Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in induci...Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in inducing loess landslides.This study focuses on three neighboring cities sequentially situated on the Loess Plateau along the direction of aeolian deposition of loess,namely Lanzhou,Dingxi,and Tianshui,which are densely populated and prone to landslide disasters.The variations in hydraulic properties,including water retention capacity and permeability,are investigated through Soil Water Characteristic Curve(SWCC)test and hydraulic conductivity test.The experimental findings revealed that Tianshui loess exhibited the highest water retention capacity,followed by Dingxi loess,while Lanzhou loess demonstrated the lowest water retention capacity.Contrastingly,the results for the saturated permeability coefficient were found to be the opposite:Tianshui loess showed the lowest permeability,whereas Lanzhou loess displayed the highest permeability.These results are supported and analyzed by scanning electron microscopy(SEM)observation.In addition,the water retention capacity is mathematically expressed using the van Genuchten model and extended to predict unsaturated hydraulic properties of loess.The experimental results exhibit a strong accordance with one another and align with the regional distribution patterns of disasters.展开更多
This study introduces a coupled electromagnetic–thermal–mechanical model to reveal the mechanisms of microcracking and mineral melting of polymineralic rocks under microwave radiation.Experimental tests validate the...This study introduces a coupled electromagnetic–thermal–mechanical model to reveal the mechanisms of microcracking and mineral melting of polymineralic rocks under microwave radiation.Experimental tests validate the rationality of the proposed model.Embedding microscopic mineral sections into the granite model for simulation shows that uneven temperature gradients create distinct molten,porous,and nonmolten zones on the fracture surface.Moreover,the varying thermal expansion coefficients and Young's moduli among the minerals induce significant thermal stress at the mineral boundaries.Quartz and biotite with higher thermal expansion coefficients are subjected to compression,whereas plagioclase with smaller coefficients experiences tensile stress.In the molten zone,quartz undergoes transgranular cracking due to theα–βphase transition.The local high temperatures also induce melting phase transitions in biotite and feldspar.This numerical study provides new insights into the distribution of thermal stress and mineral phase changes in rocks under microwave irradiation.展开更多
Objective To evaluate the safety and efficiency of hemi-semi laminectomy approach for the microsurgical treatment of spinal schwannomas.Methods A total of 22 patients underwent hemi-semi laminectomy for the microsurgi...Objective To evaluate the safety and efficiency of hemi-semi laminectomy approach for the microsurgical treatment of spinal schwannomas.Methods A total of 22 patients underwent hemi-semi laminectomy for the microsurgical removal of spinal schwannomas during a period of 2009 and 2011 in Affiliated Hospital of Nantong University.We retrospectively analyzed the clinical outcomes of these patients.Results Of them,5 cases were diagnosed with cervical schwannomas,9 with thoracic schwannomas,and 8 with lumbar schwannomas.All the tumors including two dumbbell schwannomas were totally removed without major complications.Postoperatively,all patients were followed up from 6 to 36 months.The symptoms and signs were obviously improved,and no tumor recurrence or spinal deformity occurred.Conclusion Hemi-semi laminectomy is a safe and effective method for resection of spinal schwannomas.展开更多
The influences of the substituent base position on the excited state intramolecular proton transfer fluorescence properties were explored in 2-(2'-hydroxyphenyl)imidazo[1,2-a]-pyridine(HPIP)and HPIP's derivati...The influences of the substituent base position on the excited state intramolecular proton transfer fluorescence properties were explored in 2-(2'-hydroxyphenyl)imidazo[1,2-a]-pyridine(HPIP)and HPIP's derivatives(5'Br-HPIP and 6'BrHPIP).And the density functional theory(DFT)and time-dependent DFT(TD-DFT)methods were used to calculate the molecule structures.The calculated results showed that the influence of 5'Br-HPIP on the fluorescence intensity is stronger than that of 6'Br-HPIP.The fluorescence emission peak of 5'Br-HPIP occurred a blue shift compared with HPIP,and 6'BrHPIP exhibited an opposite red shift.The change of the fluorescence emission peak was attributed to the decrease of the energy gap from 6'Br-HPIP to 5'Br-HPIP.Our work on the substituent position influence could be helpful to design and develop new materials.展开更多
