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Applicability Assessment of the 1998–2018 CLDAS Multi-Source Precipitation Fusion Dataset over China

Journal of Meteorological Research 2020年第4期34卷 879-892页

作者： shuai SUN Chunxiang SHI Yang PAN Lei BAI Bin XU Tao ZHANG shuai HAN Lipeng jiang National Meteorological Information Center China Meteorological AdministrationBeijing 100081

Traditional hourly rain gauges and automatic weather stations rarely measure solid precipitation, except for those stations with weighing-type precipitation sensors. Microwave remote sensing has only a low ability to retrieve solid precipitation. In addition, there are no long-term, high-quality precipitation data in China that can be used to drive land surface models. To address these issues, in the China Meteorological Administration(CMA) Land Data Assimilation System(CLDAS), we blended the Climate Prediction Center(CPC) morphing technique(CMORPH) and Modern-Era Retrospective analysis for Research and Applications version 2(MERRA2) precipitation datasets with observed temperature and precipitation data on various temporal scales using multigrid variational analysis and temporal downscaling to produce a multi-source precipitation fusion dataset for China(CLDAS-Prcp). This dataset covers all of China at a resolution of 6.25 km at hourly intervals from 1998 to 2018. We performed dependent and independent evaluations of the CLDAS-Prcp dataset from the perspectives of seasonal total precipitation and land surface model simulation. Our results show that the CLDAS-Prcp dataset represents reasonably the spatial distribution of precipitation in China. The dependent evaluation indicates that the CLDAS-Prcp performs better than the MERRA2 precipitation, CMORPH precipitation, Global Land Data Assimilation System version 2(GLDAS-V2.1) precipitation,and CLDAS-V2.0 winter precipitation, as compared to the meteorological observational precipitation. The independent evaluation indicates that the CLDAS-Prcp dataset performs better than the Global Precipitation Measurement(GPM) precipitation dataset and is similar to the CLDAS-V2.0 summer precipitation dataset based on the hydrological observational precipitation. The simulated soil moisture content driven by CLDAS-Prcp is slightly better than that driven by the CLDAS-V2.0 precipitation, whereas the snow depth simulation driven by C

关键词： China Meteorological Administration Land Data Assimilation System(CLDAS) precipitation data fusion Modern-Era Retrospective analysis for Research and Applications version 2(MERRA2) Climate Prediction Center(CPC)morphing technique(CMORPH) Space–Time Multiscale Variational Analysis System(STMAS) Noah land surface model with multiparameterization options(Noah-MP)

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Dissipationless layertronics in axion insulator MnBi2Te4

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National Science Review 2024年第6期11卷 189-196页

作者： shuai Li Ming Gong Shuguang Cheng Hua jiang X.C.Xie School of Physical Science and Technology Soochow University Institute for Advanced Study Soochow University International Center for Quantum Materials School of Physics Peking University Department of Physics Northwest University Interdisciplinary Center for Theoretical Physics and Information Sciences Fudan University Hefei National Laboratory

Surface electrons in axion insulators are endowed with a topological layer degree of freedom followed by exotic transport phenomena, e.g., the layer Hall effect. Here, we propose that such a layer degree of freedom can be manipulated in a dissipationless way based on the antiferromagnetic MnBi2Te4with tailored domain structure. This makes MnBi2Te4a versatile platform to exploit the ‘layertronics’ to encode, process and store information. Importantly, the layer filter, layer valve and layer reverser devices can be achieved using the layer-locked chiral domain wall modes. The dissipationless nature of the domain wall modes makes the performance of the layertronic devices superior to those in spintronics and valleytronics. Specifically, the layer reverser, a layer version of the Datta–Das transistor, also fills up the blank in designing the valley reverser in valleytronics. Our work sheds light on constructing new generation electronic devices with high performance and low-energy consumption in the framework of layertronics.

