an innovative soil amelioration approach,the efficiency and patterns of SOC accumulation remain unclear.Two field experiments were conducted in infertile subtropical upland and paddy soils with 0,30,60,and 90 Mg ha^(-1)granulated straw incorporation.After one year,SOC accumulation efficiency from straw input remained stable in upland(30.8–37.5%)with increasing amounts of straw incorporation,while declined from 60.0 to 38.3%in paddy.In both croplands,the contributions of lignin phenols to SOC increased with increasing straw incorporation,while the contributions from amino sugars remained constant at higher straw input levels.Subsequently,the ratios of lignin phenols to amino sugars increased with increasing straw incorporation,indicating faster plant residue accumulation compared to microbial necromass,as the granulation approach limited microbial involvement in straw transformation.Thus,single-time incorporation of substantial granulated straw presents an effective agricultural strategy for rapid amelioration of infertile croplands.展开更多
This study is dedicated to numerically investigate the dynamic behavior of a missile released from a helicopter under the influence of downwash from the rotating rotors using AGM-114 Hellfire and UH-60 as the testcase...This study is dedicated to numerically investigate the dynamic behavior of a missile released from a helicopter under the influence of downwash from the rotating rotors using AGM-114 Hellfire and UH-60 as the testcase.Simulations are conducted using unsteady Reynolds-averaged Navier-Stokes(URANS)with shear stress transport(SST)k-ωturbulence model,incorporating six-degree-of-freedom(6-DOF)motion and overset grid.Two releasing scenarios,viz.,hover and forward flight,are analyzed under varying missile launch thrust and helicopter forward flight speed.Results reveal that the rotor downwash significantly affects the stability of the missile,particularly during hovering case,where low thrust prolongs wake interaction.In forward flight,the increased airspeed can in principle reduce wake influence but introduces asymmetrical aerodynamic effects on the trajectory of the missile.The findings offer guidance for missile release and launch planning in rotorcraft operations.展开更多
Accumulation and releasing of trace metal elements on aluminum containing sediments of inner drinking water pipe is discussed,as studied from five variations effecting:raw water quality,chemical reagents,solution pH a...Accumulation and releasing of trace metal elements on aluminum containing sediments of inner drinking water pipe is discussed,as studied from five variations effecting:raw water quality,chemical reagents,solution pH and drinking water flow condition.In order to decrease the release of trace metal elements,and to ensure the pipe operation and human safety,water quality adjustment is suggested to avoid aluminum containing sediments formation in drinking distribution system.The maximum amounts of accumulation of common trace metal elements are given.Future trends of development in this field are also proposed.展开更多
[Objectives]This study was conducted to investigate the effects of slow-release nitrogen fertilizer on dry matter accumulation and translocation of summer maize.[Methods]With Zhoudan 9 as the test variety,six differen...[Objectives]This study was conducted to investigate the effects of slow-release nitrogen fertilizer on dry matter accumulation and translocation of summer maize.[Methods]With Zhoudan 9 as the test variety,six different treatment were set up:blank control(CK1),slow-release urea 75 kg/hm^(2)(C1),slow-release urea 150 kg/hm^(2)(C2),slow-release urea 225 kg/hm^(2)(C3),slow-release urea 300 kg/hm^(2)(C4)and ordinary urea 300 kg/hm^(2)(CK2),to study the change law of dry matter accumulation and translocation in summer maize.[Results]Treatment slow-release urea 225 kg/hm^(2)(C4)showed summer maize yield,dry matter translocation between organs,grain contribution rate and proportion of grain dry matter in the full ripe stage higher than other treatments.Considering the weight loss and cost factors,slow-release urea 225 kg/hm^(2)(C3)could be recommended as the fertilizing amount for summer maize.[Conclusions]This study provides theoretical reference for rational selection of fertilizers for reducing fertilizer application and increasing fertilizer efficiency,and for production of summer maize in Shajiang black soil region.展开更多
