This paper presents flight results and lessons learned from the Spaceborne Autonomous Formation Flying Experiment （SAFE） conducted by the German Space Operations Center in the frame of the Swedish PRISMA technology ...This paper presents flight results and lessons learned from the Spaceborne Autonomous Formation Flying Experiment （SAFE） conducted by the German Space Operations Center in the frame of the Swedish PRISMA technology demonstration mission. PR1SMA involves two fully autonomous formation-flying spacecraft which have been launched in June 2010 in a dawn/dusk orbit at an altitude of 750 km. SAFE represents one of the first demonstrations in low Earth orbit of an advanced guidance, navigation and control system for dual-spacecraft formations. Innovative techniques based on carrier-phase differential GPS （Global Positioning System）, relative eccentricity/inclination vectors and impulsive maneuvering are validated and tuned in orbit to achieve centimeter accurate real-time relative navigation, reliable formation keeping at the meter level and flexible formation reconfiguration capabilities. The technologies demonstrated within SAFE are considered as key precursors of future distributed satellite systems for unrivaled remote sensing and space exploration.展开更多
This study investigates the effects of AI-mediated communication (AMC) on trust-building and negotiation outcomes in professional remote collaboration settings. Through a mixed-methods approach combining experimental ...This study investigates the effects of AI-mediated communication (AMC) on trust-building and negotiation outcomes in professional remote collaboration settings. Through a mixed-methods approach combining experimental design and qualitative analysis (N = 120), we examine how AI intermediaries influence communication dynamics, relationship building, and decision-making processes. Results indicate that while AMC initially creates barriers to trust formation, it ultimately leads to enhanced communication outcomes and stronger professional relationships when implemented with appropriate transparency and support. The study revealed a 31% improvement in cross-cultural understanding and a 24% increase in negotiation satisfaction rates when using AI-mediated channels with proper transparency measures. These findings contribute to the theoretical understanding of technology-mediated communication and practical applications for organizations implementing AI communication tools.展开更多
The basic geological characteristics of the Qiongzhusi Formation reservoirs and conditions for shale gas enrichment and high-yield were studied by using methods such as mineral scanning,organic and inorganic geochemis...The basic geological characteristics of the Qiongzhusi Formation reservoirs and conditions for shale gas enrichment and high-yield were studied by using methods such as mineral scanning,organic and inorganic geochemistry,breakthrough pressure,and triaxial mechanics testing based on the core,logging,seismic and production data.(1)Both types of silty shale,rich in organic matter in deep water and low in organic matter in shallow water,have good gas bearing properties.(2)The brittle mineral composition of shale is characterized by comparable feldspar and quartz content.(3)The pores are mainly inorganic pores with a small amount of organic pores.Pore development primarily hinges on a synergy between felsic minerals and total organic carbon content(TOC).(4)Dominated by Type I organic matters,the hydrocarbon generating organisms are algae and acritarch,with high maturity and high hydrocarbon generation potential.(5)Deep-and shallow-water shale gas exhibit in-situ and mixed gas generation characteristics,respectively.(6)The basic law of shale gas enrichment in the Qiongzhusi Formation was proposed as“TOC controlled accumulation and inorganic pore controlled enrichment”,which includes the in-situ enrichment model of“three highs and one over”(high TOC,high felsic mineral content,high inorganic pore content,overpressured formation)for organic rich shale represented by Well ZY2,and the in-situ+carrier-bed enrichment model of“two highs,one medium and one low”(high felsic content,high formation pressure,medium inorganic pore content,low TOC)for organic-poor shale gas represented by Well JS103.It is a new type of shale gas that is different from the Longmaxi Formation,enriching the formation mechanism of deep and ultra-deep shale gas.The deployment of multiple exploration wells has achieved significant breakthroughs in shale gas exploration.展开更多
Twelve new dinosaur teeth have recently been recovered from three localities in the Upper Cretaceous Nenjiang Formation of the Songliao Basin.Although fragmentary,the material offers enough evidence to identify the fo...Twelve new dinosaur teeth have recently been recovered from three localities in the Upper Cretaceous Nenjiang Formation of the Songliao Basin.Although fragmentary,the material offers enough evidence to identify the following taxa:tyrannosaurids,dromaeosaurines,velociraptorines,hadrosauroids,and titanosaurs.In addition to the previously known dinosaurs from the basin,several new ones have been identified,extending the paleogeographic range of related taxa.The discovery of these new fossil remains provides valuable insights into dinosaur diversity and sheds light on the terrestrial ecosystem during the Late Cretaceous in the Songliao Basin.展开更多
Hylocereus polyrhizus,also known as pitaya or dragon fruit,is a climbing cactus grown worldwide because of its excellent performance under drought stress and appealing red-purple fruits.In practice,accelerating flower...Hylocereus polyrhizus,also known as pitaya or dragon fruit,is a climbing cactus grown worldwide because of its excellent performance under drought stress and appealing red-purple fruits.In practice,accelerating flower formation and inducing more flowers usually result in higher yield.However,the genes for this purpose have not been well characterized in pitaya.Previously,FLOWERING BHLHs(FBHs)have been identified as positive regulators of flower formation.In the present work,a total of eight FBHs were identified in pitaya.This is a greater number than in beet and spinach,possibly because of the recent whole-genome duplication that occurred in the pitaya genome.The phylogenetic tree indicated that the FBHs could be divided into three groups.In TYPEⅡ,the genes of Caryophyllales encode atypical FBHs and are generated by dispersed duplication.The K_(a)/K_(s) ratios indicated that HpFBHs are under purifying selection.Promoter and expression analysis of HpFBHs revealed that they are spatiotemporally activated in flower-related tissues and responsive to multiple abiotic stresses.These results indicated that HpFBHs are involved in the flower formation of pitaya.Therefore,typical HpFBH1/3 from TYPEⅡI and an atypical HpFBH8 from TYPEⅡwere selected for functional verification.HpFBH3 was found to heterodimerize with HpFBH1 in the nucleus using subcellular localization,yeast two-hybrid and luciferase complementation assays.With bioinformatic analysis,all HpFBHs were predicted to transactivate downstream genes via binding to the E-boxes,which were frequently detected in the promoters of HpCOs,HpFTs and HpSOC1s.RNA-Seq datasets showed that these flowering accelerators were expressed in coordination with HpFBH3.Yeast one-hybrid and dual-luciferase reporter assays further verified that HpFBH3 transactivated HpCO7 by selectively binding to the E-boxes in the promoter.Moreover,ectopic overexpression of HpFBH3 accelerated flower formation in Arabidopsis.In summary,this study systematically characterized the typical HpFBHs,especially HpFBH3,as positive regulators of flower formation,which could be target genes for the genetic improvement of pitaya.展开更多
