Heterogeneous federated learning(HtFL)has gained significant attention due to its ability to accommodate diverse models and data from distributed combat units.The prototype-based HtFL methods were proposed to reduce t...Heterogeneous federated learning(HtFL)has gained significant attention due to its ability to accommodate diverse models and data from distributed combat units.The prototype-based HtFL methods were proposed to reduce the high communication cost of transmitting model parameters.These methods allow for the sharing of only class representatives between heterogeneous clients while maintaining privacy.However,existing prototype learning approaches fail to take the data distribution of clients into consideration,which results in suboptimal global prototype learning and insufficient client model personalization capabilities.To address these issues,we propose a fair trainable prototype federated learning(FedFTP)algorithm,which employs a fair sampling training prototype(FSTP)mechanism and a hyperbolic space constraints(HSC)mechanism to enhance the fairness and effectiveness of prototype learning on the server in heterogeneous environments.Furthermore,a local prototype stable update(LPSU)mechanism is proposed as a means of maintaining personalization while promoting global consistency,based on contrastive learning.Comprehensive experimental results demonstrate that FedFTP achieves state-of-the-art performance in HtFL scenarios.展开更多
To investigate the complex macro-mechanical properties of coal from a micro-mechanical perspective,we have conducted a series of micro-mechanical experiments on coal using a nano-indentation instrument.These experimen...To investigate the complex macro-mechanical properties of coal from a micro-mechanical perspective,we have conducted a series of micro-mechanical experiments on coal using a nano-indentation instrument.These experiments were conducted under both dynamic and static loading conditions,allowing us to gather the micro-mechanical parameters of coal for further analysis of its micro-mechanical heterogeneity using the box counting statistical method and the Weibull model.The research findings indicate that the load–displacement curves of the coal mass under the two different loading modes exhibit noticeable discreteness.This can be attributed to the stress concentration phenomenon caused by variations in the mechanical properties of the micro-units during the loading process of the coal mass.Consequently,there are significant fluctuations in the micro-mechanical parameters of the coal mass.Moreover,the mechanical heterogeneity of the coal at the nanoscale was confirmed based on the calculation results of the standard deviation coefficient and Weibull modulus of the coal body’s micromechanical parameters.These results reveal the influence of microstructural defects and minerals on the uniformity of the stress field distribution within the loaded coal body,as well as on the ductility characteristics of the micro-defect structure.Furthermore,there is a pronounced heterogeneity in the micromechanical parameters.Furthermore,we have established a relationship between the macro and micro elastic modulus of coal by applying the Mori-Tanaka homogenization method.This relationship holds great significance for revealing the micro-mechanical failure mechanism of coal.展开更多
Project construction and development are an impor-tant part of future army designs.In today’s world,intelligent war-fare and joint operations have become the dominant develop-ments in warfare,so the construction and ...Project construction and development are an impor-tant part of future army designs.In today’s world,intelligent war-fare and joint operations have become the dominant develop-ments in warfare,so the construction and development of the army need top-down,top-level design,and comprehensive plan-ning.The traditional project development model is no longer suf-ficient to meet the army’s complex capability requirements.Projects in various fields need to be developed and coordinated to form a joint force and improve the army’s combat effective-ness.At the same time,when a program consists of large-scale project data,the effectiveness of the traditional,precise mathe-matical planning method is greatly reduced because it is time-consuming,costly,and impractical.To solve above problems,this paper proposes a multi-stage program optimization model based on a heterogeneous network and hybrid genetic algo-rithm and verifies the effectiveness and feasibility of the model and algorithm through an example.The results show that the hybrid algorithm proposed in this paper is better than the exist-ing meta-heuristic algorithm.展开更多
To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartogra...To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartography of heterogeneous combat networks based on the operational chain”(FCBOC).In this framework,a functional module detection algorithm named operational chain-based label propagation algorithm(OCLPA),which considers the cooperation and interactions among combat entities and can thus naturally tackle network heterogeneity,is proposed to identify the functional modules of the network.Then,the nodes and their modules are classified into different roles according to their properties.A case study shows that FCBOC can provide a simplified description of disorderly information of combat networks and enable us to identify their functional and structural network characteristics.The results provide useful information to help commanders make precise and accurate decisions regarding the protection,disintegration or optimization of combat networks.Three algorithms are also compared with OCLPA to show that FCBOC can most effectively find functional modules with practical meaning.展开更多
