BACKGROUND Lymphovascular invasion(LVI)and perineural invasion(PNI)are important prognostic factors for gastric cancer(GC)that indicate an increased risk of metastasis and poor outcomes.Accurate preoperative predictio...BACKGROUND Lymphovascular invasion(LVI)and perineural invasion(PNI)are important prognostic factors for gastric cancer(GC)that indicate an increased risk of metastasis and poor outcomes.Accurate preoperative prediction of LVI/PNI status could help clinicians identify high-risk patients and guide treatment deci-sions.However,prior models using conventional computed tomography(CT)images to predict LVI or PNI separately have had limited accuracy.Spectral CT provides quantitative enhancement parameters that may better capture tumor invasion.We hypothesized that a predictive model combining clinical and spectral CT parameters would accurately preoperatively predict LVI/PNI status in GC patients.AIM To develop and test a machine learning model that fuses spectral CT parameters and clinical indicators to predict LVI/PNI status accurately.METHODS This study used a retrospective dataset involving 257 GC patients(training cohort,n=172;validation cohort,n=85).First,several clinical indicators,including serum tumor markers,CT-TN stages and CT-detected extramural vein invasion(CT-EMVI),were extracted,as were quantitative spectral CT parameters from the delineated tumor regions.Next,a two-step feature selection approach using correlation-based methods and information gain ranking inside a 10-fold cross-validation loop was utilized to select informative clinical and spectral CT parameters.A logistic regression(LR)-based nomogram model was subsequently constructed to predict LVI/PNI status,and its performance was evaluated using the area under the receiver operating characteristic curve(AUC).RESULTS In both the training and validation cohorts,CT T3-4 stage,CT-N positive status,and CT-EMVI positive status are more prevalent in the LVI/PNI-positive group and these differences are statistically significant(P<0.05).LR analysis of the training group showed preoperative CT-T stage,CT-EMVI,single-energy CT values of 70 keV of venous phase(VP-70 keV),and the ratio of standardized iodine concentration of equilibrium phase(EP-NIC)were independent influencing factors.The AUCs of VP-70 keV and EP-NIC were 0.888 and 0.824,respectively,which were slightly greater than those of CT-T and CT-EMVI(AUC=0.793,0.762).The nomogram combining CT-T stage,CT-EMVI,VP-70 keV and EP-NIC yielded AUCs of 0.918(0.866-0.954)and 0.874(0.784-0.936)in the training and validation cohorts,which are significantly higher than using each of single independent factors(P<0.05).CONCLUSION The study found that using portal venous and EP spectral CT parameters allows effective preoperative detection of LVI/PNI in GC,with accuracy boosted by integrating clinical markers.展开更多
Bone formation and deposition are initiated by sensory nerve infiltration in adaptive bone remodeling. Here, we focused on the role of Semaphorin 3A(Sema3A), expressed by sensory nerves, in mechanical loads-induced bo...Bone formation and deposition are initiated by sensory nerve infiltration in adaptive bone remodeling. Here, we focused on the role of Semaphorin 3A(Sema3A), expressed by sensory nerves, in mechanical loads-induced bone formation and nerve withdrawal using orthodontic tooth movement(OTM) model. Firstly, bone formation was activated after the 3rd day of OTM,coinciding with a decrease in sensory nerves and an increase in pain threshold. Sema3A, rather than nerve growth factor(NGF),highly expressed in both trigeminal ganglion and the axons of periodontal ligament following the 3rd day of OTM. Moreover, in vitro mechanical loads upregulated Sema3A in neurons instead of in human periodontal ligament cells(hPDLCs) within 24 hours.Furthermore, exogenous Sema3A restored the suppressed alveolar bone formation and the osteogenic differentiation of hPDLCs induced by mechanical overload. Mechanistically, Sema3A prevented overstretching of F-actin induced by mechanical overload through ROCK2 pathway, maintaining mitochondrial dynamics as mitochondrial fusion. Therefore, Sema3A exhibits dual therapeutic effects in mechanical loads-induced bone formation, both as a pain-sensitive analgesic and a positive regulator for bone formation.展开更多
Three eusauropod teeth(SDUST-V1064,PMOL-AD00176,PMOL-ADt0005)are reported from the Lower Cretaceous Yixian Formation of Ningcheng,southeastern Inner Mongolia,China.Two of them(SDUST-V1064,PMOL-AD00176)are assigned to ...Three eusauropod teeth(SDUST-V1064,PMOL-AD00176,PMOL-ADt0005)are reported from the Lower Cretaceous Yixian Formation of Ningcheng,southeastern Inner Mongolia,China.Two of them(SDUST-V1064,PMOL-AD00176)are assigned to early-diverging titanosauriforms in having slightly mesiodistal expansion at the base of the tooth crown,a slenderness index value>2.0 and<4.0,and D-shaped cross section.Furthermore,SDUST-V1064 and PMOL-AD00176 are referred as an Euhelopus-like titanosauriform on the basis of having a sub-circular boss on the lingual surface and an asymmetrical crown-root margin which slants apically,respectively.CT scan data of SDUST-V1064 reveals new dental information of early-diverging titanosauriforms,for example,the enamel on the labial side thicker than that on the lingual side,an enamel/dentine ratio of 0.26 and a boss present on the lingual side of the dentine of the crown.展开更多
Ragahama Formation comprises a siliciclastic continental deposits followed by marine carbonates, representing prograding alluvial fans from adjacent high hinterlands seaward into lagoons and fringing reef environments...Ragahama Formation comprises a siliciclastic continental deposits followed by marine carbonates, representing prograding alluvial fans from adjacent high hinterlands seaward into lagoons and fringing reef environments. The present work aimed to document the facies development and sedimentology of the Raghama carbonates exposed along the eastern coastal plain of the Red Sea, northwestern Saudi Arabia. Four stratigraphic sections were measured and sampled(D1–D4) and thin sections and major and trace element analyses were prepared and applied for petrographic and geochemical approaches. The carbonates were subdivided into three successive fore-reef, reef-core, and back-reef depositional facies. Sandy stromatolitic boundstone, microbial laminites, dolomitic ooidal grainstone, bioclastic coralline algal wackestone, sandy bioclastic wackestone, and coral boundstones were the reported microfacies types. Petrographic analysis reveals that the studied carbonates were affected by dissolution, dolomitization, and aggrading recrystallization, which affects both the original micrite matrix and grains or acts as fracture and veinlet filling leading to widespread vuggy and moldic porosity. No evidence of physical compaction, suggesting rapid lithification and recrystallization during early diagenesis and prior to substantial burial and intensive flushing by meteoric waters. Most of the original microstructure of corals were leached and destructed. This is indicated by the higher depletion in Sr and Ca levels and increase in Mg,Na, Fe, and Mn levels, especially in section D1, in comparison with the worldwide carbonates.展开更多
