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Coupled conditional nonlinear optimal perturbations and their application to ENSO ensemble forecasts

Science China Earth Sciences 2024年第3期67卷 826-842页

作者： Wansuo DUAN Lei Hu Rong FENG LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Limitations are existed in current ensemble forecasting initial perturbation methods for describing the interactions among various spheres of the Earth system. In this study, a new method is proposed, namely, the coupled conditional nonlinear optimal perturbation(C-CNOP) method, which incorporates multisphere interactions much appropriately. The El Nino-Southern Oscillation(ENSO) is a typical ocean-atmosphere “coupling”(or “interaction”) phenomenon. The C-CNOP method is applied to ensemble forecasting of ENSO. It is demonstrated that the C-CNOP method can generate coupled initial perturbations(CPs) that appropriately consider initial ocean-atmosphere coupling uncertainty for ENSO ensemble forecasts. Results reveal that the CPs effectively improve the ability of ENSO ensemble-mean forecasts in both temporal variability of Nio3.4 sea surface temperature anomalies(SSTAs) and spatial variability of ENSO mature-phase SSTAs. Notably, despite the weakest ocean-atmosphere coupling strength in the tropical Pacific occurring during the boreal spring and summer, CPs still capture the uncertainties of this weak coupling when ENSO predictions are initialized at these seasons. This performance of CPs significantly suppresses the rapid increase of ENSO prediction errors due to the high ocean-atmosphere coupling instability during these seasons, and thus effectively extends the lead time of skillful ENSO forecasting. Hence, the C-CNOP method is a suitable initial perturbation approach for ENSO ensemble forecast that can describe initial ocean-atmosphere coupling uncertainty. It is expected that the CCNOP method plays a significant role in predictions of other high-impact climate phenomena, and even future Earth system predictions.

关键词： Ensemble forecast Multisphere interaction Initial perturbations ENSO

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Effect of Central Multiphase Microstructure of Thick Plates on Work Hardening and Crack Propagation

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 325-338页

作者： Lei Hu Liqin Zhang Feng hu Kuan Zheng Guohong Zhang Collaborative Innovation Center for Advanced Steels Wuhan University of Science and TechnologyWuhan430081China Department of Applied Physics Wuhan University of Science and TechnologyWuhan430081China Analysis and Testing Center Wuhan University of Science and TechnologyWuhan430081China

The effect of multiphase microstructure in the center segregation zones(CSZ)of high-strength steel thick plates on work hardening characteristics and crack initiation/propagation were studied.Microstructure was correlated with deformation damage behavior by using Taylor factor(TF)gradients,kernel average misorientation(KAM),and geometric necessary dislocation(GND)density.The results show that the segregation leads to a mixed structure of ferrite(soft phase)and martensite/bainite(hard phase)in the center of the thick plate.Compared to the 1/4 thickness(1/4 T)region,grain refinement occurred in the CSZ,with KAM values increasing from 0.24 to 0.49 and a decrease in the proportion of high-angle grain boundaries(>15°)from 77.4 to 51.8%.In the process of deformation,due to the influence of grain refinement and adjacent martensite/bainite,ferrite grains were divided into structural units with different TF values.The higher KAM value and GND density at the interface between soft/hard phases resulted in severe work hardening.In addition,the presence of micron-sized inclusions in the CSZ caused local strain concentration and non-continuous deformation of the matrix,which induced crack initiation.The fracture surface showed a mixed mode of brittle cleavage fracture and ductile fracture.

关键词： Thick plate Center segregation zone Multiphase microstructure Taylor factor Crack propagation

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Integrated Planning of an Active Distribution Network and DG Integration in Clusters Considering a Novel Formulation for Reliability Assessment

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 561-576页

作者： Di hu lei Sun Ming Ding School of Electrical Engineering and Automation Hefei University of TechnologyHefei 230009China Anhui Provincial Laboratory of Renewable Energy Utilization and Energy Saving Hefei University of TechnologyHefei 230009China

The concept of DG clusters is introduced with highly penetrated integration of distributed generation(DG)into active distribution networks(ADNs).DG clusters are referred to as parts of an ADN,including DGs,distribution lines and loads.The formation of DG clusters helps to optimally dispatch DG outputs within ADNs.In this regard,an integrated planning strategy of ADNs and DGs in cluster(IPNDGC)is proposed.In order to guarantee that the planning strategy meets the reliability requirements,a reliability assessment is considered in the proposed model.However,reliability assessment is generally accomplished according to a fixed network topology and known DG allocation,which makes it difficult to integrate reliability into planning models.To deal with this difficulty,a novel formulation method for reliability assessment is proposed considering the network topology uncertainties and isolated operating probabilities of DG clusters.The reliability index(RI)represented by expected customer interruption cost(ECOST)is employed in the proposed planning model.The planning model is formulated as a mixed integer second order conic programming planning model.An actual distribution system is employed to illustrate the accuracy and efficiency of the proposed planning model.