In this study,phosphonate-terminated magnetic mesoporous nanoparticles(pMMSNs)was designed by incorporation of MNPs in the center of mesoporous silica nanoparticles(MSNs)and followed by grafting phosphonate group on t...In this study,phosphonate-terminated magnetic mesoporous nanoparticles(pMMSNs)was designed by incorporation of MNPs in the center of mesoporous silica nanoparticles(MSNs)and followed by grafting phosphonate group on to the surface of MMSNs.The carrier exhibited a typical superparamagnetic feature and the saturation magnetization was 4.89 emu/g measured by vibrating sample magnetometer(VSM).pMMSNs had a spherical morphology and a pore size of 2.2 nm.FromN2 adsorption-desorption analysis,pMMSNs had a surface area of 613.4 m^(2)/g and a pore volume of 0.78 cm^(3)/g.Phosphonate modification improved the colloidal stability of MMSNs,and the hydrodynamic diameter of pMMSNs was around 175 nm.The hydrophilic phosphonate group significantly enhanced the negative surface charge of MMSNs from-19.3 mV to-28.8 mV pMMSNs with more negative surface charge had a 2.3-fold higher drug loading capacity than that of MMSNs.In addition,the rate and amount of release of doxorubicin(DOX)from DOX/pMMSNs was pH-dependent and increased with the decrease of pH.At pH 7.4,the release amount was quite low and only approximately 17wt%ofDOXwasreleasedin48h.AtpH5.0and3.0,the release rate increased significantly and the release amount achieved 31 wt%and 60 wt%in 48 h,respectively.To evaluate the magnetic targeting performance ofpMMSNs,FITC labeledpMMSNswas injected into mice bearing S180 solid tumor.FITC labeledpMMSNscontrolled by an external magnetic field showed higher tumor accumulation and lower normal tissue distribution.展开更多
Comparative analysis between the quantitative data of active faults and seismicity reveals that a complete earthquake recurrence cycle includes the characteristic earthquake and the sub-maxima earthquakes in-between. ...Comparative analysis between the quantitative data of active faults and seismicity reveals that a complete earthquake recurrence cycle includes the characteristic earthquake and the sub-maxima earthquakes in-between. The magnitude of the sub-maxima events is correlated with the elapsed time of the characteristic earthquake and the slip rate of the fault. The fault displacement includes the major stick-slip generated by the characteristic earthquakes and the minor stick-slip by the sub-maxima ones. The magnitude-frequency relationship still works in the complete recurrence cycle. The energy accumulation in the cycle is divided approximately into four phases, and the seismicity differs at each phase. The relation of the maximum displacement with the average displacement of the characteristic earthquake suggests the partitioning of deformation between the characteristic and the sub-maxima earthquakes. Based on the above analysis, relevant mathematical equations are put forward for the quantitative assessment of the potential magnitude and earthquake risk of seismogenic tectonics. Tentative study has been carried out in this aspect in some areas of Tianshan.展开更多
The electrochemical corrosion of ductile pipes(DPs)in drinking water distribution systems(DWDS)has a crucial impact on cement-mortar lining(CML)failure and metal release,potentially leading to drinking water quality d...The electrochemical corrosion of ductile pipes(DPs)in drinking water distribution systems(DWDS)has a crucial impact on cement-mortar lining(CML)failure and metal release,potentially leading to drinking water quality deterioration and posing a risk to public health.An in-situ scanning vibrating electrode technique(SVET)with micron-scale resolution,microscopic scale detection and water quality analysis were used to investigate the corrosion behavior and metal release from DPs throughout the whole CML failure process.Metal pollutants release occurred at three different stages of CML failure process,and there are potential risks of water quality deterioration exceeding the maximum allowable levels set by national standards in the partial failure stage and lining peeling stage.Furthermore,the effects of water chemistry(Cl^(−),SO_(4)^(2−),NO_(3)−,and Ca^(2+))on corrosion scale growth and iron release activity,were investigated during the CML partial failure stage.Results showed that the CML failure process in DPs was accelerated by the autocatalysis of localized corrosion.Cl^(−)was found to damage the uncorroded metal surface,while SO_(4)^(2−)mainly dissolved the corrosion scale surface,increasing iron release.Both the oxidation of NO_(3)−and selective sedimentation of Ca2+were found to enhance the stability of corrosion scales and inhibit iron release.展开更多
Arsenic(As)pollution seriously threatens human and ecological health.Microalgal cell wall and extracellular polymeric substances(EPS)are known to interactwith As,but their roles in the As resistance,accumulation and s...Arsenic(As)pollution seriously threatens human and ecological health.Microalgal cell wall and extracellular polymeric substances(EPS)are known to interactwith As,but their roles in the As resistance,accumulation and speciation inmicroalgae remain unclear.Here,we used two strains of Chlamydomonas reinhardtii,namely CC-125(wild type)and CC-503(cell walldeficientmutant),to examine the algal growth,EPS synthesis,As adsorption,absorption and transformation under 10–1000μg/L As(III)and As(V)treatments for 96 h.In both strains,the As absorption increased after the EPS removal,but the growth,As adsorption,and transformation of C.reinhardtii declined.The CC-125 strain was more tolerant to As stress and more efficient in EPS production,As accumulation,and redox transformation than CC-503,irrespective of EPS presence or absence.Three-dimension excitation-emission matrix(3DEEM)and attenuated total reflectance infrared spectroscopy(ATR-IR)analyses showed that As was bound with functional groups in the EPS and cell wall,such as-COOH,NH and-OH in proteins,polysaccharides and amino acids.Together,this study demonstrated that EPS and cell wall acted as barriers to lower the As uptake by C.reinhardtii.However,the cell wall mutant strain wasmore susceptible to As toxicity due to lower EPS induction and higher As absorption.展开更多
Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to ...Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.展开更多
Cascading thermal runaway(TR)propagation poses a critical safety concern for large-format sodium-ion battery(SIB)systems because of the heightened risks of fires or explosions.However,effectively suppressing TR propag...Cascading thermal runaway(TR)propagation poses a critical safety concern for large-format sodium-ion battery(SIB)systems because of the heightened risks of fires or explosions.However,effectively suppressing TR propagation without introducing unintended side effects remains a significant challenge.Herein,we demonstrate a localized energy release method to mitigate TR,by reducing the state of charge(SOC)of cells adjacent to the thermally runaway unit.We discover that as the SOCs decreased from 100%to 25%,the TR trigger temperature decreased significantly,and the maximum temperature decrease from 367 to 229℃.Meanwhile,the volume of gas decreased to one-third of its original value,while the range of explosion limits significantly narrowed.The analysis of the morphology of the debris further confirms that the structural damage is greater at higher SOC levels.Moreover,an Entropy Weight and Technique for Order Preference by Similarity to an Ideal Solution(EW-TOPSIS)method has been established to assess the safety status of SIBs,showing that the TR possibility is nearly linear with the SOCs,and the TR hazard is exponentially related to the SOCs.Finally,when the SOC of cells adjacent to the TR cell is reduced to 25%,TR can be directly blocked without the need for additional cooling or thermal insulation methods.This study not only advances the understanding of TR behavior in SIBs but also offers a straightforward approach to mitigating the TR risk in SIB systems.展开更多
To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conduct...To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.展开更多
Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was desi...Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was designed for cold storage applications.The optimal number of PCM plates was determined through numerical simulations to meet the required cold storage temperature and control time.Additionally,the air temperature field,flow field,and melting characteristics of the PCMplates during the cooling release process were analyzed.The effects of plate positioning and thickness on the cooling release performance were further investigated.The results indicated that when 64PCMplateswere used,the duration formaintaining temperatures below−18℃increased from0.6 h to approximately 16.94 h.During the cooling release process,the temperature field in the cold storage exhibited stratification,and the melting of the PCM plates was non-uniform.Placing the PCM plates at the top or within the interlayers without cargo above proved more effective,with their cooling release power being approximately twice that of the PCM plates placed in the interlayers with cargo above.Furthermore,reducing the thickness of the PCMplates from15 to 7.5mmresulted in a 3.6-h increase in the time below−18℃and a 4.5-h reduction in the time required to reach 80%liquid phase fraction.展开更多
Based on petroleum exploration and new progress of oil and gas geology study in the Qiongdongnan Basin,combined with seismic,logging,drilling,core,sidewall coring,geochemistry data,a systematic study is conducted on t...Based on petroleum exploration and new progress of oil and gas geology study in the Qiongdongnan Basin,combined with seismic,logging,drilling,core,sidewall coring,geochemistry data,a systematic study is conducted on the source,reservoir-cap conditions,trap types,migration and accumulation characteristics,enrichment mechanisms,and reservoir formation models of ultra-deep water and ultra-shallow natural gas,taking the Lingshui 36-1 gas field as an example.(1)The genetic types of the ultra-deep water and ultra-shallow natural gas in the Qiongdongnan Basin include thermogenic gas and biogenic gas,and dominated by thermogenic gas.(2)The reservoirs are mainly composed of the Quaternary deep-water submarine fan sandstone.(3)The types of cap rocks include deep-sea mudstone,mass transport deposits mudstone,and hydrate-bearing formations.