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Probabilistic Wind Gust Forecasting during the 2022 Beijing Winter Olympics

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Journal of Meteorological Research 2023年第6期37卷 743-756页

作者： Minquan xiong National Meteorological Centre China Meteorological AdministrationBeijing100081China

The probabilistic forecast of wind gusts poses a significant challenge during the post-processing of numerical model *** analysis of probabilistic forecasting methods plays a crucial role in enhancing forecast *** the context of meteorological services for alpine skiing at the 2022 Beijing Winter Olympics,The ECMWF ensemble products were used to evaluate six post-processing *** methods include ensemble model output statistics(EMOS),backpropagation neural networks(BP),particle swarm optimization algorithms with backpropagation neural networks(PSO),truncated normal distributions,truncated logarithmic distributions,and generalized extreme value(GEV) *** performance of these methods in predicting gust probabilities at five observation points along a ski track was *** six methods exhibited a substantial reduction in forecast errors compared to the original ECMWF products;however,the ability to correct the model forecast results varied significantly across different wind speed ***,the EMOS,truncated normal distribution,truncated logarithmic distribution,and GEV distribution demonstrated advantages in low wind-speed ranges,whereas the BP and PSO methods exhibit lower forecast errors for high wind-speed ***,this study affirms the rationality of utilizing the statistical characteristics derived from ensemble forecasts as probabilistic forecast *** application of probability integral transform(PIT) and quantile–quantile(QQ) plots demonstrates that gust variations at the majority of observation sites conform to the GEV distribution,thereby indicating the potential for further enhanced forecast *** results also underscore the significant utility of the PSO hybrid model,which amalgamates particle swarm optimization with a BP neural network,in the probabilistic forecasting of strong winds within the field of meteorology.

关键词： post-processing wind gusts Beijing Winter Olympics probabilistic forecasting neural network

Organic field-effect optical waveguides: a new break-through all organic optoelectronics

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Science China Chemistry 2019年第3期62卷 293-294页

作者： xiong Gong College of Polymer Science and Polymer Engineering The University of Akron

Optical waveguide, a physical structure that guides electromagnetic waves in the optical spectrum, is the key elements of photonic devices that perform guiding, coupling, switching, splitting, multiplexing and demultiplexing of optical signals [1]. In general, an optical waveguide is tuned by electrical field through a two-terminal diode [1]. Such integration was widely used in current photonic devices, but restricts its potentials in tiny optical chips for bio/medical and space applications [2].

关键词： Optical physical structure electromagnetic

Shaking table tests and dynamic analyses of masonry wall buildings with frame-shear walls at lower stories

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Earthquake Engineering and Engineering Vibration 2008年第3期7卷 271-283页

作者： xiong Lihong David xiong Wu Ruifeng Xia Jingqian Institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China Key Lab of Urban Security ＆ Disaster Engineering MOE Beijing University of Technology Beijing 100022 China Arup Engineering Consultant Ltd Hong Kong Department of Engineering Mechanics Dalian University of Technology Dalian 116024 China

This paper describes shaking table tests of three eight-story building models： all are masonry structures in the upper stories, with or without frame-shear walls of one- or two- stories at the bottom. The test results of damage characteristics and seismic responses are provided and compared. Then, nonlinear response analyses are conducted to examine the reliability of the dynamic analysis. Finally, many nonlinear response analyses are performed and it is concluded that for relatively hard sites under a certain lateral stiffness ratio （i.e., the ratio of the stiffness of the lowest upper masonry story to that of the frame- shear wall story）, the masonry structure with one-story frame-shear wall at the bottom performs better than a structure built entirely of masonry, and a masonry structure with frame-shear wall of two stories performs better than with one-story frame- shear wall. In relatively soft soil conditions, all three structures have similar performane. In addition, some suggestions that could be helpful for design of masonry structures with ground story of frame-shear wall structure in seismic intensity region VII, such as the appropriate lateral stiffness ratio, shear force increase factor of the frame-shear wall story, and permissible maximum height of the building, are proposed.