Ephedroid macrofossils have been widely documented in Cretaceous deposits,including numerous from the Lower Cretaceous Yixian Formation of NE China.However,few ephedroid macrofossils have been reported from South Amer...Ephedroid macrofossils have been widely documented in Cretaceous deposits,including numerous from the Lower Cretaceous Yixian Formation of NE China.However,few ephedroid macrofossils have been reported from South America.Herein,we describe a new plant of the family Ephedraceae,Arlenea delicata gen.et sp.nov.,from the Lower Cretaceous Crato Formation of the Araripe Basin,Northeast Brazil,based on the vegetative and reproductive structures.It has the typical morphological characteristics of ephedroid plants,including fertile reproductive branches,opposite phyllotaxy,terminal female cones,a sympodial branching system,longitudinally striated internodes,and swollen nodes.Our new finding is unusual in having inner chlamydosperms subtended by two pairs of bracts,reproductive units connected to branches through swollen receptacles and a smooth seed surface.This new ephedroid taxon from the Crato Formation increases our understanding of plant diversity of this group during the Early Cretaceous.Furthermore,the general morphology(fleshy bracts and enlarged receptacles)of this new fossil discovery indicates that seeds of this plant may have been dispersed by animals such as pterosaurs(mainly the Tapejaridae)and birds(Enantiornithes and Ornituromorpha).If true,this would explain the cosmopolitan distribution of Ephedraceae in the Lower Cretaceous.展开更多
Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission ...Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can occur.Optical emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.It has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.展开更多
Pedestrian self-organizing movement plays a significant role in evacuation studies and architectural design.Lane formation,a typical self-organizing phenomenon,helps pedestrian system to become more orderly,the majori...Pedestrian self-organizing movement plays a significant role in evacuation studies and architectural design.Lane formation,a typical self-organizing phenomenon,helps pedestrian system to become more orderly,the majority of following behavior model and overtaking behavior model are imprecise and unrealistic compared with pedestrian movement in the real world.In this study,a pedestrian dynamic model considering detailed modelling of the following behavior and overtaking behavior is constructed,and a method of measuring the lane formation and pedestrian system order based on information entropy is proposed.Simulation and analysis demonstrate that the following and avoidance behaviors are important factors of lane formation.A high tendency of following results in good lane formation.Both non-selective following behavior and aggressive overtaking behavior cause the system order to decrease.The most orderly following strategy for a pedestrian is to overtake the former pedestrian whose speed is lower than approximately 70%of his own.The influence of the obstacle layout on pedestrian lane and egress efficiency is also studied with this model.The presence of a small obstacle does not obstruct the walking of pedestrians;in contrast,it may help to improve the egress efficiency by guiding the pedestrian flow and mitigating the reduction of pedestrian system orderliness.展开更多
This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the fe...This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.展开更多
In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent mo...In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent months of 2011,when Cushing Oklahoma had reached capacity and the crude oil export ban removal in 2015 as breakpoints,we apply this method both in the full sample and the three resultant regimes.First,results suggest our results show that both WTI and Brent display very similar behaviour with the refined products.Second,when attending to each regime,results derived from the first and third regimes are quite similar to the full sample results.Therefore,during the second regime,Brent crude oil became the benchmark in the petrol market,and it influenced the distillate products.Furthermore,our model can let us determine the price-setters and price-followers in the price formation mechanism through refined products.These results possess important considerations to policymakers and the market participants and the price formation.展开更多
Star-forming processes strongly influence the ISM chemistry.Nowadays,many high-quality databases are available at millimeter wavelengths.Using them,it is possible to carry out studies that review and deepen previous r...Star-forming processes strongly influence the ISM chemistry.Nowadays,many high-quality databases are available at millimeter wavelengths.Using them,it is possible to carry out studies that review and deepen previous results.If these studies involve large samples of sources,it is preferred to use direct tools to study the molecular gas.With the aim of testing these tools such as the use of the HCN/HNC ratio as a thermometer,and the use of H^(13)CO^(+),HC_(3)N,N_(2)H^(+) and C_(2)H as "chemical clocks," we present a molecular line study toward 55 sources representing massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDCs),highmass protostellar objects(HMPOs),hot molecular cores(HMCs) and ultracompact H II regions.We found that the use of the HCN/HNC ratio as a universal thermometer in the ISM should be taken with care because the HCN optical depth is a big issue that can affect the method.Hence,this tool should be utilized only after a careful analysis of the HCN spectrum,checking that no line,neither the main nor the hyperfine ones,presents absorption features.We point out that the analysis of the emission of H^(13)CO^(+),HC_(3)N,N_(2)H^(+) and C_(2)H could be useful to trace and distinguish regions among IRDCs,HMPOs and HMCs.The molecular line widths of these four species increase from the IRDC to the HMC stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular clumps.Our results not only contribute with more statistics,acting as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.展开更多
Lacustrine shale oil and gas are important fields for unconventional exploration and development in China,and organic-rich shale deposition lays down the critical foundation for hydrocarbon generation.There are two se...Lacustrine shale oil and gas are important fields for unconventional exploration and development in China,and organic-rich shale deposition lays down the critical foundation for hydrocarbon generation.There are two sets of shale,the Dongyuemiao and Da’anzhai Members,in the Ziliujing Formation in the Sichuan Basin.To identify the differential enrichment characteristics of organic matter and clarify its controlling factors,geochemical analyses of organic and inorganic geochemical analyses were performed.The results showed that the total organic carbon content of the Dongyuemiao shale(1.36%)is slightly higher than that of the Da’anzhai shale(0.95%).The enrichment of organic matter in the two shales resulted from the comprehensive controls of paleoproductivity,paleoenvironment,and terrigenous input,but different factors have different effects.In addition,driven by climate,the change in the sulfate concentration in the bottom water further led to the different intensities of bacterial sulfate reduction in early diagenesis.This made a great difference regarding organic matter accumulation in the two members.In general,climate may have played a dominant role in organic matter enrichment in the two sets of shale.展开更多