The rapid development of military technology has prompted different types of equipment to break the limits of operational domains and emerged through complex interactions to form a vast combat system of systems(CSoS),...The rapid development of military technology has prompted different types of equipment to break the limits of operational domains and emerged through complex interactions to form a vast combat system of systems(CSoS),which can be abstracted as a heterogeneous combat network(HCN).It is of great military significance to study the disintegration strategy of combat networks to achieve the breakdown of the enemy’s CSoS.To this end,this paper proposes an integrated framework called HCN disintegration based on double deep Q-learning(HCN-DDQL).Firstly,the enemy’s CSoS is abstracted as an HCN,and an evaluation index based on the capability and attack costs of nodes is proposed.Meanwhile,a mathematical optimization model for HCN disintegration is established.Secondly,the learning environment and double deep Q-network model of HCN-DDQL are established to train the HCN’s disintegration strategy.Then,based on the learned HCN-DDQL model,an algorithm for calculating the HCN’s optimal disintegration strategy under different states is proposed.Finally,a case study is used to demonstrate the reliability and effectiveness of HCNDDQL,and the results demonstrate that HCN-DDQL can disintegrate HCNs more effectively than baseline methods.展开更多
Many evidences including those from magmatism and igneous rocks strongly support the heterogeneity of lithosphere in Tibetan plateau.By estimation, volcanic and plutonic rocks occupy an area of 300000km\+2, equaling t...Many evidences including those from magmatism and igneous rocks strongly support the heterogeneity of lithosphere in Tibetan plateau.By estimation, volcanic and plutonic rocks occupy an area of 300000km\+2, equaling to 10% of total area of the Tibetan Plateau. Temporal and spatial distribution of igneous rocks in the Tibetan Plateau is very inhomogeneous (Mo et al., 1998). Temporarily, most of plutonic and volcanic rocks, which occurred in 60% of total area of igneous rocks in the plateau, formed in the period of 65～45Ma. Spatially, 80% of igneous rocks in the plateau concentrated in the Gangdise—Nyainqentanglha region formed a huge complex granite\|volcanic belt. Petrotectonic assemblage and type of igneous rocks also vary from district to district. While Himalayas (especially High\|Himalayan region) were characterized by well development of muscovite\|bearing granites with no high\|potassium volcanic rocks and other volcanic contemporaries, North Tibet (Qiangtang region) by highly potassic volcanic rock series without muscovite\|bearing granites. Besides wide\|spreading calc\|alkaline igneous rocks, however, both highly potassic volcanic rocks and muscovite\|bearing granites developed in the central portion of Gangdise\|Nyainqentanglha region. It was lack of igneous activities in the Pamirs. Mantle\|derived nodules and their hosted rocks have been found only on northern and eastern margins of the plateau so far. All mentioned above, combined with other evidences from geophysics, geochemistry and structural geology, give us a hint to understand the heterogeneity of the lithosphere in its structure, thermal state and evolution processes underneath Tibetan plateau.展开更多
The influence of heterogeneity on mechanical and acoustic emission characteristics of rock specimen under uniaxial compress was studied with numerical simulation methods.Weibull distribution function was adopted to de...The influence of heterogeneity on mechanical and acoustic emission characteristics of rock specimen under uniaxial compress was studied with numerical simulation methods.Weibull distribution function was adopted to describe the mesoscopic heterogeneity of rocks.The failure process of heterogeneous rock specimen under uniaxial loading was simulated using FLAC 3D software.Five schemes were adopted to investigate the influence of heterogeneity.The results demonstrate that as the homogeneity increases,the peak strength and brittleness of rocks increase,and the macro elastic modulus improves as well.Heterogeneity has great influence on macro elastic modulus and strength when the homogeneity coefficient is less than 20.0.The volume expansion is not so obvious when the homogeneity increases.As the homogeneity coefficient increases the acoustic emissions modes change from swarm shock to main shock.When the homogeneity coefficient is high,the cumulative acoustic emission events-axial strain curve is gentle before the rock failure.The numerical results agree with the previously numerical results and earlier experimental measurements.展开更多