关键词： masonry structure soft story seismic performance shaking table test nonlinear time history analysis

Effects of deep placement of fertilizer on periphytic biofilm development and nitrogen cycling in paddy systems

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Pedosphere 2021年第1期31卷 125-133页

作者： Yanhui ZHAO xiong xiong Chenxi WU State Key Laboratory of Freshwater Ecology and Biotechnology Institute of HydrobiologyChinese Academy of SciencesWuhan 430072China University of Chinese Academy of Sciences Beijing 100049China

Periphytic biofilms are commonly presented at the water-soil interface in paddy fields. Different fertilization methods can affect the concentration and distribution of nutrients in paddy fields and thus affect the development of periphytic biofilms. In this study, the roles of periphytic biofilms in nitrogen(N) cycling in paddy systems and how they are affected by different fertilization methods were studied using microcosm experiments. Microcosms were prepared using soil samples from a paddy field and treated with surface and deep fertilization under light and dark conditions. Surface fertilization under light condition promoted the development of periphytic biofilms, while deep fertilization under dark condition inhibited their development. The development of periphytic biofilms increased the pH and dissolved oxygen levels in the overlying water. Surface fertilization resulted in high N concentrations in the overlying water and the topsoil layers, which enhanced NH3 volatilization and nitrification-denitrification but inhibited N fixation. The development of periphytic biofilms reduced NH3 volatilization loss but increased nitrification-denitrification loss and the overall N loss in the paddy system. The results from this work suggest that the presence of periphytic biofilms in paddy fields could increase N loss by 3.10%–7.11%. Deep fertilization is an effective method to retard the development of periphytic biofilms in the paddy system and can potentially increase the overall N use efficiency.

关键词： deep fertilization denitrification potential N loss N use efficiency NH3 volatilization paddy field

INFORMATION IDENTIFICATION IN DIFFERENT NETWORKS WITH HETEROGENEOUS INFORMATION SOURCES

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Journal of Systems Science & Complexity 2014年第1期27卷 92-116页

作者： FENG Xu ZHANG Wei ZHANG Yongjie xiong xiong College of Management and Economics Tianjin University China Center for Social Computing Tianjin University

Traditional cheaptalk game model with homogeneous information sources provided a con clusion that dishonest information sources will not be identified if he changes strategy stochastically. In this paper, the authors incorporate different information diffusion networks and heterogeneous in formation sources into an agentbased artificial stock market. The obtained results are different with traditional results that identification ability of uninformed agents has been highly improved with diffu sion networks and heterogeneous information sources. Additionally, the authors find uninformed agents can improve identification ability only if there exists a sufficient number of heterogeneous information sources in stock market.

关键词： Agent-based heterogeneous information information diffusion networks.

Unsteady analysis of six-DOF motion of a 6:1 prolate spheroid in viscous fluid

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Science China(Physics,Mechanics & Astronomy) 2017年第11期60卷 24-40页

作者： Ying xiong Ying xiong Hui Guan ChuiJie Wu The Unite 91550 of People's Liberation Army of China Dalian 112023 China School of Aeronautics and Astronautics Dalian University of Technology Dalian 112024 China College of Meteorology and Oceanography National University of Defense Technology Nanjing 211101 China

Free-moving simulations of airplanes, submarines and other automobiles under extreme and emergency conditions are becoming increasingly important from operational and tactical perspectives. Such simulations are fairly challenging due to the extreme unsteady motions and high Re(Reynolds) numbers. The aim of this study is to perform a six-DOF motion simulation of a 6:1prolate spheroid that is falling in a fluid field. Prior to conducting the six-DOF simulation, some verification simulations were performed. First, a laminar flow past an inclined prolate spheroid at a Re number of 1000 and incidence angle of 45. with a tetrahedral mesh was simulated to verify the relevant targeted discrete method for an unstructured mesh. Second, to verify the LES(large eddy simulation) models and dependent parameters for the DDES(delayed detached eddy simulation), a turbulent flow past a sphere was performed at a subcritical Re number of 10000. Third, a steady maneuvering problem about a prolate spheroid pitching up from 0. to 30. incidence at a uniform angular velocity was established based on a dynamic tetrahedral mesh with changing topology and the ALE(arbitrary Lagrangian-Eulerian) method of fluid-structure coupling at a Re number of 4.2 × 10~***, two six-DOF motions of an inclined 6:1 prolate spheroid at an initial incidence of 45. were simulated at different Re numbers of 10000 and 4.2 × 10~6.