During the Late Carboniferous to Early Permian,a rift was formed by post-collisional extension after ocean closure or an island arc-related basin formed by Paleo-Asian Ocean(PAO)subduction in the Xi Ujimqin area.Never...During the Late Carboniferous to Early Permian,a rift was formed by post-collisional extension after ocean closure or an island arc-related basin formed by Paleo-Asian Ocean(PAO)subduction in the Xi Ujimqin area.Nevertheless,the closure time of the PAO is still under debate.Thus,to identify the origin of the PAO,the geochemistry and U-Pb age of zircons were analyzed for the extra-large deep marine,polymict clastic boulders and sandstones in the Shoushangou Formation within the basin.The analyses revealed magmatic activity and tectonic evolution.The conglomerates include megaclasts of granite(298.8±9.1 Ma)and granodiorite porphyry(297.1±3.1 Ma),which were deposited by muddy debris flow.Results of this study demonstrated that the boulders of granitoids have the geochemistry of typical I-type granite,characterized by low Zr+Nb+Ce+Y and low Ga/Al values.The granitoid boulders were formed in island arc setting,indicating the presence of arc magmatism in the area that is composed of the Late Carboniferous to Early Permian subduction-related granitoid in southern Xi Ujimqin.Multiple diagrams for determining sedimentary provenance using major and trace elements indicate that Shoushangou sediments originated from continental island arc-related felsic rocks.Detrital zircon U-Pb age cluster of 330–280 Ma was obtained,indicating input from granite,ophiolite,Xilin Gol complex,and Carboniferous sources to the south.The basin was geographically developed behind the arc during the Early Permian period because the outcropped intrusive rocks in the Late Carboniferous to Early Permian form a volcanic arc.The comprehensive analyses of source areas suggest that Shoushangou sediments developed in a backarc basin in response to the northward subduction of the PAO.The backarc basin and intrusive rocks,in addition to previously published Late Carboniferous to Early Permian magmatic rocks of arc unit in Xilin Gol,confirm the presence of an Early Permian trencharc-basin system in the region,represented by the Baolidao arc and Xi Ujimqin backarc basin.This study highlights the importance and potential of combined geochemical and geochronological studies of conglomerates and sandstone for reconstructing the geodynamic setting of a basin.展开更多
This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown nonlinearities.To eli...This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown nonlinearities.To eliminate nonlinearities,neural networks are applied to approximate the inherent dynamics of the system.In addition,due to the limitations of the actual working conditions,each follower agent can only obtain the locally measurable partial state information of the leader agent.To address this problem,a neural network state observer based on the leader state information is designed.Then,a finite-time prescribed performance adaptive output feedback control strategy is proposed by restricting the sliding mode surface to a prescribed region,which ensures that the closed-loop system has practical finite-time stability and that formation errors of the multi-agent systems converge to the prescribed performance bound in finite time.Finally,a numerical simulation is provided to demonstrate the practicality and effectiveness of the developed algorithm.展开更多
The Fengcheng Formation is a crucial source rock and the primary reservoir for oil accumulation in the Mahu Sag.Crude oils are distributed throughout the Fengcheng Formation,ranging from the edge to the interior of th...The Fengcheng Formation is a crucial source rock and the primary reservoir for oil accumulation in the Mahu Sag.Crude oils are distributed throughout the Fengcheng Formation,ranging from the edge to the interior of the sag in the southern Mahu Sag.These crude oils originate from in-situ source rocks in shallowly buried areas and the inner deep sag.During migration,the crude oil from the inner deep sag affects the source rocks close to carrier beds,leading to changes in the organic geochemical characteristics of the source rocks.These changes might alter source rock evaluations and oil-source correlation.Based on data such as total organic carbon(TOC),Rock-Eval pyrolysis of source rocks,and gas chromatography-mass spectrometry(GC-MS)of the saturated fraction,and considering the geological characteristics of the study area,we define the identification characteristics of source rock affected by migrated hydrocarbons and establish the various patterns of influence that migrated hydrocarbons have on the source rock of the Fengcheng Formation in the southern Mahu Sag.The source rocks of the Fengcheng Formation are mostly fair to good,containing mainly Type II organic matter and being thermally mature enough to generate oil.Source rocks affected by migrated hydrocarbons exhibit relatively high hydrocarbon contents(S1/TOC>110 mg HC/g TOC,Extract/TOC>30%,HC:hydrocarbon),relatively low Rock-Eval Tmax values,and relatively high tricyclic terpane contents with a descending and mountain-shaped distribution.Furthermore,biomarker composition parameters indicate a higher thermal maturity than in-situ source rocks.Through a comparison of the extract biomarker fingerprints of adjacent reservoirs and mudstones in different boreholes,three types of influence patterns of migrated hydrocarbons are identified:the edge-influence of thin sandstone-thick mudstone,the mixed-influence of sandstone-mudstone interbedded,and the full-influence of thick sandstone-thin mudstone.This finding reminds us that the influence of migrated hydrocarbons must be considered when evaluating source rocks and conducting oil-source correlation.展开更多
Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for t...Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and deployment.To improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is proposed.The formation of the cluster determines the effectiveness of jamming.First,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is proposed.Then,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is designed.Finally,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific scenarios.The results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO algorithm.Compared with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources.展开更多
With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention recently.Affected by multi-stage tectonic ...With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention recently.Affected by multi-stage tectonic movements,the strike-slip faults have controlled the distribution of hydrocarbon resources owing to the special fault characteristics and fault-related structures.In contrast,the kinematics and formation mechanism of strike-slip faults in buried sedimentary basins are difficult to investigate,limiting the discussion of these faults and hydrocarbon accumulation.In this study,we identified the characteristics of massive sigmoidal tension gashes(STGs)that formed in the Shunnan area of the Tarim Basin.High-resolution three-dimensional seismic data and attribute analyses were used to investigate their geometric and kinematic characteristics.Then,the stress state of each point of the STGs was calculated using seismic curvature attributes.Finally,the formation mechanism of the STGs and their roles in controlling hydrocarbon migration and accumulation were discussed.The results suggest that:(1)the STGs developed in the Shunnan area have a wide distribution,with a tensile fault arranged in an enéchelon pattern,showing an S-shaped bending.These STGs formed in multiple stages,and differential rotation occurred along the direction of strike-slip stress during formation.(2)Near the principal displacement zone of the strike-slip faults,the stress value of the STGs was higher,gradually decreasing at both ends.The shallow layer deformation was greater than the deep layer deformation.(3)STGs are critical for connecting source rocks,migrating oil and gas,sealing horizontally,and developing efficient reservoirs.This study not only provides seismic evidence for the formation and evolution of super large STGs,but also provides certain guidance for oil and gas exploration in this area.展开更多