Rock is more sensitive to tensile loading than compressive loading,since the tensile strength of rock is much lower than compressive strength.The fracture characteristics of rock in the tensile state are of great sign...Rock is more sensitive to tensile loading than compressive loading,since the tensile strength of rock is much lower than compressive strength.The fracture characteristics of rock in the tensile state are of great significance to the understanding of rock failure mechanisms.To this end,we have conducted numerical simulation researches on modeⅠcracking process of rock with varying homogeneity,using the Realistic Failure Process Analysis program.With the increase of homogeneity,cracks are concentrating to the ligament area with a decreasing number of crack bifurcations,and the main crack path is becoming smooth.Crack behaviors and mechanical properties are influenced significantly when the homogeneity index is in the range of 1.5 to 5.When the homogeneity index is greater than 30,they are not affected by rock homogeneity and the rock can be considered as essentially homogeneous.It is considered that the global and local strengths are affected by the distribution of rock mechanical properties at mesoscale,which influence the crack behaviors and mechanical characteristics.展开更多
Homogeneity and heterogeneity are two totally different concepts in nature.At the particle length scale,rocks exhibit strong heterogeneity in their constituents and porosities.When the heterogeneity of porosity obeys ...Homogeneity and heterogeneity are two totally different concepts in nature.At the particle length scale,rocks exhibit strong heterogeneity in their constituents and porosities.When the heterogeneity of porosity obeys the random uniform distribution,both the mean value and the variance of porosities in the heterogeneous porosity field can be used to reflect the overall heterogeneous characteristics of the porosity field.The main purpose of this work is to investigate the effects of porosity heterogeneity on chemical dissolution front instability in fluid-saturated rocks by the computational simulation method.The related computational simulation results have demonstrated that:1) since the propagation speed of a chemical dissolution front is inversely proportional to the difference between the final porosity and the mean value of porosities in the initial porosity field,an increase in the extent of the porosity heterogeneity can cause an increase in the mean value of porosities in the initial porosity field and an increase in the propagation speed of the chemical dissolution front.2) An increase in the variance of porosities in the initial porosity field can cause an increase in the instability probability of the chemical dissolution front in the fluid-saturated rock.3) The greater the mean value of porosities in the initial porosity field,the quicker the irregular morphology of the chemical dissolution front changes in the supercritical chemical dissolution systems.This means that the irregular morphology of a chemical dissolution front grows quicker in a porosity field of heterogeneity than it does in that of homogeneity when the chemical dissolution system is at a supercritical stage.展开更多
Cast Al alloys are widely employed for engine components,structural parts,gear box,chassis,etc.and subjected to mechanical cyclic load during operation.The accurate fatigue life prediction of these alloys is essential...Cast Al alloys are widely employed for engine components,structural parts,gear box,chassis,etc.and subjected to mechanical cyclic load during operation.The accurate fatigue life prediction of these alloys is essential for normal operation as fatigue cracks initiated during operation induce the lubrication oil leak and serious safety hazard.Microstructural heterogeneity,including shrinkage/gaspores and secondary phase particles,is the most detrimental factor that affects fatigue life of cast Al alloys.The approximate fatigue life cycles could be estimated based on the size distribution and locations of shrinkage pores/defects.The relationship between crack population and stress was reported by statistical distributions and the cumulative probability for cast Al alloys fail at a certain stress could be predicted by combination of Paris law and pore size distribution.Pore depth was found to dominate the stress field around the pore on the surface and the maximum stress increases sharply when the pore intercepted with the surface at its top.The microstructure of cast Al alloys usually is composed of primary Al dendrites,eutectic silicon,Fe-rich particles and other intermetallic particles are dependent upon alloy composition and heat treatment.The coalescence of microcracks initiated from the fractured secondary phases was clearly found and can accelerate the initiation and propagation of the fatigue cracks.A link between defect features and the fatigue strength needs to be established through a good understanding of the fatigue damage mechanisms associated with the microstructural features under specific loading conditions.This paper reviews the influences of shrinkage/gaspores and secondary phase particles,formed during casting process,on the fatigue life of Al-Si-Mg cast Al alloys.展开更多
Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology and numerous approaches had been proposed to characterize heterogeneity in the past several decades.However。
To solve the problem that the existing situation awareness research focuses on multi-sensor data fusion,but the expert knowledge is not fully utilized,a heterogeneous informa-tion fusion recognition method based on be...To solve the problem that the existing situation awareness research focuses on multi-sensor data fusion,but the expert knowledge is not fully utilized,a heterogeneous informa-tion fusion recognition method based on belief rule structure is proposed.By defining the continuous probabilistic hesitation fuzzy linguistic term sets(CPHFLTS)and establishing CPHFLTS distance measure,the belief rule base of the relationship between feature space and category space is constructed through information integration,and the evidence reasoning of the input samples is carried out.The experimental results show that the proposed method can make full use of sensor data and expert knowledge for recognition.Compared with the other methods,the proposed method has a higher correct recognition rate under different noise levels.展开更多