Controlled by fluctuating paleoclimates and sedimentary environments,the organic and inorganic features of the Lucaogou Formation exhibit strong heterogeneity in the vertical profile,challenging conventional geologica...Controlled by fluctuating paleoclimates and sedimentary environments,the organic and inorganic features of the Lucaogou Formation exhibit strong heterogeneity in the vertical profile,challenging conventional geological interpretation.To elucidate the possible influence of heterogeneity on resource evaluation,a high-resolution sampling approach was applied to an 86.2 cm long core from the Lucaogou Formation of the Jimsar sag in the Junggar Basin.86 sets of samples were micro-drilled from the core and subjected to comparative Rock-Eval pyrolysis.Following the classical guidelines,the organic abundance,kerogen type,and maturity of source rocks were exhaustively analyzed.Experimental results revealed that organic richness and composition vary significantly under different sedimentary backgrounds,which in turn leads to differential hydrocarbon generation.The combination of hydrocarbon generation,transport,and expulsion results in peculiar patterns for hydrocarbon accumulation in the Lucaogou Formation.Laminated shales in the Lucaogou Formation serve as both hydrocarbon source rocks and reservoirs,with laminae being migration pathways.Organic-rich dolomites in the Lucaogou Formation have a considerable hydrocarbon-generating capacity and present the characteristics of self-generation and self-storage.However,massive mudstones act purely as hydrocarbon source rocks.展开更多
This paper discusses the characteristics and formation mechanism of thin dolomite reservoirs in the lower submember of the second member of the Permian Maokou Formation(lower Mao 2 Member)in the Wusheng-Tongnan area o...This paper discusses the characteristics and formation mechanism of thin dolomite reservoirs in the lower submember of the second member of the Permian Maokou Formation(lower Mao 2 Member)in the Wusheng-Tongnan area of the Sichuan Basin,SW China,through comprehensive analysis of geological,geophysical and geochemical data.The reservoir rocks of the lower Mao 2 Member are dominated by porphyritic vuggy dolomite and calcareous dolomite or dolomitic limestone,which have typical karst characteristics of early diagenetic stage.The dolomites at the edge of the karst system and in the fillings have dissolved estuaries,and the dolomite breccia has micrite envelope and rim cement at the edge,indicating that dolomitization is earlier than the early diagenetic karstification.The shoal facies laminated dolomite is primarily formed by the seepage reflux dolomitization of moderate-salinity seawater.The key factors of reservoir formation are the bioclastic shoal deposition superimposed with seepgae reflux dolomitization and the karstification of early diagenetic stage,which are locally reformed by fractures and hydrothermal processes.The development of dolomite vuggy reservoir is closely related to the upward-shallowing sequence,and mainly occurs in the late highstand of the fourth-order cycle.Moreover,the size of dolomite is closely related to formation thickness,and it is concentrated in the formation thickness conversion area,followed by the thinner area.According to the understanding of insufficient accommodation space in the geomorphic highland and the migration of granular shoal to geomorphic lowland in the late highstand of the third-order cycle,it is proposed that the large-scale shoal-controlled dolomite reservoirs are distributed along structural highs and slopes,and the reservoir-forming model with shoal,dolomitization and karstification jointly controlled by the microgeomorphy and sea-level fluctuation in the sedimentary period is established.On this basis,the paleogeomorphology in the lower Mao 2 Member is restored using well-seismic data,and the reservoir distribution is predicted.The prediction results have been verified by the latest results of exploration wells and tests,which provide an important reference for the prediction of thin dolomite reservoirs under similar geological setting.展开更多
Investigations into rail corrugation within metro systems have traditionally focused on specific mechanisms,thereby limiting the generalizability of proposed theories.Understanding the commonalities in rail corrugatio...Investigations into rail corrugation within metro systems have traditionally focused on specific mechanisms,thereby limiting the generalizability of proposed theories.Understanding the commonalities in rail corrugation across diverse metro lines remains pivotal for elucidating its underlying mechanisms.The present study conducted extensive field surveys and tracking tests across 14 Chinese metro lines.By employing t-distributed stochastic neighbor embedding(t-SNE)for dimensional reduction and employing the unsupervised clustering algorithm DBSCAN,the research redefines the classification of metro rail corrugation based on characteristic information.The analysis encompassed spatial distribution and temporal evolution of this phenomenon.Findings revealed that floating slab tracks exhibited the highest proportion of rail corrugation at 47%.Notably,ordinary monolithic bed tracks employing damping fasteners were more prone to inducing rail corrugation.Corrugation primarily manifested in curve sections with radii between 300 and 500 m,featuring ordinary monolithic bed track and steel-spring floating slab track structures,with wavelengths typically between 30 and 120 mm.Stick–slip vibrations of the wheel–rail system maybe led to short-wavelength corrugations(40–60 mm),while longer wavelengths(200–300 mm)exhibited distinct fatigue damage characteristics,mainly observed in steel-spring floating slab tracks and small-radius curve sections of ordinary monolithic bed tracks and ladder sleeper tracks.A classification system comprising 57 correlated features categorized metro rail corrugation into four distinct types.These research outcomes serve as critical benchmarks for validating various theories pertaining to rail corrugation formation.展开更多
The 7 ka old Qixiangzhan lava flow(QXZ,Tianchi volcano)represents the last eruptive event before the 946 CE,caldera-forming‘Millennium’eruption(ME).Petrographic,whole rock,mineral composition,Sr-Nd isotopic data on ...The 7 ka old Qixiangzhan lava flow(QXZ,Tianchi volcano)represents the last eruptive event before the 946 CE,caldera-forming‘Millennium’eruption(ME).Petrographic,whole rock,mineral composition,Sr-Nd isotopic data on QXZ show that:(a)the lava consists of two components,constituted by comenditic obsidian fragments immersed in a continuous,aphanitic component;(b)both components have the same geochemical and isotopic variations of the ME magma.The QXZ and ME comendites result from fractional crystallization and crustal assimilation processes.The temperature of the QXZ magma was about 790℃ and the depth of the magma reservoir around 7 km,the same values as estimated for ME.QXZ had a viscosity of 10^(5.5)-10^(9) Pa s and a velocity of 3-10 km/yr.The emplacement time was 0.5-1.6yr and the flow rate 0.48-1.50 m^(3)/s.These values lie within the range estimated for other rhyolitic flows worldwide.The QXZ lava originated through a mixed explosive-effusive activity with the obsidian resulting from the ascent of undercooling,degassing and the fragmentation of magma along the conduit walls,whereas the aphanitic component testifies to the less undercooled and segregated flow at the center of the conduit.The QXZ lava demonstrates the extensive history of the ME magma chamber.展开更多
The Majiagou Formation in the Fuxian area of the southeastern Ordos Basin has undergone a complex diagenetic evolution history under the influence of eustacy and the Caledonian karstification,resulting in several comp...The Majiagou Formation in the Fuxian area of the southeastern Ordos Basin has undergone a complex diagenetic evolution history under the influence of eustacy and the Caledonian karstification,resulting in several complex reservoir types.Through analyses of mineralogy,petrology,and reservoir geology,three major types of dolomite reservoirs with different genetic mechanisms,including anhydritic moldicdissolved pore type,dolomitic intercrystalline-pore type,and fractured type were identified,and their formation mechanisms and distribution patterns were examined.The aphanocrystalline to very finecrystalline anhydritic dolomite was resulted from Sabhak dolomitization,and is characterized by small size of crystals and high content of anhydrite.Dolomite reservoirs of anhydritic moldic-dissolved pore type were developed in multi-stage dissolution processes and mainly distributed at higher positions of the paleogeomorphology where the filling was weak.The very fine to fine-crystalline dolomite of shoal facies was formed under seepage-reflux dolomitization,and characterized by larger sizes of crystals and well-developed intercrystalline pores.Dolomite reservoirs of intercrystalline-pore type were mainly developed at the lower positions of the paleogeomorphology where bedding-parallel karst dissolution was strong.The fractured dolomite reservoirs,generated by the anhydrite swelling and karst cave collapse,occur in multiple horizons but within limited areas due to multi-stage fillings.展开更多