In the process of production or processing of materials by various methods,there is a need for a large volume of water of the required quality.Today in many regions of the world,there is an acute problem of providing ...In the process of production or processing of materials by various methods,there is a need for a large volume of water of the required quality.Today in many regions of the world,there is an acute problem of providing industry with water of a required quality.Its solution is an urgent and difficult task.The water quality of surface water bodies is formed by a combination of a large number of both natural and anthropogenic factors,and is often significantly heterogeneous not only in the water area,but also in depth.As a rule,the water supply of large industrial enterprises is located along the river network.Mergers are the most important nodes of river systems.Understanding the mechanism of transport of pollutants at the confluence of rivers is critical for assessing water quality.In recent years,thanks to the data of satellite images,the interest of researchers in the phenomenon of mixing the waters of merging rivers has increased.The nature of the merger is influenced by the formation of transverse circulation.Within the framework of this work,a study of vorticity,as well as the width of the mixing zone,depending on the distance from the confluence,the speeds of the merging rivers and the angle of confluence was carried out.Since the consumer properties of water are largely determined by its chemical and physical indicators,the intensity of mixing,determined largely by the nature of the secondary circulation,is of fundamental importance for assessing the distribution of hydrochemical indicators of water quality in the mixing zone.These characteristics are important not only for organizing water intake for drinking and technical purposes with the best consumer properties,but also for organizing an effective monitoring system for confluence zones.展开更多
Ankylosing spondylitis(AS)has a very high disability rate.How to effectively inhibit the formation of new bones has become a difficult point in clinical treatment.In recent years,research has shown that different trea...Ankylosing spondylitis(AS)has a very high disability rate.How to effectively inhibit the formation of new bones has become a difficult point in clinical treatment.In recent years,research has shown that different treatment plans can have an impact on inhibiting new bone formation.In this paper,the different effects of new bone formation in the treatment of AS with traditional Chinese and Western medicine are systematically listed.展开更多
Based on the study of the distribution of intra-platform shoals and the characteristics of dolomite reservoirs in the Middle Permian Qixia Formation in the Gaoshiti–Moxi area of the Sichuan Basin,SW China,the control...Based on the study of the distribution of intra-platform shoals and the characteristics of dolomite reservoirs in the Middle Permian Qixia Formation in the Gaoshiti–Moxi area of the Sichuan Basin,SW China,the controlling factors of reservoir development were analyzed,and the formation model of“intra-platform shoal thin-layer dolomite reservoir”was established.The Qixia Formation is a regressive cycle from bottom to top,in which the first member(Qi1 Member)develops low-energy open sea microfacies,and the second member(Qi2 Member)evolves into intra-platform shoal and inter-shoal sea with decreases in sea level.The intra-platform shoal is mainly distributed near the top of two secondary shallowing cycles of the Qi2 Member.The most important reservoir rock of the Qixia Formation is thin-layer fractured-vuggy dolomite,followed by vuggy dolomite.The semi-filled saddle dolomite is common in fracture-vug,and intercrystalline pores and residual dissolution pores combined with fractures to form the effective pore-fracture network.Based on the coupling analysis of sedimentary and diagenesis characteristics,the reservoir formation model of“pre-depositional micro-paleogeomorphology controlling shoal,sedimentary shoal controlling dolomite,penecontemporaneous dolomite benefiting preservation of pores,and late hydrothermal action effectively improving reservoir quality”was systematically established.The“first-order high zone”micro-paleogeomorphology before the deposition of the Qixia Formation controlled the development of large area of intra-platform shoals in Gaoshiti area during the deposition of the Qi2 Member.Shoal facies is the basic condition of early dolomitization,and the distribution range of intra-platform shoal and dolomite reservoir is highly consistent.The grain limestone of shoal facies is transformed by two stages of dolomitization.The penecontemporaneous dolomitization is conducive to the preservation of primary pores and secondary dissolved pores.The burial hydrothermal fluid enters the early dolomite body along the fractures associated with the Emeishan basalt event,makes it recrystallized into medium–coarse crystal dolomite.With the intercrystalline pores and the residual vugs after the hydrothermal dissolution along the fractures,the high-quality intra-platform shoal-type thin-layer dolomite reservoirs are formed.The establishment of this reservoir formation model can provide important theoretical support for the sustainable development of Permian gas reservoirs in the Sichuan Basin.展开更多
XRF and EDX analyses were carried out on 18 batches of representative raw samples to determine the distribution of major chemical elements in the petroleum source rocks of Donga and Yogou formations of Termit sediment...XRF and EDX analyses were carried out on 18 batches of representative raw samples to determine the distribution of major chemical elements in the petroleum source rocks of Donga and Yogou formations of Termit sedimentary basin. The chemical composition of these formations is dominated by silicon (Si), aluminum (Al) and iron (Fe). This is consistent with the oxide composition, which is also dominated by silicon oxide (SiO2), aluminum oxide (Al<sub>2</sub>O<sub>3</sub>) and iron monoxide (FeO). No less important chemical elements are calcium (Ca), potassium (K), sulfur (S), titanium (Ti), magnesium (Mg), manganese (Mn) and barium (Ba), as well as some of their oxides. All these major chemical elements are carried by silicate detrital minerals associated with pyrite and goethite and/or clay minerals such as kaolinite and interstratified illite, smectite and chlorite. This trend is illustrated by the values of the Si/Al and SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratios.展开更多
基金Supported by Science and Technology Project of Fujian Province,No.2022Y0025.
