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IEEE International Conference on Computational Electromagnetics (ICCEM)

作者： Yichun Cui Shengjun Zhang Jiaqi Liu Xin liu Hui Xue Borong Zhang National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076 China Beijing Institute of System Engineering Beijing China

ISBN: (纸本)9781538612422

In terms that most researches about Frequency Selective Surface (FSS) concentrate on single layer structure design or FSS with one fundamental mode, a multilayer heterogeneous dual-band frequency selective surface composed of slot FSS, dielectric medium, patch FSS is proposed. This FSS possess miniaturized unit cell with dimension of 6×6mm 2 , it acts as a dual-band filter in given bands while behaving as an entire reflector in others. Results show that this dual-band frequency selective surface has narrow transmission bandwidths near 8.5GHz and 19.5GHz and flat rejection bands except for that. The structure exhibits excellent stability for oblique incident angles and provides polarization-independent response with compact design which moves the operating bands away from grating lobes. A method to adjust the element's size is proposed as well based on basic elements when given pass band frequency changed.

关键词： electromagnetic wave polarisation frequency selective surfaces microwave filters multilayers frequency selective surfaces electromagnetic wave polarisation Microwave filters unit cell multilayers Dual band belt cleaner compact design

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The Study on Porous Media Phase Change Coupling Heat transfer model in Enclosed Metal Cavity

The Study on Porous Media Phase Change Coupling Heat transfe...

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The 2nd International Conference on Materials science and Engineering technology (MSET 2015)

作者： WU Run-hui LIU Jia-qi LIU Xin REN Ai-min ZHANG Sheng-jun MENG Gang National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical

This thesis is aimed to the external instantaneous high energy heat source,according to enclosed metal cavity,porous medium in the cavity,porous media can by phase change heat transfer characteristic of variegated medium coupling state target's special requirements in the field of aerospace,it is innovatively to put forward a kind of applicable to simulate sealed coupling target,under the condition of instant high energy heat source excitation,By heat source-metal cavityporous medium—porous medium's phase-changeable phase change process heat-transfer characteristic numerical calculation model-creation approach,in use of the metal cavity,in the porous medium incompressible flow phase transition of working medium's heat energy conservation,momentum conservation and mass conservation principle,it is to establish analysis model of coupled heat transfer characteristics of multiple parts,in order to acquire the full target area of airtight coupling state targets,temperature field,pressure field,velocity field and phase change of phase transition of working medium characteristics change with time and space change numerical value to analog *** study results points out:when the incentive heat source keep constant,the change rule of full target area temperature,pressure flow rate and phase change characteristic parameters is in conformity with theory of heat transfer *** heat transfer model can be popularized and applied to the optimization design of incentive heat source,and comprehensive performance optimization of enclosed coupling state objects.

关键词： Enclosed metal cavity,Porous foam materials,Phase transition working medium,Heat transfer model,numerical modeling

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Moving target modelling and indication in MIMO GEO SAR

Moving target modelling and indication in MIMO GEO SAR

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IET International Radar Conference 2018, IRC 2018

作者： Cui, Chang Liu, Xiangrong Dong, Xichao Hu, Cheng Li, Yuanhao School of Information and Electronics Beijing Institute of Technology Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology Beijing China

Multiple-input multiple-output geosynchronous synthetic aperture radar (MIMO GEO SAR), composed by several mini-satellites in GEO orbits, has more spatial degrees of freedom, which helps to suppress clutter and improves the performance of ground moving target indication (GMTI). However, in order to ensure the satellite safety, the satellite spacing in MIMO GEO SAR is very large. It results in the failure of far-field assumption and causes the moving target defocusing because of the mismatch between the steering vector in far-field sources and the moving target echo. Here, a new signal model based on the near-field sources is first given according to the GEO SAR satellite-ground geometry relationship. Then, considering the phase difference between the different channels, the spatial steering vector is derived and the weight vector for adaptive processing is proposed to suppress clutter and indicate the moving target. Finally, computer simulations are carried out for the validation of the proposed method. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Synthetic aperture radar

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Relationship Between East Asian Winter Monsoon and Summer Monsoon