(4)The types of traps are mainly lithological,and also include structural-lithological traps.(5)The migration channels include vertical transport channels such as faults,gas chimneys,fracture zones,and lateral transport layers such as large sand bodies and unconformity surfaces,forming a single or composite transport framework.A new natural gas accumulation model is proposed for ultra-deep water and ultra-shallow layers,that is,dual source hydrocarbon supply,gas chimney and submarine fan composite migration,deep-sea mudstone-mass transport deposits mudstone-hydrate-bearing strata ternary sealing,late dynamic accumulation,and large-scale enrichment at ridges.The new understanding obtained from the research has reference and enlightening significance for the next step of deepwater and ultra-shallow layers,as well as oil and gas exploration in related fields or regions.展开更多
Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in c...Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41401563,41301544,41201094)the Natural Science Foundation of Shandong Province(Nos.ZR2014JL028+2 种基金ZR2012DQ003)the China Postdoctoral Science Foundation(No.2015M571830)the Taishan Scholar Program of Shandong Province for supporting his research
文摘Changes in metal concentrations in the litter of Potamogeton crispus were monitored during a consecutive 40-day in situ decomposition experiment using the litterbag method.The accumulation index was calculated and used to indicate the changes in the metals in litter.The results showed that the concentrations of Al,Cd,Cr,Fe,Mn,and Pb in litter increased significantly during the decomposition,while Cu and Zn concentrations decreased dramatically.Significant positive correlations were found between the concentrations of Al,Cr,Fe,and Mn and between Cu and Zn.Moreover,Cu and Zn both negatively correlated with Al and Fe.The remaining dry mass was negatively correlated with Al and Fe concentrations but positively correlated with Cu and Zn concentrations.Generally the accumulation index values of metals other than Al were less than one,indicating that the litter of P.crispus acted as a source of metals to the surrounding water body.Al was the only metal that showed continuous net accumulation in litter.The net accumulation of Fe and Mn in litter during the last 10 days of the experiment may indicate the precipitation of Feand Mn-oxides.It was estimated that 160 g/m^2（dry weight）P.crispus was decomposed in40 days.This was equivalent to releasing the following amounts of metals：0.01 mg Cd,0.03 mg Cr,0.71 mg Cu,0.55 mg Mn,0.02 mg Pb and 13.8 mg Zn into surrounding water,and accumulating 149 mg Al and 11 mg Fe,in a 1 m^2 area.
基金supported by the National Natural Science Foundation of China(Nos.52273102,31870957,and 52302344)the Fundamental Research Funds for the Central Universities(Nos.DUT24YG155,DUT20YG103,and DUT22LAB601)Liaoning Provincial Science and Technology Plan Joint Plan(No.2023JH2/101700341)。
文摘Encapsulation of water-soluble cargoes in millimeter-sized capsules has enabled major advances in various fields,including pharmaceuticals,food,cosmetics,packaging,and materials.However,because of the lack of fabrication precision,low cargo retention,suboptimal mechanical properties,and difficulty in preventing water evaporation,this technique is more challenging than microencapsulation techniques.In this study,we developed a surfactant-free and organic solvent-free water-in-oil in-air emulsification approach for synthesizing double-layered“milli-capsules”for the precise encapsulation,enhanced retention,and force-triggered burst release of water-soluble bioactive cargoes.In particular,we synthesized milli-capsules with a first shell of poly(ethylene glycol dimethacrylate)for the efficient encapsulation of bioactive cargoes and a second shell of beeswax to prolong the retention of the entrapped bioactive compounds.Unlike traditional milli-capsules,which exhibit poor shape uniformity and mechanical stability,we introduced metallic ions to stabilize the interfacial tension and employed constant rotation to balance the gravity,buoyancy,inertial,and viscous forces imposed on the droplets,resulting in uniform and rigid milli-capsules with narrow rupture forces.Furthermore,additional hydrophobic beeswax coating prevented water volatilization and substantially prolonged the shelf life of the encapsulated compounds from a few days to a few months while maintaining their bioactivities.The proposed milli-capsule system addresses the challenge of precise fabrication of large carriers for water-soluble cargoes,representing a significant step toward the long-term storage and controlled release of bioactive cargoes for various industrial applications.
基金supported by the Scientific Research Foundation supported by Yunnan Agricultural University(A3012024035044)International Cooperation and Exchange of the National Natural Science Foundation of China(No.42361144885).