文摘BACKGROUND Lymphovascular invasion(LVI)and perineural invasion(PNI)are important prognostic factors for gastric cancer(GC)that indicate an increased risk of metastasis and poor outcomes.Accurate preoperative prediction of LVI/PNI status could help clinicians identify high-risk patients and guide treatment deci-sions.However,prior models using conventional computed tomography(CT)images to predict LVI or PNI separately have had limited accuracy.Spectral CT provides quantitative enhancement parameters that may better capture tumor invasion.We hypothesized that a predictive model combining clinical and spectral CT parameters would accurately preoperatively predict LVI/PNI status in GC patients.AIM To develop and test a machine learning model that fuses spectral CT parameters and clinical indicators to predict LVI/PNI status accurately.METHODS This study used a retrospective dataset involving 257 GC patients(training cohort,n=172;validation cohort,n=85).First,several clinical indicators,including serum tumor markers,CT-TN stages and CT-detected extramural vein invasion(CT-EMVI),were extracted,as were quantitative spectral CT parameters from the delineated tumor regions.Next,a two-step feature selection approach using correlation-based methods and information gain ranking inside a 10-fold cross-validation loop was utilized to select informative clinical and spectral CT parameters.A logistic regression(LR)-based nomogram model was subsequently constructed to predict LVI/PNI status,and its performance was evaluated using the area under the receiver operating characteristic curve(AUC).RESULTS In both the training and validation cohorts,CT T3-4 stage,CT-N positive status,and CT-EMVI positive status are more prevalent in the LVI/PNI-positive group and these differences are statistically significant(P<0.05).LR analysis of the training group showed preoperative CT-T stage,CT-EMVI,single-energy CT values of 70 keV of venous phase(VP-70 keV),and the ratio of standardized iodine concentration of equilibrium phase(EP-NIC)were independent influencing factors.The AUCs of VP-70 keV and EP-NIC were 0.888 and 0.824,respectively,which were slightly greater than those of CT-T and CT-EMVI(AUC=0.793,0.762).The nomogram combining CT-T stage,CT-EMVI,VP-70 keV and EP-NIC yielded AUCs of 0.918(0.866-0.954)and 0.874(0.784-0.936)in the training and validation cohorts,which are significantly higher than using each of single independent factors(P<0.05).CONCLUSION The study found that using portal venous and EP spectral CT parameters allows effective preoperative detection of LVI/PNI in GC,with accuracy boosted by integrating clinical markers.
基金supported in part by National Natural Science Foundation of China(32271364 & 31971240)Interdisciplinary innovation project from West China Hospital of Stomatology, Sichuan University(RD-03-202305)。
文摘Bone formation and deposition are initiated by sensory nerve infiltration in adaptive bone remodeling. Here, we focused on the role of Semaphorin 3A(Sema3A), expressed by sensory nerves, in mechanical loads-induced bone formation and nerve withdrawal using orthodontic tooth movement(OTM) model. Firstly, bone formation was activated after the 3rd day of OTM,coinciding with a decrease in sensory nerves and an increase in pain threshold. Sema3A, rather than nerve growth factor(NGF),highly expressed in both trigeminal ganglion and the axons of periodontal ligament following the 3rd day of OTM. Moreover, in vitro mechanical loads upregulated Sema3A in neurons instead of in human periodontal ligament cells(hPDLCs) within 24 hours.Furthermore, exogenous Sema3A restored the suppressed alveolar bone formation and the osteogenic differentiation of hPDLCs induced by mechanical overload. Mechanistically, Sema3A prevented overstretching of F-actin induced by mechanical overload through ROCK2 pathway, maintaining mitochondrial dynamics as mitochondrial fusion. Therefore, Sema3A exhibits dual therapeutic effects in mechanical loads-induced bone formation, both as a pain-sensitive analgesic and a positive regulator for bone formation.
基金supported by the Scientific Research Foundation of Shenyang Normal University(Grant No.BS202207)Program for Innovative Research Team of Excellent Talents in University of Shandong Province(Grant No.2019KJH004)+3 种基金Taishan Scholar Program of Shandong Province(Grant No.tsqn201812070)Educational Department of Liaoning Province(Grant No.JYTQN2023422)Shandong Provincial Natural Science Foundation(Grant No.ZR2017MD031)the National Natural Science Foundation of China(Grant Nos.41972025,41688103,42161134003).
文摘Three eusauropod teeth(SDUST-V1064,PMOL-AD00176,PMOL-ADt0005)are reported from the Lower Cretaceous Yixian Formation of Ningcheng,southeastern Inner Mongolia,China.Two of them(SDUST-V1064,PMOL-AD00176)are assigned to early-diverging titanosauriforms in having slightly mesiodistal expansion at the base of the tooth crown,a slenderness index value>2.0 and<4.0,and D-shaped cross section.Furthermore,SDUST-V1064 and PMOL-AD00176 are referred as an Euhelopus-like titanosauriform on the basis of having a sub-circular boss on the lingual surface and an asymmetrical crown-root margin which slants apically,respectively.CT scan data of SDUST-V1064 reveals new dental information of early-diverging titanosauriforms,for example,the enamel on the labial side thicker than that on the lingual side,an enamel/dentine ratio of 0.26 and a boss present on the lingual side of the dentine of the crown.
基金supported and funded by the Researchers Supporting Project number (RSPD2023R781), King Saud University, Riyadh, Saudi Arabia.
文摘Ragahama Formation comprises a siliciclastic continental deposits followed by marine carbonates, representing prograding alluvial fans from adjacent high hinterlands seaward into lagoons and fringing reef environments. The present work aimed to document the facies development and sedimentology of the Raghama carbonates exposed along the eastern coastal plain of the Red Sea, northwestern Saudi Arabia. Four stratigraphic sections were measured and sampled(D1–D4) and thin sections and major and trace element analyses were prepared and applied for petrographic and geochemical approaches. The carbonates were subdivided into three successive fore-reef, reef-core, and back-reef depositional facies. Sandy stromatolitic boundstone, microbial laminites, dolomitic ooidal grainstone, bioclastic coralline algal wackestone, sandy bioclastic wackestone, and coral boundstones were the reported microfacies types. Petrographic analysis reveals that the studied carbonates were affected by dissolution, dolomitization, and aggrading recrystallization, which affects both the original micrite matrix and grains or acts as fracture and veinlet filling leading to widespread vuggy and moldic porosity. No evidence of physical compaction, suggesting rapid lithification and recrystallization during early diagenesis and prior to substantial burial and intensive flushing by meteoric waters. Most of the original microstructure of corals were leached and destructed. This is indicated by the higher depletion in Sr and Ca levels and increase in Mg,Na, Fe, and Mn levels, especially in section D1, in comparison with the worldwide carbonates.