OBJECTIVE Gastric cancer is one of the most common malignant tumors,and the incidence rate is the highest in all kinds of tumors in China.However,it remains unclear that how signifi.cantly gastric cells are dependent ...OBJECTIVE Gastric cancer is one of the most common malignant tumors,and the incidence rate is the highest in all kinds of tumors in China.However,it remains unclear that how signifi.cantly gastric cells are dependent on glycolysis,and which type of gastric cells are sensitive to glycolysis inhibition.In this study,several kind of gastric cancer cell lines were used as the research object,and the metabolic characteristics of different cell lines were systematically analyzed to provide theoretical support for the accurate treatment of gastric cancer.METHODS We examined the energy metabolism of four gastric cancer cell lines(MGC-803,SGC-7901,HGC-27 and BGC-823) by using glycolysis inhibitor,2-deoxy-D-glucose(2-DG) and inhibitor of oxidative phosphorylation,oligomycin.Oxygen consumption rates(OCR) and L-lactate were also measured with an XF96 Analyzer(Seahorse Biosciences) to deter.mine the significance of metabolism of oxidative phosphorylation and aerobic glycolysisin gastric cells.In addition,western blot was used to detect the contribution of AMP-activated protein kinase(AMPK),and anti-apoptotic proteins(Bcl-2 and survivin) to clarify the mechanism of death or survival of gastric cancer cells treated by 2-DG or oligomycin.RESULTS In this study,it was shown that the growth of gastric cell lines were suppressed by 2-DG.However,the sensitivity to 2-DG was quite different among cell lines:IC 50 of 2-DG was from 3.28 mmol·L^(-1)(MGC-803) to 15.57 mmol·L^(-1)(BGC-823).MGC-803 was relatively sensitive to 2-DG(IC 50:3.28 mmol·L^(-1)),consumed more glucose and produced more lactate(waste product of glycolysis) than the three other cell lines.Consequently,MGC-803 could be more dependent on glycolysis than other cell lines,which was further confirmed by the fact that glucose(+) FCS(-) medium showed more growth and survival than glucose(-) FCS(+) medium.Alternatively,BGC-823,most resistant to 2-DG(IC50:15.57 mmol · L-1),was most sensitive to oligomycin,and showed more growth and survival in glucose(-) FCS(+) medium than in glucose(+) FCS(-) medium.Thus,we had reasons to think BGC-823 cells depended on oxidative phosphorylation for energy production.In BGC-823,AMPK,which is activated when ATP becomes limiting,was rapidly phosphorylated by 2-DG,and expression of Bcl-2 was augmented,which might result in resistance to 2-DG.Interestingly,AMPK phosphorylation and augmentation of Bcl-2 expression by 2-DG were not observed in MGC-803,which is 2-DG sensitive.CONCLUSION There is a large metabolic difference between gastric cancer cell lines,which will facilitate the future gastric cancer therapy by targeting metabolic pathways.展开更多
To address the charging infrastructure challenges associated with slow electric vehicle(EV)industry growth,this study investigates the collaboration between private charging-pile-sharing platforms struggling with prof...To address the charging infrastructure challenges associated with slow electric vehicle(EV)industry growth,this study investigates the collaboration between private charging-pile-sharing platforms struggling with profitability and automotive companies.This collaboration is crucial,as it demands a balanced price and service quality management due to consumer expectations.This paper introduces a Stackelberg game model to explore the relationship between a charging platform and an automotive company.Through numerical analysis,we assess how this cooperation might improve the platform’s efficiency and benefit society,potentially overcoming existing industry hurdles.Our findings indicate that such partnerships could benefit all parties involved,despite possible negative environmental impacts.However,after collaborat-ing,platforms may increase consumer prices and payments to suppliers,potentially lowering service quality for brand-associated consumers due to a compromise between shorter waiting times and service quality.This research offers valu-able insights for stakeholders on the effects of cooperation,enabling better strategic decisions in the EV charging sector.展开更多
Overlooking the issue of false alarm suppression in heterogeneous change detection leads to inferior detection per-formance.This paper proposes a method to handle false alarms in heterogeneous change detection.A light...Overlooking the issue of false alarm suppression in heterogeneous change detection leads to inferior detection per-formance.This paper proposes a method to handle false alarms in heterogeneous change detection.A lightweight network of two channels is bulit based on the combination of convolutional neural network(CNN)and graph convolutional network(GCN).CNNs learn feature difference maps of multitemporal images,and attention modules adaptively fuse CNN-based and graph-based features for different scales.GCNs with a new kernel filter adaptively distinguish between nodes with the same and those with different labels,generating change maps.Experimental evaluation on two datasets validates the efficacy of the pro-posed method in addressing false alarms.展开更多
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01B187).