关键词： axion insulator MnBi2Te4 layertronics antiferromagnetic domain wall dissipationless transport

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Cladding of aluminum alloy 6061-T6 to mild steel by an electromagnetic tube bulging process: finite element modeling

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Advances in Manufacturing 2019年第1期7卷 73-83页

作者： Zhi-Song Fan Su-ting Huang jiang-Hua Deng School of Mechanical Engineering and Automation Fuzhou University Fuzhou 350116 People's Republic of China

Bimetal tubes have useful applications in various industries where service conditions demand more different requirements in the tube core than its outside surface. The recent use of electromagnetic forces to deform or join metallic workpieces at high speeds has undergone rapid growth for materials processing. However, to date, no sufficient systematic understanding of the underlying principles of a subsequent high-speed electromagnetic tube bulging process to manufacture bimetal tubes has been gained. In this work, magnetic pulse cladding of Al/Fe clad bimetal tubes was analyzed by finite element modeling (FEM) using ANSYS software. The validity of FEM analyses was first confirmed by experiments in terms of the deformed shape. Second, the effect of cladding parameters (such as axial feeding being the dominant factor in the multi-step process) on the bulging and thinning behavior of the Al clad tube was presented in detail. Both the numerical simulation and experimental results show that no more than 70% of the bulging-coil length is an appropriate amount for the feeding length to prevent defects from being introduced by non-uniform deformation in the transition zone of the Al clad tube. The distributions of the magnetic flux line, magnetic force, and plastic strain in different cladding steps were then analyzed. It was concluded that during the multi-step cladding process, there was an uneven distribution of the magnetic field force along the transition zone. Consequently, inharmonious plastic deformation behavior occurs, which results in a limited acceleration of the transition zone to a certain impact velocity.

关键词： Bimetal tubes Magnetic pulse cladding Finite element (FE) simulation Axial feeding

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Joint Optimization of Resource Allocation and Trajectory Based on User Trajectory for UAV-Assisted Backscatter Communication System

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China Communications 2024年第2期21卷 197-209页

作者： Peizhong Xie Junjie jiang ting Li Yin Lu School of Communication and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing 210003China

The Backscatter communication has gained widespread attention from academia and industry in recent years. In this paper, A method of resource allocation and trajectory optimization is proposed for UAV-assisted backscatter communication based on user trajectory. This paper will establish an optimization problem of jointly optimizing the UAV trajectories, UAV transmission power and BD scheduling based on the large-scale channel state signals estimated in advance of the known user trajectories, taking into account the constraints of BD data and working energy consumption, to maximize the energy efficiency of the system. The problem is a non-convex optimization problem in fractional form, and there is nonlinear coupling between optimization *** iterative algorithm is proposed based on Dinkelbach algorithm, block coordinate descent method and continuous convex optimization technology. First, the objective function is converted into a non-fractional programming problem based on Dinkelbach method,and then the block coordinate descent method is used to decompose the original complex problem into three independent sub-problems. Finally, the successive convex approximation method is used to solve the trajectory optimization sub-problem. The simulation results show that the proposed scheme and algorithm have obvious energy efficiency gains compared with the comparison scheme.

关键词： energy efficiency joint optimization UAV-assisted backscatter communication user trajectory

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Shape-Controlled CuCl Crystallite Catalysts for Aniline Coupling

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Nano Research 2010年第3期3卷 174-179页

作者： ting Xie Ming Gong Zhiqiang Niu shuai Li Xiaoyu Yan Yadong Li Department of Chemistry Tsinghua UniversityBeijing 100084China

The catalytic activity of crystallites depends mainly upon the arrangement of surface atoms,the number of dangling bonds,and defect site distribution on different crystal ***,we report the shape-controlled synthesis of CuCl crystallites,including tetrahedra,face-centered-etched tetrahedra,tripod dendrites,and *** different morphologies of CuCl crystallites expose different proportions of{111}and{110}crystal planes,and materials with a preponderance of{111}crystal planes have better catalytic activity in aniline coupling than those with more{110}planes.