关键词： DG cluster distribution network planning reliability

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SPATULA as a Versatile Tool in Plant:The Progress and Perspectives of SPATULA(SPT)Transcriptional Factor

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Phyton-International Journal of Experimental Botany 2024年第3期93卷 517-531页

作者： lei Liang Xiangyang hu Shanghai Key Laboratory of Bio-Energy Crops Research Center for Natural ProductsPlant Science CenterSchool of Life SciencesShanghai UniversityShanghai200444China

With the rapid development of modern molecular biology and bioinformatics,many studies have proved that transcription factors play an important role in regulating the growth and development of plants.SPATULA(SPT)belongs to the bHLH transcription family and participates in many processes of regulating plant growth and development.This review systemically summarizes the multiple roles of SPT in plant growth,development,and stress response,including seed germination,ﬂowering,leaf size,carpel development,and root elongation,which is helpful for us to better understand the functions of SPT.

关键词： SPT bHLH plant growth plant development Arabidopsis thaliana

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Hydrogenation of CO_(2) to formate catalyzed by SBA-15-supported cyclic(alkyl)(amino)carbene-iridium

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Chinese Journal of Chemical Engineering 2022年第10期50卷 283-291页

作者： lei Zhou Lingling Peng Xingbang hu College of Chemistry and Chemical Engineering Yangzhou Polytechnic InstituteYangzhou 225127China School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210093China

Recently,cyclic(alkyl)(amino)carbenes(CAACs)have been widely used as ligands to enhance the catalytic reactivity of center metal,but the problem of recycling this expensive ligand remains to be solved.In this work,the heterogeneous SBA-15-CAAC-Ir catalyst was prepared by a covalent attachment method.and using SBA-15 as the carrier.It shows high reactivity for the hydrogenation of CO_(2) to formate.After immobilization,the ordered mesoporous structure and the overall rod-like morphology of the original SBA-15 have been preserved very well.Using SBA-15-CAAC-Ir as catalyst,up to 21050 TON can be obtained at 60℃.In addition,the catalyst can be separated easily by centrifugation,and the catalytic activity of SBA-15-CAAC-Ir can still remain very high after multiple cycles.

关键词： Cyclic(alkyl)(amino)carbenes Carbon dioxide Hydrogenation SBA-15 Formate

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Toward monolithic growth integration of nanowire electronics in 3D architecture: a review

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Science China(Information Sciences) 2023年第10期66卷 105-134页

作者： lei LIANG Ruijin hu Linwei YU School of Electronic Science and Engineering Nanjing University School of Physical Science and Technology/Microelectronics Industry Research Institute Yangzhou University

Quasi-one-dimensional(1D) semiconducting nanowires(NWs), with excellent electrostatic control capability, are widely regarded as advantageous channels for the fabrication of high-performance microelectronics, memories... 详细信息

关键词： catalytic growth silicon nanowires electronics monolithic 3D-integration

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Multi-Equipment Detection Method for Distribution Lines Based on Improved YOLOx-s

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Computers, Materials & Continua 2023年第12期77卷 2735-2749页

作者： Lei Hu Yuanwen Lu Si Wang Wenbin Wang Yongmei Zhang School of Computer and Information Engineering Jiangxi Normal UniversityNanchang330022China School of Digital Industry Jiangxi Normal UniversityShangrao334005China Department of Science and Technology State Grid Jiangxi Electric Power Research InstituteNanchang330096China School of Information North China University of TechnologyBeijing100144China

The YOLOx-s network does not sufficiently meet the accuracy demand of equipment detection in the autonomous inspection of distribution lines by Unmanned Aerial Vehicle(UAV)due to the complex background of distribution lines,variable morphology of equipment,and large differences in equipment sizes.Therefore,aiming at the difficult detection of power equipment in UAV inspection images,we propose a multi-equipment detection method for inspection of distribution lines based on the YOLOx-s.Based on the YOLOx-s network,we make the following improvements:1)The Receptive Field Block(RFB)module is added after the shallow feature layer of the backbone network to expand the receptive field of the network.2)The Coordinate Attention(CA)module is added to obtain the spatial direction information of the targets and improve the accuracy of target localization.3)After the first fusion of features in the Path Aggregation Network(PANet),the Adaptively Spatial Feature Fusion(ASFF)module is added to achieve efficient re-fusion of multi-scale deep and shallow feature maps by assigning adaptive weight parameters to features at different scales.4)The loss function Binary Cross Entropy(BCE)Loss in YOLOx-s is replaced by Focal Loss to alleviate the difficulty of network convergence caused by the imbalance between positive and negative samples of small-sized targets.The experiments take a private dataset consisting of four types of power equipment:Transformers,Isolators,Drop Fuses,and Lightning Arrestors.On average,the mean Average Precision(mAP)of the proposed method can reach 93.64%,an increase of 3.27%.The experimental results show that the proposed method can better identify multiple types of power equipment of different scales at the same time,which helps to improve the intelligence of UAV autonomous inspection in distribution lines.