文摘Heterogeneous federated learning(HtFL)has gained significant attention due to its ability to accommodate diverse models and data from distributed combat units.The prototype-based HtFL methods were proposed to reduce the high communication cost of transmitting model parameters.These methods allow for the sharing of only class representatives between heterogeneous clients while maintaining privacy.However,existing prototype learning approaches fail to take the data distribution of clients into consideration,which results in suboptimal global prototype learning and insufficient client model personalization capabilities.To address these issues,we propose a fair trainable prototype federated learning(FedFTP)algorithm,which employs a fair sampling training prototype(FSTP)mechanism and a hyperbolic space constraints(HSC)mechanism to enhance the fairness and effectiveness of prototype learning on the server in heterogeneous environments.Furthermore,a local prototype stable update(LPSU)mechanism is proposed as a means of maintaining personalization while promoting global consistency,based on contrastive learning.Comprehensive experimental results demonstrate that FedFTP achieves state-of-the-art performance in HtFL scenarios.
基金Projects(U23B2093,52274245)supported by the National Natural Science Foundation of ChinaProject(KFJJ22-15M)supported by the Opening Project of State Key Laboratory of Explosion Science and Technology,China。
文摘To investigate the complex macro-mechanical properties of coal from a micro-mechanical perspective,we have conducted a series of micro-mechanical experiments on coal using a nano-indentation instrument.These experiments were conducted under both dynamic and static loading conditions,allowing us to gather the micro-mechanical parameters of coal for further analysis of its micro-mechanical heterogeneity using the box counting statistical method and the Weibull model.The research findings indicate that the load–displacement curves of the coal mass under the two different loading modes exhibit noticeable discreteness.This can be attributed to the stress concentration phenomenon caused by variations in the mechanical properties of the micro-units during the loading process of the coal mass.Consequently,there are significant fluctuations in the micro-mechanical parameters of the coal mass.Moreover,the mechanical heterogeneity of the coal at the nanoscale was confirmed based on the calculation results of the standard deviation coefficient and Weibull modulus of the coal body’s micromechanical parameters.These results reveal the influence of microstructural defects and minerals on the uniformity of the stress field distribution within the loaded coal body,as well as on the ductility characteristics of the micro-defect structure.Furthermore,there is a pronounced heterogeneity in the micromechanical parameters.Furthermore,we have established a relationship between the macro and micro elastic modulus of coal by applying the Mori-Tanaka homogenization method.This relationship holds great significance for revealing the micro-mechanical failure mechanism of coal.
基金supported by the National Natural Science Foundation of China(724701189072431011).
文摘Project construction and development are an impor-tant part of future army designs.In today’s world,intelligent war-fare and joint operations have become the dominant develop-ments in warfare,so the construction and development of the army need top-down,top-level design,and comprehensive plan-ning.The traditional project development model is no longer suf-ficient to meet the army’s complex capability requirements.Projects in various fields need to be developed and coordinated to form a joint force and improve the army’s combat effective-ness.At the same time,when a program consists of large-scale project data,the effectiveness of the traditional,precise mathe-matical planning method is greatly reduced because it is time-consuming,costly,and impractical.To solve above problems,this paper proposes a multi-stage program optimization model based on a heterogeneous network and hybrid genetic algo-rithm and verifies the effectiveness and feasibility of the model and algorithm through an example.The results show that the hybrid algorithm proposed in this paper is better than the exist-ing meta-heuristic algorithm.
文摘To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartography of heterogeneous combat networks based on the operational chain”(FCBOC).In this framework,a functional module detection algorithm named operational chain-based label propagation algorithm(OCLPA),which considers the cooperation and interactions among combat entities and can thus naturally tackle network heterogeneity,is proposed to identify the functional modules of the network.Then,the nodes and their modules are classified into different roles according to their properties.A case study shows that FCBOC can provide a simplified description of disorderly information of combat networks and enable us to identify their functional and structural network characteristics.The results provide useful information to help commanders make precise and accurate decisions regarding the protection,disintegration or optimization of combat networks.Three algorithms are also compared with OCLPA to show that FCBOC can most effectively find functional modules with practical meaning.
基金supported by the National Natural Science Foundation of China(7200120972231011+2 种基金72071206)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province(2020RC4046)the Science Foundation for Outstanding Youth Scholars of Hunan Province(2022JJ20047).