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Advances in Atmospheric sciences 2011年第6期28卷 1345-1356页

作者：晏红明杨辉袁媛李崇银 Yunnan Climate Center State Key Laboratory of Numerical Modeling for Atmospheric and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences National Climate Center School of Meteorology PLA University of Science and Technology

Using national Centers for Environmental Prediction/national Centre for Atmospheric Research（NCEP/NCAR） reanalysis data and monthly Hadley Center sea surface temperature（SST） data,and selecting a representative East Asian winter monsoon（EAWM） index,this study investigated the relationship between EAWM and East Asian summer monsoon（EASM） using statistical analyses and numerical *** possible mechanisms regarding this relationship were also *** indicate a close relationship between EAWM and EASM：a strong EAWM led to a strong EASM in the following summer,and a weak EAWM led to a weak EASM in the following *** EAWM has persistent impacts on the variation of SST in the tropical Indian Ocean and the South China Sea,and on the equatorial atmospheric thermal anomalies at both lower and upper *** these impacts,the EAWM influences the land-sea thermal contrast in summer and the low-level atmospheric divergence and convergence over the Indo-Pacific *** further affects the meridional monsoon circulation and other features of the *** simulations support the results of diagnostic *** study provides useful information for predicting the EASM by analyzing the variations of preceding EAWM and tropical SST.

关键词： East Asian winter monsoon East Asian summer monsoon interannual variation interaction possible mechanism

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SIP-IFVM: A time-evolving coronal model with an extended magnetic field decomposition strategy

arXiv

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arXiv 2025年

作者： Wang, Hao P. Yang, Li P. Poedts, S. Lani, A. Zhou, Yu H. Gao, Yu H. Linan, L. Lv, Jia K. Baratashvili, T. Guo, Jing H. Rong, L. Su, Z. Li, Cai X. Zhang, M. Wei, Wen W. Yang, Y. Li, Yu C. Ma, Xin Y. Husidic, E. Jeong, H.-J. Mahdi, Najafi Z. Wang, J. Schmieder, B. Centre for Mathematical Plasma-Astrophysics Department of Mathematics KU Leuven Celestijnenlaan 200B Leuven3001 Belgium State Key Laboratory of Space Weather Chinese Academy of Sciences Beijing100190 China Institute of Physics University of Maria Curie-Sklodowska ul. Radziszewskiego 10 Lublin20-031 Poland Von Karman Institute For Fluid Dynamics Waterloosesteenweg 72 Sint-Genesius-Rode Brussels1640 Belgium School of Earth and Space Sciences Peking University Beijing100871 China Beijing Institute of Applied Meteorology Beijing100029 China School of Astronomy and Space Science Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Nanjing210023 China SIGMA Weather Group State Key Laboratory for Space Weather National Space Science Center Chinese Academy of Sciences Beijing100190 China Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Intense Laser Application Technology College of Engineering Physics Shenzhen Technology University Shenzhen518118 China Space Sciences Laboratory University of California BerkeleyCA94720 United States School of Mathematical Sciences Nanjing Normal University Nanjing210023 China Ministry of Education Key Laboratory of NSLSCS China College of Earth and Planetary Sciences University of Chinese Academy of Sciences Beijing100049 China School of Systems Science Beijing Normal University Beijing100875 China Meudon Principal F-92195 Cedex France SUPA School of Physics & Astronomy University of Glasgow GlasgowG12 8QQ United Kingdom

Time-evolving magnetohydrodynamic (MHD) coronal modeling, driven by a series of time-dependent photospheric magnetograms, represents a new generation of coronal simulations. This approach offers greater realism compared to traditional coronal models constrained by a static magnetogram. However, its practical application is seriously limited by low computational efficiency and poor numerical stability. Therefore, we propose an extended magnetic field decomposition strategy and implement it in the implicit MHD model to develop a coronal model that is both efficient and numerically stable enough for simulating the long-term evolutions of the global corona. The traditional decomposition strategies split the magnetic field into a time-invariant potential field and a time-dependent component B1. It works well for quasi-steady-state coronal simulations where |B1| is typically small. However, as the inner-boundary magnetic field evolves, |B1| can grow significantly larger and its discretization errors often lead to nonphysical negative thermal pressure, ultimately causing the code to crash. In this paper, we mitigate such undesired situations by introducing a temporally piecewise-constant variable to accommodate part of the non-potential field and remain |B1| consistently small throughout the simulations. We incorporate this novel magnetic field decomposition strategy into our implicit MHD coronal model and apply it to simulate the evolution of coronal structures within 0.1 AU over two solar-maximum Carrington rotations. The results show that this coronal model effectively captures observations and performs more than 80 times faster than real time using only 192 CPU cores, making it well-suited for practical applications in simulating the time-evolving corona. © 2025, CC BY-NC-SA.

