The knowledge graph(KG) that represents structural relations among entities has become an increasingly important research field for knowledge-driven artificial intelligence. In this survey, a comprehensive review of K...The knowledge graph(KG) that represents structural relations among entities has become an increasingly important research field for knowledge-driven artificial intelligence. In this survey, a comprehensive review of KG and KG reasoning is provided. It introduces an overview of KGs, including representation, storage, and essential technologies. Specifically, it summarizes several types of knowledge reasoning approaches, including logic rules-based, representation-based, and neural network-based methods. Moreover, this paper analyzes the representation methods of knowledge hypergraphs. To effectively model hyper-relational data and improve the performance of knowledge reasoning, a three-layer knowledge hypergraph model is proposed. Finally, it analyzes the advantages of three-layer knowledge hypergraphs through reasoning and update algorithms which could facilitate future research.展开更多
Occurrence and mobility of shale oil are prerequisites for evaluating shale oil reserves and prioritizing exploration targets,particularly for heterogeneous lacustrine shales.The Qingshankou Formation in the Gulong Sa...Occurrence and mobility of shale oil are prerequisites for evaluating shale oil reserves and prioritizing exploration targets,particularly for heterogeneous lacustrine shales.The Qingshankou Formation in the Gulong Sag,Songliao Basin is a classic lacustrine pure shale reservoir that contains abundant shale oil resources.The predicted geological reserves of the shale are 1.268×10^(9) t.In this study,field emission scanning electron microscope(FE-SEM),the modular automated processing system(MAPS),pyrolysisgas chromatography(Py-GC),low-pressure nitrogen gas adsorption(LPNA),Soxhlet extraction,pyrolysis,and 2-D nuclear magnetic resonance(NMR)were integrated to describe the shale oil components,microscopic occurrence,mobility,and the effective pore size distribution.Meanwhile,the related controlling factors are discussed.The shale oil in the Qingshankou Fm exists dominantly in the matrix pores of the clay minerals,with small amounts distributed in the intergranular pores of terrigenous clastic grains,intercrystalline pores of pyrite,intragranular pores of ostracod shells,and micro-fractures.Shale oil is distributed in the pore spaces of variable sizes in different lithofacies.The clay mineral-laminated shales are characterized by the broadest range of pore size and largest volume of pore spaces with shale oil distribution,while the ostracod-laminated shales have limited pore spaces retaining oil.Furthermore,the proposed integrated analysis evaluates the shale oil molecules existing in two states:movable,and adsorbed oil,respectively.The result illustrates that movable oil takes up 30.6%e79.4%of the total residual oil.TOC,mineral composition,and pore structures of the shale joint together to control the states and mobility of the shale oil.TOC values are positively correlated with the quantities of shale oil regardless of the state of oil.The mineral components significantly impact the state of shale oil.Noticeable differences in the states of oil were observed following the changing types of minerals,possibly due to their difference in adsorption capacity and wettability.Clay minerals attract more adsorbed oil than movable oil.Felsic minerals generally decrease the occurrence of total and adsorbed oil.Carbonate plays a positive role in hydrocarbon retention of all the shale oil states.As for the pore structure,the average pore size exerts a critical impact on the total,movable,and adsorbed oil content.The total pore volume and specific surface area of shales play a principal role in controlling the total yields and amounts of adsorbed oil.This research improves the understanding of the occurrence characteristics and enrichment mechanisms of shale oil in terrestrial pure shales and provides a reference for locating favorable shale oil exploration areas.展开更多
