The contradiction between the efficiency and the ice tolerance remains a challenge to the traditional aerodynamic design considering the icing effect.To address the problem,a new ice-tolerant concept based on the vari...The contradiction between the efficiency and the ice tolerance remains a challenge to the traditional aerodynamic design considering the icing effect.To address the problem,a new ice-tolerant concept based on the variable drooping leading edge is proposed and extended to a single-aisle commercial aircraft with the swept wing.The outer-wing and full-spanwise drooping leading edge configurations are set up to distinguish the effect of different ice tolerant strategies.The Reynolds-averaged Navier-Stokes results reveal that the stall angle of attack is delayed by 25.0%,and the maximum lift coefficient is increased by 23.3%with the full-spanwise drooping in the presence of horn-shaped ice on the wing.This improvement is primarily driven by the recovery of leading-edge suction.With the formulation of the improved delayed detached eddy simulation,the structures and the behaviors of the separated flow near the stall point are analyzed via the comparison before and after drooping the leading edge in full-spanwise.The results indicate that the suppression of the spatial development of the shedding shear layer promotes the closure of the separation bubble and mitigates the sweeping motion of the large-scale spanwise vortex.These integrated effects contribute to the enhancement of ice tolerance.展开更多
Uneven power distribution,transient voltage,and frequency deviations are observed in the photovoltaic storage hybrid inverter during the switching between grid-connected and island modes.In response to these issues,th...Uneven power distribution,transient voltage,and frequency deviations are observed in the photovoltaic storage hybrid inverter during the switching between grid-connected and island modes.In response to these issues,this paper proposes a grid-connected/island switching control strategy for photovoltaic storage hybrid inverters based on the modified chimpanzee optimization algorithm.The proposed strategy incorporates coupling compensation and power differentiation elements based on the traditional droop control.Then,it combines the angular frequency and voltage amplitude adjustments provided by the phase-locked loop-free pre-synchronization control strategy.Precise pre-synchronization is achieved by regulating the virtual current to zero and aligning the photovoltaic storage hybrid inverter with the grid voltage.Additionally,two novel operators,learning and emotional behaviors are introduced to enhance the optimization precision of the chimpanzee algorithm.These operators ensure high-precision and high-reliability optimization of the droop control parameters for photovoltaic storage hybrid inverters.A Simulink model was constructed for simulation analysis,which validated the optimized control strategy’s ability to evenly distribute power under load transients.This strategy effectively mitigated transient voltage and current surges during mode transitions.Consequently,seamless and efficient switching between gridconnected and island modes was achieved for the photovoltaic storage hybrid inverter.The enhanced energy utilization efficiency,in turn,offers robust technical support for grid stability.展开更多
Conventional coordinated control strategies for DC bus voltage signal(DBS)in islanded DC microgrids(IDCMGs)struggle with coordinating multiple distributed generators(DGs)and cannot effectively incorporate state of cha...Conventional coordinated control strategies for DC bus voltage signal(DBS)in islanded DC microgrids(IDCMGs)struggle with coordinating multiple distributed generators(DGs)and cannot effectively incorporate state of charge(SOC)information of the energy storage system,thereby reducing the system flexibility.In this study,we propose an adaptive coordinated control strategy that employs a two-layer fuzzy neural network controller(FNNC)to adapt to varying operating conditions in an IDCMG with multiple PV and battery energy storage system(BESS)units.The first-layer FNNC generates optimal operating mode commands for each DG,thereby avoiding the requirement for complex operating modes based on SOC segmentation.An optimal switching sequence logic prioritizes the most appropriate units during mode transitions.The second-layer FNNC dynamically adjusts the droop power to overcome power distribution challenges among DG groups.This helps in preventing the PV power from exceeding the limits and mitigating the risk of BESS overcharging or over-discharging.The simulation results indicate that the proposed strategy enhances the coordinated operation of multi-DG IDCMGs,thereby ensuring the efficient and safe utilization of PV and BESS.展开更多
Climate change has prompted the aviation industry to reduce greenhouse gas emissions.Variable-camber leading edges,with their adaptable aerodynamic shapes,hold significant potential for laminar flow wings and contribu...Climate change has prompted the aviation industry to reduce greenhouse gas emissions.Variable-camber leading edges,with their adaptable aerodynamic shapes,hold significant potential for laminar flow wings and contribute to greener aviation.In response to this need,this paper proposes a design optimization method for a variable-camber leading edge featuring an outer variablethickness composite compliant skin and an inner open-kinematic-chain mechanism.The optimization methodology employs a fiber continuity model based on a ply-drop sequence,a guiding sequence and a thickness sequence to describe the variable-thickness composite compliant skin structure,enabling direct generation of a composite layup sequence that meets fiber continuity criteria.Additionally,the design methodology for the inner open kinematic chain considers the rigidflexible coupling effect and analyzes the number of driving ribs along the span-wise direction.Finally,a full-scale physical prototype for a large-scale civil aircraft is developed and experimented in the FL-10 wind tunnel,demonstrating that the variable-camber leading edge can smoothly and precisely achieve its target shape and hold its final profile under the corresponding aerodynamic loads,thereby validating the proposed design methodology.展开更多