文摘The rapid development of military technology has prompted different types of equipment to break the limits of operational domains and emerged through complex interactions to form a vast combat system of systems(CSoS),which can be abstracted as a heterogeneous combat network(HCN).It is of great military significance to study the disintegration strategy of combat networks to achieve the breakdown of the enemy’s CSoS.To this end,this paper proposes an integrated framework called HCN disintegration based on double deep Q-learning(HCN-DDQL).Firstly,the enemy’s CSoS is abstracted as an HCN,and an evaluation index based on the capability and attack costs of nodes is proposed.Meanwhile,a mathematical optimization model for HCN disintegration is established.Secondly,the learning environment and double deep Q-network model of HCN-DDQL are established to train the HCN’s disintegration strategy.Then,based on the learned HCN-DDQL model,an algorithm for calculating the HCN’s optimal disintegration strategy under different states is proposed.Finally,a case study is used to demonstrate the reliability and effectiveness of HCNDDQL,and the results demonstrate that HCN-DDQL can disintegrate HCNs more effectively than baseline methods.
文摘Many evidences including those from magmatism and igneous rocks strongly support the heterogeneity of lithosphere in Tibetan plateau.By estimation, volcanic and plutonic rocks occupy an area of 300000km\+2, equaling to 10% of total area of the Tibetan Plateau. Temporal and spatial distribution of igneous rocks in the Tibetan Plateau is very inhomogeneous (Mo et al., 1998). Temporarily, most of plutonic and volcanic rocks, which occurred in 60% of total area of igneous rocks in the plateau, formed in the period of 65～45Ma. Spatially, 80% of igneous rocks in the plateau concentrated in the Gangdise—Nyainqentanglha region formed a huge complex granite\|volcanic belt. Petrotectonic assemblage and type of igneous rocks also vary from district to district. While Himalayas (especially High\|Himalayan region) were characterized by well development of muscovite\|bearing granites with no high\|potassium volcanic rocks and other volcanic contemporaries, North Tibet (Qiangtang region) by highly potassic volcanic rock series without muscovite\|bearing granites. Besides wide\|spreading calc\|alkaline igneous rocks, however, both highly potassic volcanic rocks and muscovite\|bearing granites developed in the central portion of Gangdise\|Nyainqentanglha region. It was lack of igneous activities in the Pamirs. Mantle\|derived nodules and their hosted rocks have been found only on northern and eastern margins of the plateau so far. All mentioned above, combined with other evidences from geophysics, geochemistry and structural geology, give us a hint to understand the heterogeneity of the lithosphere in its structure, thermal state and evolution processes underneath Tibetan plateau.
基金Project(2007CB209407) supported by the National Basic Research Program of ChinaProject(50729904) supported by the National Natural Science Foundation of China
文摘The influence of heterogeneity on mechanical and acoustic emission characteristics of rock specimen under uniaxial compress was studied with numerical simulation methods.Weibull distribution function was adopted to describe the mesoscopic heterogeneity of rocks.The failure process of heterogeneous rock specimen under uniaxial loading was simulated using FLAC 3D software.Five schemes were adopted to investigate the influence of heterogeneity.The results demonstrate that as the homogeneity increases,the peak strength and brittleness of rocks increase,and the macro elastic modulus improves as well.Heterogeneity has great influence on macro elastic modulus and strength when the homogeneity coefficient is less than 20.0.The volume expansion is not so obvious when the homogeneity increases.As the homogeneity coefficient increases the acoustic emissions modes change from swarm shock to main shock.When the homogeneity coefficient is high,the cumulative acoustic emission events-axial strain curve is gentle before the rock failure.The numerical results agree with the previously numerical results and earlier experimental measurements.
基金Project(BJJWZYJH01201911413037)supported by the Beijing Outstanding Young Scientist Program,ChinaProjects(51622404,41877257)supported by the National Natural Science Foundation of ChinaProject(2018SMHKJ-A-J-03)supported by Shaanxi Coal Group Key Project,China。
文摘Rock is more sensitive to tensile loading than compressive loading,since the tensile strength of rock is much lower than compressive strength.The fracture characteristics of rock in the tensile state are of great significance to the understanding of rock failure mechanisms.To this end,we have conducted numerical simulation researches on modeⅠcracking process of rock with varying homogeneity,using the Realistic Failure Process Analysis program.With the increase of homogeneity,cracks are concentrating to the ligament area with a decreasing number of crack bifurcations,and the main crack path is becoming smooth.Crack behaviors and mechanical properties are influenced significantly when the homogeneity index is in the range of 1.5 to 5.When the homogeneity index is greater than 30,they are not affected by rock homogeneity and the rock can be considered as essentially homogeneous.It is considered that the global and local strengths are affected by the distribution of rock mechanical properties at mesoscale,which influence the crack behaviors and mechanical characteristics.
