The rising frequency of extreme disaster events seriously threatens the safe and secure operation of the regional integrated electricity-natural gas system(RIENGS).With the growing level of coupling between electric a...The rising frequency of extreme disaster events seriously threatens the safe and secure operation of the regional integrated electricity-natural gas system(RIENGS).With the growing level of coupling between electric and natural gas systems,it is critical to enhance the load restoration capability of both systems.This paper proposes a coordinated optimization strategy for resilience-enhanced RIENGS load restoration and repair scheduling and transforms it into a mixed integer second-order cone programming(MISOCP)model.The proposed model considers the distribution network reconfiguration and the coordinated repair strategy between the two systems,minimizing the total system load loss cost and repair time.In addition,a bi-directional gas flow model is used to describe the natural gas system,which can provide the RIENGS with more flexibility for load restoration during natural gas system failure.Finally,the effectiveness of the proposed approach is verified by conducting case studies on the test systems RIENGS E13-G7 and RIENGS E123-G20.展开更多
The development of rice cultivars with improved nitrogen use efficiency(NUE)is desirable for sustainable agriculture.Achieving this goal depends in part on understanding how rice responds to low soil nitrogen(N)and id...The development of rice cultivars with improved nitrogen use efficiency(NUE)is desirable for sustainable agriculture.Achieving this goal depends in part on understanding how rice responds to low soil nitrogen(N)and identifying causative genes underlying this trait.To identify quantitative trait loci(QTL)or genes associated with low N response,we conducted a genome-wide association study(GWAS)using a diverse panel of 230 rice accessions and performed a transcriptomic investigation of rice accessions with differential responses to low N stress at two N levels.We detected 411 GWAS-associated genes in 5 QTL and 2722 differentially expressed genes in response to low N,of which 24 were identified by both methods and ranked according to gene annotations,literature queries,gene expression,and genetic diversity analysis.The large-scale datasets obtained from this study reveal low N-responsive characteristics and provide insights towards understanding the regulatory mechanisms of N-deficiency tolerance in rice,and the candidate genes or QTL would be valuable resources for increasing rice NUE via molecular biotechnology.展开更多
The blended-fuel based eddy-dissipation-concept combustion model was newly developed in the FireFOAM framework, and applied to simulate30 cm×30 cm heptane-ethanol pool fire. Comparison was made of fire height,cen...The blended-fuel based eddy-dissipation-concept combustion model was newly developed in the FireFOAM framework, and applied to simulate30 cm×30 cm heptane-ethanol pool fire. Comparison was made of fire height,centerline temperature against experimental measurements, which shows that they match very well with each other. However, further studies are needed to examine the validation of this model in fire simulations with various scales.展开更多
The interaction of single water droplet impacting on immiscible liquid surface was focused with the temperature varying from 50℃ to 210℃.The impact behavior is recorded with a high-speed camera running at 2000 frame...The interaction of single water droplet impacting on immiscible liquid surface was focused with the temperature varying from 50℃ to 210℃.The impact behavior is recorded with a high-speed camera running at 2000 frames per second.It is found that droplet diameter,oil temperature,andWeber number have important influences on impact behaviors.Three typical phenomena,including penetration,crater-jet,and crater-jet–secondary jet,were observed.Penetration only occurs when the Weber number is below 105.With Weber number increasing to 302,the jet begins to appear.Moreover,to gain deeper physical insight into the crater formation and jet formation,the energy of droplet impingement onto the liquid pool surface was estimated.The oil temperature has a significant effect on the energy conversion efficiency.High temperature is beneficial to improve energy conversion efficiency.展开更多
Stragglers can temporize jobs and reduce cluster efficiency seriously.Many researches have been contributed to the solution, such as Blacklist[8], speculative execution[1, 6], Dolly[8]. In this paper, we put forward a...Stragglers can temporize jobs and reduce cluster efficiency seriously.Many researches have been contributed to the solution, such as Blacklist[8], speculative execution[1, 6], Dolly[8]. In this paper, we put forward a new approach for mitigating stragglers in MapReduce, name Hummer. It starts task clones only for high-risk delaying tasks. Related experiments have been carried and results show that it can decrease the job delaying risk with fewer resources consumption. For small jobs, Hummer also improves job completion time by 48% and 10% compared to LATE and Dolly.展开更多