Conventional droop control in multi-parallel grid-forming inverters exhibits poor reactive power sharing accuracy due to line impedance mismatches.In this study,we proposed a coordination control strategy integrating ...Conventional droop control in multi-parallel grid-forming inverters exhibits poor reactive power sharing accuracy due to line impedance mismatches.In this study,we proposed a coordination control strategy integrating adaptive virtual impedance with dynamic Q-V droop regulation to overcome this issue.We established a coupling model between the line impedance and power allocation to determine the quantitative relationship between reactive power deviation and impedance difference and to analyze the mechanism of reactive power deviation formation.Based on this,we proposed a transformer neural network-based online identification method for adaptive virtual impedance and dynamic droop coefficients.The self-attention mechanism dynamically characterizes the spatial distribution features of the impedance parameters considering the real-time voltage/reactive power time-series data as inputs to realize the dynamic impedance compensation without communication interaction.The contradiction constraint between the voltage drop and distribution accuracy caused by the introduction of conventional virtual impedance is improved by dynamic droop coefficient reconstruction.Lastly,we established a hardware-in-the-loop simulation platform to experimentally validate the operational efficacy and dynamic performance of the proposed control strategy under various grid scenarios.展开更多
YABBY genes are plant-specific transcription factors(TFs)that function in plant growth and development.We investigated the functions of the YABBY genes in plants’stress tolerance by analyzing the YABBY genes in foxta...YABBY genes are plant-specific transcription factors(TFs)that function in plant growth and development.We investigated the functions of the YABBY genes in plants’stress tolerance by analyzing the YABBY genes in foxtail millet(Setaria italica)and studying their functions on plant growth and responses to different stresses.Eight YABBY genes were identified on five chromosomes,which showed strong relationships with YABBY genes in other monocot species.Phylogenetical Si YABs were classified into four clades:FIL/YAB3,YAB2,INO,and CRC.No monocot YABBY member was classified into the YAB5 clade.Four conserved motifs were identified,and motif 1 constituted the YABBY domain,whereas motifs 2 and 3 formed the C2-C2 region.Si YAB genes were highly expressed in reproductive tissues.Si DL,one of the Si YABs,was selected to be overexpressed in Arabidopsis thaliana to check the functions of the YABBY genes.Overexpression of Si DL in A.thaliana caused delayed flowering,leaf curling,and reduced seed size.In addition,Si DL acted as a negative regulator in plant response to salt stress.Our study provides information to assist in studying the YABBY gene functions in S.italica.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.12302300,12272312,12372288 and 12388101)the Open Fund of Key Laboratory of Icing and Anti/De-icing,China(No.IADL20220413)the 1-0 Major Engineering Science Problem Project of Northwestern Polytechnical University(No.G2024KY0613)。
文摘The contradiction between the efficiency and the ice tolerance remains a challenge to the traditional aerodynamic design considering the icing effect.To address the problem,a new ice-tolerant concept based on the variable drooping leading edge is proposed and extended to a single-aisle commercial aircraft with the swept wing.The outer-wing and full-spanwise drooping leading edge configurations are set up to distinguish the effect of different ice tolerant strategies.The Reynolds-averaged Navier-Stokes results reveal that the stall angle of attack is delayed by 25.0%,and the maximum lift coefficient is increased by 23.3%with the full-spanwise drooping in the presence of horn-shaped ice on the wing.This improvement is primarily driven by the recovery of leading-edge suction.With the formulation of the improved delayed detached eddy simulation,the structures and the behaviors of the separated flow near the stall point are analyzed via the comparison before and after drooping the leading edge in full-spanwise.The results indicate that the suppression of the spatial development of the shedding shear layer promotes the closure of the separation bubble and mitigates the sweeping motion of the large-scale spanwise vortex.These integrated effects contribute to the enhancement of ice tolerance.
基金received funding from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX23_1633)2023 University Student Innovation and Entrepreneurship Training Program(202311463009Z)+1 种基金Changzhou Science and Technology Support Project(CE20235045)Open Project of Jiangsu Key Laboratory of Power Transmission&Distribution Equipment Technology(2021JSSPD12).
文摘Uneven power distribution,transient voltage,and frequency deviations are observed in the photovoltaic storage hybrid inverter during the switching between grid-connected and island modes.In response to these issues,this paper proposes a grid-connected/island switching control strategy for photovoltaic storage hybrid inverters based on the modified chimpanzee optimization algorithm.The proposed strategy incorporates coupling compensation and power differentiation elements based on the traditional droop control.Then,it combines the angular frequency and voltage amplitude adjustments provided by the phase-locked loop-free pre-synchronization control strategy.Precise pre-synchronization is achieved by regulating the virtual current to zero and aligning the photovoltaic storage hybrid inverter with the grid voltage.Additionally,two novel operators,learning and emotional behaviors are introduced to enhance the optimization precision of the chimpanzee algorithm.These operators ensure high-precision and high-reliability optimization of the droop control parameters for photovoltaic storage hybrid inverters.A Simulink model was constructed for simulation analysis,which validated the optimized control strategy’s ability to evenly distribute power under load transients.This strategy effectively mitigated transient voltage and current surges during mode transitions.Consequently,seamless and efficient switching between gridconnected and island modes was achieved for the photovoltaic storage hybrid inverter.The enhanced energy utilization efficiency,in turn,offers robust technical support for grid stability.
