1.Objective The Songliao Basin(SB)is situated on the eastern margin of Eurasia continent(Northeast Asia).During the Late Jurassic to Early Cretaceous,hundreds of rifting basins developed in this area,and the SB is a u...1.Objective The Songliao Basin(SB)is situated on the eastern margin of Eurasia continent(Northeast Asia).During the Late Jurassic to Early Cretaceous,hundreds of rifting basins developed in this area,and the SB is a unique case among them as it evolved into the largest rift basin.The rift basin filling of SB includes Huoshiling Formation,Shahezi Formation,and Yingcheng Formation in ascending order.The mega-rifting was controlled by the Mongol-Okhotsk Collisional Belt to the north and northwest and the Pacific Subduction Zone to the east(Wang PJ et al.,2016).As the first rifting succession,the Huoshiling Formation contains key information about the formation of the rifting basins and records the evolution of the Mongol-Okhotsk Collisional Belt and the Pacific Subduction Zone.However,the geological period of the Huoshiling Formation has not been well constrained for two main reasons.First,it is easily confused with the Yingcheng Formation,as both are dominated by volcanogenic-sedimentary successions.Second,there is lack of reliable dating samples from the uppermost part of the Huoshiling Formation due to its considerable burial depth.展开更多
In addition to its well-known fossils,the Upper Miocene Baogeda Ula Formation is coupled with multiple basaltic lava flows,creating an ideal setting for studying its depositional history,geochronology,and associated v...In addition to its well-known fossils,the Upper Miocene Baogeda Ula Formation is coupled with multiple basaltic lava flows,creating an ideal setting for studying its depositional history,geochronology,and associated vertebrate fossils.This paper,in honor of Prof.Qiu Zhanxiang for his widely admired emphasis on the geological contexts of vertebrate fossils,attempts to synthesize known contact relationships,existing K-Ar dates,and capping basalt elevations to reframe our concept of the lithostratigraphy,magnetostratigraphy,and lateral distribution of the Baogeda Ula Formation.Within this new framework,the Baogeda Ula Formation is defined by unconformable contact with the underlying Tunggur Formation at the lower boundary and a capping basalt at the upper boundary.In many sections,two or three layers of basalts are interbedded within sedimentary strata,with the capping basalts typically belonging to the top two basalts.The newly defined Baogeda Ula Formation includes a lower member as exemplified by Halajin Hushu section and Ulan Hushuyin Nur section,and an upper member at Baogeda Ula section.This expanded concept of the Baogeda Ula Formation includes two major faunas,i.e.,the Bahean Halajin Hushu Fauna and Baodean Baogeda Ula Fauna,both falling within the Upper Miocene.We also describe rare fossil skunks(Promephitis)found in recent years that support the age assessments presented herein.展开更多
The multi-satellite electromagnetic formation flight system is nonlinear and strongly coupled,which makes modeling and optimization challenging.To simplify electromagnetic force evaluation and dynamics modeling,we int...The multi-satellite electromagnetic formation flight system is nonlinear and strongly coupled,which makes modeling and optimization challenging.To simplify electromagnetic force evaluation and dynamics modeling,we introduce a reference frame consistent with each satellite body frame,in which the electromagnetic dipoles and electromagnetic forces are represented as two-dimensional vectors.Then,the maneuver time is divided into time intervals,and different satellite sets are activated in each interval,converting the multi-satellite formation reconfiguration problem into an optimal trajectory problem of each two-satellite subsystem.To this end,a token-based dynamic programming method with a switching penalty of active satellite sets is proposed to determine the sequence of satellite sets participating in each time interval,thereby enabling all satellites to reach their desired states.For the two-satellite subsystem with the objectives of minimizing maneuver time and energy consumption,the Gauss pseudo-spectral method is employed to generate the optimal reconfiguration trajectory.Numerical simulations verify the effectiveness of the proposed optimization method.展开更多
This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relativ...This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.展开更多
Dear Editor,This letter addresses the formation control problem for unmanned surface vehicles(USVs)under GPS-denied environments.A novel visual servo formation control scheme,utilizing a monocular camera on the follow...Dear Editor,This letter addresses the formation control problem for unmanned surface vehicles(USVs)under GPS-denied environments.A novel visual servo formation control scheme,utilizing a monocular camera on the follower to obtain the leader’s global position,is developed,which is also capable of guaranteeing collision avoidance and visibility maintenance(CA&VM)raised by the requirement of actual formation navigation.展开更多
Foodborne bacteria produce biofilms and their viable but non-culturable(VBNC)formation,can affect food quality and safety.Studies have shown that these characteristics are regulated by the bacterial quorum sensing(QS)...Foodborne bacteria produce biofilms and their viable but non-culturable(VBNC)formation,can affect food quality and safety.Studies have shown that these characteristics are regulated by the bacterial quorum sensing(QS)system.Quenching the QS system of foodborne bacteria and blocking the expression of the corresponding genes may be an effective way to improve food quality and safety.Therefore,this article reviews the QS systems for foodborne bacteria,the regulatory mechanisms of QS systems in biofilm and VBNC formation and resuscitation,the research progress on quorum sensing inhibitors(QSIs)for Gram-negative and Gram-positive bacteria,and introduces QSIs from various sources.In addition,we have also summarized the current research issues on QS regulation of biofilms and VBNC formation.The systematic study of the QS phenomenon of foodborne bacteria in practical situations,the mechanism of bacterial QS cooperation-cheating,the screening of novel and highly active QSIs,the combination of QSIs and other technologies to improve their bioavailability,and the regulatory network between biofilm and VBNC formation and resuscitation are research directions that need to be paid attention to in the future.展开更多