Glial cells play an important role in signal transduction,energy metabolism,extracellular ion homeostasis and neuroprotection of the central nervous system.However,few studies have explained the potential effects of e...Glial cells play an important role in signal transduction,energy metabolism,extracellular ion homeostasis and neuroprotection of the central nervous system.However,few studies have explained the potential effects of exosomes from glial cells on central nervous system health and disease.In this study,the genes expressed in exosomes from astrocytes and microglia were identified by deep RNA sequencing.Kyoto Encyclopedia of Genes and Genomes analysis indicated that several pathways in these exosomes are responsible for promoting neurodegenerative diseases,including Alzheimer's disease,Parkinson's disease and Huntington's disease.Gene ontology analysis showed that extracellular exosome,mitochondrion and growth factor activity were enriched in exosomes from the unique astrocyte group,while extracellular exosome and mitochondrion were enriched in exosomes from the unique microglia group.Next,combined with the screening of hub genes,the protein-protein interaction network analysis showed that exosomes from astrocytes influence neurodegenerative diseases through metabolic balance and ubiquitin-dependent protein balance,whereas exosomes from microglia influence neurodegenerative diseases through immune inflammation and oxidative stress.Although there were differences in RNA expression between exosomes from astrocytes and microglia,the groups were related by the hub genes,ubiquitin B and heat shock protein family A(Hsp70) member 8.Ubiquitin B appeared to be involved in pleiotropic regulatory functions,including immune regulation,inflammation inhibition,protein catabolism,intracellular protein transport,exosomes and oxidative stress.The results revealed the clinical significance of exosomes from glia in neurodegenerative diseases.This study was approved by the Animal Ethics Committee of Nantong University,China(approval No.S20180102-152) on January 2,2018.展开更多
Alpha linolenic acid(ALA)is an essential polyunsaturated fatty acids that can improve human health.Rapeseed is the second largest oil crop in the world but the ALA content in its seed fatty acids is only about 10%.Two...Alpha linolenic acid(ALA)is an essential polyunsaturated fatty acids that can improve human health.Rapeseed is the second largest oil crop in the world but the ALA content in its seed fatty acids is only about 10%.Two rapeseed germplasms YH25005 and R8Q10 with high content(up to 21%)ALA were developed by intervarietal crossing.They were used as the maternal parent(P_(1))when crossed with a low ALA parent SW(P2)to produce the seeds of the F1 hybrid,F2,and backcrosses to P1(BCP1)and P2(BCP2).A multigeneration joint segregation analysis was conducted to determine major gene t polygene effects of the content of three major unsaturated fatty acids including oleic(OA),linoleic(LA)and ALA.The results showed that,although some genes favorable to ALA accumulation were not allelic in R8Q10 and YH25005,all the inheritances of OA,LA and ALA in YH25005×SW and R8Q10×SW followed a genetic model of‘two pairs of additive major genes t additive-dominant polygenes’.It is suggested that the contents of OA,LA and ALA are closely related and the major genes in the parent SW containing loss-of-function mutations in FAD2 and FAD3 loci had strong effect to reduce ALA and elevate OA.However,total genetic effect of the polygenes was greater than that of the two major genes,especial on ALA content.It indicated that it is necessary to employ a larger F2 population to find the plant that accumulate enough minor-effect polygenes for high ALA content.The results are useful for high ALA rapeseed breeding and future work of gene mapping.展开更多
This work presents a route for the study on the absorption performance of gas into liquid under the condition of adding particles in a stirred constant temperature reactor.Two evaluated systems,hydrogen–water and hyd...This work presents a route for the study on the absorption performance of gas into liquid under the condition of adding particles in a stirred constant temperature reactor.Two evaluated systems,hydrogen–water and hydrogen–methanol,with the addition of activated carbon particles(ACP)were carried out,respectively.The results showed that the addition of ACP into the water can enhance the mass transfer between hydrogen and water,the enhancement factor increases rapidly with the increase of the ACP content,and then tends to be unchanged.However,for the hydrogen–methanol system,ACP has little effect on the mass transfer performance.In addition,a gas–liquid mass transfer model considering the effect of solid particle enhancement was established based on the shuttle effect and two-film model.Results indicated that the predicted value agreed well with the experimental value in both hydrogen–methanol–ACP and hydrogen–water–ACP systems.展开更多