关键词： CuCl aniline coupling catalytic activity crystal plane effects

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Repair of Second-Generation Recycled Fine Aggregate of Waste Concrete from Freeze-Thaw Environment by Carbonation Treatment

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Journal of Renewable Materials 2024年第1期12卷 187-201页

作者： Jie Huang Rongbin jiang Xiaobo Sun Yingyong shuai School of Building Engineering Taizhou Polytechnic CollegeTaizhou225300China

The reuse of waste recycled concrete from harsh environments has become a research hotspot in the field of *** study investigated the repair effect of carbonation treatment on second-generation recycled fine aggregate(SRFA)obtained from recycled fine aggregate concrete(RFAC)subjected to freeze-thaw(FT)*** and after carbonation,the properties of SRFA were *** second-generation recycled fine aggregate(CSRFA)at five substitution rates(0%,25%,50%,75%,100%)to replace SRFA was used to prepare carbonated second-generation recycled fine aggregate concrete(CSRFAC).The water absorption,porosity and mechanical properties of CSRFAC were tested,and its frost-resisting durability was *** results showed after carbonation treatment,the physical properties of SRFA was improved and met the requirements of II *** micro-hardness of the interfacial transition zone and attached mortar in CSRFA was 50.5%and 31.2%higher than that in SRFA,*** the increase of CSRFA replacement rate,the water absorption and porosity of CSRFAC gradually decreased,and the mechanical properties and frost resistance of CSRFAC were gradually *** treatment effectively repairs the damage of SRFA caused by FT cycles and improves its application potential.

关键词： Carbonation treatment repair freeze-thaw cycles second-generation recycled fine aggregate

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Forest canopy height mapping over China using GLAS and MODIS data

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Science China Earth Sciences 2015年第1期58卷 96-105页

作者： YANG ting WANG Cheng LI GuiCai LUO SheZhou XI XiaoHuan GAO shuai ZENG HongCheng Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of Sciences University of Chinese Academy of Sciences National Satellite Meteorological Center China Meteorological Administration National Key Laboratory of Remote Sensing Institute of Remote Sensing and Digital EarthChinese Academy of Sciences Faculty of Forestry University of Toronto

The Geoscience Laser Altimeter System(GLAS)accurately detects the vertical structural information of a target within its laser spot and is a promising system for the inversion of structural features and other biophysical parameters of forest *** the GLAS footprints are discontinuously distributed with a relativity low density,continuous vegetation height distributions cannot be mapped with a high accuracy using GLAS data *** MODIS BRDF product provides more forest structural information than other optical remote sensing *** study aimed to map forest canopy heights over China from the GLAS and MODIS BRDF ***,the waveform characteristic parameters were extracted from the GLAS data by the method of wavelet analysis,and the terrain index was calculated using the ASTER GDEM ***,the model reducing the topographic influence was constructed from the waveform characteristic parameters and terrain ***,the final canopy height estimation model was constructed from the neural network combining the canopy height estimated with the GLAS point and the MODIS BRDF data,and applied to get the continuous canopy height map over ***,the map was validated by the measured data and the airborne Li DAR data,and the validation results indicated that forest canopy heights can be estimated with high accuracy from combined GLAS and MODIS data.

关键词： GLAS waveform decomposition terrain index canopy height model

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Fabrication of rigid and flexible SrGe409 nanotube-based sensors for room-temperature ammonia detection

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Nano Research 2018年第1期11卷 431-439页

作者： tingting Huang Zheng Lou shuai Chen Rui Li Kai jiang Guozhen Shen [1College of Physics and Mathematics and Beiing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science University of Science and Technology Beiing Beiing 100083 China [2State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China [3Institute & Hospital of Hepatobiliary Surgery Key Laboratory of Digital Hepatobiliary Surgery of Chinese PLA Chinese PLA Medical School Chinese PLA General Hospital Beijing 100853 China [4College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Beijing 100049 China

Ammonia （NH3） detection at room temperature has attracted considerable attention because of the increasing demand for health monitoring, personal safety protection, and industrial manufacturing. Herein, we report the synthesis of polycrystalline SrGe409 nanotubes （NTs） via an electrospinning process. These NTs are a new sensing material for the detection of ammonia at room temperature. The SrGe409 NTs exhibited a maximum sensing response of 2.49 for 100 ppm NH3, which was increased to 7.08 by decorating the NTs with Pt nanoparticles. Flexible gas sensors were fabricated, which exhibited comparable performance to the rigid device. Additionally, the flexible devices showed excellent flexibility, mechanical stability, and sensing stability under different bending states, manifesting their potential applications in flexible and wearable electronics.