基金the Conselho Nacional de Desenvolvimento Científico e Tecnologico CNPq Processo nº406902/2022e4(INCT PALEOVERT)Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior-CAPES for the financial support grant to A.M.N.Ribeiro(88887520216/2020e00)+1 种基金the Fundaçao Cearense de Apoio ao Desenvolvimento Científico e Tecnologico-FUNCAP for the financial support grant to R.A.M.Bantim(#BMD-0124-00302.01.01/19)A.A.F.Saraiva(#BP3-013900202.01.00/18).
文摘Ephedroid macrofossils have been widely documented in Cretaceous deposits,including numerous from the Lower Cretaceous Yixian Formation of NE China.However,few ephedroid macrofossils have been reported from South America.Herein,we describe a new plant of the family Ephedraceae,Arlenea delicata gen.et sp.nov.,from the Lower Cretaceous Crato Formation of the Araripe Basin,Northeast Brazil,based on the vegetative and reproductive structures.It has the typical morphological characteristics of ephedroid plants,including fertile reproductive branches,opposite phyllotaxy,terminal female cones,a sympodial branching system,longitudinally striated internodes,and swollen nodes.Our new finding is unusual in having inner chlamydosperms subtended by two pairs of bracts,reproductive units connected to branches through swollen receptacles and a smooth seed surface.This new ephedroid taxon from the Crato Formation increases our understanding of plant diversity of this group during the Early Cretaceous.Furthermore,the general morphology(fleshy bracts and enlarged receptacles)of this new fossil discovery indicates that seeds of this plant may have been dispersed by animals such as pterosaurs(mainly the Tapejaridae)and birds(Enantiornithes and Ornituromorpha).If true,this would explain the cosmopolitan distribution of Ephedraceae in the Lower Cretaceous.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)–Project No.454848899。
文摘Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can occur.Optical emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.It has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.
基金Project supported by the National Natural Science Foundation of China(Grant No.71603146).
文摘Pedestrian self-organizing movement plays a significant role in evacuation studies and architectural design.Lane formation,a typical self-organizing phenomenon,helps pedestrian system to become more orderly,the majority of following behavior model and overtaking behavior model are imprecise and unrealistic compared with pedestrian movement in the real world.In this study,a pedestrian dynamic model considering detailed modelling of the following behavior and overtaking behavior is constructed,and a method of measuring the lane formation and pedestrian system order based on information entropy is proposed.Simulation and analysis demonstrate that the following and avoidance behaviors are important factors of lane formation.A high tendency of following results in good lane formation.Both non-selective following behavior and aggressive overtaking behavior cause the system order to decrease.The most orderly following strategy for a pedestrian is to overtake the former pedestrian whose speed is lower than approximately 70%of his own.The influence of the obstacle layout on pedestrian lane and egress efficiency is also studied with this model.The presence of a small obstacle does not obstruct the walking of pedestrians;in contrast,it may help to improve the egress efficiency by guiding the pedestrian flow and mitigating the reduction of pedestrian system orderliness.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62173312 and 61803348in part by the National Major Scientific Instruments Development Project under Grant No.61927807+3 种基金in part by the Program for the Innovative Talents of Higher Education Institutions of ShanxiShanxi Province Science Foundation for Excellent Youthsin part by the Shanxi"1331 Project"Key Subjects Construction(1331KSC)in part by Graduate Innovation Project of Shanxi Province under Grant No.2021Y617。
文摘This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.
文摘In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent months of 2011,when Cushing Oklahoma had reached capacity and the crude oil export ban removal in 2015 as breakpoints,we apply this method both in the full sample and the three resultant regimes.First,results suggest our results show that both WTI and Brent display very similar behaviour with the refined products.Second,when attending to each regime,results derived from the first and third regimes are quite similar to the full sample results.Therefore,during the second regime,Brent crude oil became the benchmark in the petrol market,and it influenced the distillate products.Furthermore,our model can let us determine the price-setters and price-followers in the price formation mechanism through refined products.These results possess important considerations to policymakers and the market participants and the price formation.
基金partially supported by the Argentina grants PIP2021 11220200100012PICT 2021-GRF-TII-00061awarded by CONICET and ANPCYT。
文摘Star-forming processes strongly influence the ISM chemistry.Nowadays,many high-quality databases are available at millimeter wavelengths.Using them,it is possible to carry out studies that review and deepen previous results.If these studies involve large samples of sources,it is preferred to use direct tools to study the molecular gas.With the aim of testing these tools such as the use of the HCN/HNC ratio as a thermometer,and the use of H^(13)CO^(+),HC_(3)N,N_(2)H^(+) and C_(2)H as "chemical clocks," we present a molecular line study toward 55 sources representing massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDCs),highmass protostellar objects(HMPOs),hot molecular cores(HMCs) and ultracompact H II regions.We found that the use of the HCN/HNC ratio as a universal thermometer in the ISM should be taken with care because the HCN optical depth is a big issue that can affect the method.Hence,this tool should be utilized only after a careful analysis of the HCN spectrum,checking that no line,neither the main nor the hyperfine ones,presents absorption features.We point out that the analysis of the emission of H^(13)CO^(+),HC_(3)N,N_(2)H^(+) and C_(2)H could be useful to trace and distinguish regions among IRDCs,HMPOs and HMCs.The molecular line widths of these four species increase from the IRDC to the HMC stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular clumps.Our results not only contribute with more statistics,acting as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.
基金This work was funded by the National Natural Science Foundation of China(Grant No.42002139 and U20B6001)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA14010404).
文摘Lacustrine shale oil and gas are important fields for unconventional exploration and development in China,and organic-rich shale deposition lays down the critical foundation for hydrocarbon generation.There are two sets of shale,the Dongyuemiao and Da’anzhai Members,in the Ziliujing Formation in the Sichuan Basin.To identify the differential enrichment characteristics of organic matter and clarify its controlling factors,geochemical analyses of organic and inorganic geochemical analyses were performed.The results showed that the total organic carbon content of the Dongyuemiao shale(1.36%)is slightly higher than that of the Da’anzhai shale(0.95%).The enrichment of organic matter in the two shales resulted from the comprehensive controls of paleoproductivity,paleoenvironment,and terrigenous input,but different factors have different effects.In addition,driven by climate,the change in the sulfate concentration in the bottom water further led to the different intensities of bacterial sulfate reduction in early diagenesis.This made a great difference regarding organic matter accumulation in the two members.In general,climate may have played a dominant role in organic matter enrichment in the two sets of shale.