It is of great significance for deep oil and gas exploration to understand the origin and evolution behind overpressure.Overpressure occurs in the deep Shahezi Formation of Xujiaweizi fault depression.However,due to l...It is of great significance for deep oil and gas exploration to understand the origin and evolution behind overpressure.Overpressure occurs in the deep Shahezi Formation of Xujiaweizi fault depression.However,due to limited degree of exploration,there are some problems in the study area,such as unclear understanding of the origin of overpressure and the vague investigation of overpressure evolution.To clarify the impact of overpressure on oil and gas migration and accumulation in the study area,this study focuses on the research of the origin and evolution of overpressure in the Shahezi Formation of the study area,utilizing single well logging parameters and combining methods such as microthermometry of fluid inclusions,laser Raman spectrum,and basin simulation.The results show that the overpressure of the Shahezi Formation in Xujiaweizi fault depression is primarily generated by hydrocarbon generation pressurization,and the evolution of overpressure is closely related to hydrocarbon generation.The development of overpressure can be divided into two evolutionary stages:early hydrocarbon generation pressurization and late uplift release,with slight variations in different regions.Tight glutenite gas reservoirs in the Shahezi Formation are characterized by continuous charging.The overall charging period ranges from the late Denglouku to the early Mingshui(110-67 Ma ago).There is an obvious paleo-overpressure during the gas reservoir formation period.The gas generation period of source rocks occurred approximately 125-60 Ma ago,and the main gas generation period(112-67 Ma ago)highly coincides with the period of natural gas charging.The anomalously high pressure during the accumulation period is considered the significant driving force for natural gas charging.In addition,the sustained effect of overpressure provides better conditions for the preservation of tight gas reservoirs within the source.The results of the study are of guiding significance for the in-depth exploration and development of deep tight sandstone gas in the Shahezi Formation of Xujiaweizi fault depression.展开更多
Severe ground-level ozone(O_(3))pollution over major Chinese cities has become one of the most challenging problems,which have deleterious effects on human health and the sustainability of society.This study explored ...Severe ground-level ozone(O_(3))pollution over major Chinese cities has become one of the most challenging problems,which have deleterious effects on human health and the sustainability of society.This study explored the spatiotemporal distribution characteristics of ground-level O_(3) and its precursors based on conventional pollutant and meteorological monitoring data in Zhejiang Province from 2016 to 2021.Then,a high-performance convolutional neural network(CNN)model was established by expanding the moment and the concentration variations to general factors.Finally,the response mechanism of O_(3) to the variation with crucial influencing factors is explored by controlling variables and interpolating target variables.The results indicated that the annual average MDA8-90th concentrations in Zhejiang Province are higher in the northern and lower in the southern.When the wind direction(WD)ranges from east to southwest and the wind speed(WS)ranges between 2 and 3 m/sec,higher O_(3) concentration prone to occur.At different temperatures(T),the O_(3) concentration showed a trend of first increasing and subsequently decreasing with increasing NO_(2) concentration,peaks at the NO_(2) concentration around 0.02mg/m^(3).The sensitivity of NO_(2) to O_(3) formation is not easily affected by temperature,barometric pressure and dew point temperature.Additionally,there is a minimum IRNO_(2) at each temperature when the NO_(2) concentration is 0.03 mg/m^(3),and this minimum IRNO_(2) decreases with increasing temperature.The study explores the response mechanism of O_(3) with the change of driving variables,which can provide a scientific foundation and methodological support for the targeted management of O_(3) pollution.展开更多
The recent discovery of natural gas within the fifth member of the Xujiahe Formation(T_(3)x_(5))in the Dongfeng area within the Sichuan Basin highlights the significant exploration potential of this member.However,the...The recent discovery of natural gas within the fifth member of the Xujiahe Formation(T_(3)x_(5))in the Dongfeng area within the Sichuan Basin highlights the significant exploration potential of this member.However,the unconvincing previous understanding of the sedimentary microfacies,combined with a total lack of studies on the sand body architecture and reservoir distribution,hampers the further exploration of this member.Using core data,log curves,and seismic data,along with sedimentary microfacies analysis,this study investigated the interfaces between the sand bodies of various scales in the Dongfeng area.Furthermore,this study explored the morphological characteristics,types,and stacking patterns of these sand bodies and determined the distributions of sand bodies and reservoirs in the area.The results indicate that the first sand group of the T_(3)x_(5) member(T_(3)x^(1)_(5))exhibits delta-front deposits,including subaqueous distributary channels,sheet sands,and interdistributary bays.Seven levels of sand body interfaces are identified in the T_(3)x^(1)_(5) sand group.Among them,the interfaces of the first and second levels were identifed only in cores,those of the third and fourth levels were recog-nizable from cores combined with log curves,while those of the fifth,sixth,and seventh levels were distinguishable using seismic data.Three superimposed subaqueous distributary channel complexes are found in the Dongfeng area.Among them,complex 1 in the northwest exhibits the strongest water body energy,while complex 2 in the south displays the weakest.Complex 2 was formed earlier than com-plexes 1 and 3.Also,complex 1 is further subdivided into three vertically stacked subaqueous distrib-utary channels.The subdivision of sedimentary microfacies in the T_(3)x_(5) member reveals nine lithofacies types.Among them,stacked pancake-shaped,carbonaceous debris-bearing,massive,and cross-bedded medium-grained sandstones are considered favorable lithofacies.These four lithofacies types exhibit high porosity,as well as low natural gamma-ray(GR)values,low-to-medium deep investigate double lateral resistivity(RD),and high interval transit time(AC)on the log curves.Additionally,the reservoir distribution in the Dongfeng area was delineated based on the characterization of the favorable lith-ofacies.This study serves as a guide for future exploration and evaluation of the T_(3)x_(5) member in the Dongfeng area while also augmenting the methodologies for describing tight sandstone reservoirs.展开更多
Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the ...Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.展开更多
Uranium–molybdenum(U–Mo) alloys are critical for nuclear power generation and propulsion because of their superior thermal conductivity, irradiation stability, and anti-swelling properties. This study explores the p...Uranium–molybdenum(U–Mo) alloys are critical for nuclear power generation and propulsion because of their superior thermal conductivity, irradiation stability, and anti-swelling properties. This study explores the plastic deformation mechanisms of γ-phase U–Mo alloys using molecular dynamics(MD) simulations. In the slip model, the generalized stacking fault energy(GSFE) and the modified Peierls–Nabarro(P–N) model are used to determine the competitive relationships among different slip systems. In the twinning model, the generalized plane fault energy(GPFE) is assessed to evaluate the competition between slip and twinning. The findings reveal that among the three slip systems, the {110}<111>slip system is preferentially activated, while in the {112}<111> system, twinning is favored over slip, as confirmed by MD tensile simulations conducted in various directions. Additionally, the impact of Mo content on deformation behavior is emphasized. Insights are provided for optimizing process conditions to avoid γ → α′′ transitions, thereby maintaining a higher proportion of γ-phase U–Mo alloys for practical applications.展开更多