Class-Incremental Few-Shot Named Entity Recognition(CIFNER)aims to identify entity categories that have appeared with only a few newly added(novel)class examples.However,existing class-incremental methods typically in...Class-Incremental Few-Shot Named Entity Recognition(CIFNER)aims to identify entity categories that have appeared with only a few newly added(novel)class examples.However,existing class-incremental methods typically introduce new parameters to adapt to new classes and treat all information equally,resulting in poor generalization.Meanwhile,few-shot methods necessitate samples for all observed classes,making them difficult to transfer into a class-incremental setting.Thus,a decoupled two-phase framework method for the CIFNER task is proposed to address the above issues.The whole task is converted to two separate tasks named Entity Span Detection(ESD)and Entity Class Discrimination(ECD)that leverage parameter-cloning and label-fusion to learn different levels of knowledge separately,such as class-generic knowledge and class-specific knowledge.Moreover,different variants,such as the Conditional Random Field-based(CRF-based),word-pair-based methods in ESD module,and add-based,Natural Language Inference-based(NLI-based)and prompt-based methods in ECD module,are investigated to demonstrate the generalizability of the decoupled framework.Extensive experiments on the three Named Entity Recognition(NER)datasets reveal that our method achieves the state-of-the-art performance in the CIFNER setting.展开更多
The phenomena of flame spread over aviation kerosene with an obstacle in liquid phase are investigated experimentally through surface temperature measurement by using infrared camera,schlieren images of subsurface flo...The phenomena of flame spread over aviation kerosene with an obstacle in liquid phase are investigated experimentally through surface temperature measurement by using infrared camera,schlieren images of subsurface flow in front of and behind obstacle and residence time of flame obtained from video recording.Experimental results reveal that obstacle has no effect on gas phase controlled flame spread.But for liquid phase controlled flame spread,flame can be stopped by an obstacle with its top edge flush with oil surface,and the residence time decreases with the increase of initial temperature of fuel.That conduction and radiation only play a subsidiary role in flame spread over liquid fuel was proved by schlieren images and surface temperature profiles.展开更多
The leaks of pressurized hydrogen can be ignited if an ignition source is within a certain distance from the source of the leaks, and jet fires or explosions may take place. In this paper, a high speed camera was used...The leaks of pressurized hydrogen can be ignited if an ignition source is within a certain distance from the source of the leaks, and jet fires or explosions may take place. In this paper, a high speed camera was used to investigate the ignition kernel development, ignition probability and flame propagation along the axis of hydrogen jets, which leaked from a 3-mm-internal-diameter nozzle and were ignited by an electric spark. Experimental results indicate that for successful ignition events, the ignition delay time increases with an increase of the distance between the nozzle and the electrode. Ignitable zone of the hydrogen jets is underestimated if using the predicted hydrogen concentration along the jets centerline. The average rate of downstream flame decreases but that of the upstream flame increases with the electrode going far from the nozzle.展开更多
The self-extinguishing behavior of kerosene spray fire was investigated in a completely enclosed compartment with the size of 3 m × 3 m × 3.4 m.The spray was generated by locating one BETE nozzle at the cent...The self-extinguishing behavior of kerosene spray fire was investigated in a completely enclosed compartment with the size of 3 m × 3 m × 3.4 m.The spray was generated by locating one BETE nozzle at the center of the bottom wall.A series of spray fire videos were obtained by changing BETE nozzle type and injecting pressure.The results show that spray fire undergoes four stages: the growth stage,the quasi-steady stage,the stretch stage and the self-extinguishing stage.Consumption of large quantities of oxygen causes spray fire to first be stretched and then quench.In this process,fire base migrates away from spray region and leads to the emergence of ghosting fire.Ghosting fire promotes the instability of spray fire and large fluctuation of its height,which provides help to its self-extinguishing.With increasing the injecting pressure or the nozzle diameter,the self-extinguishing time decreases.It is found that the self-extinguishing time is approximately in inverse relation with injecting flow rate.Additionally,we also observed the occurrence of two-phase deflagration just after ignition,and it accelerates the spray fire growth and induces a larger fire height than the following quasi-steady spray fire.The deflagration turns stronger with increasing the injecting pressure.展开更多
基金funded by the Science and Technology Project of State Grid Jilin Electric Power Co.,Ltd.(Project Name:Research onDistributionNetworkResilience Assessment and Improvement Technology for Natural Disaster Areas).