文摘The establishment of plantations has become a critical approach for reducing greenhouse gas emissions,particularly in fragile environments with carbon sequestration potential.In karst areas,plantations based on fastgrowing afforestation species made significant contributions to enhancing carbon sequestration.However,the impact of understory vegetation on carbon accumulation remains unclear.Especially,the carbon accumulation associated with litter produced during the replacement of understory species receives insufficient attention,which leads to the neglect of the carbon sequestration potential in plantations of karst areas.Leaf is a crucial organ that links the litter production.To explore how leaf traits adapt to competitive environments and drive litter carbon accumulation during understory species replacement,this study observed leaf traits and litter carbon content changes in three types of plantations in the Liujiang River Basin,a typical karst area.A total of 37 sampling plots were selected for field investigation over a twoyear period.Leaf traits,species diversity,vegetation coverage,and litter carbon characteristics in understory vegetation were measured.Variance analysis,allometric equations,and path analysis were used for data analysis.The results showed that most understory species adopted a biomass conservation strategy under high-coverage conditions(>44.27%)and expanded competitive leaf area under low-coverage conditions(<44.27%).However,Bidens pilosa and Miscanthus floridulus exhibited strong competitiveness during understory species replacement.They showed an expansion of competitive leaf area under high-coverage conditions.This competitive strategy reduced species diversity and community specific leaf area.But the rapid expansion of Bidens pilosa and Miscanthus floridulus increased understory vegetation coverage,and their increased specific leaf area facilitated leaf shedding,resulting in significant litter weight accumulation(P<0.05),thereby enhancing litter carbon content per unit area.These competitive strategies were key driving factors for the increase in litter carbon content per square meter,which reached a maximum of 49.6% higher than that in natural grasslands.And the maximum increase in litter carbon accumulation derived from understory vegetation reached 3.37 times from 2023 to 2024 in plantations.In the understory vegetation of plantations,the competitive strategies reflected by leaf adaptation of key competitive species are critical factors influencing litter carbon accumulation.Future research could deeply explore the carbon sequestration effects resulting from the dynamic changes in competition within the understory vegetation of plantations.
基金financially supported by the National Key R&D Program of China(2024YFD1200800)the Guangdong Basic and Applied Basic Research Foundation,China(2024A1515030094)。
文摘Highlights OsCAX2 is localized to tonoplast,and cadmium induces its expression.OsCAX2 overexpression reduces cadmium concentration in indica rice grains by 49.1%.Cadmium(Cd)exposure poses significant health risks to humans,and the International Agency for Research on Cancer has classified it as a Group I carcinogen.Cadmium undergoes minimal metabolism in the human body;consequently,prolonged Cd^(2+)exposure can cause severe damage to multiple organs including the liver,kidneys,lungs,bones,and immune system(Shao et al.2024).Rice,one of the three global staple crops,and Cd exposure in humans primarily occurs the consumption of contaminated rice grains.The contribution of rice to the total dietary Cd intake is over 50% for non-smoking Asian populations(Chen et al.2018;Shi et al.2020).
文摘Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.
基金financially supported by the National Key R&D Program of China(2021YFD1901203 and 2021YFD1901204)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0440404)+2 种基金the National Natural Science Foundation of China(42377348)the Science Foundation for Distinguished Young Scholars of Hunan Province,China(2024JJ2052)the Natural Science Foundation of Guangxi,China(2025GXNSFAA069337)。
文摘Rapidly improving infertile croplands and enhancing their soil organic carbon(SOC)pool necessitate substantial organic materials incorporation.Converting loose crop straw into granulated form facilitates uniform incorporation within the plough soil layer.As an innovative soil amelioration approach,the efficiency and patterns of SOC accumulation remain unclear.Two field experiments were conducted in infertile subtropical upland and paddy soils with 0,30,60,and 90 Mg ha^(-1)granulated straw incorporation.After one year,SOC accumulation efficiency from straw input remained stable in upland(30.8–37.5%)with increasing amounts of straw incorporation,while declined from 60.0 to 38.3%in paddy.In both croplands,the contributions of lignin phenols to SOC increased with increasing straw incorporation,while the contributions from amino sugars remained constant at higher straw input levels.Subsequently,the ratios of lignin phenols to amino sugars increased with increasing straw incorporation,indicating faster plant residue accumulation compared to microbial necromass,as the granulation approach limited microbial involvement in straw transformation.Thus,single-time incorporation of substantial granulated straw presents an effective agricultural strategy for rapid amelioration of infertile croplands.