关键词： Electric corona

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Determination of the Backward Predictability Limit and Its Relationship with the Forward Predictability Limit

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Advances in Atmospheric sciences 2019年第6期36卷 669-677页

作者： Xuan LI Ruiqiang DING Jianping LI State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology College of Global Change and Earth System Sciences (GCESS) Beijing Normal University

In this work, two types of predictability are proposed—forward and backward predictability—and then applied in the nonlinear local Lyapunov exponent approach to the Lorenz63 and Lorenz96 models to quantitatively estimate the local forward and backward predictability limits of states in phase space. The forward predictability mainly focuses on the forward evolution of initial errors superposed on the initial state over time, while the backward predictability is mainly concerned with when the given state can be predicted before this state happens. From the results, there is a negative correlation between the local forward and backward predictability limits. That is, the forward predictability limits are higher when the backward predictability limits are lower, and vice versa. We also find that the sum of forward and backward predictability limits of each state tends to fluctuate around the average value of sums of the forward and backward predictability limits of sufficient ***, the average value is constant when the states are sufficient. For different chaotic systems, the average value is dependent on the chaotic systems and more complex chaotic systems get a lower average value. For a single chaotic system,the average value depends on the magnitude of initial perturbations. The average values decrease as the magnitudes of initial perturbations increase.

关键词： nonlinear local Lyapunov exponent forward and backward predictability limit negative correlation average value

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Influence of the Preceding Austral Summer Southern Hemisphere Annular Mode on the Amplitude of ENSO Decay

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Advances in Atmospheric sciences 2017年第11期34卷 1358-1379页

作者： Fei ZHENG Jianping LI Ruiqiang DING State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technologyqingdao 266237China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technologychengdu 610103China

There is increasing evidence of the possible role of extratropical forcing in the evolution of ENSO. The Southern Hemi- sphere Annular Mode （SAM） is the dominant mode of atmospheric circulation in the Southern Hemisphere extratropics. This study shows that the austral summer （December-January-February; DJF） SAM may also influence the amplitude of ENSO decay during austral autumn （March-April-May; MAM）. The mechanisms associated with this SAM-ENSO relationship can be briefly summarized as follows： The SAM is positively （negatively） correlated with SST in the Southern Hemisphere middle （high） latitudes. This dipole-like SST anomaly pattern is referred to as the Southern Ocean Dipole （SOD）. The DJF SOD, caused by the DJF SAM, could persist until MAM and then influence atmospheric circulation, including trade winds, over the Nifio3.4 area. Anomalous trade winds and SST anomalies over the Nifio3.4 area related to the DJF SAM are further developed through the Bjerkness feedback, which eventually results in a cooling （warming） over the Nifio3.4 area followed by the positive （negative） DJF SAM.

关键词： Southern Hemisphere Annular Mode ENSO Southern Ocean Dipole

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A REMAPPING METHOD BASED ON MULTI-POINT FLUX CORNER TRANSPORT UPWIND ADVECTION ALGORITHM

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Journal of Computational mathematics 2013年第6期31卷 592-619页

作者： Zhijun Shen Guixia Lv National Key Laboratory of Science and Technology on Computational Physics Institute of Applied Physics and Computational Mathematics P.O.Box 8009-26 Beijing 100088 China Center for Applied Physics and Technology HEDPS Peking University Beijing 100871 China