Osteoporosis is a systemic skeletal disorder characterized by reduced bone mass,compromised bone microstructure,and an increased risk of fractures,primarily due to excessive osteoclast-mediated bone resorption relativ...Osteoporosis is a systemic skeletal disorder characterized by reduced bone mass,compromised bone microstructure,and an increased risk of fractures,primarily due to excessive osteoclast-mediated bone resorption relative to osteoblast-mediated bone formation.While current anti-osteoporosis drugs,such as bisphosphonates and denosumab,predominantly focus on reducing bone resorption,osteoanabolic approaches are essential for restoring bone microarchitecture and ultimately reducing fracture risk.Traditional Chinese medicines(TCMs)and their active ingredients have long been used in China for osteoporosis prevention and treatment.This review provides a comprehensive evaluation of the effects and molecular mechanisms of 65 natural products across 24 categories on osteoblast-mediated bone formation.These compounds promote bone formation by regulating key transcription factors(RUNX2 and Osterix)and signaling pathways,including WNT/β-catenin,bone morphogenic protein(BMP),mitogen-activated protein kinase(MAPK),phosphoinositide 3-kinase/protein kinase B(PI3K/AKT),oxidative stress,autophagy,and epigenetic regulation.Notably,certain natural products[e.g.,icariin(ICA)]exert their effects through multiple targets and pathways.Many of these natural products have demonstrated significant therapeutic efficacy in animal models,such as ovariectomized(OVX)mice.Our findings suggest that natural products with kidney-tonifying,anti-inflammatory,and antioxidant properties,as well as those inhibiting adipocyte differentiation,may hold promise for osteoporosis treatment.Additionally,we highlight current research gaps and propose future directions,including high-throughput screening and validation in diverse animal models,development of novel bone-targeting delivery systems,and identification of natural compounds targeting osteocytes.展开更多
The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have bee...The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.展开更多
Quantonenpollenites,a pollen taxon which was assumed to be angiosperm,is of great significance in confirming the geological age of its bearing strata.Aims to clarify the taxonomic affiliation of Quantonenpollenites,we...Quantonenpollenites,a pollen taxon which was assumed to be angiosperm,is of great significance in confirming the geological age of its bearing strata.Aims to clarify the taxonomic affiliation of Quantonenpollenites,we investigated the external morphology and internal structure using Light Microscopy(LM),Scanning Electron Microscopy(SEM),and Transmission Electron Microscopy(TEM).According to TEM observations,the exine of Quantonenpollenites pollen is unstratified with the absence of a columellar layer,and the exine is tightly connected with the intine.Based on comprehensive morphological evidence,especially the lack of columellar layer which is typical characteristics existing in almost all angiosperm pollen,the botanical affinity of Quantonenpollenites should be attributed to gymnosperms rather than angiosperms as previously thought.Through comparative analysis,it may have a close affinity with Ephedra,but further analytical data are still needed for verification.As a characteristic palynological type of the Quantou Formation in the Songliao Basin,the occurrence of Quantonenpollenites has indicative significance for determining the age of the hosting strata.By systematically clarifying the phylogenetic affiliation of Quantonenpollenites,together with the other associated palynomorphs,this study provides crucial reference materials for defining the stratigraphic age range of the Quantou Formation(Cenomanian to early Turonian),improves the resolution of stratigraphic age calibration of the Quantou Formation,and provides key paleontological evidence for the refined division of the terrestrial Cretaceous chronostratigraphic framework in the Songliao Basin.展开更多
Formation control of multiple spacecraft has attracted extensive research attention.However,achieving reliable performance under sensor failures remains a significant challenge.This paper develops an integrated framew...Formation control of multiple spacecraft has attracted extensive research attention.However,achieving reliable performance under sensor failures remains a significant challenge.This paper develops an integrated framework that jointly designs distributed observers and local controllers to ensure robust formation control in the presence of external disturbances and sensor malfunctions.Treating the spacecraft formation as a single interconnected system,each spacecraft constructs a distributed observer that estimates the overall system state by incorporating both its own measurements and the predicted control information shared among the spacecraft.Based on the observer estimates,a local control law is synthesized to maintain the desired formation.Rigorous theoretical analysis and numerical simulations demonstrate that the proposed integrated approach effectively guarantees formation stability and resilience against sensor failures and disturbances.展开更多
Five new small theropod teeth and one manual ungual have recently been recovered from the Upper Cretaceous Nenjiang Formation in the Songliao Basin.The specimens were examined for their morphological characteristics,l...Five new small theropod teeth and one manual ungual have recently been recovered from the Upper Cretaceous Nenjiang Formation in the Songliao Basin.The specimens were examined for their morphological characteristics,leading to the identification of four distinct taxa.The first taxon consists of three foliodont teeth characterized by a pronounced basal constriction and large hook-like distal denticles,which can be attributed to Troodontidae.The second taxon is represented by an elongated tooth featuring prominent longitudinal ridges,allowing for its assignment to Paronychodon.The third taxon is a bladelike tooth with notably small distal denticles,corresponding to Richardoestesia.The fourth taxon comprises a manual ungual characterized by a transversely wide and nearly symmetrical proximal articular surface,fully enclosed ventral foramina,a flattened ventral surface,and the absence of a flexor tubercle,resembling Alvarezsauridae.These specimens significantly enhance the known dinosaur diversity of the Nenjiang Formation and provide crucial insights for understanding the terrestrial ecosystem in Northeast Asia during the Late Cretaceous.展开更多