基金supported by National Key R&D Program of ChinaunderGrant,(2021YFB2601403).
文摘Conventional coordinated control strategies for DC bus voltage signal(DBS)in islanded DC microgrids(IDCMGs)struggle with coordinating multiple distributed generators(DGs)and cannot effectively incorporate state of charge(SOC)information of the energy storage system,thereby reducing the system flexibility.In this study,we propose an adaptive coordinated control strategy that employs a two-layer fuzzy neural network controller(FNNC)to adapt to varying operating conditions in an IDCMG with multiple PV and battery energy storage system(BESS)units.The first-layer FNNC generates optimal operating mode commands for each DG,thereby avoiding the requirement for complex operating modes based on SOC segmentation.An optimal switching sequence logic prioritizes the most appropriate units during mode transitions.The second-layer FNNC dynamically adjusts the droop power to overcome power distribution challenges among DG groups.This helps in preventing the PV power from exceeding the limits and mitigating the risk of BESS overcharging or over-discharging.The simulation results indicate that the proposed strategy enhances the coordinated operation of multi-DG IDCMGs,thereby ensuring the efficient and safe utilization of PV and BESS.
基金supported by the National Research Project“Variable CAmber wing TechNology(VCAN)”,China。
文摘Climate change has prompted the aviation industry to reduce greenhouse gas emissions.Variable-camber leading edges,with their adaptable aerodynamic shapes,hold significant potential for laminar flow wings and contribute to greener aviation.In response to this need,this paper proposes a design optimization method for a variable-camber leading edge featuring an outer variablethickness composite compliant skin and an inner open-kinematic-chain mechanism.The optimization methodology employs a fiber continuity model based on a ply-drop sequence,a guiding sequence and a thickness sequence to describe the variable-thickness composite compliant skin structure,enabling direct generation of a composite layup sequence that meets fiber continuity criteria.Additionally,the design methodology for the inner open kinematic chain considers the rigidflexible coupling effect and analyzes the number of driving ribs along the span-wise direction.Finally,a full-scale physical prototype for a large-scale civil aircraft is developed and experimented in the FL-10 wind tunnel,demonstrating that the variable-camber leading edge can smoothly and precisely achieve its target shape and hold its final profile under the corresponding aerodynamic loads,thereby validating the proposed design methodology.
基金supported by the National Natural Science Foundation of China(No.62063016)the Science and Technology Plan of Gansu Province(No.25JRRA088).
文摘Conventional droop control in multi-parallel grid-forming inverters exhibits poor reactive power sharing accuracy due to line impedance mismatches.In this study,we proposed a coordination control strategy integrating adaptive virtual impedance with dynamic Q-V droop regulation to overcome this issue.We established a coupling model between the line impedance and power allocation to determine the quantitative relationship between reactive power deviation and impedance difference and to analyze the mechanism of reactive power deviation formation.Based on this,we proposed a transformer neural network-based online identification method for adaptive virtual impedance and dynamic droop coefficients.The self-attention mechanism dynamically characterizes the spatial distribution features of the impedance parameters considering the real-time voltage/reactive power time-series data as inputs to realize the dynamic impedance compensation without communication interaction.The contradiction constraint between the voltage drop and distribution accuracy caused by the introduction of conventional virtual impedance is improved by dynamic droop coefficient reconstruction.Lastly,we established a hardware-in-the-loop simulation platform to experimentally validate the operational efficacy and dynamic performance of the proposed control strategy under various grid scenarios.
基金supported by grants from the National Key R&D Program of China(2021YFD1901101)the Key Science and Technology Program of Shanxi Province,China(20210140601026)the Project of Biological Breeding of Shanxi Agricultural University,China(YZGC102)。
文摘YABBY genes are plant-specific transcription factors(TFs)that function in plant growth and development.We investigated the functions of the YABBY genes in plants’stress tolerance by analyzing the YABBY genes in foxtail millet(Setaria italica)and studying their functions on plant growth and responses to different stresses.Eight YABBY genes were identified on five chromosomes,which showed strong relationships with YABBY genes in other monocot species.Phylogenetical Si YABs were classified into four clades:FIL/YAB3,YAB2,INO,and CRC.No monocot YABBY member was classified into the YAB5 clade.Four conserved motifs were identified,and motif 1 constituted the YABBY domain,whereas motifs 2 and 3 formed the C2-C2 region.Si YAB genes were highly expressed in reproductive tissues.Si DL,one of the Si YABs,was selected to be overexpressed in Arabidopsis thaliana to check the functions of the YABBY genes.Overexpression of Si DL in A.thaliana caused delayed flowering,leaf curling,and reduced seed size.In addition,Si DL acted as a negative regulator in plant response to salt stress.Our study provides information to assist in studying the YABBY gene functions in S.italica.