基金supported by the National Natural Science Foundation of China(No.11602200)。
文摘This study is dedicated to numerically investigate the dynamic behavior of a missile released from a helicopter under the influence of downwash from the rotating rotors using AGM-114 Hellfire and UH-60 as the testcase.Simulations are conducted using unsteady Reynolds-averaged Navier-Stokes(URANS)with shear stress transport(SST)k-ωturbulence model,incorporating six-degree-of-freedom(6-DOF)motion and overset grid.Two releasing scenarios,viz.,hover and forward flight,are analyzed under varying missile launch thrust and helicopter forward flight speed.Results reveal that the rotor downwash significantly affects the stability of the missile,particularly during hovering case,where low thrust prolongs wake interaction.In forward flight,the increased airspeed can in principle reduce wake influence but introduces asymmetrical aerodynamic effects on the trajectory of the missile.The findings offer guidance for missile release and launch planning in rotorcraft operations.
基金This work was supported by City Collage of Science and Technology.Chongqing University and Chongqing HaiRun institute of energy saving research。
文摘Accumulation and releasing of trace metal elements on aluminum containing sediments of inner drinking water pipe is discussed,as studied from five variations effecting:raw water quality,chemical reagents,solution pH and drinking water flow condition.In order to decrease the release of trace metal elements,and to ensure the pipe operation and human safety,water quality adjustment is suggested to avoid aluminum containing sediments formation in drinking distribution system.The maximum amounts of accumulation of common trace metal elements are given.Future trends of development in this field are also proposed.
文摘[Objectives]This study was conducted to investigate the effects of slow-release nitrogen fertilizer on dry matter accumulation and translocation of summer maize.[Methods]With Zhoudan 9 as the test variety,six different treatment were set up:blank control(CK1),slow-release urea 75 kg/hm^(2)(C1),slow-release urea 150 kg/hm^(2)(C2),slow-release urea 225 kg/hm^(2)(C3),slow-release urea 300 kg/hm^(2)(C4)and ordinary urea 300 kg/hm^(2)(CK2),to study the change law of dry matter accumulation and translocation in summer maize.[Results]Treatment slow-release urea 225 kg/hm^(2)(C4)showed summer maize yield,dry matter translocation between organs,grain contribution rate and proportion of grain dry matter in the full ripe stage higher than other treatments.Considering the weight loss and cost factors,slow-release urea 225 kg/hm^(2)(C3)could be recommended as the fertilizing amount for summer maize.[Conclusions]This study provides theoretical reference for rational selection of fertilizers for reducing fertilizer application and increasing fertilizer efficiency,and for production of summer maize in Shajiang black soil region.
文摘In this study,phosphonate-terminated magnetic mesoporous nanoparticles(pMMSNs)was designed by incorporation of MNPs in the center of mesoporous silica nanoparticles(MSNs)and followed by grafting phosphonate group on to the surface of MMSNs.The carrier exhibited a typical superparamagnetic feature and the saturation magnetization was 4.89 emu/g measured by vibrating sample magnetometer(VSM).pMMSNs had a spherical morphology and a pore size of 2.2 nm.FromN2 adsorption-desorption analysis,pMMSNs had a surface area of 613.4 m^(2)/g and a pore volume of 0.78 cm^(3)/g.Phosphonate modification improved the colloidal stability of MMSNs,and the hydrodynamic diameter of pMMSNs was around 175 nm.The hydrophilic phosphonate group significantly enhanced the negative surface charge of MMSNs from-19.3 mV to-28.8 mV pMMSNs with more negative surface charge had a 2.3-fold higher drug loading capacity than that of MMSNs.In addition,the rate and amount of release of doxorubicin(DOX)from DOX/pMMSNs was pH-dependent and increased with the decrease of pH.At pH 7.4,the release amount was quite low and only approximately 17wt%ofDOXwasreleasedin48h.AtpH5.0and3.0,the release rate increased significantly and the release amount achieved 31 wt%and 60 wt%in 48 h,respectively.To evaluate the magnetic targeting performance ofpMMSNs,FITC labeledpMMSNswas injected into mice bearing S180 solid tumor.FITC labeledpMMSNscontrolled by an external magnetic field showed higher tumor accumulation and lower normal tissue distribution.