This study investigates the facies development and sedimentology of the Late Permian Chhidru Formation,a mixed carbonate-siliciclastic unit exposed in the Western Salt Range,Potwar Basin,Pakistan.The formation is subd...This study investigates the facies development and sedimentology of the Late Permian Chhidru Formation,a mixed carbonate-siliciclastic unit exposed in the Western Salt Range,Potwar Basin,Pakistan.The formation is subdivided into four lithological units reflecting lateral variability,with thicknesses and lithologies ranging from fossiliferous sandy limestone to interbedded limestone and sandstone.These successions record a depositional shift from a carbonate platform to mixed carbonate-clastic,and ultimately,clastic-dominated environments.Lithostratigraphy suggests deposition on the underlying Wargal Limestone carbonates during a Late Permian sea-level fall on the northwest Indian margin of Gondwana.Similar Permian successions with identical lithological characteristics are documented in the Persian Gulf(Dalan Formation),Arabian Platform(Khuff Formation),and Iran(Nesen and Hambust formations).Petrographic analysis reveals deposition in the distal middle to proximal inner shelf settings of a carbonate-siliciclastic mixed,unrimmed platform.Based on identified foraminiferal assemblages,the Chhidru Formation's age is estimated to range from the late Wuchiapingian to Changhsingian stages of the Lopingian epoch.展开更多
This paper presents an adaptive formation control method for a heterogeneous robot swarm,utilising a multilevel formation task tree to model various types of formation tasks and a single-state distributed k-winner-tak...This paper presents an adaptive formation control method for a heterogeneous robot swarm,utilising a multilevel formation task tree to model various types of formation tasks and a single-state distributed k-winner-take-all(S-DKWTA)algorithm to address the MRTA problem.In addition,we propose an enhanced load reassignment algorithm to resolve conflicts when using S-DKWTA.The S-DKWTA algorithm demonstrates the capability to manage multiple objectives and dynamically select leaders in real-time,thereby optimising formation efficiency and reducing energy consumption.The proposed approach integrates an enhanced artificial potential field(APF)to govern the motion of heterogeneous robot systems which encompasses both unmanned ground vehicles(UGVs)and unmanned aerial vehicles(UAVs),thereby achieving collision and obstacle avoidance.Simulations employing UGVs and UAVs swarm to achieve formation movement demonstrate the efficacy of this approach.The amalgamation of S-DKWTA and improved APF ensures stable and adaptable formation control,underscoring its potential for diverse multirobot applications.展开更多
A clear goal in cold tumor research is to identify strategies for converting them into immunologically‘hot’tumors with enhanced immune cell infiltration and activity,thereby improving their responsiveness to immunot...A clear goal in cold tumor research is to identify strategies for converting them into immunologically‘hot’tumors with enhanced immune cell infiltration and activity,thereby improving their responsiveness to immunotherapy.The genesis of cold tumors is exceedingly intricate.In recent times,as the analysis of this phenomenon has been pursued with greater depth,a suite of advanced diagnostic and therapeutic technologies has surfaced.These novel approaches and tactics are anticipated to modulate the tumor immune microenvironment across various dimensions,thereby facilitating the advancement of personalized and precise treatment modalities for cold tumors.The present article addresses the challenge of diminished therapeutic responsiveness to“cold tumors”within clinical settings.It systematically elucidates the multi-faceted regulatory mechanisms underlying immune evasion in cold tumors and offers a detailed analysis of advanced therapeutic strategies that incorporate nanotechnology,gene editing,and artificial intelligence methodologies.Furthermore,the future development trends of immunotherapy were explored in greater depth.It was posited that the convergence of artificial intelligence,multidimensional genomics,and emerging biotechnologies has presented positive prospects for the treatment of cold tumors,and has offered a theoretical foundation and technical framework for the transformation of cold tumors into“hot tumors”.展开更多
Conventional error cancellation approaches separate molecules into smaller fragments and sum the errors of all fragments to counteract the overall computational error of the parent molecules.However,these approaches m...Conventional error cancellation approaches separate molecules into smaller fragments and sum the errors of all fragments to counteract the overall computational error of the parent molecules.However,these approaches may be ineffective for systems with strong localized chemical effects,as fragmenting specific substructures into simpler chemical bonds can introduce additional errors instead of mitigating them.To address this issue,we propose the Substructure-Preserved Connection-Based Hierarchy(SCBH),a method that automatically identifies and freezes substructures with significant local chemical effects prior to molecular fragmentation.The SCBH is validated by the gas-phase enthalpy of formation calculation of CHNO molecules.Therein,based on the atomization scheme,the reference and test values are derived at the levels of Gaussian-4(G4)and M062X/6-31+G(2df,p),respectively.Compared to commonly used approaches,SCBH reduces the average computational error by half and requires only15%of the computational cost of G4 to achieve comparable accuracy.Since different types of local effect structures have differentiated influences on gas-phase enthalpy of formation,substituents with strong electronic effects should be retained preferentially.SCBH can be readily extended to diverse classes of organic compounds.Its workflow and source code allow flexible customization of molecular moieties,including azide,carboxyl,trinitromethyl,phenyl,and others.This strategy facilitates accurate,rapid,and automated computations and corrections,making it well-suited for high-throughput molecular screening and dataset construction for gas-phase enthalpy of formation.展开更多