关键词： Distribution lines UAV autonomous inspection power equipment detection YOLOx-s

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Porous tantalum structure integrated on Ti6Al4V base by Laser Powder Bed Fusion for enhanced bony-ingrowth implants:In vitro and in vivo validation

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Bioactive Materials 2022年第1期7卷 3-13页

作者： Pengfei lei hu Qian Taomei Zhang Ting lei Yihe hu Chao Chen Kechao Zhou Department of Orthopedic Surgery Hunan Engineering Research Center of Biomedical Metal and Ceramic ImplantsXiangya HospitalCentral South UniversityChangsha 410008China Department of Orthopedic Surgery The First Affiliated HospitalCollege of MedicineZhejiang UniversityChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China

Despite the widespread application of Ti6Al4V and tantalum(Ta)in orthopedics,bioinertia and high cost limit their further applicability,respectively,and tremendous efforts have been made on the Ti6Al4V-Ta alloy and Ta coating to address these drawbacks.However,the scaffolds obtained are unsatisfactory.In this study,novel high-interface-strength Ti6Al4V-based porous Ta scaffolds were successfully manufactured using Laser Powder Bed Fusion for the first time,in which porous Ta was directly manufactured on a solid Ti6Al4V substrate.Mechanical testing revealed that the novel scaffolds were biomechanically compatible,and the interfacial bonding strength was as high as 447.5 MPa.In vitro biocompatibility assay,using rat bone marrow mesenchymal stem cells(r-BMSCs),indicated that the novel scaffolds were biocompatible.Alkaline phosphatase and mineralized nodule determination demonstrated that the scaffolds favored the osteogenic differentiation of r-BMSCs.Moreover,scaffolds were implanted into rabbits with femur bone defects,and imaging and histological evaluation identified considerable new bone formation and bone ingrowth,suggesting that the scaffolds were well integrated with the host bone.Overall,these results demonstrated good mechanical compatibility,biocompatibility,and osteointegration performance of the novel Ti6Al4V-based porous Ta scaffold,which possesses great potential for orthopedic clinical applications.

关键词： Tantalum Ti6Al4V Laser powder bed fusion Orthopedic scaffolds Osteointegration

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A small first-order DPA resistant AES implementation with no fresh randomness

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Science China(Information Sciences) 2022年第6期65卷 261-263页

作者： Man WEI Siwei SUN Zihao WEI Zheng GONG Lei Hu State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences Data Assurance and Communication Security Research Center Chinese Academy of Sciences School of Cyber Security University of Chinese Academy of Sciences School of Compute Science South China Normal University

Dear editor,Cryptographic algorithms exist in the form of software or hardware components inside security-critical information systems, which are often deployed in a hostile environment.Therefore, other than guaranteeing the security of the cryptographic algorithms in the black-box model, ensuring the security of the software or hardware components against the attacks exploiting the physical leakage of the underlying devices is considerably important. Among these attacks,

关键词： side channel analysis DPA threshold implementation domain-oriented masking AES

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Variability of turbulence dispersion characteristics during heavy haze process: A case study in Beijing

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Journal of Environmental Sciences 2023年第2期124卷 440-450页

作者： lei Liu Yu Shi Zhe Zhang Fei hu LAPC Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

The turbulent standard deviations and the turbulent third-order and fourth-order moments are the key turbulence dispersion parameters in Lagrangian dispersion models.However,the characteristics of these parameters under heavy haze conditions in urban areas have not been fully investigated,and the commonly used similarity relations of these parameters in modelswere based on observations in highly flat and sparsely populated areas.In this paper,the vertical profiles of these parameters and their local similarity relations under heavy haze conditions in the wintertime of Beijing have been analyzed by using data collected at a 325-m meteorological tower.The heavy haze process has been divided into three stages:transport stage(TS),cumulative stage(CS),and dispersion stage(DS).Results show that the turbulent dispersion parameters behave differently during three stages.In the TS and DS,the maxima appear in the profiles of the turbulent standard deviations above the urban canopy;in the CS,the turbulent standard deviation are almost constant with height.The analysis of the third and fourth order moments shows that the wind velocities above the urban canopy in the TS deviate from the Gaussian distribution more significantly than those in the CS and DS.The local similarity relations of the turbulent dispersion parameters in the TS,especially for the longitudinal wind components,are normally different from those in the CS and DS.Thus,different from the common assumptions in Lagrangian models,the turbulence dispersion in horizontal directions is anisotropic and should be parameterized by multiple similarity relations under heavy haze conditions.

关键词： Heavy haze Turbulence dispersion Local similarity Lagrangian model

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