基金Project(11272359)supported by the National Natural Science Foundation of China
文摘Homogeneity and heterogeneity are two totally different concepts in nature.At the particle length scale,rocks exhibit strong heterogeneity in their constituents and porosities.When the heterogeneity of porosity obeys the random uniform distribution,both the mean value and the variance of porosities in the heterogeneous porosity field can be used to reflect the overall heterogeneous characteristics of the porosity field.The main purpose of this work is to investigate the effects of porosity heterogeneity on chemical dissolution front instability in fluid-saturated rocks by the computational simulation method.The related computational simulation results have demonstrated that:1) since the propagation speed of a chemical dissolution front is inversely proportional to the difference between the final porosity and the mean value of porosities in the initial porosity field,an increase in the extent of the porosity heterogeneity can cause an increase in the mean value of porosities in the initial porosity field and an increase in the propagation speed of the chemical dissolution front.2) An increase in the variance of porosities in the initial porosity field can cause an increase in the instability probability of the chemical dissolution front in the fluid-saturated rock.3) The greater the mean value of porosities in the initial porosity field,the quicker the irregular morphology of the chemical dissolution front changes in the supercritical chemical dissolution systems.This means that the irregular morphology of a chemical dissolution front grows quicker in a porosity field of heterogeneity than it does in that of homogeneity when the chemical dissolution system is at a supercritical stage.
基金Projects(11790282,U1534204,11572267,51804202,51705344)supported by the National Natural Science Foundation of ChinaProject(E2019210292)supported by the Natural Science Foundation of Hebei Province,China+6 种基金Project(A2019210204)supported by the National Natural Science Foundation for Distinguished Young Scholars,ChinaProject(KQTD20170810160424889)supported by the Shenzhen Peacock Team Program,ChinaProject(2019DB013)supported by the Key Research Project of Southern Xinjiang,ChinaProject(C201821)supported by the High Level Talent Support Project in Hebei,ChinaProject supported by the Youth Top-notch Talents Supporting Plan of Hebei Province,ChinaProject(MCMS-E-0519G04)supported by the State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics,ChinaProject(201919)supported by the Open Fund of State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,China。
文摘Cast Al alloys are widely employed for engine components,structural parts,gear box,chassis,etc.and subjected to mechanical cyclic load during operation.The accurate fatigue life prediction of these alloys is essential for normal operation as fatigue cracks initiated during operation induce the lubrication oil leak and serious safety hazard.Microstructural heterogeneity,including shrinkage/gaspores and secondary phase particles,is the most detrimental factor that affects fatigue life of cast Al alloys.The approximate fatigue life cycles could be estimated based on the size distribution and locations of shrinkage pores/defects.The relationship between crack population and stress was reported by statistical distributions and the cumulative probability for cast Al alloys fail at a certain stress could be predicted by combination of Paris law and pore size distribution.Pore depth was found to dominate the stress field around the pore on the surface and the maximum stress increases sharply when the pore intercepted with the surface at its top.The microstructure of cast Al alloys usually is composed of primary Al dendrites,eutectic silicon,Fe-rich particles and other intermetallic particles are dependent upon alloy composition and heat treatment.The coalescence of microcracks initiated from the fractured secondary phases was clearly found and can accelerate the initiation and propagation of the fatigue cracks.A link between defect features and the fatigue strength needs to be established through a good understanding of the fatigue damage mechanisms associated with the microstructural features under specific loading conditions.This paper reviews the influences of shrinkage/gaspores and secondary phase particles,formed during casting process,on the fatigue life of Al-Si-Mg cast Al alloys.
文摘Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology and numerous approaches had been proposed to characterize heterogeneity in the past several decades.However。
基金This work was supported by the Youth Foundation of National Science Foundation of China(62001503)the Special Fund for Taishan Scholar Project(ts 201712072).
文摘To solve the problem that the existing situation awareness research focuses on multi-sensor data fusion,but the expert knowledge is not fully utilized,a heterogeneous informa-tion fusion recognition method based on belief rule structure is proposed.By defining the continuous probabilistic hesitation fuzzy linguistic term sets(CPHFLTS)and establishing CPHFLTS distance measure,the belief rule base of the relationship between feature space and category space is constructed through information integration,and the evidence reasoning of the input samples is carried out.The experimental results show that the proposed method can make full use of sensor data and expert knowledge for recognition.Compared with the other methods,the proposed method has a higher correct recognition rate under different noise levels.
基金Foundation Item：Strategic Environmental Research and Development Program （SERDP）AcknowLedgements Supports from the Strategic Environmental Research and Development Program （SERDP） subcontracted through the University of Iowa as well niversity of Waterloo are also thank two anonymous constructive and insightful as that throug acknowledged. reviewers for suggestions.