Researchers are increasingly focused on enabling groups of multiple unmanned vehicles to operate cohesively in complex,real-world environments,where coordinated formation control and obstacle avoidance are essential f...Researchers are increasingly focused on enabling groups of multiple unmanned vehicles to operate cohesively in complex,real-world environments,where coordinated formation control and obstacle avoidance are essential for executing sophisticated collective tasks.This paper presents a Distributed Formation Control and Obstacle Avoidance(DFCOA)framework for multi-unmanned ground vehicles(UGV).DFCOA integrates a virtual leader structure for global guidance,an improved A^(*)path planning algorithm with an advanced cost function for efficient path planning,and a repulsive-force-based improved vector field histogram star(VFH^(*))technique for collision avoidance.The virtual leader generates a reference trajectory while enabling distributed execution;the improved A^(*)algorithm reduces planning time and number of nodes to determine the shortest path from the starting position to the goal;and the improved VFH^(*)uses 2D LiDAR data with inter-agent repulsive force to simultaneously avoid collision with obstacles and maintain safe inter-vehicle distances.The formation stability of the proposed DFCOA reaches 95.8%and 94.6%in two scenarios,with root mean square(RMS)centroid errors of 0.9516 and 1.0008 m,respectively.Velocity tracking is precise(velocity centroid error RMS of 0.2699 and 0.1700 m/s),and linear velocities closely match the desired 0.3 m/s.Safety metrics showed average collision risks of 0.7773 and 0.5143,with minimum inter-vehicle distances of 0.4702 and 0.8763 m,confirming collision-free navigation of four UGVs.DFCOA outperforms conventional methods in formation stability,path efficiency,and scalability,proving its suitability for decentralized multi-UGV applications.展开更多
Cholelithiasis has a complex pathogenesis,necessitating better therapeutic and preventive strategies.We recently read with interest Wang et al’s study on lysine acetyltransferase 2A(KAT2A)-mediated adenosine monophos...Cholelithiasis has a complex pathogenesis,necessitating better therapeutic and preventive strategies.We recently read with interest Wang et al’s study on lysine acetyltransferase 2A(KAT2A)-mediated adenosine monophosphate-activated protein kinase(AMPK)succinylation in cholelithiasis.Using mouse models and gallbladder mucosal epithelial cells,they found that KAT2A inhibits gallstones through AMPK K170 succinylation,thereby activating the AMPK/silent information regulator 1 pathway to reduce inflammation and pyroptosis.This study is the first to connect lysine succinylation with cholelithiasis,offering new insights and identifying succinylation as a potential therapeutic target.Future research should confirm these findings using patient samples,investigate other posttranslational modifications,and use structural biology to clarify succinylationinduced conformational changes,thereby bridging basic research to clinical applications.展开更多
This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization usin...This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.展开更多
Although the concentration of fine particulate matter(PM_(2.5))is reducing continuously,the proportion of secondary organic aerosols(SOA)in PM_(2.5) and the O_(3) levels are increasing.This is causing severe complex a...Although the concentration of fine particulate matter(PM_(2.5))is reducing continuously,the proportion of secondary organic aerosols(SOA)in PM_(2.5) and the O_(3) levels are increasing.This is causing severe complex atmospheric pollution in North China.It is essential to identify and quantify the driving factors of SOA and O_(3),including the various pollution sources and meteorological factors.PM_(2.5) and volatile organic compounds(VOCs)samples were collected simultaneously in three cities in Shandong Province during different pollution scenarios from 2021 to 2023.Then,the carbonaceous aerosol and 99 VOC species were analyzed.Random forest(RF)combined with positive matrix factorization and an observation-based model(OBM)were used to quantify the key drivers of SOA and O_(3).Aromatic hydrocarbons were the main contributors to secondary organic aerosol potential(74.3%-89.9%),whereas alkenes contributed the most to the ozone formation potential(27.0%-62.3%).The RF modeling identified temperature and NOx as the dominant drivers of ozone formation.These accounted for 47.8%and 17.4%,respectively.Temperature showed a positive correlation with O_(3) because an increase in temperature can promote ozone formation.NOx had a significant negative correlation with O_(3),which was consistent with the conclusions from the sensitivity analysis of the OBM.The dominant contributors to SOA were vehicle emissions,solvent use,and industrial emissions.These accounted for 43.9%,18.2%,and 10.5%,respectively.An evident positive correlation existed between these emission sources and SOA.展开更多
Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagati...Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagation behavior.To address the unclear mechanisms governing fracture penetration across coal-gangue interfaces,this study employs the Continuum-Discontinuum Element Method(CDEM)to simulate and analyze the vertical propagation of hydraulic fractures initiating within coal seams,based on geomechanical parameters derived from the deep Benxi Formation coal seams in the southeastern Ordos Basin.The investigation systematically examines the influence of geological and operational parameters on cross-interfacial fracture growth.Results demonstrate that vertical stress difference,elastic modulus contrast between coal and gangue layers,interfacial stress differential,and interfacial cohesion at coal-gangue interfaces are critical factors governing hydraulic fracture penetration through these interfaces.High vertical stress differences(>3 MPa)inhibit interfacial dilation,promoting predominant crosslayer fracture propagation.Reduced interfacial stress contrasts and enhanced interfacial cohesion facilitate fracture penetration across interfaces.Furthermore,smaller elastic modulus contrasts between coal and gangue correlate with increased interfacial aperture.Finally,lower injection rates effectively suppress vertical fracture propagation in deep coal reservoirs.This study elucidates the characteristics and mechanisms governing cross-layer fracture propagation in coal–rock composites with interbedded partings,and delineates the dynamic evolution laws and dominant controlling factors involved.Thefindings provide critical theoretical insights for the optimization of fracture design and the efficient development of deep coalbed methane reservoirs.展开更多