Spark is the most popular in-memory processing framework for big data analytics.Memory is the crucial resource for workloads to achieve performance acceleration on Spark.The extant memory capacity configuration approa...Spark is the most popular in-memory processing framework for big data analytics.Memory is the crucial resource for workloads to achieve performance acceleration on Spark.The extant memory capacity configuration approach in Spark is to statically configure the memory capacity for workloads based on user’s specifications.However,without the deep knowledge of the workload’s system-level characteristics,users in practice often conservatively overestimate the memory utilizations of their workloads and require resource manager to grant more memory share than that they actually need,which leads to the severe waste of memory resources.To address the above issue,SMConf,an automated memory capacity configuration solution for in-memory computing workloads in Spark is proposed.SMConf is designed based on the observation that,though there is not one-size-fit-all proper configuration,the one-size-fit-bunch configuration can be found for in-memory computing workloads.SMConf classifies typical Spark workloads into categories based on metrics across layers of Spark system stack.For each workload category,an individual memory requirement model is learned from the workload’s input data size and the strong-correlated configuration parameters.For an ad-hoc workload,SMConf matches its memory requirement signature to one of the workload categories with small-sized input data and determines its proper memory capacity configuration with the corresponding memory requirement model.Experimental results demonstrate that,compared to the conservative default configuration,SMConf can reduce the memory resource provision to Spark workloads by up to 69%with the slight performance degradation,and reduce the average turnaround time of Spark workloads by up to 55%in the multi-tenant environments.展开更多
Al-enabled system simulation and modelling has become useful tools to facilitate humans to understand systems in different do-mains,such as physics,astrophysics,chemistry,biology,economics,engineering and social scien...Al-enabled system simulation and modelling has become useful tools to facilitate humans to understand systems in different do-mains,such as physics,astrophysics,chemistry,biology,economics,engineering and social science.A complex system is featured with a large number of interacting components(agents,processes,etc.),whose aggregate activities are nonlinear and self-organized.Complex systems are hard to be simulated or mod-elled by using traditional computational approaches due to complex relationships among system components,distributed features of resources,and dynamics of environments.Meanwhile,agent and multi-agent systems have demonstrated advantages and great potentials in modelling and simulating complex systems.展开更多
The dense alumina shell on the surface of aluminum powder will hinder the combustion of aluminum powder and increase its ignition temperature.In this study,the aluminum oxide shell layer on the surface of aluminum pow...The dense alumina shell on the surface of aluminum powder will hinder the combustion of aluminum powder and increase its ignition temperature.In this study,the aluminum oxide shell layer on the surface of aluminum powder was removed with hydrofluoric acid by one-pot method,and 3-Perfluorohexyl-1,2-epoxypropane(PFHP)(F3C(CF2)5CH2C2H3O)was coated to form a uniform and controllable core-shell Al@PFHP.The core-shell AI@PFHP showed better thermal reaction and ignition performance.The exothermic enthalpy of Al@0.15 PFHP was increased by about 1.9 times,with lower ignition temperature(reduced by about 140℃)and longer burning duration(increased by about 1.5 times)after coating with PFHP,compared with raw aluminum powder.In addition,the formation of PFHP coating shell can effectively improve the hydrophobicity and corrosion resistance of aluminum powder.展开更多
Biological receptor-ligand adhesion governed by mammalian cells involves a series of mechanochemical pro-cesses that can realize reversible,loading rate-dependent specific interfacial bonding,and even exhibit a counte...Biological receptor-ligand adhesion governed by mammalian cells involves a series of mechanochemical pro-cesses that can realize reversible,loading rate-dependent specific interfacial bonding,and even exhibit a counterintuitive behavior called catch bonds that tend to have much longer lifetimes when larger pulling forces are applied.Inspired by these catch bonds,we designed a hydrogen bonding-meditated hydrogel made from acrylic acid-N-acryloyl glycinamide(AA-NAGA)copolymers and tannic acids(TA),which formed repeatable specific adhesion to polar surfaces in an ultra-fast and robust way,but hardly adhered to nonpolar materials.It demonstrated up to five-fold increase in shear adhesive strength and interfacial adhesive toughness with external loading rates varying from 5 to 500 mm min^(-1).With a mechanochemical coupling model based on Monte Carlo simulations,we quantitatively revealed the nonlinear dependence of rate-sensitive interfacial adhesion on external loading,which was in good agreement with the experimental data.Likewise,the developed hydrogels were biocompatible,possessed antioxidant and antibacterial properties and promoted wound healing.This work not only reports a stimuli-responsive hydrogel adhesive suitable for multiple biomedical applications,but also offers an innovative strategy for bionic designs of smart hydrogels with loading rate-sensitive specific adhesion for various emerging areas including flexible electronics and soft robotics.展开更多