A local remapping algorithm for scalar function on quadrilateral meshes is described. The remapper from a distorted grid to a rezoned grid is usually regarded as a conservative interpolation problem. The present paper introduces a pseudo time to transform the interpolation into an initial value problem on a moving grid, and construct a moving mesh method to solve it. The new feature of the algorithm is the introduction of multi- point information on each edge, which leads to the numerical flux consistent with grid node motion. During the procedure of deriving scheme, we illustrate a framework about how the algorithms on a rectangular mesh are easily generated to those on a moving mesh. The basic ideas include：（i） introducing coordinate transformation, which maps the irregular domain in physical space to a perfectly regular computational domain, and （ii） deriving finite volume methods in the physical domain, which can be viewed as a discretization of the transformed equation. The resulting scheme is second-order accurate, conservative and monotonicity preserving. numerical examples are carried out to show the good performance of ore＂ schemes.

关键词： Remapping Advection Multi-point flux Coordinate transformation Geometric conservation law.

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Impacts of the MJO on Winter Rainfall and Circulation in China

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Advances in Atmospheric sciences 2011年第3期28卷 521-533页

作者：贾小龙陈丽娟任福民李崇银 National Climate Center China Meteorological Administration State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences Institute of Meteorology PLA University of Science and Technology

Impacts of the MJO on winter rainfall and circulation in China are investigated using a real-time multivariate MJO *** results using the daily rainfall anomalies and "rainy day" anomalies according to eight different MJO phases show that the MJO has considerable influence on winter rainfall in China. Rainfall anomalies show systematic and substantial changes(enhanced/suppressed) in the Yangtze River Basin and South China with the eastward propagation of the MJO convective center from the Indian Ocean to the western *** the MJO is in phase 2 and 3(MJO convective center is located over the Indian Ocean),rainfall probability is significantly *** in phase 6 and 7(MJO convective center is over the western Pacific),rainfall probability is significantly reduced. MJO in winter influences the rainfall in China mainly through modulating the circulation in the subtropics and mid-high *** the subtropics,MJO influences the northward moisture transport coming from the Bay of Bengal and the South China Sea by modulating the southern trough of the Bay of Bengal and the western Pacific subtropical *** the mid-high latitudes,the propagation of the low frequency perturbations associated with the eastward-propagating MJO convection modulate the circulation in the mid-high latitudes,*** East Asian winter monsoon and the low trough over central Asia.

关键词： MJO rainfall anomaly subtropics mid-high latitudes vertical motion

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Estimating the Predictability Limit of Tropical Cyclone Tracks over the Western North Pacific Using Observational Data

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Advances in Atmospheric sciences 2018年第12期35卷 1491-1504页

作者： Quanjia ZHONG Lifeng ZHANG Jianping LI Ruiqiang DING Jie FENG State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences College of Meteorology and Oceanography National University of Defense Technology College of Earth Science University of Chinese Academy of Sciences Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology College of Global Change and Earth System Sciences Beijing Normal University School of Meteorology University of Oklahoma

In this study,the nonlinear local Lyapunov exponent(NLLE)approach was used to quantitatively determine the predictability limit of tropical cyclone(TC)tracks based on observed TC track data obtained from the Joint Typhoon Warning *** results show that the predictability limit of all TC tracks over the whole western North Pacific(WNP)basin is about 102 h,and the average lifetime of all TC tracks is about 174 *** predictability limits of the TC tracks for short-,medium-,and long-lived TCs are approximately 72 h,120 h,and 132 h,*** predictability limit of the TC tracks depends on the TC genesis location,lifetime,and intensity,and further analysis indicated that these three metrics are closely *** more intense and longer-lived TCs tend to be generated on the eastern side of the WNP(EWNP),whereas the weaker and shorter-lived TCs tend to form in the west of the WNP(WWNP)and the South China Sea(SCS).The relatively stronger and longer-lived TCs,which are generated mainly in the EWNP,have a longer travel time before they curve northeastwards and hence tend to be more predictable than the relatively weaker and shorter-lived TCs that form in the WWNP region and ***,the results show that the predictability limit of the TC tracks obtained from the best-track data may be underestimated due to the relatively short observational records currently *** work is needed,employing a numerical model to assess the predictability of TC tracks.

关键词： predictability tropical cyclone tracks nonlinear local Lyapunov exponent

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