基金supported by the National Natural Science Foundation of China(42102135,42072140,42202122 and 41790453)Science and Technology Research Program of Chongqing Municipal Education Commission(KJZD-M202101502,KJQN202201549 and KJQN202101535)+1 种基金Natural Science Foundation of Chongqing(CSTB2022NSCQ-JQX0031 and CSTB2022NSCQMSX1586)China Scholarship Council(202208505055)。
文摘1.Objective The Songliao Basin(SB)is situated on the eastern margin of Eurasia continent(Northeast Asia).During the Late Jurassic to Early Cretaceous,hundreds of rifting basins developed in this area,and the SB is a unique case among them as it evolved into the largest rift basin.The rift basin filling of SB includes Huoshiling Formation,Shahezi Formation,and Yingcheng Formation in ascending order.The mega-rifting was controlled by the Mongol-Okhotsk Collisional Belt to the north and northwest and the Pacific Subduction Zone to the east(Wang PJ et al.,2016).As the first rifting succession,the Huoshiling Formation contains key information about the formation of the rifting basins and records the evolution of the Mongol-Okhotsk Collisional Belt and the Pacific Subduction Zone.However,the geological period of the Huoshiling Formation has not been well constrained for two main reasons.First,it is easily confused with the Yingcheng Formation,as both are dominated by volcanogenic-sedimentary successions.Second,there is lack of reliable dating samples from the uppermost part of the Huoshiling Formation due to its considerable burial depth.
文摘In addition to its well-known fossils,the Upper Miocene Baogeda Ula Formation is coupled with multiple basaltic lava flows,creating an ideal setting for studying its depositional history,geochronology,and associated vertebrate fossils.This paper,in honor of Prof.Qiu Zhanxiang for his widely admired emphasis on the geological contexts of vertebrate fossils,attempts to synthesize known contact relationships,existing K-Ar dates,and capping basalt elevations to reframe our concept of the lithostratigraphy,magnetostratigraphy,and lateral distribution of the Baogeda Ula Formation.Within this new framework,the Baogeda Ula Formation is defined by unconformable contact with the underlying Tunggur Formation at the lower boundary and a capping basalt at the upper boundary.In many sections,two or three layers of basalts are interbedded within sedimentary strata,with the capping basalts typically belonging to the top two basalts.The newly defined Baogeda Ula Formation includes a lower member as exemplified by Halajin Hushu section and Ulan Hushuyin Nur section,and an upper member at Baogeda Ula section.This expanded concept of the Baogeda Ula Formation includes two major faunas,i.e.,the Bahean Halajin Hushu Fauna and Baodean Baogeda Ula Fauna,both falling within the Upper Miocene.We also describe rare fossil skunks(Promephitis)found in recent years that support the age assessments presented herein.
文摘The multi-satellite electromagnetic formation flight system is nonlinear and strongly coupled,which makes modeling and optimization challenging.To simplify electromagnetic force evaluation and dynamics modeling,we introduce a reference frame consistent with each satellite body frame,in which the electromagnetic dipoles and electromagnetic forces are represented as two-dimensional vectors.Then,the maneuver time is divided into time intervals,and different satellite sets are activated in each interval,converting the multi-satellite formation reconfiguration problem into an optimal trajectory problem of each two-satellite subsystem.To this end,a token-based dynamic programming method with a switching penalty of active satellite sets is proposed to determine the sequence of satellite sets participating in each time interval,thereby enabling all satellites to reach their desired states.For the two-satellite subsystem with the objectives of minimizing maneuver time and energy consumption,the Gauss pseudo-spectral method is employed to generate the optimal reconfiguration trajectory.Numerical simulations verify the effectiveness of the proposed optimization method.
文摘This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.
基金supported by the National Natural Science Foundation of China(62421004,U24A20279,62473243,62533004)。
文摘Dear Editor,This letter addresses the formation control problem for unmanned surface vehicles(USVs)under GPS-denied environments.A novel visual servo formation control scheme,utilizing a monocular camera on the follower to obtain the leader’s global position,is developed,which is also capable of guaranteeing collision avoidance and visibility maintenance(CA&VM)raised by the requirement of actual formation navigation.
基金financially supported by the National Natural Science Foundation of China(32202191)and(32272279)the Key R&D Project of Shandong Province(2023CXPT007 and 2024CXPT014)the Key R&D Project of Qingdao Science and Technology Plan(24-2-3-4-zyyd-jch).
文摘Foodborne bacteria produce biofilms and their viable but non-culturable(VBNC)formation,can affect food quality and safety.Studies have shown that these characteristics are regulated by the bacterial quorum sensing(QS)system.Quenching the QS system of foodborne bacteria and blocking the expression of the corresponding genes may be an effective way to improve food quality and safety.Therefore,this article reviews the QS systems for foodborne bacteria,the regulatory mechanisms of QS systems in biofilm and VBNC formation and resuscitation,the research progress on quorum sensing inhibitors(QSIs)for Gram-negative and Gram-positive bacteria,and introduces QSIs from various sources.In addition,we have also summarized the current research issues on QS regulation of biofilms and VBNC formation.The systematic study of the QS phenomenon of foodborne bacteria in practical situations,the mechanism of bacterial QS cooperation-cheating,the screening of novel and highly active QSIs,the combination of QSIs and other technologies to improve their bioavailability,and the regulatory network between biofilm and VBNC formation and resuscitation are research directions that need to be paid attention to in the future.