With oil and gas exploration transferring to deeper and more ancient marine strata,more researches have been conducted about the Meso—Neoproterozoic and Cambrian microbial carbonate rocks by petroleum geologists.The ...With oil and gas exploration transferring to deeper and more ancient marine strata,more researches have been conducted about the Meso—Neoproterozoic and Cambrian microbial carbonate rocks by petroleum geologists.The Cambrian deposits experienced the first transgression of the Paleozoic,with shallow marine facies depositing in most areas,which are favorable for different kinds of biological reproduction.The Lower Cambrian in Beijing area is lithologically dominated by purple red shales interbedded with limestones,the Middle Cambrian is mainly composed of thick oolitic limestones,and the Upper Cambrian consists of thin limestones and flat-pebble conglomerates.Two beds of microbial carbonate rocks were discovered in the Cambrian outcrops in the vicinity of Beijing.One is from the Zhangxia Formation of Middle Cambrian,and the other is from the Gushan Formation of Upper Cambrian.The microbialites are characterized by combination of multiple stromatolites forming different bioherms.The bioherms are mostly in oval shape and with different sizes,which are 3-4 m long,and 1-3 m high.The surrounding strata beneath the bioherms are oolitic limestones.A central core of flat-pebble conglomerates occurred within each bioherm.Wavy or columnar stromatolites grow on the basis of flat-pebble conglomerates,with dentate erosional surfaces.The bioherm carbonate rocks are interpreted as products from a deep ramp sedimentary environment where potential oil and gas reservoirs can be found.The analysis of sedimentological characteristics of bioherm carbonate rocks and its lithofacies palaeogeography has significant implication for petroleum exploration.Research on geological record of microbialites is beneficial to investigating the Earth evolution,biodiversity,palaeoenvironment and palaeoclimate change,as well as biological extinction event during geological transitions.It also gives warning to human beings of modern biological crisis.展开更多
A new gold(I)self-relay catalysis consisting of a 3,3-rearrangement,Nazarov cyclization and Michael addition cascade of 1,3-enyne acetates with aurones and their derived azadienes is reported,and used to produce a ser...A new gold(I)self-relay catalysis consisting of a 3,3-rearrangement,Nazarov cyclization and Michael addition cascade of 1,3-enyne acetates with aurones and their derived azadienes is reported,and used to produce a series of densely functionalized cyclopentenones bearing a cyclic quaternary stereocenter in moderate to good yields under mild conditions.This tandem protocol demonstrates high regioselectivity,broad substrate flexibility and good functional group tolerance of substrates without inert atmosphere protection,providing a catalytic and convergent approach for creating all-carbon stereoscopic centers.展开更多
Molecular scaffolds endowed with all-carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules.However,efficient construction of this type of structure units is full of chal...Molecular scaffolds endowed with all-carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules.However,efficient construction of this type of structure units is full of challenge due to their congested chemical envi-ronment.Herein,we report a new gold(Ⅰ)self-relay catalysis merging[3,3]-sigmatropic rearrangement/Nazarov cyclization with al-lylic alkylation starting from 1,3-enyne acetates and allylic alcohols,producing a wide range of synthetically important allyl cyclo-pentenones with an all-carbon quaternary stereocenter in good yields under mild conditions.This protocol demonstrates the precise control of regioselectivity,high functional group tolerance of substrates and the low loading of gold catalyst without inert atmos-phere protection,providing a catalytic and efficient entry to all-carbon quaternary stereocenters.展开更多
基金supported by the Key Science and Technology R&D Project of Sichuan Province under Grants No. 2022YFG0038 and No. 2021YFG0018
文摘The knowledge graph(KG) that represents structural relations among entities has become an increasingly important research field for knowledge-driven artificial intelligence. In this survey, a comprehensive review of KG and KG reasoning is provided. It introduces an overview of KGs, including representation, storage, and essential technologies. Specifically, it summarizes several types of knowledge reasoning approaches, including logic rules-based, representation-based, and neural network-based methods. Moreover, this paper analyzes the representation methods of knowledge hypergraphs. To effectively model hyper-relational data and improve the performance of knowledge reasoning, a three-layer knowledge hypergraph model is proposed. Finally, it analyzes the advantages of three-layer knowledge hypergraphs through reasoning and update algorithms which could facilitate future research.
基金funded by the National Natural Science Foundation of China(Project 42090025 and 42202152)Heilongjiang Province open competition projects:“Research on the shale oil phase state,seepage mechanism,and integrated geologicalengineering stimulation technology in the Gulong Sag”and“Research on the diagenetic dynamic evolution process and its coupling relationship with pores and fractures”.