文摘Comparative analysis between the quantitative data of active faults and seismicity reveals that a complete earthquake recurrence cycle includes the characteristic earthquake and the sub-maxima earthquakes in-between. The magnitude of the sub-maxima events is correlated with the elapsed time of the characteristic earthquake and the slip rate of the fault. The fault displacement includes the major stick-slip generated by the characteristic earthquakes and the minor stick-slip by the sub-maxima ones. The magnitude-frequency relationship still works in the complete recurrence cycle. The energy accumulation in the cycle is divided approximately into four phases, and the seismicity differs at each phase. The relation of the maximum displacement with the average displacement of the characteristic earthquake suggests the partitioning of deformation between the characteristic and the sub-maxima earthquakes. Based on the above analysis, relevant mathematical equations are put forward for the quantitative assessment of the potential magnitude and earthquake risk of seismogenic tectonics. Tentative study has been carried out in this aspect in some areas of Tianshan.
基金supported by the National Natural Science Foundation of China(Nos.51808158,52170101,and 52200116)Tianjin Natural Science Foundation(No.23JCYBJC00640).
文摘The electrochemical corrosion of ductile pipes(DPs)in drinking water distribution systems(DWDS)has a crucial impact on cement-mortar lining(CML)failure and metal release,potentially leading to drinking water quality deterioration and posing a risk to public health.An in-situ scanning vibrating electrode technique(SVET)with micron-scale resolution,microscopic scale detection and water quality analysis were used to investigate the corrosion behavior and metal release from DPs throughout the whole CML failure process.Metal pollutants release occurred at three different stages of CML failure process,and there are potential risks of water quality deterioration exceeding the maximum allowable levels set by national standards in the partial failure stage and lining peeling stage.Furthermore,the effects of water chemistry(Cl^(−),SO_(4)^(2−),NO_(3)−,and Ca^(2+))on corrosion scale growth and iron release activity,were investigated during the CML partial failure stage.Results showed that the CML failure process in DPs was accelerated by the autocatalysis of localized corrosion.Cl^(−)was found to damage the uncorroded metal surface,while SO_(4)^(2−)mainly dissolved the corrosion scale surface,increasing iron release.Both the oxidation of NO_(3)−and selective sedimentation of Ca2+were found to enhance the stability of corrosion scales and inhibit iron release.
基金supported by the National Natural Science Foundation of China(Nos.32171623 and 31770548)the National Key Research and Development Program of China(Nos.2016YFD0800306 and 2017YFD0800305).
文摘Arsenic(As)pollution seriously threatens human and ecological health.Microalgal cell wall and extracellular polymeric substances(EPS)are known to interactwith As,but their roles in the As resistance,accumulation and speciation inmicroalgae remain unclear.Here,we used two strains of Chlamydomonas reinhardtii,namely CC-125(wild type)and CC-503(cell walldeficientmutant),to examine the algal growth,EPS synthesis,As adsorption,absorption and transformation under 10–1000μg/L As(III)and As(V)treatments for 96 h.In both strains,the As absorption increased after the EPS removal,but the growth,As adsorption,and transformation of C.reinhardtii declined.The CC-125 strain was more tolerant to As stress and more efficient in EPS production,As accumulation,and redox transformation than CC-503,irrespective of EPS presence or absence.Three-dimension excitation-emission matrix(3DEEM)and attenuated total reflectance infrared spectroscopy(ATR-IR)analyses showed that As was bound with functional groups in the EPS and cell wall,such as-COOH,NH and-OH in proteins,polysaccharides and amino acids.Together,this study demonstrated that EPS and cell wall acted as barriers to lower the As uptake by C.reinhardtii.However,the cell wall mutant strain wasmore susceptible to As toxicity due to lower EPS induction and higher As absorption.
基金financially supported by the Science and Technology Innovation Foundation of the Command Center of Integrated Natural Resources Survey Center(KC20230002)the China Geological Survey Project(DD20230471,DD20220855 and DD20243282)+1 种基金the National Natural Science Foundation of China(41872100)the National Key R&D Plan(2022YFC2903402)。
文摘Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.