基金supported by the National Natural Science Foundation of China(No.31800059)。
文摘Osteoporosis is a systemic skeletal disorder characterized by reduced bone mass,compromised bone microstructure,and an increased risk of fractures,primarily due to excessive osteoclast-mediated bone resorption relative to osteoblast-mediated bone formation.While current anti-osteoporosis drugs,such as bisphosphonates and denosumab,predominantly focus on reducing bone resorption,osteoanabolic approaches are essential for restoring bone microarchitecture and ultimately reducing fracture risk.Traditional Chinese medicines(TCMs)and their active ingredients have long been used in China for osteoporosis prevention and treatment.This review provides a comprehensive evaluation of the effects and molecular mechanisms of 65 natural products across 24 categories on osteoblast-mediated bone formation.These compounds promote bone formation by regulating key transcription factors(RUNX2 and Osterix)and signaling pathways,including WNT/β-catenin,bone morphogenic protein(BMP),mitogen-activated protein kinase(MAPK),phosphoinositide 3-kinase/protein kinase B(PI3K/AKT),oxidative stress,autophagy,and epigenetic regulation.Notably,certain natural products[e.g.,icariin(ICA)]exert their effects through multiple targets and pathways.Many of these natural products have demonstrated significant therapeutic efficacy in animal models,such as ovariectomized(OVX)mice.Our findings suggest that natural products with kidney-tonifying,anti-inflammatory,and antioxidant properties,as well as those inhibiting adipocyte differentiation,may hold promise for osteoporosis treatment.Additionally,we highlight current research gaps and propose future directions,including high-throughput screening and validation in diverse animal models,development of novel bone-targeting delivery systems,and identification of natural compounds targeting osteocytes.
基金supported by the National Natural Science Foundation of China(Grant Nos.12534013,12047561,and 12104507)the Science and Technology Innovation Program of Hunan Province(Grant Nos.2025ZYJ001 and 2021RC4026)the National University of Defense Technology Research Fund Project.
文摘The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.
基金supported by the National Key Research and Development Program of China (2023YFC2906701)National Natural Science Foundation of China (42372041, 42072027)China Geological Survey (DD20221646)
文摘Quantonenpollenites,a pollen taxon which was assumed to be angiosperm,is of great significance in confirming the geological age of its bearing strata.Aims to clarify the taxonomic affiliation of Quantonenpollenites,we investigated the external morphology and internal structure using Light Microscopy(LM),Scanning Electron Microscopy(SEM),and Transmission Electron Microscopy(TEM).According to TEM observations,the exine of Quantonenpollenites pollen is unstratified with the absence of a columellar layer,and the exine is tightly connected with the intine.Based on comprehensive morphological evidence,especially the lack of columellar layer which is typical characteristics existing in almost all angiosperm pollen,the botanical affinity of Quantonenpollenites should be attributed to gymnosperms rather than angiosperms as previously thought.Through comparative analysis,it may have a close affinity with Ephedra,but further analytical data are still needed for verification.As a characteristic palynological type of the Quantou Formation in the Songliao Basin,the occurrence of Quantonenpollenites has indicative significance for determining the age of the hosting strata.By systematically clarifying the phylogenetic affiliation of Quantonenpollenites,together with the other associated palynomorphs,this study provides crucial reference materials for defining the stratigraphic age range of the Quantou Formation(Cenomanian to early Turonian),improves the resolution of stratigraphic age calibration of the Quantou Formation,and provides key paleontological evidence for the refined division of the terrestrial Cretaceous chronostratigraphic framework in the Songliao Basin.
基金supported by the National Natural Science Foundation of China(62088101,62522307,62273045,U2341213)Beijing Nova Program(20230484481)。
文摘Formation control of multiple spacecraft has attracted extensive research attention.However,achieving reliable performance under sensor failures remains a significant challenge.This paper develops an integrated framework that jointly designs distributed observers and local controllers to ensure robust formation control in the presence of external disturbances and sensor malfunctions.Treating the spacecraft formation as a single interconnected system,each spacecraft constructs a distributed observer that estimates the overall system state by incorporating both its own measurements and the predicted control information shared among the spacecraft.Based on the observer estimates,a local control law is synthesized to maintain the desired formation.Rigorous theoretical analysis and numerical simulations demonstrate that the proposed integrated approach effectively guarantees formation stability and resilience against sensor failures and disturbances.
基金Supported by National Nature Science Foundation of China(No.41202012)Ministry of Science and Higher Education of the Russian Federation(No.123120600034-2)。
文摘Five new small theropod teeth and one manual ungual have recently been recovered from the Upper Cretaceous Nenjiang Formation in the Songliao Basin.The specimens were examined for their morphological characteristics,leading to the identification of four distinct taxa.The first taxon consists of three foliodont teeth characterized by a pronounced basal constriction and large hook-like distal denticles,which can be attributed to Troodontidae.The second taxon is represented by an elongated tooth featuring prominent longitudinal ridges,allowing for its assignment to Paronychodon.The third taxon is a bladelike tooth with notably small distal denticles,corresponding to Richardoestesia.The fourth taxon comprises a manual ungual characterized by a transversely wide and nearly symmetrical proximal articular surface,fully enclosed ventral foramina,a flattened ventral surface,and the absence of a flexor tubercle,resembling Alvarezsauridae.These specimens significantly enhance the known dinosaur diversity of the Nenjiang Formation and provide crucial insights for understanding the terrestrial ecosystem in Northeast Asia during the Late Cretaceous.