As one of the key technologies of intelligent transportation systems, short-term traffic volume prediction plays an increasingly important role in solving urban traffic problems. In the last decade, many approaches we...As one of the key technologies of intelligent transportation systems, short-term traffic volume prediction plays an increasingly important role in solving urban traffic problems. In the last decade, many approaches were proposed for the traffic volume prediction from different perspectives. However, most of these approaches are based on a large amount of historical data. When there are only finite collected traffic data, they cannot be well trained, so the prediction accuracy of these approaches will be poor. In this paper, a tensor model is proposed to capture the change patterns of continuous traffic volumes. From collected traffic volume data, the element data are extracted to update the corresponding elements of the tensor model. Then, a tucker decomposition and gradient descent based algorithm is employed to impute the missing elements of the tensor model. After missing element imputation, the tensor model can be directly applied to the short-term traffic volume prediction through searching the corresponding elements of the model and the storage cost of the model is low. Our model is evaluated on real traffic volume data from PeMS dataset, which indicates that our model has higher traffic volume prediction accuracy than other approaches in the situation of finite traffic volume data.展开更多
When multiple central processing unit(CPU)cores and integrated graphics processing units(GPUs)share off-chip main memory,CPU and GPU applications compete for the critical memory resource.This causes serious resource c...When multiple central processing unit(CPU)cores and integrated graphics processing units(GPUs)share off-chip main memory,CPU and GPU applications compete for the critical memory resource.This causes serious resource competition and has a negative impact on the overall performance of the system.We describe the competition for shared-memory resources in a CPU-GPU heterogeneous multi-core architecture,and a sharedmemory request scheduling strategy based on perceptual and predictive batch-processing is proposed.By sensing the CPU and GPU memory request conditions in the request buffer,the proposed scheduling strategy estimates the GPU latency tolerance and reduces mutual interference between CPU and GPU by processing CPU or GPU memory requests in batches.According to the simulation results,the scheduling strategy improves CPU performance by8.53%and reduces mutual interference by 10.38%with low hardware complexity.展开更多
Named entity recognition(NER)is essential in many natural language processing(NLP)tasks such as information extraction and document classification.A construction document usually contains critical named entities,and a...Named entity recognition(NER)is essential in many natural language processing(NLP)tasks such as information extraction and document classification.A construction document usually contains critical named entities,and an effective NER method can provide a solid foundation for downstream applications to improve construction management efficiency.This study presents a NER method for Chinese construction documents based on conditional random field(CRF),including a corpus design pipeline and a CRF model.The corpus design pipeline identifies typical NER tasks in construction management,enables word-based tokenization,and controls the annotation consistency with a newly designed annotating specification.The CRF model engineers nine transformation features and seven classes of state features,covering the impacts of word position,part-of-speech(POS),and word/character states within the context.The F1-measure on a labeled construction data set is 87.9%.Furthermore,as more domain knowledge features are infused,the marginal performance improvement of including POS information will decrease,leading to a promising research direction of POS customization to improve NLP performance with limited data.展开更多
This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available ...This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available agents, it is hard for the single-objective and single (task)-to-single (agent) task allocation approaches to handle task allocation in such circumstances. To this end, two multi-objective coalition formation for task allocation models are proposed for disaster rescues in this paper. First, through coalition formation, the proposed models enable agents to cooperatively perform complex tasks that cannot be completed by single agent. In addition, through adjusting the weights of multiple task allocation objectives, the proposed models can employ the linear programming to generate more adaptive task allocation plans, which can satisfy different task allocation requirements in disaster rescue. Finally, through employing the multi-stage task allocation mechanism of the dynamic programming, the proposed models can handle the dynamics of tasks and agents in disaster environments. Experimental results indicate that the proposed models have good performance on coalition formation for task allocation in disaster environments, which can generate suitable task allocation plans according to various objectives of task allocation.展开更多