基金Funding for this project was provided by the China Geological Survey Project(Grant Nos.DD20230316 and DD20190099)Deep Resources Exploration and Mining Project(Grant No.2019YFC0605202).
文摘During the Late Carboniferous to Early Permian,a rift was formed by post-collisional extension after ocean closure or an island arc-related basin formed by Paleo-Asian Ocean(PAO)subduction in the Xi Ujimqin area.Nevertheless,the closure time of the PAO is still under debate.Thus,to identify the origin of the PAO,the geochemistry and U-Pb age of zircons were analyzed for the extra-large deep marine,polymict clastic boulders and sandstones in the Shoushangou Formation within the basin.The analyses revealed magmatic activity and tectonic evolution.The conglomerates include megaclasts of granite(298.8±9.1 Ma)and granodiorite porphyry(297.1±3.1 Ma),which were deposited by muddy debris flow.Results of this study demonstrated that the boulders of granitoids have the geochemistry of typical I-type granite,characterized by low Zr+Nb+Ce+Y and low Ga/Al values.The granitoid boulders were formed in island arc setting,indicating the presence of arc magmatism in the area that is composed of the Late Carboniferous to Early Permian subduction-related granitoid in southern Xi Ujimqin.Multiple diagrams for determining sedimentary provenance using major and trace elements indicate that Shoushangou sediments originated from continental island arc-related felsic rocks.Detrital zircon U-Pb age cluster of 330–280 Ma was obtained,indicating input from granite,ophiolite,Xilin Gol complex,and Carboniferous sources to the south.The basin was geographically developed behind the arc during the Early Permian period because the outcropped intrusive rocks in the Late Carboniferous to Early Permian form a volcanic arc.The comprehensive analyses of source areas suggest that Shoushangou sediments developed in a backarc basin in response to the northward subduction of the PAO.The backarc basin and intrusive rocks,in addition to previously published Late Carboniferous to Early Permian magmatic rocks of arc unit in Xilin Gol,confirm the presence of an Early Permian trencharc-basin system in the region,represented by the Baolidao arc and Xi Ujimqin backarc basin.This study highlights the importance and potential of combined geochemical and geochronological studies of conglomerates and sandstone for reconstructing the geodynamic setting of a basin.
基金the National Natural Science Foundation of China(62203356)Fundamental Research Funds for the Central Universities of China(31020210502002)。
文摘This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown nonlinearities.To eliminate nonlinearities,neural networks are applied to approximate the inherent dynamics of the system.In addition,due to the limitations of the actual working conditions,each follower agent can only obtain the locally measurable partial state information of the leader agent.To address this problem,a neural network state observer based on the leader state information is designed.Then,a finite-time prescribed performance adaptive output feedback control strategy is proposed by restricting the sliding mode surface to a prescribed region,which ensures that the closed-loop system has practical finite-time stability and that formation errors of the multi-agent systems converge to the prescribed performance bound in finite time.Finally,a numerical simulation is provided to demonstrate the practicality and effectiveness of the developed algorithm.
基金We want to thank the Exploration and Development Research Institute of Xinjiang Oilfield for allowing the publication of the manuscript.The institute provided us with part of the crude oil geochemistry testing data and the logging data.We also thank the reviewers and editors for their detailed comments on this manuscript,which makes this paper more complete and meaningful.
文摘The Fengcheng Formation is a crucial source rock and the primary reservoir for oil accumulation in the Mahu Sag.Crude oils are distributed throughout the Fengcheng Formation,ranging from the edge to the interior of the sag in the southern Mahu Sag.These crude oils originate from in-situ source rocks in shallowly buried areas and the inner deep sag.During migration,the crude oil from the inner deep sag affects the source rocks close to carrier beds,leading to changes in the organic geochemical characteristics of the source rocks.These changes might alter source rock evaluations and oil-source correlation.Based on data such as total organic carbon(TOC),Rock-Eval pyrolysis of source rocks,and gas chromatography-mass spectrometry(GC-MS)of the saturated fraction,and considering the geological characteristics of the study area,we define the identification characteristics of source rock affected by migrated hydrocarbons and establish the various patterns of influence that migrated hydrocarbons have on the source rock of the Fengcheng Formation in the southern Mahu Sag.The source rocks of the Fengcheng Formation are mostly fair to good,containing mainly Type II organic matter and being thermally mature enough to generate oil.Source rocks affected by migrated hydrocarbons exhibit relatively high hydrocarbon contents(S1/TOC>110 mg HC/g TOC,Extract/TOC>30%,HC:hydrocarbon),relatively low Rock-Eval Tmax values,and relatively high tricyclic terpane contents with a descending and mountain-shaped distribution.Furthermore,biomarker composition parameters indicate a higher thermal maturity than in-situ source rocks.Through a comparison of the extract biomarker fingerprints of adjacent reservoirs and mudstones in different boreholes,three types of influence patterns of migrated hydrocarbons are identified:the edge-influence of thin sandstone-thick mudstone,the mixed-influence of sandstone-mudstone interbedded,and the full-influence of thick sandstone-thin mudstone.This finding reminds us that the influence of migrated hydrocarbons must be considered when evaluating source rocks and conducting oil-source correlation.
基金the National Natural Science Foundation of China(Grant No.62101579).
文摘Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and deployment.To improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is proposed.The formation of the cluster determines the effectiveness of jamming.First,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is proposed.Then,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is designed.Finally,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific scenarios.The results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO algorithm.Compared with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources.
基金Thanks to the Northwest Oilfield Branch,SINOPEC,for providing the seismic data.We thank Dr.Yi-Duo Liu of University of Houston,Ying-Chang Cao and Fang Hao of China University of Petroleum(East China)for their constructive suggestions of this manuscript.We also thank two anonymous reviewers for their comments that helped us to improve the manuscript.This research is jointly supported by the National Natural Science Foundation of China(No.42272155)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA14010301)+1 种基金the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.41821002)National Natural Science Foundation of China(No.41702138).