基金Dr.Stergios D.Zarkogiannis would like to acknowledge UK Research and Innovation Grant(SODIOM)EP/Y004221/1 in supporting the research reported here.
文摘This study investigates the facies development and sedimentology of the Late Permian Chhidru Formation,a mixed carbonate-siliciclastic unit exposed in the Western Salt Range,Potwar Basin,Pakistan.The formation is subdivided into four lithological units reflecting lateral variability,with thicknesses and lithologies ranging from fossiliferous sandy limestone to interbedded limestone and sandstone.These successions record a depositional shift from a carbonate platform to mixed carbonate-clastic,and ultimately,clastic-dominated environments.Lithostratigraphy suggests deposition on the underlying Wargal Limestone carbonates during a Late Permian sea-level fall on the northwest Indian margin of Gondwana.Similar Permian successions with identical lithological characteristics are documented in the Persian Gulf(Dalan Formation),Arabian Platform(Khuff Formation),and Iran(Nesen and Hambust formations).Petrographic analysis reveals deposition in the distal middle to proximal inner shelf settings of a carbonate-siliciclastic mixed,unrimmed platform.Based on identified foraminiferal assemblages,the Chhidru Formation's age is estimated to range from the late Wuchiapingian to Changhsingian stages of the Lopingian epoch.
基金supported by the National Natural Science Foundation of China(624B2140).
文摘This paper presents an adaptive formation control method for a heterogeneous robot swarm,utilising a multilevel formation task tree to model various types of formation tasks and a single-state distributed k-winner-take-all(S-DKWTA)algorithm to address the MRTA problem.In addition,we propose an enhanced load reassignment algorithm to resolve conflicts when using S-DKWTA.The S-DKWTA algorithm demonstrates the capability to manage multiple objectives and dynamically select leaders in real-time,thereby optimising formation efficiency and reducing energy consumption.The proposed approach integrates an enhanced artificial potential field(APF)to govern the motion of heterogeneous robot systems which encompasses both unmanned ground vehicles(UGVs)and unmanned aerial vehicles(UAVs),thereby achieving collision and obstacle avoidance.Simulations employing UGVs and UAVs swarm to achieve formation movement demonstrate the efficacy of this approach.The amalgamation of S-DKWTA and improved APF ensures stable and adaptable formation control,underscoring its potential for diverse multirobot applications.
文摘A clear goal in cold tumor research is to identify strategies for converting them into immunologically‘hot’tumors with enhanced immune cell infiltration and activity,thereby improving their responsiveness to immunotherapy.The genesis of cold tumors is exceedingly intricate.In recent times,as the analysis of this phenomenon has been pursued with greater depth,a suite of advanced diagnostic and therapeutic technologies has surfaced.These novel approaches and tactics are anticipated to modulate the tumor immune microenvironment across various dimensions,thereby facilitating the advancement of personalized and precise treatment modalities for cold tumors.The present article addresses the challenge of diminished therapeutic responsiveness to“cold tumors”within clinical settings.It systematically elucidates the multi-faceted regulatory mechanisms underlying immune evasion in cold tumors and offers a detailed analysis of advanced therapeutic strategies that incorporate nanotechnology,gene editing,and artificial intelligence methodologies.Furthermore,the future development trends of immunotherapy were explored in greater depth.It was posited that the convergence of artificial intelligence,multidimensional genomics,and emerging biotechnologies has presented positive prospects for the treatment of cold tumors,and has offered a theoretical foundation and technical framework for the transformation of cold tumors into“hot tumors”.
基金the support of the National Natural Science Foundation of China(22575230)。
文摘Conventional error cancellation approaches separate molecules into smaller fragments and sum the errors of all fragments to counteract the overall computational error of the parent molecules.However,these approaches may be ineffective for systems with strong localized chemical effects,as fragmenting specific substructures into simpler chemical bonds can introduce additional errors instead of mitigating them.To address this issue,we propose the Substructure-Preserved Connection-Based Hierarchy(SCBH),a method that automatically identifies and freezes substructures with significant local chemical effects prior to molecular fragmentation.The SCBH is validated by the gas-phase enthalpy of formation calculation of CHNO molecules.Therein,based on the atomization scheme,the reference and test values are derived at the levels of Gaussian-4(G4)and M062X/6-31+G(2df,p),respectively.Compared to commonly used approaches,SCBH reduces the average computational error by half and requires only15%of the computational cost of G4 to achieve comparable accuracy.Since different types of local effect structures have differentiated influences on gas-phase enthalpy of formation,substituents with strong electronic effects should be retained preferentially.SCBH can be readily extended to diverse classes of organic compounds.Its workflow and source code allow flexible customization of molecular moieties,including azide,carboxyl,trinitromethyl,phenyl,and others.This strategy facilitates accurate,rapid,and automated computations and corrections,making it well-suited for high-throughput molecular screening and dataset construction for gas-phase enthalpy of formation.