This paper concerns the exponential attitude-orbit coordinated control problems for gravitational-wave detection formation spacecraft systems.Notably,the large-scale communication delays resulting from oversized inter...This paper concerns the exponential attitude-orbit coordinated control problems for gravitational-wave detection formation spacecraft systems.Notably,the large-scale communication delays resulting from oversized inter-satellite distance of space-based laser interferometers are first modeled.Subject to the delayed communication behaviors,a new delay-dependent attitude-orbit coordinated controller is designed.Moreover,by reconstructing the less conservative Lyapunov-Krasovskii functional and free-weight matrices,sufficient criteria are derived to ensure the exponential stability of the closed-loop relative translation and attitude error system.Finally,a simulation example is employed to illustrate the numerical validity of the proposed controller for in-orbit detection missions.展开更多
Alumina dispersion-strengthened copper (ADSC), as a representative particle-reinforced metal matrix composite (PRMMC), exhibits superior wear resistance and high strength. However, challenges arise in their processabi...Alumina dispersion-strengthened copper (ADSC), as a representative particle-reinforced metal matrix composite (PRMMC), exhibits superior wear resistance and high strength. However, challenges arise in their processability because of the non-uniform material properties of biphasic materials. In particular, limited research has been conducted on the reinforcement mechanism and behavior of particles during material cutting deformation of PRMMC with nanoscale particles. In this study, a cutting simulation model for ADSC was established, separating the nanoscale reinforcement particles from the matrix. This model was utilized to analyze the interactions among particles, matrix, and tool during the cutting process, providing insights into chip formation and fracture. Particles with high strength and hardness are more prone to storing stress concentrations, anchoring themselves at grain boundaries to resist grain fibration, thereby influencing the stress distribution in the cutting deformation zone. Stress concentration around the particles leads to the formation of discontinuous chips, indicating that ADSC with high-volume fractions of particle (VFP) exhibits low cutting continuity, which is consistent with the results of cutting experiments. The tool tip that is in contact with particles experiences stress concentration, thereby accelerating tool wear. Cutting ADSC with 1.1% VFP results in tool blunting, which increases the radius of cutting edge from 0.5 to 1.9 μm, accompanied with remarkable coating delamination and wear. Simulation results indicate that the minimum uncut chip thickness increases from 0.04 to 0.07 μm as VFP increases from 0.3% to 1.1%. In conjunction with scratch experiments, MUCT increases with the augmentation of VFP. Computational analysis of the specific cutting force indicates that particles contribute to the material’s size effect. The results of this study provide theoretical guidance for practical engineering machining of ADSC, indicating its great importance for the process design of components made from ADSC.展开更多
As mining activities expand deeper,deep high-temperature formations seriously threaten the future safe exploitation,while deep geothermal energy has great potential for development.Combining the formation cooling and ...As mining activities expand deeper,deep high-temperature formations seriously threaten the future safe exploitation,while deep geothermal energy has great potential for development.Combining the formation cooling and geothermal mining in mines to establish a thermos-hydraulic coupling numerical model for fractured formation.The study investigates the formation heat transfer behaviour,heat recovery performance and thermal economic benefits influenced during the life cycle.The results show that the accumulation of cold energy during the cold storage phase induces a decline in formation temperature.The heat recovery phase is determined by the extent of the initial cold domain,which contracts inward from the edge and decelerates the heat recovery rate gradually.With groundwater velocity increases,the thermal regulation efficiency gradually increases,the production temperature decreases,while the effective radius and thermal power increase first and then decrease.The injected volume and temperature significantly affect,with higher injection temperatures slowing thermal recovery,and the thermal regulation efficiency is more sensitive to changes in formation permeability and thermal conductivity.The heat extraction performance is positively correlated with all factors.The levelized cost of electricity is estimated at 0.1203$/(kW·h)during the cold storage.During the heat recovery,annual profit is primarily driven by cooling benefits.展开更多
The storage layer within the Moxizhuang Oilfield in the Junggar Basin develops various types of interlayer barriers with significant differences in morphology and scale of development. In response to the issues of int...The storage layer within the Moxizhuang Oilfield in the Junggar Basin develops various types of interlayer barriers with significant differences in morphology and scale of development. In response to the issues of interlayer barriers affecting the formation of oil and gas reservoirs and controlling oil-water distribution, this study proposes precise classification and quantitative identification of interlayer barriers in the study area based on a fully connected neural network combined with grey relational analysis. Taking the second member of the Sangonghe Formation (J1S22) in the Moxizhuang Oilfield as an example, combined with previous research, this study statistically analyzes the lithology and logging response characteristics of three types of interlayer barriers in the study area. Based on differences in composition, lithology, and genesis, interlayer barrier types are classified. Sensitive logging data such as natural gamma, acoustic time difference, and resistivity are selected through crossover plots. Grey relational analysis is used to calculate comprehensive discrimination indicators for interlayer barriers. Combined with the fully connected neural network method, an interlayer barrier identification model is established, and model training is conducted to verify the accuracy of interlayer barrier identification. The results indicate that the interlayer barrier identification model based on a fully connected neural network can rapidly and accurately identify interlayer barriers and their types. Its application in the second member of the Sangonghe Formation in the Moxizhuang Oilfield in the Junggar Basin has proven that the identification results of this method for interlayer barriers have a conformity rate exceeding 90% with core data, demonstrating excellent performance in interlayer barrier identification and proving the effectiveness of the model for interlayer barrier identification and prediction in this area. The research conclusions can provide theoretical guidance and technical reference for the identification and evaluation of interlayer barriers in the second member of the Sangonghe Formation in the Moxizhuang Oilfield in the Junggar Basin.展开更多
文摘This paper presents flight results and lessons learned from the Spaceborne Autonomous Formation Flying Experiment （SAFE） conducted by the German Space Operations Center in the frame of the Swedish PRISMA technology demonstration mission. PR1SMA involves two fully autonomous formation-flying spacecraft which have been launched in June 2010 in a dawn/dusk orbit at an altitude of 750 km. SAFE represents one of the first demonstrations in low Earth orbit of an advanced guidance, navigation and control system for dual-spacecraft formations. Innovative techniques based on carrier-phase differential GPS （Global Positioning System）, relative eccentricity/inclination vectors and impulsive maneuvering are validated and tuned in orbit to achieve centimeter accurate real-time relative navigation, reliable formation keeping at the meter level and flexible formation reconfiguration capabilities. The technologies demonstrated within SAFE are considered as key precursors of future distributed satellite systems for unrivaled remote sensing and space exploration.