关键词： unsteady six-DOF tetrahedral dynamic mesh discrete method DDES

Microstructure Characteristics of the Eutectics of Die Cast AM60B Magnesium Alloy

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Journal of Materials Science & Technology 2011年第12期27卷 1150-1156页

作者： MengwuWu Shoumei xiong Department of Mechanical Engineering Tsinghua University Beijing 100084 China State Key Laboratory of Automobile Safety and Energy Tsinghua University Beijing 100084 China

Under the cold-chamber high pressure die casting （HPDC） process, samples were produced with AM60B magnesium alloy to investigate the microstructure characteristics of the eutectics, especially focusing on the constitution, morphology and distribution of the eutectics over cross section of the castings. Attentions were also paid to study the effect of heat treatment on the eutectics in the die castings. Based on experimental analysis using optical microscopy （OM）, X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy-dispersive spectroscopy （EDS）, it was determined that fully divorced eutectics consisting of c^-Mg and l%MglzA112 appeared at the grain boundary of the primary c^-Mg in the as-cast microstructure. Islands and networks of β-Mg17Al12 phase were observed in the central region of the castings, while the β-Mg17Al12 phase revealed a more dispersed and granular morphology on the surface layer. The two phases ratio β/α in the central region of the castings was approximately 10%, which was higher than that on the surface layer. Besides, the defect bands contained a higher percentage of the eutectics than the adjacent regions. After aging treatment （T6）, only α-Mg phase was detected by XRD in the AM60B magnesium alloy, though a small amount of precipitated β-MgITAI12 phase was observed at the grain boundary. In contrast to the microstructure of die cast AZ91D magnesium alloy under the same T0 heat treatment, no discontinuous precipitation of the β-MgITAI12 phase was observed in AMO0B magnesium alloy die castings.

关键词： AM60B magnesium alloy High pressure die casting Fully divorced eutectic Heat treatment

Revising Space Groups from Simulated SHELXfcf Structure Factors. More Examples of Incorrect Space Groups, an Example of a Chemically-Incorrect Structure and the Special Case of Pgl to PRevisions

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Chinese Journal of Structural Chemistry 2003年第6期22卷 691-699页

作者： NgSeikWeng XIEZhao-xiong DepartmentofChemistry UniversityofMalaya50603KualaLumpurMalaysia StateKeyLaboratoryforPhysicalChemistryofSolidSurfaces XiamenUniversityXiamen361005China

The structure factors of any crystal structure can be simulated from its atomic coordinates (and temperature factors) in a SHELXL-97 run on a dummy hkl in which only the scale factor is refined. The squares of the structure factors are retrieved from the fcf, and such simulated data are used in the revision of the space groups of several incorrectly-refined crystal structures. Two cases, a P1 to P1 revision and a chemically-incorrect structure that is refined in a correct space group, are discussed.

关键词： space-group correction crystal structure revision simulated structure factors

Rapid Springback Compensation for Age Forming Based on Quasi Newton Method

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Chinese Journal of Mechanical Engineering 2014年第3期27卷 551-557页

作者： xiong Wei GAN Zhong xiong Shipeng XIA Yushan Department of Mechanical Engineering Guilin University of Aerospace Technology Key Laboratory of Contemporary Design and Integrated Manufacturing Technology of Ministry of Education Northwestern Polytechnical University

Iterative methods based on finite element simulation are effective approaches to design mold shape to compensate springback in sheet metal forming. However, convergence rate of iterative methods is difficult to improve greatly. To increase the springback compensate speed of designing age forming mold, process of calculating springback for a certain mold with finite element method is analyzed. Springback compensation is abstracted as finding a solution for a set of nonlinear functions and a springback compensation algorithm is presented on the basis of quasi Newton method. The accuracy of algorithm is verified by developing an ABAQUS secondary development program with MATLAB. Three rectangular integrated panels of dimensions 710 mmx750 mm integrated panels with intersected ribs of 10 mm are selected to perform case studies. The algorithm is used to compute mold contours for the panels with cylinder, sphere and saddle contours respectively and it takes 57%, 22% and 33% iterations as compared to that of displacement adjustment （DA） method. At the end of iterations, maximum deviations on the three panels are 0.618 4 mm, 0.624 1 mm and 0.342 0 mm that are smaller than the deviations determined by DA method （0.740 8 mm, 0.740 8 mm and 0.713 7 mm respectively）. In following experimental verification, mold contour for another integrated panel with 400 ram^380 mm size is designed by the algorithm. Then the panel is age formed in an autoclave and measured by a three dimensional digital measurement devise. Deviation between measuring results and the panel＇s design contour is less than 1 mm. Finally, the iterations with different mesh sizes （40 mm, 35 mm, 30 mm, 25 mm, 20 mm） in finite element models are compared and found no considerable difference. Another possible compensation method, Broyden-Fletcher-Shanmo method, is also presented based on the solving nonlinear fimctions idea. The Broyden-Fletcher-Shanmo method is employed to compute mold contour for the second panel. It

关键词： age forming quasi Newton method springback compensation mold design displacement adjustment method