基金the financial support for the research presented in this paper from National Natural Science Foundation of China(42201142,42067066,51778590)。
文摘Loess has distinctive characteristics,leading to frequent landslide disasters and posing serious threats to the lives and properties of local re sidents.The involvement of water repre sents a critical factor in inducing loess landslides.This study focuses on three neighboring cities sequentially situated on the Loess Plateau along the direction of aeolian deposition of loess,namely Lanzhou,Dingxi,and Tianshui,which are densely populated and prone to landslide disasters.The variations in hydraulic properties,including water retention capacity and permeability,are investigated through Soil Water Characteristic Curve(SWCC)test and hydraulic conductivity test.The experimental findings revealed that Tianshui loess exhibited the highest water retention capacity,followed by Dingxi loess,while Lanzhou loess demonstrated the lowest water retention capacity.Contrastingly,the results for the saturated permeability coefficient were found to be the opposite:Tianshui loess showed the lowest permeability,whereas Lanzhou loess displayed the highest permeability.These results are supported and analyzed by scanning electron microscopy(SEM)observation.In addition,the water retention capacity is mathematically expressed using the van Genuchten model and extended to predict unsaturated hydraulic properties of loess.The experimental results exhibit a strong accordance with one another and align with the regional distribution patterns of disasters.
基金the National Natural Science Foundation of China(No.52074349)the Graduate Research Innovation Project of Hunan Province,China(No.CX20230194)。
文摘This study introduces a coupled electromagnetic–thermal–mechanical model to reveal the mechanisms of microcracking and mineral melting of polymineralic rocks under microwave radiation.Experimental tests validate the rationality of the proposed model.Embedding microscopic mineral sections into the granite model for simulation shows that uneven temperature gradients create distinct molten,porous,and nonmolten zones on the fracture surface.Moreover,the varying thermal expansion coefficients and Young's moduli among the minerals induce significant thermal stress at the mineral boundaries.Quartz and biotite with higher thermal expansion coefficients are subjected to compression,whereas plagioclase with smaller coefficients experiences tensile stress.In the molten zone,quartz undergoes transgranular cracking due to theα–βphase transition.The local high temperatures also induce melting phase transitions in biotite and feldspar.This numerical study provides new insights into the distribution of thermal stress and mineral phase changes in rocks under microwave irradiation.
文摘Objective To evaluate the safety and efficiency of hemi-semi laminectomy approach for the microsurgical treatment of spinal schwannomas.Methods A total of 22 patients underwent hemi-semi laminectomy for the microsurgical removal of spinal schwannomas during a period of 2009 and 2011 in Affiliated Hospital of Nantong University.We retrospectively analyzed the clinical outcomes of these patients.Results Of them,5 cases were diagnosed with cervical schwannomas,9 with thoracic schwannomas,and 8 with lumbar schwannomas.All the tumors including two dumbbell schwannomas were totally removed without major complications.Postoperatively,all patients were followed up from 6 to 36 months.The symptoms and signs were obviously improved,and no tumor recurrence or spinal deformity occurred.Conclusion Hemi-semi laminectomy is a safe and effective method for resection of spinal schwannomas.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11874180 and 11704146)the Program of Science and Technology Development Plan of Jilin Province,China(Grant Nos.20190201138TC and 20190103101JH)。
文摘The influences of the substituent base position on the excited state intramolecular proton transfer fluorescence properties were explored in 2-(2'-hydroxyphenyl)imidazo[1,2-a]-pyridine(HPIP)and HPIP's derivatives(5'Br-HPIP and 6'BrHPIP).And the density functional theory(DFT)and time-dependent DFT(TD-DFT)methods were used to calculate the molecule structures.The calculated results showed that the influence of 5'Br-HPIP on the fluorescence intensity is stronger than that of 6'Br-HPIP.The fluorescence emission peak of 5'Br-HPIP occurred a blue shift compared with HPIP,and 6'BrHPIP exhibited an opposite red shift.The change of the fluorescence emission peak was attributed to the decrease of the energy gap from 6'Br-HPIP to 5'Br-HPIP.Our work on the substituent position influence could be helpful to design and develop new materials.