文摘This study investigates the effects of AI-mediated communication (AMC) on trust-building and negotiation outcomes in professional remote collaboration settings. Through a mixed-methods approach combining experimental design and qualitative analysis (N = 120), we examine how AI intermediaries influence communication dynamics, relationship building, and decision-making processes. Results indicate that while AMC initially creates barriers to trust formation, it ultimately leads to enhanced communication outcomes and stronger professional relationships when implemented with appropriate transparency and support. The study revealed a 31% improvement in cross-cultural understanding and a 24% increase in negotiation satisfaction rates when using AI-mediated channels with proper transparency measures. These findings contribute to the theoretical understanding of technology-mediated communication and practical applications for organizations implementing AI communication tools.
基金Supported by the Sinopec Major Science and Technology Project(P22081)National Natural Science Foundation of China(U24B60001).
文摘The basic geological characteristics of the Qiongzhusi Formation reservoirs and conditions for shale gas enrichment and high-yield were studied by using methods such as mineral scanning,organic and inorganic geochemistry,breakthrough pressure,and triaxial mechanics testing based on the core,logging,seismic and production data.(1)Both types of silty shale,rich in organic matter in deep water and low in organic matter in shallow water,have good gas bearing properties.(2)The brittle mineral composition of shale is characterized by comparable feldspar and quartz content.(3)The pores are mainly inorganic pores with a small amount of organic pores.Pore development primarily hinges on a synergy between felsic minerals and total organic carbon content(TOC).(4)Dominated by Type I organic matters,the hydrocarbon generating organisms are algae and acritarch,with high maturity and high hydrocarbon generation potential.(5)Deep-and shallow-water shale gas exhibit in-situ and mixed gas generation characteristics,respectively.(6)The basic law of shale gas enrichment in the Qiongzhusi Formation was proposed as“TOC controlled accumulation and inorganic pore controlled enrichment”,which includes the in-situ enrichment model of“three highs and one over”(high TOC,high felsic mineral content,high inorganic pore content,overpressured formation)for organic rich shale represented by Well ZY2,and the in-situ+carrier-bed enrichment model of“two highs,one medium and one low”(high felsic content,high formation pressure,medium inorganic pore content,low TOC)for organic-poor shale gas represented by Well JS103.It is a new type of shale gas that is different from the Longmaxi Formation,enriching the formation mechanism of deep and ultra-deep shale gas.The deployment of multiple exploration wells has achieved significant breakthroughs in shale gas exploration.
基金supported financially by China Geological Survey(Grant No.DD20230221)the Key Laboratory of Stratigraphy and Palaeontology,Ministry of Natural Resources(Grant No.KLSP SP202301)National Nature Science Foundation of China(Grant No.41202012).
文摘Twelve new dinosaur teeth have recently been recovered from three localities in the Upper Cretaceous Nenjiang Formation of the Songliao Basin.Although fragmentary,the material offers enough evidence to identify the following taxa:tyrannosaurids,dromaeosaurines,velociraptorines,hadrosauroids,and titanosaurs.In addition to the previously known dinosaurs from the basin,several new ones have been identified,extending the paleogeographic range of related taxa.The discovery of these new fossil remains provides valuable insights into dinosaur diversity and sheds light on the terrestrial ecosystem during the Late Cretaceous in the Songliao Basin.
基金supported by the National Natural Science Foundation of China(32160681 and 32060663)the National Guidance Foundation for Local Science and Technology Development of China(2023-009)+1 种基金the Guizhou Provincial Basic Research Program(Natural Science)(ZK[2022]YB132)the Foundation of Postgraduate of Guizhou Province,China(YJSKYJJ[2021]057)。
文摘Hylocereus polyrhizus,also known as pitaya or dragon fruit,is a climbing cactus grown worldwide because of its excellent performance under drought stress and appealing red-purple fruits.In practice,accelerating flower formation and inducing more flowers usually result in higher yield.However,the genes for this purpose have not been well characterized in pitaya.Previously,FLOWERING BHLHs(FBHs)have been identified as positive regulators of flower formation.In the present work,a total of eight FBHs were identified in pitaya.This is a greater number than in beet and spinach,possibly because of the recent whole-genome duplication that occurred in the pitaya genome.The phylogenetic tree indicated that the FBHs could be divided into three groups.In TYPEⅡ,the genes of Caryophyllales encode atypical FBHs and are generated by dispersed duplication.The K_(a)/K_(s) ratios indicated that HpFBHs are under purifying selection.Promoter and expression analysis of HpFBHs revealed that they are spatiotemporally activated in flower-related tissues and responsive to multiple abiotic stresses.These results indicated that HpFBHs are involved in the flower formation of pitaya.Therefore,typical HpFBH1/3 from TYPEⅡI and an atypical HpFBH8 from TYPEⅡwere selected for functional verification.HpFBH3 was found to heterodimerize with HpFBH1 in the nucleus using subcellular localization,yeast two-hybrid and luciferase complementation assays.With bioinformatic analysis,all HpFBHs were predicted to transactivate downstream genes via binding to the E-boxes,which were frequently detected in the promoters of HpCOs,HpFTs and HpSOC1s.RNA-Seq datasets showed that these flowering accelerators were expressed in coordination with HpFBH3.Yeast one-hybrid and dual-luciferase reporter assays further verified that HpFBH3 transactivated HpCO7 by selectively binding to the E-boxes in the promoter.Moreover,ectopic overexpression of HpFBH3 accelerated flower formation in Arabidopsis.In summary,this study systematically characterized the typical HpFBHs,especially HpFBH3,as positive regulators of flower formation,which could be target genes for the genetic improvement of pitaya.