基金supported by the National Key R&D Program of China(2023YFB2407900)the National Natural Science Foundation of China(52302512)+1 种基金State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(KFZD202305)Zhejiang Province Science and Technology Program Grant(2024C0127(SD2))。
文摘Cascading thermal runaway(TR)propagation poses a critical safety concern for large-format sodium-ion battery(SIB)systems because of the heightened risks of fires or explosions.However,effectively suppressing TR propagation without introducing unintended side effects remains a significant challenge.Herein,we demonstrate a localized energy release method to mitigate TR,by reducing the state of charge(SOC)of cells adjacent to the thermally runaway unit.We discover that as the SOCs decreased from 100%to 25%,the TR trigger temperature decreased significantly,and the maximum temperature decrease from 367 to 229℃.Meanwhile,the volume of gas decreased to one-third of its original value,while the range of explosion limits significantly narrowed.The analysis of the morphology of the debris further confirms that the structural damage is greater at higher SOC levels.Moreover,an Entropy Weight and Technique for Order Preference by Similarity to an Ideal Solution(EW-TOPSIS)method has been established to assess the safety status of SIBs,showing that the TR possibility is nearly linear with the SOCs,and the TR hazard is exponentially related to the SOCs.Finally,when the SOC of cells adjacent to the TR cell is reduced to 25%,TR can be directly blocked without the need for additional cooling or thermal insulation methods.This study not only advances the understanding of TR behavior in SIBs but also offers a straightforward approach to mitigating the TR risk in SIB systems.
文摘To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.
基金supported by National Natural Science Foundation of China(Nos.51806092,52201410)Non-Carbon Energy Conversion and Utilization Institute under the Shanghai Class IV Peak Disciplinary Development Program,High-End Foreign Experts Recruitment Plan of China(G2022013028L).
文摘Phase Change Material(PCM)-based cold energy storage system(CESS)can effectively utilize the peak and valley power resources to reduce the excessive dependence on the power grid.In this study,a PCM-based CESS was designed for cold storage applications.The optimal number of PCM plates was determined through numerical simulations to meet the required cold storage temperature and control time.Additionally,the air temperature field,flow field,and melting characteristics of the PCMplates during the cooling release process were analyzed.The effects of plate positioning and thickness on the cooling release performance were further investigated.The results indicated that when 64PCMplateswere used,the duration formaintaining temperatures below−18℃increased from0.6 h to approximately 16.94 h.During the cooling release process,the temperature field in the cold storage exhibited stratification,and the melting of the PCM plates was non-uniform.Placing the PCM plates at the top or within the interlayers without cargo above proved more effective,with their cooling release power being approximately twice that of the PCM plates placed in the interlayers with cargo above.Furthermore,reducing the thickness of the PCMplates from15 to 7.5mmresulted in a 3.6-h increase in the time below−18℃and a 4.5-h reduction in the time required to reach 80%liquid phase fraction.
基金Supported by the Research Project of CNOOC(KJZH-2021-0003-00).
文摘Based on petroleum exploration and new progress of oil and gas geology study in the Qiongdongnan Basin,combined with seismic,logging,drilling,core,sidewall coring,geochemistry data,a systematic study is conducted on the source,reservoir-cap conditions,trap types,migration and accumulation characteristics,enrichment mechanisms,and reservoir formation models of ultra-deep water and ultra-shallow natural gas,taking the Lingshui 36-1 gas field as an example.(1)The genetic types of the ultra-deep water and ultra-shallow natural gas in the Qiongdongnan Basin include thermogenic gas and biogenic gas,and dominated by thermogenic gas.(2)The reservoirs are mainly composed of the Quaternary deep-water submarine fan sandstone.(3)The types of cap rocks include deep-sea mudstone,mass transport deposits mudstone,and hydrate-bearing formations.(4)The types of traps are mainly lithological,and also include structural-lithological traps.(5)The migration channels include vertical transport channels such as faults,gas chimneys,fracture zones,and lateral transport layers such as large sand bodies and unconformity surfaces,forming a single or composite transport framework.A new natural gas accumulation model is proposed for ultra-deep water and ultra-shallow layers,that is,dual source hydrocarbon supply,gas chimney and submarine fan composite migration,deep-sea mudstone-mass transport deposits mudstone-hydrate-bearing strata ternary sealing,late dynamic accumulation,and large-scale enrichment at ridges.The new understanding obtained from the research has reference and enlightening significance for the next step of deepwater and ultra-shallow layers,as well as oil and gas exploration in related fields or regions.
基金Supported by the PetroChina Basic Project(2024DJ23)CNPC Science Research and Technology Development Project(2021DJ0101)。
文摘Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.