基金supported by the National Natural Science Foundation of China,No.81870975 (to SLZ)Innovation and Entrepreneurship Training Program for College Students in Jiangsu Province of China,No.202010304034Z (to FYZ)。
文摘Glial cells play an important role in signal transduction,energy metabolism,extracellular ion homeostasis and neuroprotection of the central nervous system.However,few studies have explained the potential effects of exosomes from glial cells on central nervous system health and disease.In this study,the genes expressed in exosomes from astrocytes and microglia were identified by deep RNA sequencing.Kyoto Encyclopedia of Genes and Genomes analysis indicated that several pathways in these exosomes are responsible for promoting neurodegenerative diseases,including Alzheimer's disease,Parkinson's disease and Huntington's disease.Gene ontology analysis showed that extracellular exosome,mitochondrion and growth factor activity were enriched in exosomes from the unique astrocyte group,while extracellular exosome and mitochondrion were enriched in exosomes from the unique microglia group.Next,combined with the screening of hub genes,the protein-protein interaction network analysis showed that exosomes from astrocytes influence neurodegenerative diseases through metabolic balance and ubiquitin-dependent protein balance,whereas exosomes from microglia influence neurodegenerative diseases through immune inflammation and oxidative stress.Although there were differences in RNA expression between exosomes from astrocytes and microglia,the groups were related by the hub genes,ubiquitin B and heat shock protein family A(Hsp70) member 8.Ubiquitin B appeared to be involved in pleiotropic regulatory functions,including immune regulation,inflammation inhibition,protein catabolism,intracellular protein transport,exosomes and oxidative stress.The results revealed the clinical significance of exosomes from glia in neurodegenerative diseases.This study was approved by the Animal Ethics Committee of Nantong University,China(approval No.S20180102-152) on January 2,2018.
基金supported by the project of Key R&D plans of Shaanxi Province(2021NY-074)Yangling Seed Industry Innovation Plan.
文摘Alpha linolenic acid(ALA)is an essential polyunsaturated fatty acids that can improve human health.Rapeseed is the second largest oil crop in the world but the ALA content in its seed fatty acids is only about 10%.Two rapeseed germplasms YH25005 and R8Q10 with high content(up to 21%)ALA were developed by intervarietal crossing.They were used as the maternal parent(P_(1))when crossed with a low ALA parent SW(P2)to produce the seeds of the F1 hybrid,F2,and backcrosses to P1(BCP1)and P2(BCP2).A multigeneration joint segregation analysis was conducted to determine major gene t polygene effects of the content of three major unsaturated fatty acids including oleic(OA),linoleic(LA)and ALA.The results showed that,although some genes favorable to ALA accumulation were not allelic in R8Q10 and YH25005,all the inheritances of OA,LA and ALA in YH25005×SW and R8Q10×SW followed a genetic model of‘two pairs of additive major genes t additive-dominant polygenes’.It is suggested that the contents of OA,LA and ALA are closely related and the major genes in the parent SW containing loss-of-function mutations in FAD2 and FAD3 loci had strong effect to reduce ALA and elevate OA.However,total genetic effect of the polygenes was greater than that of the two major genes,especial on ALA content.It indicated that it is necessary to employ a larger F2 population to find the plant that accumulate enough minor-effect polygenes for high ALA content.The results are useful for high ALA rapeseed breeding and future work of gene mapping.
基金supported by National Key Research and Development Program of China(2019YFA0210302)the National Natural Science Foundation of China(21878009,21901141)Basic Research Plan for Public Welfare of Zhejiang Province,China(LZY21B060001).
文摘This work presents a route for the study on the absorption performance of gas into liquid under the condition of adding particles in a stirred constant temperature reactor.Two evaluated systems,hydrogen–water and hydrogen–methanol,with the addition of activated carbon particles(ACP)were carried out,respectively.The results showed that the addition of ACP into the water can enhance the mass transfer between hydrogen and water,the enhancement factor increases rapidly with the increase of the ACP content,and then tends to be unchanged.However,for the hydrogen–methanol system,ACP has little effect on the mass transfer performance.In addition,a gas–liquid mass transfer model considering the effect of solid particle enhancement was established based on the shuttle effect and two-film model.Results indicated that the predicted value agreed well with the experimental value in both hydrogen–methanol–ACP and hydrogen–water–ACP systems.