文摘The rising frequency of extreme disaster events seriously threatens the safe and secure operation of the regional integrated electricity-natural gas system(RIENGS).With the growing level of coupling between electric and natural gas systems,it is critical to enhance the load restoration capability of both systems.This paper proposes a coordinated optimization strategy for resilience-enhanced RIENGS load restoration and repair scheduling and transforms it into a mixed integer second-order cone programming(MISOCP)model.The proposed model considers the distribution network reconfiguration and the coordinated repair strategy between the two systems,minimizing the total system load loss cost and repair time.In addition,a bi-directional gas flow model is used to describe the natural gas system,which can provide the RIENGS with more flexibility for load restoration during natural gas system failure.Finally,the effectiveness of the proposed approach is verified by conducting case studies on the test systems RIENGS E13-G7 and RIENGS E123-G20.
基金supported by the National Natural Science Foundation of China(31661143006,32101755,31971872,U2004204)the Key Research and Development Program of Zhejiang Province(2021C02056)+1 种基金the Central Public-interest Institution Basal Research Fund(CNRRI-202110,CNRRI-202111)the Ten-Thousand-Talent Program of Zhejiang Province(2019R52031)。
文摘The development of rice cultivars with improved nitrogen use efficiency(NUE)is desirable for sustainable agriculture.Achieving this goal depends in part on understanding how rice responds to low soil nitrogen(N)and identifying causative genes underlying this trait.To identify quantitative trait loci(QTL)or genes associated with low N response,we conducted a genome-wide association study(GWAS)using a diverse panel of 230 rice accessions and performed a transcriptomic investigation of rice accessions with differential responses to low N stress at two N levels.We detected 411 GWAS-associated genes in 5 QTL and 2722 differentially expressed genes in response to low N,of which 24 were identified by both methods and ranked according to gene annotations,literature queries,gene expression,and genetic diversity analysis.The large-scale datasets obtained from this study reveal low N-responsive characteristics and provide insights towards understanding the regulatory mechanisms of N-deficiency tolerance in rice,and the candidate genes or QTL would be valuable resources for increasing rice NUE via molecular biotechnology.
基金supported by the National Basic Research Program of China(2012CB719704)EU IIFFP7 Project(909658)+1 种基金the National Natural Science Foundation of China(51276177)the Fundamental Research Funds for the Central Universities
文摘The blended-fuel based eddy-dissipation-concept combustion model was newly developed in the FireFOAM framework, and applied to simulate30 cm×30 cm heptane-ethanol pool fire. Comparison was made of fire height,centerline temperature against experimental measurements, which shows that they match very well with each other. However, further studies are needed to examine the validation of this model in fire simulations with various scales.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFC0805100)the Fundamental Research Funds for the Central Universities of China(Grant No.PA2020GDGP0052).
文摘The interaction of single water droplet impacting on immiscible liquid surface was focused with the temperature varying from 50℃ to 210℃.The impact behavior is recorded with a high-speed camera running at 2000 frames per second.It is found that droplet diameter,oil temperature,andWeber number have important influences on impact behaviors.Three typical phenomena,including penetration,crater-jet,and crater-jet–secondary jet,were observed.Penetration only occurs when the Weber number is below 105.With Weber number increasing to 302,the jet begins to appear.Moreover,to gain deeper physical insight into the crater formation and jet formation,the energy of droplet impingement onto the liquid pool surface was estimated.The oil temperature has a significant effect on the energy conversion efficiency.High temperature is beneficial to improve energy conversion efficiency.
基金This work is sponsored in part by the National Basic Research Program of China (973) under Grant No.2014CB340303, the National Natural Science Foundation of China under Grant No. 61222205, the Program for New Century Excellent Talents in University, and the Fok Ying-Tong Education Foundation under Grant No. 141066.