基金supported by the National Natural Science Foundation of China(No.U22B6004)the Basic Research and Strategic Reserve Technology Research Project of CNPC(No.2020D-5008-01)the Scientific Research and Technology Development Project of PetroChina Exploration&Development Research Institute(Nos.2021DJ0104 and 2021DJ1808)。
文摘Controlled by fluctuating paleoclimates and sedimentary environments,the organic and inorganic features of the Lucaogou Formation exhibit strong heterogeneity in the vertical profile,challenging conventional geological interpretation.To elucidate the possible influence of heterogeneity on resource evaluation,a high-resolution sampling approach was applied to an 86.2 cm long core from the Lucaogou Formation of the Jimsar sag in the Junggar Basin.86 sets of samples were micro-drilled from the core and subjected to comparative Rock-Eval pyrolysis.Following the classical guidelines,the organic abundance,kerogen type,and maturity of source rocks were exhaustively analyzed.Experimental results revealed that organic richness and composition vary significantly under different sedimentary backgrounds,which in turn leads to differential hydrocarbon generation.The combination of hydrocarbon generation,transport,and expulsion results in peculiar patterns for hydrocarbon accumulation in the Lucaogou Formation.Laminated shales in the Lucaogou Formation serve as both hydrocarbon source rocks and reservoirs,with laminae being migration pathways.Organic-rich dolomites in the Lucaogou Formation have a considerable hydrocarbon-generating capacity and present the characteristics of self-generation and self-storage.However,massive mudstones act purely as hydrocarbon source rocks.
基金Supported by the National Natural Science Foundation of China(42172166)National Natural Science Foundation and CNPC Joint Fund Project(U23B20154)CNPC-Southwest Petroleum University Science and Technology Cooperation Project(2020CX010000).
文摘This paper discusses the characteristics and formation mechanism of thin dolomite reservoirs in the lower submember of the second member of the Permian Maokou Formation(lower Mao 2 Member)in the Wusheng-Tongnan area of the Sichuan Basin,SW China,through comprehensive analysis of geological,geophysical and geochemical data.The reservoir rocks of the lower Mao 2 Member are dominated by porphyritic vuggy dolomite and calcareous dolomite or dolomitic limestone,which have typical karst characteristics of early diagenetic stage.The dolomites at the edge of the karst system and in the fillings have dissolved estuaries,and the dolomite breccia has micrite envelope and rim cement at the edge,indicating that dolomitization is earlier than the early diagenetic karstification.The shoal facies laminated dolomite is primarily formed by the seepage reflux dolomitization of moderate-salinity seawater.The key factors of reservoir formation are the bioclastic shoal deposition superimposed with seepgae reflux dolomitization and the karstification of early diagenetic stage,which are locally reformed by fractures and hydrothermal processes.The development of dolomite vuggy reservoir is closely related to the upward-shallowing sequence,and mainly occurs in the late highstand of the fourth-order cycle.Moreover,the size of dolomite is closely related to formation thickness,and it is concentrated in the formation thickness conversion area,followed by the thinner area.According to the understanding of insufficient accommodation space in the geomorphic highland and the migration of granular shoal to geomorphic lowland in the late highstand of the third-order cycle,it is proposed that the large-scale shoal-controlled dolomite reservoirs are distributed along structural highs and slopes,and the reservoir-forming model with shoal,dolomitization and karstification jointly controlled by the microgeomorphy and sea-level fluctuation in the sedimentary period is established.On this basis,the paleogeomorphology in the lower Mao 2 Member is restored using well-seismic data,and the reservoir distribution is predicted.The prediction results have been verified by the latest results of exploration wells and tests,which provide an important reference for the prediction of thin dolomite reservoirs under similar geological setting.
基金support extended by the Joint Funds of Beijing Municipal Natural Science Foundation and Fengtai Rail Transit Frontier Research(Grant No.L211006)the Fundamental Research Funds for the Central Universities(Science and technology leading talent team project,Grant No.2022JBXT010)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2023YJS052)the National Natural Science Foundation of China(Grant No.52308426)。
文摘Investigations into rail corrugation within metro systems have traditionally focused on specific mechanisms,thereby limiting the generalizability of proposed theories.Understanding the commonalities in rail corrugation across diverse metro lines remains pivotal for elucidating its underlying mechanisms.The present study conducted extensive field surveys and tracking tests across 14 Chinese metro lines.By employing t-distributed stochastic neighbor embedding(t-SNE)for dimensional reduction and employing the unsupervised clustering algorithm DBSCAN,the research redefines the classification of metro rail corrugation based on characteristic information.The analysis encompassed spatial distribution and temporal evolution of this phenomenon.Findings revealed that floating slab tracks exhibited the highest proportion of rail corrugation at 47%.Notably,ordinary monolithic bed tracks employing damping fasteners were more prone to inducing rail corrugation.Corrugation primarily manifested in curve sections with radii between 300 and 500 m,featuring ordinary monolithic bed track and steel-spring floating slab track structures,with wavelengths typically between 30 and 120 mm.Stick–slip vibrations of the wheel–rail system maybe led to short-wavelength corrugations(40–60 mm),while longer wavelengths(200–300 mm)exhibited distinct fatigue damage characteristics,mainly observed in steel-spring floating slab tracks and small-radius curve sections of ordinary monolithic bed tracks and ladder sleeper tracks.A classification system comprising 57 correlated features categorized metro rail corrugation into four distinct types.These research outcomes serve as critical benchmarks for validating various theories pertaining to rail corrugation formation.
基金funded by the National Natural Science Foundation of China(Grant Nos.41972313 and 41790453)the Engineering Research Center of Geothermal Resources Development Technology and Equipment,Ministry of Education,Jilin University。
文摘The 7 ka old Qixiangzhan lava flow(QXZ,Tianchi volcano)represents the last eruptive event before the 946 CE,caldera-forming‘Millennium’eruption(ME).Petrographic,whole rock,mineral composition,Sr-Nd isotopic data on QXZ show that:(a)the lava consists of two components,constituted by comenditic obsidian fragments immersed in a continuous,aphanitic component;(b)both components have the same geochemical and isotopic variations of the ME magma.The QXZ and ME comendites result from fractional crystallization and crustal assimilation processes.The temperature of the QXZ magma was about 790℃ and the depth of the magma reservoir around 7 km,the same values as estimated for ME.QXZ had a viscosity of 10^(5.5)-10^(9) Pa s and a velocity of 3-10 km/yr.The emplacement time was 0.5-1.6yr and the flow rate 0.48-1.50 m^(3)/s.These values lie within the range estimated for other rhyolitic flows worldwide.The QXZ lava originated through a mixed explosive-effusive activity with the obsidian resulting from the ascent of undercooling,degassing and the fragmentation of magma along the conduit walls,whereas the aphanitic component testifies to the less undercooled and segregated flow at the center of the conduit.The QXZ lava demonstrates the extensive history of the ME magma chamber.
基金The research project is funded by the Geological Joint Fund(U2244209).