基金National Key R&D Program of China(No.2017YFC0803300)the National Natural Science of Foundation of China(No.61703013).
文摘Spark is the most popular in-memory processing framework for big data analytics.Memory is the crucial resource for workloads to achieve performance acceleration on Spark.The extant memory capacity configuration approach in Spark is to statically configure the memory capacity for workloads based on user’s specifications.However,without the deep knowledge of the workload’s system-level characteristics,users in practice often conservatively overestimate the memory utilizations of their workloads and require resource manager to grant more memory share than that they actually need,which leads to the severe waste of memory resources.To address the above issue,SMConf,an automated memory capacity configuration solution for in-memory computing workloads in Spark is proposed.SMConf is designed based on the observation that,though there is not one-size-fit-all proper configuration,the one-size-fit-bunch configuration can be found for in-memory computing workloads.SMConf classifies typical Spark workloads into categories based on metrics across layers of Spark system stack.For each workload category,an individual memory requirement model is learned from the workload’s input data size and the strong-correlated configuration parameters.For an ad-hoc workload,SMConf matches its memory requirement signature to one of the workload categories with small-sized input data and determines its proper memory capacity configuration with the corresponding memory requirement model.Experimental results demonstrate that,compared to the conservative default configuration,SMConf can reduce the memory resource provision to Spark workloads by up to 69%with the slight performance degradation,and reduce the average turnaround time of Spark workloads by up to 55%in the multi-tenant environments.
文摘Al-enabled system simulation and modelling has become useful tools to facilitate humans to understand systems in different do-mains,such as physics,astrophysics,chemistry,biology,economics,engineering and social science.A complex system is featured with a large number of interacting components(agents,processes,etc.),whose aggregate activities are nonlinear and self-organized.Complex systems are hard to be simulated or mod-elled by using traditional computational approaches due to complex relationships among system components,distributed features of resources,and dynamics of environments.Meanwhile,agent and multi-agent systems have demonstrated advantages and great potentials in modelling and simulating complex systems.
文摘The dense alumina shell on the surface of aluminum powder will hinder the combustion of aluminum powder and increase its ignition temperature.In this study,the aluminum oxide shell layer on the surface of aluminum powder was removed with hydrofluoric acid by one-pot method,and 3-Perfluorohexyl-1,2-epoxypropane(PFHP)(F3C(CF2)5CH2C2H3O)was coated to form a uniform and controllable core-shell Al@PFHP.The core-shell AI@PFHP showed better thermal reaction and ignition performance.The exothermic enthalpy of Al@0.15 PFHP was increased by about 1.9 times,with lower ignition temperature(reduced by about 140℃)and longer burning duration(increased by about 1.5 times)after coating with PFHP,compared with raw aluminum powder.In addition,the formation of PFHP coating shell can effectively improve the hydrophobicity and corrosion resistance of aluminum powder.
基金National Natural Science Foundation of China(Grant nos.11972001,11972002,12072001 and 91848201)Beijing Natural Science Foundation(Grant no.Z200017)National Key Research and Development Program of China(Grant no.2021YFA1000201).
文摘Biological receptor-ligand adhesion governed by mammalian cells involves a series of mechanochemical pro-cesses that can realize reversible,loading rate-dependent specific interfacial bonding,and even exhibit a counterintuitive behavior called catch bonds that tend to have much longer lifetimes when larger pulling forces are applied.Inspired by these catch bonds,we designed a hydrogen bonding-meditated hydrogel made from acrylic acid-N-acryloyl glycinamide(AA-NAGA)copolymers and tannic acids(TA),which formed repeatable specific adhesion to polar surfaces in an ultra-fast and robust way,but hardly adhered to nonpolar materials.It demonstrated up to five-fold increase in shear adhesive strength and interfacial adhesive toughness with external loading rates varying from 5 to 500 mm min^(-1).With a mechanochemical coupling model based on Monte Carlo simulations,we quantitatively revealed the nonlinear dependence of rate-sensitive interfacial adhesion on external loading,which was in good agreement with the experimental data.Likewise,the developed hydrogels were biocompatible,possessed antioxidant and antibacterial properties and promoted wound healing.This work not only reports a stimuli-responsive hydrogel adhesive suitable for multiple biomedical applications,but also offers an innovative strategy for bionic designs of smart hydrogels with loading rate-sensitive specific adhesion for various emerging areas including flexible electronics and soft robotics.