关键词： gas sensors ammonia nanotubes flexible electronics

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Exploring Tree Species Classification in Subtropical Regions with a Modified Hierarchy-Based Classifier Using High Spatial Resolution Multisensor Data

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Journal of Remote Sensing 2022年第1期2022卷 146-161页

作者： Xiandie jiang shuai Zhao Yaoliang Chen Dengsheng Lu State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province Fujian Normal UniversityFuzhouChina 350007 Institute of Geography Fujian Normal UniversityFuzhouChina

Tree species distribution is valuable for forest resource ***,it is a challenge to classify tree species in subtropical regions due to complex landscapes and limitations of remote sensing *** objective of this study was to propose a modified hierarchy-based classifier(MHBC)by optimizing the classification tree structures and variable selection *** steps to create an MHBC include automatic determination of classification tree structures based on the Z-score algorithm,selection and optimization of variables for each node,and classification using the optimized *** based on the fusion of Gaofen-1/Ziyuan-3 panchromatic(GF-1/ZY-3 PAN)and Sentinel-2 multispectral(MS)data indicated that(1)the MHBC provided overall classification accuracies of 85.19%for Gaofeng Forest Farm in China’s southern subtropical region and 94.4%for Huashi Township in China’s northern subtropical region,which had higher accuracies than random forest(RF)and classification and regression tree(CART);(2)critical variables for each class can be identified using the MHBC,and optimal variables of most nodes are spectral bands and vegetation indices;(3)compared to results from RF and CART,MHBC mainly improved the accuracies of the lower levels of classification tree structures(difficult classes to separate).The novelty in using MHBC is its simple and practical operation,easy-to-understand,and visualized variables that were selected in each node of the automatically constructed hierarchical *** robust performance of MHBC implies the potential to apply this approach to other sites for accurate classification of forest types.

关键词： Spatial Modified steps

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Bolt insertion damage and mechanical behaviors investigation of CFRP/CFRP interference fit bolted joints

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Chinese Journal of Aeronautics 2022年第9期35卷 354-365页

作者： Yangjie ZUO ting YUE Ruisong jiang Zengqiang CAO Liu YANG School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China Xi’an Space Engine Co.Ltd Xi'an 710100China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China Xi’an ASN Technology Group Co.Ltd Xi'an 710072China

Interference fit has advantages in improving fatigue behaviors of composite bolted joints,however, interference fit bolt insertion tends to cause damages in laminates weakening joint mechanical properties. Therefore, an experimental study was conducted to investigate bolt insertion damages of Carbon Fiber Reinforced Polymer(CFRP)/CFRP interference fit bolted *** behaviors of joints were also evaluated experimentally under both quasi-static loads and cyclic loads. Scanning Electron Microscope(SEM) and high-resolution X-ray micro-CT scan were used to examine micro damages in laminates. Damage and failure behaviors of joints were characterized. The results demonstrated that the hole entrance in upper laminate and the laminate boundary near the hole wall were the most critical regions for damages during bolt insertions. However, the influence of those damages on quasi-static failure loads and fatigue failure modes of joints was minimal. Delamination and matrix cracking occurred first in laminates following fiber and matrix fracture in quasi-static tensile tests. Interference fit could improve the fatigue resistance of the laminate hole, however, the bolt seemed to suffer a more critical local fatigue loading *** paper can contribute to composite structure designs, especially in understanding damage and failure behaviors of composite bolted joints.

关键词： Bolted joints Composite Damage Failure Fatigue life Interference fit

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