基金supported by National Natural Science Foundation of China(81502952)
文摘OBJECTIVE Gastric cancer is one of the most common malignant tumors,and the incidence rate is the highest in all kinds of tumors in China.However,it remains unclear that how signifi.cantly gastric cells are dependent on glycolysis,and which type of gastric cells are sensitive to glycolysis inhibition.In this study,several kind of gastric cancer cell lines were used as the research object,and the metabolic characteristics of different cell lines were systematically analyzed to provide theoretical support for the accurate treatment of gastric cancer.METHODS We examined the energy metabolism of four gastric cancer cell lines(MGC-803,SGC-7901,HGC-27 and BGC-823) by using glycolysis inhibitor,2-deoxy-D-glucose(2-DG) and inhibitor of oxidative phosphorylation,oligomycin.Oxygen consumption rates(OCR) and L-lactate were also measured with an XF96 Analyzer(Seahorse Biosciences) to deter.mine the significance of metabolism of oxidative phosphorylation and aerobic glycolysisin gastric cells.In addition,western blot was used to detect the contribution of AMP-activated protein kinase(AMPK),and anti-apoptotic proteins(Bcl-2 and survivin) to clarify the mechanism of death or survival of gastric cancer cells treated by 2-DG or oligomycin.RESULTS In this study,it was shown that the growth of gastric cell lines were suppressed by 2-DG.However,the sensitivity to 2-DG was quite different among cell lines:IC 50 of 2-DG was from 3.28 mmol·L^(-1)(MGC-803) to 15.57 mmol·L^(-1)(BGC-823).MGC-803 was relatively sensitive to 2-DG(IC 50:3.28 mmol·L^(-1)),consumed more glucose and produced more lactate(waste product of glycolysis) than the three other cell lines.Consequently,MGC-803 could be more dependent on glycolysis than other cell lines,which was further confirmed by the fact that glucose(+) FCS(-) medium showed more growth and survival than glucose(-) FCS(+) medium.Alternatively,BGC-823,most resistant to 2-DG(IC50:15.57 mmol · L-1),was most sensitive to oligomycin,and showed more growth and survival in glucose(-) FCS(+) medium than in glucose(+) FCS(-) medium.Thus,we had reasons to think BGC-823 cells depended on oxidative phosphorylation for energy production.In BGC-823,AMPK,which is activated when ATP becomes limiting,was rapidly phosphorylated by 2-DG,and expression of Bcl-2 was augmented,which might result in resistance to 2-DG.Interestingly,AMPK phosphorylation and augmentation of Bcl-2 expression by 2-DG were not observed in MGC-803,which is 2-DG sensitive.CONCLUSION There is a large metabolic difference between gastric cancer cell lines,which will facilitate the future gastric cancer therapy by targeting metabolic pathways.
基金supported by the National Natural Science Foundation of China(72474034,72104034)Humanities and Social Science Fund of the Ministry of Education of China(21YJC630037,22XJC910001)China Postdoctoral Science Foundation(2022T150072)。
文摘To address the charging infrastructure challenges associated with slow electric vehicle(EV)industry growth,this study investigates the collaboration between private charging-pile-sharing platforms struggling with profitability and automotive companies.This collaboration is crucial,as it demands a balanced price and service quality management due to consumer expectations.This paper introduces a Stackelberg game model to explore the relationship between a charging platform and an automotive company.Through numerical analysis,we assess how this cooperation might improve the platform’s efficiency and benefit society,potentially overcoming existing industry hurdles.Our findings indicate that such partnerships could benefit all parties involved,despite possible negative environmental impacts.However,after collaborat-ing,platforms may increase consumer prices and payments to suppliers,potentially lowering service quality for brand-associated consumers due to a compromise between shorter waiting times and service quality.This research offers valu-able insights for stakeholders on the effects of cooperation,enabling better strategic decisions in the EV charging sector.
基金This work was supported by the Natural Science Foundation of Heilongjiang Province(LH2022F049).
文摘Overlooking the issue of false alarm suppression in heterogeneous change detection leads to inferior detection per-formance.This paper proposes a method to handle false alarms in heterogeneous change detection.A lightweight network of two channels is bulit based on the combination of convolutional neural network(CNN)and graph convolutional network(GCN).CNNs learn feature difference maps of multitemporal images,and attention modules adaptively fuse CNN-based and graph-based features for different scales.GCNs with a new kernel filter adaptively distinguish between nodes with the same and those with different labels,generating change maps.Experimental evaluation on two datasets validates the efficacy of the pro-posed method in addressing false alarms.