文摘With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention recently.Affected by multi-stage tectonic movements,the strike-slip faults have controlled the distribution of hydrocarbon resources owing to the special fault characteristics and fault-related structures.In contrast,the kinematics and formation mechanism of strike-slip faults in buried sedimentary basins are difficult to investigate,limiting the discussion of these faults and hydrocarbon accumulation.In this study,we identified the characteristics of massive sigmoidal tension gashes(STGs)that formed in the Shunnan area of the Tarim Basin.High-resolution three-dimensional seismic data and attribute analyses were used to investigate their geometric and kinematic characteristics.Then,the stress state of each point of the STGs was calculated using seismic curvature attributes.Finally,the formation mechanism of the STGs and their roles in controlling hydrocarbon migration and accumulation were discussed.The results suggest that:(1)the STGs developed in the Shunnan area have a wide distribution,with a tensile fault arranged in an enéchelon pattern,showing an S-shaped bending.These STGs formed in multiple stages,and differential rotation occurred along the direction of strike-slip stress during formation.(2)Near the principal displacement zone of the strike-slip faults,the stress value of the STGs was higher,gradually decreasing at both ends.The shallow layer deformation was greater than the deep layer deformation.(3)STGs are critical for connecting source rocks,migrating oil and gas,sealing horizontally,and developing efficient reservoirs.This study not only provides seismic evidence for the formation and evolution of super large STGs,but also provides certain guidance for oil and gas exploration in this area.
基金financial support from the Government of the Perm Territory within the Framework of Scientific Project No.S-26/828the Ministry of Science and High Education of Russia(Theme No.121031700169-1).
文摘In the process of production or processing of materials by various methods,there is a need for a large volume of water of the required quality.Today in many regions of the world,there is an acute problem of providing industry with water of a required quality.Its solution is an urgent and difficult task.The water quality of surface water bodies is formed by a combination of a large number of both natural and anthropogenic factors,and is often significantly heterogeneous not only in the water area,but also in depth.As a rule,the water supply of large industrial enterprises is located along the river network.Mergers are the most important nodes of river systems.Understanding the mechanism of transport of pollutants at the confluence of rivers is critical for assessing water quality.In recent years,thanks to the data of satellite images,the interest of researchers in the phenomenon of mixing the waters of merging rivers has increased.The nature of the merger is influenced by the formation of transverse circulation.Within the framework of this work,a study of vorticity,as well as the width of the mixing zone,depending on the distance from the confluence,the speeds of the merging rivers and the angle of confluence was carried out.Since the consumer properties of water are largely determined by its chemical and physical indicators,the intensity of mixing,determined largely by the nature of the secondary circulation,is of fundamental importance for assessing the distribution of hydrochemical indicators of water quality in the mixing zone.These characteristics are important not only for organizing water intake for drinking and technical purposes with the best consumer properties,but also for organizing an effective monitoring system for confluence zones.
基金Supported by the National Natural Science Foundation of China(82205105).
文摘Ankylosing spondylitis(AS)has a very high disability rate.How to effectively inhibit the formation of new bones has become a difficult point in clinical treatment.In recent years,research has shown that different treatment plans can have an impact on inhibiting new bone formation.In this paper,the different effects of new bone formation in the treatment of AS with traditional Chinese and Western medicine are systematically listed.
基金Supported by the National Natural Science Foundation of China(42172177)CNPC Scientific Research and Technological Development Project(2021DJ05)PetroChina-Southwest University of Petroleum Innovation Consortium Project(2020CX020000).
文摘Based on the study of the distribution of intra-platform shoals and the characteristics of dolomite reservoirs in the Middle Permian Qixia Formation in the Gaoshiti–Moxi area of the Sichuan Basin,SW China,the controlling factors of reservoir development were analyzed,and the formation model of“intra-platform shoal thin-layer dolomite reservoir”was established.The Qixia Formation is a regressive cycle from bottom to top,in which the first member(Qi1 Member)develops low-energy open sea microfacies,and the second member(Qi2 Member)evolves into intra-platform shoal and inter-shoal sea with decreases in sea level.The intra-platform shoal is mainly distributed near the top of two secondary shallowing cycles of the Qi2 Member.The most important reservoir rock of the Qixia Formation is thin-layer fractured-vuggy dolomite,followed by vuggy dolomite.The semi-filled saddle dolomite is common in fracture-vug,and intercrystalline pores and residual dissolution pores combined with fractures to form the effective pore-fracture network.Based on the coupling analysis of sedimentary and diagenesis characteristics,the reservoir formation model of“pre-depositional micro-paleogeomorphology controlling shoal,sedimentary shoal controlling dolomite,penecontemporaneous dolomite benefiting preservation of pores,and late hydrothermal action effectively improving reservoir quality”was systematically established.The“first-order high zone”micro-paleogeomorphology before the deposition of the Qixia Formation controlled the development of large area of intra-platform shoals in Gaoshiti area during the deposition of the Qi2 Member.Shoal facies is the basic condition of early dolomitization,and the distribution range of intra-platform shoal and dolomite reservoir is highly consistent.The grain limestone of shoal facies is transformed by two stages of dolomitization.The penecontemporaneous dolomitization is conducive to the preservation of primary pores and secondary dissolved pores.The burial hydrothermal fluid enters the early dolomite body along the fractures associated with the Emeishan basalt event,makes it recrystallized into medium–coarse crystal dolomite.With the intercrystalline pores and the residual vugs after the hydrothermal dissolution along the fractures,the high-quality intra-platform shoal-type thin-layer dolomite reservoirs are formed.The establishment of this reservoir formation model can provide important theoretical support for the sustainable development of Permian gas reservoirs in the Sichuan Basin.
文摘XRF and EDX analyses were carried out on 18 batches of representative raw samples to determine the distribution of major chemical elements in the petroleum source rocks of Donga and Yogou formations of Termit sedimentary basin. The chemical composition of these formations is dominated by silicon (Si), aluminum (Al) and iron (Fe). This is consistent with the oxide composition, which is also dominated by silicon oxide (SiO2), aluminum oxide (Al<sub>2</sub>O<sub>3</sub>) and iron monoxide (FeO). No less important chemical elements are calcium (Ca), potassium (K), sulfur (S), titanium (Ti), magnesium (Mg), manganese (Mn) and barium (Ba), as well as some of their oxides. All these major chemical elements are carried by silicate detrital minerals associated with pyrite and goethite and/or clay minerals such as kaolinite and interstratified illite, smectite and chlorite. This trend is illustrated by the values of the Si/Al and SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratios.