文摘The Majiagou Formation in the Fuxian area of the southeastern Ordos Basin has undergone a complex diagenetic evolution history under the influence of eustacy and the Caledonian karstification,resulting in several complex reservoir types.Through analyses of mineralogy,petrology,and reservoir geology,three major types of dolomite reservoirs with different genetic mechanisms,including anhydritic moldicdissolved pore type,dolomitic intercrystalline-pore type,and fractured type were identified,and their formation mechanisms and distribution patterns were examined.The aphanocrystalline to very finecrystalline anhydritic dolomite was resulted from Sabhak dolomitization,and is characterized by small size of crystals and high content of anhydrite.Dolomite reservoirs of anhydritic moldic-dissolved pore type were developed in multi-stage dissolution processes and mainly distributed at higher positions of the paleogeomorphology where the filling was weak.The very fine to fine-crystalline dolomite of shoal facies was formed under seepage-reflux dolomitization,and characterized by larger sizes of crystals and well-developed intercrystalline pores.Dolomite reservoirs of intercrystalline-pore type were mainly developed at the lower positions of the paleogeomorphology where bedding-parallel karst dissolution was strong.The fractured dolomite reservoirs,generated by the anhydrite swelling and karst cave collapse,occur in multiple horizons but within limited areas due to multi-stage fillings.
基金supported by Innovative Research Group Project of the National Natural Science Foundation of China(Grant Nos.42072151,42272137 and 42372144)China National Petroleum Corporation(CNPC)Forward-looking Basic and Strategic Technology Research Project(Grant No.2021DJ0205)。
文摘It is of great significance for deep oil and gas exploration to understand the origin and evolution behind overpressure.Overpressure occurs in the deep Shahezi Formation of Xujiaweizi fault depression.However,due to limited degree of exploration,there are some problems in the study area,such as unclear understanding of the origin of overpressure and the vague investigation of overpressure evolution.To clarify the impact of overpressure on oil and gas migration and accumulation in the study area,this study focuses on the research of the origin and evolution of overpressure in the Shahezi Formation of the study area,utilizing single well logging parameters and combining methods such as microthermometry of fluid inclusions,laser Raman spectrum,and basin simulation.The results show that the overpressure of the Shahezi Formation in Xujiaweizi fault depression is primarily generated by hydrocarbon generation pressurization,and the evolution of overpressure is closely related to hydrocarbon generation.The development of overpressure can be divided into two evolutionary stages:early hydrocarbon generation pressurization and late uplift release,with slight variations in different regions.Tight glutenite gas reservoirs in the Shahezi Formation are characterized by continuous charging.The overall charging period ranges from the late Denglouku to the early Mingshui(110-67 Ma ago).There is an obvious paleo-overpressure during the gas reservoir formation period.The gas generation period of source rocks occurred approximately 125-60 Ma ago,and the main gas generation period(112-67 Ma ago)highly coincides with the period of natural gas charging.The anomalously high pressure during the accumulation period is considered the significant driving force for natural gas charging.In addition,the sustained effect of overpressure provides better conditions for the preservation of tight gas reservoirs within the source.The results of the study are of guiding significance for the in-depth exploration and development of deep tight sandstone gas in the Shahezi Formation of Xujiaweizi fault depression.
基金supported by the National Key Research and Development Program of China (Nos.2022YFC3702000 and 2022YFC3703500)the Key R&D Project of Zhejiang Province (No.2022C03146).
文摘Severe ground-level ozone(O_(3))pollution over major Chinese cities has become one of the most challenging problems,which have deleterious effects on human health and the sustainability of society.This study explored the spatiotemporal distribution characteristics of ground-level O_(3) and its precursors based on conventional pollutant and meteorological monitoring data in Zhejiang Province from 2016 to 2021.Then,a high-performance convolutional neural network(CNN)model was established by expanding the moment and the concentration variations to general factors.Finally,the response mechanism of O_(3) to the variation with crucial influencing factors is explored by controlling variables and interpolating target variables.The results indicated that the annual average MDA8-90th concentrations in Zhejiang Province are higher in the northern and lower in the southern.When the wind direction(WD)ranges from east to southwest and the wind speed(WS)ranges between 2 and 3 m/sec,higher O_(3) concentration prone to occur.At different temperatures(T),the O_(3) concentration showed a trend of first increasing and subsequently decreasing with increasing NO_(2) concentration,peaks at the NO_(2) concentration around 0.02mg/m^(3).The sensitivity of NO_(2) to O_(3) formation is not easily affected by temperature,barometric pressure and dew point temperature.Additionally,there is a minimum IRNO_(2) at each temperature when the NO_(2) concentration is 0.03 mg/m^(3),and this minimum IRNO_(2) decreases with increasing temperature.The study explores the response mechanism of O_(3) with the change of driving variables,which can provide a scientific foundation and methodological support for the targeted management of O_(3) pollution.
基金funded by a SINOPEC project entitled Exploration Potential and Target Evaluation of Xujiahe Formation in the Northeastern Sichuan Basin(No.P23130).
文摘The recent discovery of natural gas within the fifth member of the Xujiahe Formation(T_(3)x_(5))in the Dongfeng area within the Sichuan Basin highlights the significant exploration potential of this member.However,the unconvincing previous understanding of the sedimentary microfacies,combined with a total lack of studies on the sand body architecture and reservoir distribution,hampers the further exploration of this member.Using core data,log curves,and seismic data,along with sedimentary microfacies analysis,this study investigated the interfaces between the sand bodies of various scales in the Dongfeng area.Furthermore,this study explored the morphological characteristics,types,and stacking patterns of these sand bodies and determined the distributions of sand bodies and reservoirs in the area.The results indicate that the first sand group of the T_(3)x_(5) member(T_(3)x^(1)_(5))exhibits delta-front deposits,including subaqueous distributary channels,sheet sands,and interdistributary bays.Seven levels of sand body interfaces are identified in the T_(3)x^(1)_(5) sand group.Among them,the interfaces of the first and second levels were identifed only in cores,those of the third and fourth levels were recog-nizable from cores combined with log curves,while those of the fifth,sixth,and seventh levels were distinguishable using seismic data.Three superimposed subaqueous distributary channel complexes are found in the Dongfeng area.Among them,complex 1 in the northwest exhibits the strongest water body energy,while complex 2 in the south displays the weakest.Complex 2 was formed earlier than com-plexes 1 and 3.Also,complex 1 is further subdivided into three vertically stacked subaqueous distrib-utary channels.The subdivision of sedimentary microfacies in the T_(3)x_(5) member reveals nine lithofacies types.Among them,stacked pancake-shaped,carbonaceous debris-bearing,massive,and cross-bedded medium-grained sandstones are considered favorable lithofacies.These four lithofacies types exhibit high porosity,as well as low natural gamma-ray(GR)values,low-to-medium deep investigate double lateral resistivity(RD),and high interval transit time(AC)on the log curves.Additionally,the reservoir distribution in the Dongfeng area was delineated based on the characterization of the favorable lith-ofacies.This study serves as a guide for future exploration and evaluation of the T_(3)x_(5) member in the Dongfeng area while also augmenting the methodologies for describing tight sandstone reservoirs.