文摘Occurrence and mobility of shale oil are prerequisites for evaluating shale oil reserves and prioritizing exploration targets,particularly for heterogeneous lacustrine shales.The Qingshankou Formation in the Gulong Sag,Songliao Basin is a classic lacustrine pure shale reservoir that contains abundant shale oil resources.The predicted geological reserves of the shale are 1.268×10^(9) t.In this study,field emission scanning electron microscope(FE-SEM),the modular automated processing system(MAPS),pyrolysisgas chromatography(Py-GC),low-pressure nitrogen gas adsorption(LPNA),Soxhlet extraction,pyrolysis,and 2-D nuclear magnetic resonance(NMR)were integrated to describe the shale oil components,microscopic occurrence,mobility,and the effective pore size distribution.Meanwhile,the related controlling factors are discussed.The shale oil in the Qingshankou Fm exists dominantly in the matrix pores of the clay minerals,with small amounts distributed in the intergranular pores of terrigenous clastic grains,intercrystalline pores of pyrite,intragranular pores of ostracod shells,and micro-fractures.Shale oil is distributed in the pore spaces of variable sizes in different lithofacies.The clay mineral-laminated shales are characterized by the broadest range of pore size and largest volume of pore spaces with shale oil distribution,while the ostracod-laminated shales have limited pore spaces retaining oil.Furthermore,the proposed integrated analysis evaluates the shale oil molecules existing in two states:movable,and adsorbed oil,respectively.The result illustrates that movable oil takes up 30.6%e79.4%of the total residual oil.TOC,mineral composition,and pore structures of the shale joint together to control the states and mobility of the shale oil.TOC values are positively correlated with the quantities of shale oil regardless of the state of oil.The mineral components significantly impact the state of shale oil.Noticeable differences in the states of oil were observed following the changing types of minerals,possibly due to their difference in adsorption capacity and wettability.Clay minerals attract more adsorbed oil than movable oil.Felsic minerals generally decrease the occurrence of total and adsorbed oil.Carbonate plays a positive role in hydrocarbon retention of all the shale oil states.As for the pore structure,the average pore size exerts a critical impact on the total,movable,and adsorbed oil content.The total pore volume and specific surface area of shales play a principal role in controlling the total yields and amounts of adsorbed oil.This research improves the understanding of the occurrence characteristics and enrichment mechanisms of shale oil in terrestrial pure shales and provides a reference for locating favorable shale oil exploration areas.
基金financed by the China National Science Foundation(research project No. 2016ZX05004-001)support from RIPED and related oilfield companies
文摘With oil and gas exploration transferring to deeper and more ancient marine strata,more researches have been conducted about the Meso—Neoproterozoic and Cambrian microbial carbonate rocks by petroleum geologists.The Cambrian deposits experienced the first transgression of the Paleozoic,with shallow marine facies depositing in most areas,which are favorable for different kinds of biological reproduction.The Lower Cambrian in Beijing area is lithologically dominated by purple red shales interbedded with limestones,the Middle Cambrian is mainly composed of thick oolitic limestones,and the Upper Cambrian consists of thin limestones and flat-pebble conglomerates.Two beds of microbial carbonate rocks were discovered in the Cambrian outcrops in the vicinity of Beijing.One is from the Zhangxia Formation of Middle Cambrian,and the other is from the Gushan Formation of Upper Cambrian.The microbialites are characterized by combination of multiple stromatolites forming different bioherms.The bioherms are mostly in oval shape and with different sizes,which are 3-4 m long,and 1-3 m high.The surrounding strata beneath the bioherms are oolitic limestones.A central core of flat-pebble conglomerates occurred within each bioherm.Wavy or columnar stromatolites grow on the basis of flat-pebble conglomerates,with dentate erosional surfaces.The bioherm carbonate rocks are interpreted as products from a deep ramp sedimentary environment where potential oil and gas reservoirs can be found.The analysis of sedimentological characteristics of bioherm carbonate rocks and its lithofacies palaeogeography has significant implication for petroleum exploration.Research on geological record of microbialites is beneficial to investigating the Earth evolution,biodiversity,palaeoenvironment and palaeoclimate change,as well as biological extinction event during geological transitions.It also gives warning to human beings of modern biological crisis.
基金the National Natural Science Foundation of China(no.21971090)the Top-Notch Academic Programs Project of Jiangsu Higher Education Institution(TAPP).
文摘A new gold(I)self-relay catalysis consisting of a 3,3-rearrangement,Nazarov cyclization and Michael addition cascade of 1,3-enyne acetates with aurones and their derived azadienes is reported,and used to produce a series of densely functionalized cyclopentenones bearing a cyclic quaternary stereocenter in moderate to good yields under mild conditions.This tandem protocol demonstrates high regioselectivity,broad substrate flexibility and good functional group tolerance of substrates without inert atmosphere protection,providing a catalytic and convergent approach for creating all-carbon stereoscopic centers.
基金We are grateful for financial support from the National Natural Science Foundation of China(Nos.21871112 and 21971090)the Science and Technology of Xuzhou(KC21022)。
文摘Molecular scaffolds endowed with all-carbon quaternary stereocenter are ubiquitous in natural products and significant bioactive molecules.However,efficient construction of this type of structure units is full of challenge due to their congested chemical envi-ronment.Herein,we report a new gold(Ⅰ)self-relay catalysis merging[3,3]-sigmatropic rearrangement/Nazarov cyclization with al-lylic alkylation starting from 1,3-enyne acetates and allylic alcohols,producing a wide range of synthetically important allyl cyclo-pentenones with an all-carbon quaternary stereocenter in good yields under mild conditions.This protocol demonstrates the precise control of regioselectivity,high functional group tolerance of substrates and the low loading of gold catalyst without inert atmos-phere protection,providing a catalytic and efficient entry to all-carbon quaternary stereocenters.