基金supported by the National Natural Science Foundation of China(No.62276011,62072016)the Natural Science Foundation of Beijing Municipality(No.4212016)Urban Carbon Neutral Science and Technology Innovation Fund Project of Beijing University of Technology(No.040000514122608).
文摘As one of the key technologies of intelligent transportation systems, short-term traffic volume prediction plays an increasingly important role in solving urban traffic problems. In the last decade, many approaches were proposed for the traffic volume prediction from different perspectives. However, most of these approaches are based on a large amount of historical data. When there are only finite collected traffic data, they cannot be well trained, so the prediction accuracy of these approaches will be poor. In this paper, a tensor model is proposed to capture the change patterns of continuous traffic volumes. From collected traffic volume data, the element data are extracted to update the corresponding elements of the tensor model. Then, a tucker decomposition and gradient descent based algorithm is employed to impute the missing elements of the tensor model. After missing element imputation, the tensor model can be directly applied to the short-term traffic volume prediction through searching the corresponding elements of the model and the storage cost of the model is low. Our model is evaluated on real traffic volume data from PeMS dataset, which indicates that our model has higher traffic volume prediction accuracy than other approaches in the situation of finite traffic volume data.
基金Project supported by the National Natural Science Foundation of China(Nos.62276011 and 61202076)the Natural Science Foundation of Beijing,China(No.4192007)。
文摘When multiple central processing unit(CPU)cores and integrated graphics processing units(GPUs)share off-chip main memory,CPU and GPU applications compete for the critical memory resource.This causes serious resource competition and has a negative impact on the overall performance of the system.We describe the competition for shared-memory resources in a CPU-GPU heterogeneous multi-core architecture,and a sharedmemory request scheduling strategy based on perceptual and predictive batch-processing is proposed.By sensing the CPU and GPU memory request conditions in the request buffer,the proposed scheduling strategy estimates the GPU latency tolerance and reduces mutual interference between CPU and GPU by processing CPU or GPU memory requests in batches.According to the simulation results,the scheduling strategy improves CPU performance by8.53%and reduces mutual interference by 10.38%with low hardware complexity.
基金This work is supported by the National Natural Science Foundation of China(Grant No.71971196).
文摘Named entity recognition(NER)is essential in many natural language processing(NLP)tasks such as information extraction and document classification.A construction document usually contains critical named entities,and an effective NER method can provide a solid foundation for downstream applications to improve construction management efficiency.This study presents a NER method for Chinese construction documents based on conditional random field(CRF),including a corpus design pipeline and a CRF model.The corpus design pipeline identifies typical NER tasks in construction management,enables word-based tokenization,and controls the annotation consistency with a newly designed annotating specification.The CRF model engineers nine transformation features and seven classes of state features,covering the impacts of word position,part-of-speech(POS),and word/character states within the context.The F1-measure on a labeled construction data set is 87.9%.Furthermore,as more domain knowledge features are infused,the marginal performance improvement of including POS information will decrease,leading to a promising research direction of POS customization to improve NLP performance with limited data.
文摘This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available agents, it is hard for the single-objective and single (task)-to-single (agent) task allocation approaches to handle task allocation in such circumstances. To this end, two multi-objective coalition formation for task allocation models are proposed for disaster rescues in this paper. First, through coalition formation, the proposed models enable agents to cooperatively perform complex tasks that cannot be completed by single agent. In addition, through adjusting the weights of multiple task allocation objectives, the proposed models can employ the linear programming to generate more adaptive task allocation plans, which can satisfy different task allocation requirements in disaster rescue. Finally, through employing the multi-stage task allocation mechanism of the dynamic programming, the proposed models can handle the dynamics of tasks and agents in disaster environments. Experimental results indicate that the proposed models have good performance on coalition formation for task allocation in disaster environments, which can generate suitable task allocation plans according to various objectives of task allocation.