文摘Researchers are increasingly focused on enabling groups of multiple unmanned vehicles to operate cohesively in complex,real-world environments,where coordinated formation control and obstacle avoidance are essential for executing sophisticated collective tasks.This paper presents a Distributed Formation Control and Obstacle Avoidance(DFCOA)framework for multi-unmanned ground vehicles(UGV).DFCOA integrates a virtual leader structure for global guidance,an improved A^(*)path planning algorithm with an advanced cost function for efficient path planning,and a repulsive-force-based improved vector field histogram star(VFH^(*))technique for collision avoidance.The virtual leader generates a reference trajectory while enabling distributed execution;the improved A^(*)algorithm reduces planning time and number of nodes to determine the shortest path from the starting position to the goal;and the improved VFH^(*)uses 2D LiDAR data with inter-agent repulsive force to simultaneously avoid collision with obstacles and maintain safe inter-vehicle distances.The formation stability of the proposed DFCOA reaches 95.8%and 94.6%in two scenarios,with root mean square(RMS)centroid errors of 0.9516 and 1.0008 m,respectively.Velocity tracking is precise(velocity centroid error RMS of 0.2699 and 0.1700 m/s),and linear velocities closely match the desired 0.3 m/s.Safety metrics showed average collision risks of 0.7773 and 0.5143,with minimum inter-vehicle distances of 0.4702 and 0.8763 m,confirming collision-free navigation of four UGVs.DFCOA outperforms conventional methods in formation stability,path efficiency,and scalability,proving its suitability for decentralized multi-UGV applications.
基金Supported by Wenzhou Science and Technology Bureau,No.Y20240207.
文摘Cholelithiasis has a complex pathogenesis,necessitating better therapeutic and preventive strategies.We recently read with interest Wang et al’s study on lysine acetyltransferase 2A(KAT2A)-mediated adenosine monophosphate-activated protein kinase(AMPK)succinylation in cholelithiasis.Using mouse models and gallbladder mucosal epithelial cells,they found that KAT2A inhibits gallstones through AMPK K170 succinylation,thereby activating the AMPK/silent information regulator 1 pathway to reduce inflammation and pyroptosis.This study is the first to connect lysine succinylation with cholelithiasis,offering new insights and identifying succinylation as a potential therapeutic target.Future research should confirm these findings using patient samples,investigate other posttranslational modifications,and use structural biology to clarify succinylationinduced conformational changes,thereby bridging basic research to clinical applications.
基金supports for this project from the National Natural Science Foundation of China(22378295).
文摘This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.
基金supported by Qingdao Natural Science Foundation(No. 23-2-1-224-zyyd-jch)。
文摘Although the concentration of fine particulate matter(PM_(2.5))is reducing continuously,the proportion of secondary organic aerosols(SOA)in PM_(2.5) and the O_(3) levels are increasing.This is causing severe complex atmospheric pollution in North China.It is essential to identify and quantify the driving factors of SOA and O_(3),including the various pollution sources and meteorological factors.PM_(2.5) and volatile organic compounds(VOCs)samples were collected simultaneously in three cities in Shandong Province during different pollution scenarios from 2021 to 2023.Then,the carbonaceous aerosol and 99 VOC species were analyzed.Random forest(RF)combined with positive matrix factorization and an observation-based model(OBM)were used to quantify the key drivers of SOA and O_(3).Aromatic hydrocarbons were the main contributors to secondary organic aerosol potential(74.3%-89.9%),whereas alkenes contributed the most to the ozone formation potential(27.0%-62.3%).The RF modeling identified temperature and NOx as the dominant drivers of ozone formation.These accounted for 47.8%and 17.4%,respectively.Temperature showed a positive correlation with O_(3) because an increase in temperature can promote ozone formation.NOx had a significant negative correlation with O_(3),which was consistent with the conclusions from the sensitivity analysis of the OBM.The dominant contributors to SOA were vehicle emissions,solvent use,and industrial emissions.These accounted for 43.9%,18.2%,and 10.5%,respectively.An evident positive correlation existed between these emission sources and SOA.
文摘Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagation behavior.To address the unclear mechanisms governing fracture penetration across coal-gangue interfaces,this study employs the Continuum-Discontinuum Element Method(CDEM)to simulate and analyze the vertical propagation of hydraulic fractures initiating within coal seams,based on geomechanical parameters derived from the deep Benxi Formation coal seams in the southeastern Ordos Basin.The investigation systematically examines the influence of geological and operational parameters on cross-interfacial fracture growth.Results demonstrate that vertical stress difference,elastic modulus contrast between coal and gangue layers,interfacial stress differential,and interfacial cohesion at coal-gangue interfaces are critical factors governing hydraulic fracture penetration through these interfaces.High vertical stress differences(>3 MPa)inhibit interfacial dilation,promoting predominant crosslayer fracture propagation.Reduced interfacial stress contrasts and enhanced interfacial cohesion facilitate fracture penetration across interfaces.Furthermore,smaller elastic modulus contrasts between coal and gangue correlate with increased interfacial aperture.Finally,lower injection rates effectively suppress vertical fracture propagation in deep coal reservoirs.This study elucidates the characteristics and mechanisms governing cross-layer fracture propagation in coal–rock composites with interbedded partings,and delineates the dynamic evolution laws and dominant controlling factors involved.Thefindings provide critical theoretical insights for the optimization of fracture design and the efficient development of deep coalbed methane reservoirs.