基金Supported by Leading Talent Program of Autonomous Region(2022TSYCLJ0070)PetroChina Prospective and Basic Technological Project(2021DJ0108)Natural Science Foundation for Outstanding Young People in Shandong Province(ZR2022YQ30).
文摘Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.
基金Project supported by the National Natural Science Foundation of China (Grant No. 52271105)。
文摘Uranium–molybdenum(U–Mo) alloys are critical for nuclear power generation and propulsion because of their superior thermal conductivity, irradiation stability, and anti-swelling properties. This study explores the plastic deformation mechanisms of γ-phase U–Mo alloys using molecular dynamics(MD) simulations. In the slip model, the generalized stacking fault energy(GSFE) and the modified Peierls–Nabarro(P–N) model are used to determine the competitive relationships among different slip systems. In the twinning model, the generalized plane fault energy(GPFE) is assessed to evaluate the competition between slip and twinning. The findings reveal that among the three slip systems, the {110}<111>slip system is preferentially activated, while in the {112}<111> system, twinning is favored over slip, as confirmed by MD tensile simulations conducted in various directions. Additionally, the impact of Mo content on deformation behavior is emphasized. Insights are provided for optimizing process conditions to avoid γ → α′′ transitions, thereby maintaining a higher proportion of γ-phase U–Mo alloys for practical applications.
基金supported by the Na⁃tional Key R&D Program of China(No.2022YFC2204800)the Graduate Student Independent Exploration and Innovation Program of Central South University(No.2024ZZTS 0767).
文摘This paper concerns the exponential attitude-orbit coordinated control problems for gravitational-wave detection formation spacecraft systems.Notably,the large-scale communication delays resulting from oversized inter-satellite distance of space-based laser interferometers are first modeled.Subject to the delayed communication behaviors,a new delay-dependent attitude-orbit coordinated controller is designed.Moreover,by reconstructing the less conservative Lyapunov-Krasovskii functional and free-weight matrices,sufficient criteria are derived to ensure the exponential stability of the closed-loop relative translation and attitude error system.Finally,a simulation example is employed to illustrate the numerical validity of the proposed controller for in-orbit detection missions.
基金supported by the National Key R&D Program of China(Grant No.2023YFC2413303)the National Natural Science Foundation of China(Grant No.52075128)the Natural Science Foundation of Heilongjiang Province,China(Grant No.YQ2020E013).
文摘Alumina dispersion-strengthened copper (ADSC), as a representative particle-reinforced metal matrix composite (PRMMC), exhibits superior wear resistance and high strength. However, challenges arise in their processability because of the non-uniform material properties of biphasic materials. In particular, limited research has been conducted on the reinforcement mechanism and behavior of particles during material cutting deformation of PRMMC with nanoscale particles. In this study, a cutting simulation model for ADSC was established, separating the nanoscale reinforcement particles from the matrix. This model was utilized to analyze the interactions among particles, matrix, and tool during the cutting process, providing insights into chip formation and fracture. Particles with high strength and hardness are more prone to storing stress concentrations, anchoring themselves at grain boundaries to resist grain fibration, thereby influencing the stress distribution in the cutting deformation zone. Stress concentration around the particles leads to the formation of discontinuous chips, indicating that ADSC with high-volume fractions of particle (VFP) exhibits low cutting continuity, which is consistent with the results of cutting experiments. The tool tip that is in contact with particles experiences stress concentration, thereby accelerating tool wear. Cutting ADSC with 1.1% VFP results in tool blunting, which increases the radius of cutting edge from 0.5 to 1.9 μm, accompanied with remarkable coating delamination and wear. Simulation results indicate that the minimum uncut chip thickness increases from 0.04 to 0.07 μm as VFP increases from 0.3% to 1.1%. In conjunction with scratch experiments, MUCT increases with the augmentation of VFP. Computational analysis of the specific cutting force indicates that particles contribute to the material’s size effect. The results of this study provide theoretical guidance for practical engineering machining of ADSC, indicating its great importance for the process design of components made from ADSC.
基金financial support from the National Natural Science Foundation of China(Nos.52434006,52374151,and 51927808)。
文摘As mining activities expand deeper,deep high-temperature formations seriously threaten the future safe exploitation,while deep geothermal energy has great potential for development.Combining the formation cooling and geothermal mining in mines to establish a thermos-hydraulic coupling numerical model for fractured formation.The study investigates the formation heat transfer behaviour,heat recovery performance and thermal economic benefits influenced during the life cycle.The results show that the accumulation of cold energy during the cold storage phase induces a decline in formation temperature.The heat recovery phase is determined by the extent of the initial cold domain,which contracts inward from the edge and decelerates the heat recovery rate gradually.With groundwater velocity increases,the thermal regulation efficiency gradually increases,the production temperature decreases,while the effective radius and thermal power increase first and then decrease.The injected volume and temperature significantly affect,with higher injection temperatures slowing thermal recovery,and the thermal regulation efficiency is more sensitive to changes in formation permeability and thermal conductivity.The heat extraction performance is positively correlated with all factors.The levelized cost of electricity is estimated at 0.1203$/(kW·h)during the cold storage.During the heat recovery,annual profit is primarily driven by cooling benefits.
文摘The storage layer within the Moxizhuang Oilfield in the Junggar Basin develops various types of interlayer barriers with significant differences in morphology and scale of development. In response to the issues of interlayer barriers affecting the formation of oil and gas reservoirs and controlling oil-water distribution, this study proposes precise classification and quantitative identification of interlayer barriers in the study area based on a fully connected neural network combined with grey relational analysis. Taking the second member of the Sangonghe Formation (J1S22) in the Moxizhuang Oilfield as an example, combined with previous research, this study statistically analyzes the lithology and logging response characteristics of three types of interlayer barriers in the study area. Based on differences in composition, lithology, and genesis, interlayer barrier types are classified. Sensitive logging data such as natural gamma, acoustic time difference, and resistivity are selected through crossover plots. Grey relational analysis is used to calculate comprehensive discrimination indicators for interlayer barriers. Combined with the fully connected neural network method, an interlayer barrier identification model is established, and model training is conducted to verify the accuracy of interlayer barrier identification. The results indicate that the interlayer barrier identification model based on a fully connected neural network can rapidly and accurately identify interlayer barriers and their types. Its application in the second member of the Sangonghe Formation in the Moxizhuang Oilfield in the Junggar Basin has proven that the identification results of this method for interlayer barriers have a conformity rate exceeding 90% with core data, demonstrating excellent performance in interlayer barrier identification and proving the effectiveness of the model for interlayer barrier identification and prediction in this area. The research conclusions can provide theoretical guidance and technical reference for the identification and evaluation of interlayer barriers in the second member of the Sangonghe Formation in the Moxizhuang Oilfield in the Junggar Basin.