文摘Stragglers can temporize jobs and reduce cluster efficiency seriously.Many researches have been contributed to the solution, such as Blacklist[8], speculative execution[1, 6], Dolly[8]. In this paper, we put forward a new approach for mitigating stragglers in MapReduce, name Hummer. It starts task clones only for high-risk delaying tasks. Related experiments have been carried and results show that it can decrease the job delaying risk with fewer resources consumption. For small jobs, Hummer also improves job completion time by 48% and 10% compared to LATE and Dolly.
基金supported by the National Natural Science Foundation of China(No.62006243)。
文摘Class-Incremental Few-Shot Named Entity Recognition(CIFNER)aims to identify entity categories that have appeared with only a few newly added(novel)class examples.However,existing class-incremental methods typically introduce new parameters to adapt to new classes and treat all information equally,resulting in poor generalization.Meanwhile,few-shot methods necessitate samples for all observed classes,making them difficult to transfer into a class-incremental setting.Thus,a decoupled two-phase framework method for the CIFNER task is proposed to address the above issues.The whole task is converted to two separate tasks named Entity Span Detection(ESD)and Entity Class Discrimination(ECD)that leverage parameter-cloning and label-fusion to learn different levels of knowledge separately,such as class-generic knowledge and class-specific knowledge.Moreover,different variants,such as the Conditional Random Field-based(CRF-based),word-pair-based methods in ESD module,and add-based,Natural Language Inference-based(NLI-based)and prompt-based methods in ECD module,are investigated to demonstrate the generalizability of the decoupled framework.Extensive experiments on the three Named Entity Recognition(NER)datasets reveal that our method achieves the state-of-the-art performance in the CIFNER setting.
基金supported by the National Natural Science Foundation of China (No.51036007)
文摘The phenomena of flame spread over aviation kerosene with an obstacle in liquid phase are investigated experimentally through surface temperature measurement by using infrared camera,schlieren images of subsurface flow in front of and behind obstacle and residence time of flame obtained from video recording.Experimental results reveal that obstacle has no effect on gas phase controlled flame spread.But for liquid phase controlled flame spread,flame can be stopped by an obstacle with its top edge flush with oil surface,and the residence time decreases with the increase of initial temperature of fuel.That conduction and radiation only play a subsidiary role in flame spread over liquid fuel was proved by schlieren images and surface temperature profiles.
基金Supported by the Fundamental Research Funds for the Central UniversitiesNational Natural Science Foundation of China(No.50806071)and(No.51276177)
文摘The leaks of pressurized hydrogen can be ignited if an ignition source is within a certain distance from the source of the leaks, and jet fires or explosions may take place. In this paper, a high speed camera was used to investigate the ignition kernel development, ignition probability and flame propagation along the axis of hydrogen jets, which leaked from a 3-mm-internal-diameter nozzle and were ignited by an electric spark. Experimental results indicate that for successful ignition events, the ignition delay time increases with an increase of the distance between the nozzle and the electrode. Ignitable zone of the hydrogen jets is underestimated if using the predicted hydrogen concentration along the jets centerline. The average rate of downstream flame decreases but that of the upstream flame increases with the electrode going far from the nozzle.
基金supported by National Natural Science Foundation of China(Grant No.51276177)
文摘The self-extinguishing behavior of kerosene spray fire was investigated in a completely enclosed compartment with the size of 3 m × 3 m × 3.4 m.The spray was generated by locating one BETE nozzle at the center of the bottom wall.A series of spray fire videos were obtained by changing BETE nozzle type and injecting pressure.The results show that spray fire undergoes four stages: the growth stage,the quasi-steady stage,the stretch stage and the self-extinguishing stage.Consumption of large quantities of oxygen causes spray fire to first be stretched and then quench.In this process,fire base migrates away from spray region and leads to the emergence of ghosting fire.Ghosting fire promotes the instability of spray fire and large fluctuation of its height,which provides help to its self-extinguishing.With increasing the injecting pressure or the nozzle diameter,the self-extinguishing time decreases.It is found that the self-extinguishing time is approximately in inverse relation with injecting flow rate.Additionally,we also observed the occurrence of two-phase deflagration just after ignition,and it accelerates the spray fire growth and induces a larger fire height than the following quasi-steady spray fire.The deflagration turns stronger with increasing the injecting pressure.
