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Implementation of a particle-in-cell method for the energy solver in 3D spherical geodynamic modeling

Earth and Planetary Physics 2024年第3期8卷 549-563页

作者： Hao Dong ZeBin Cao LiJun Liu YanChong Li SanZhong Li LiMing Dai XinYu Li Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Laboratory of Submarine Geosciences and Prospecting TechniquesMinistry of Education and College of Marine GeosciencesOcean University of ChinaQingdao 266100China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Laboratory for Marine Geology Laoshan LaboratoryQingdao 266237China Department of Earth Science&Environmental Change University of Illinois at Urbana-ChampaignUrbanaIL 61801USA Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

The thermal evolution of the Earth’s interior and its dynamic effects are the focus of Earth ***,the commonly adopted grid-based temperature solver is usually prone to numerical oscillations,especially in the presence of sharp thermal gradients,such as when modeling subducting slabs and rising *** phenomenon prohibits the correct representation of thermal evolution and may cause incorrect implications of geodynamic *** examining several approaches for removing these numerical oscillations,we show that the Lagrangian method provides an ideal way to solve this *** this study,we propose a particle-in-cell method as a strategy for improving the solution to the energy equation and demonstrate its effectiveness in both one-dimensional and three-dimensional thermal problems,as well as in a global spherical simulation with data *** have implemented this method in the open-source finite-element code CitcomS,which features a spherical coordinate system,distributed memory parallel computing,and data assimilation algorithms.

关键词： numerical oscillation overshooting and undershooting particle-in-cell method three-dimensional spherical geodynamic modeling energy solver finite element method

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Design of large ring-column antenna satellite attitude-orbit integrated füll propulsion system

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Zhendong yu Chongji/Journal of Vibration and Shock 2025年第11期44卷 1-11页

作者： Wang, Shijie Sun, Minzhe Gao, Feng Ji, Yi Sun, Guanghui Dong, Fuxiang School of Astronautics Harbin Institute of Technology Harbin150001 China Frontier Science Center of Space Environment and Interaction of Matters Harbin150001 China State Key Lab for Modeling and Simulation of Complex Systems Harbin150001 China General Department of Communication and Navigation Satellite China Academy of Space Technology Beijing100094 China

As a key space structure in geostationary orbit, 100-meter level large ring-column antenna satellite is tasked with providing high-speed information transmission and stable communication Service in this orbit. This requires satellites having precise orbit maintenance and attitude control capabilities. Due to such satellites typically having larger masses and special structural designs, here, the high-precision orbit prediction algorithm was used to finely model and analyze effects of key space environmental factors of solar pressure, non-spherical perturbations and 3-body gravity on space Operation of such spacecrafts. Furthermore, referring to the design concept of formation-flying gravity field measurement satellites, a distributed füll thrust control strategy based on thruster layout optimization for such spacecrafts was proposed. Then, an improved explicit model predictive control algorithm was proposed based on Laguerre function to convert device capability limitations and Performance requirements into input-output constraints, combine multi-parameter programming, and realize attitude-orbit integrated control of such satellites. The simulation results showed that during stable Operation, position maintenance errors of such satellites can be controlled within a meter-level ränge, and attitude angle errors are better than 0. 03°;the computational efficiency of the proposed control algorithm is significantly higher than that of the Standard model predictive control algorithm and Laguerre function-based model predictive control algorithm;the hardware memory occupied is much lower than that of the explicit model predictive control *** theoretical analysis and numerical verification, it was shown that this study can provide an effective solving scheme for füll thruster integrated control of large ring-column antenna satellites in oomplex space environment using onboard Computers with limited Computing power. © 2025 Chinese Vibration Engineering Society.

关键词： Geostationary satellites

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华北农村清洁取暖成本收益的空间不均衡

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science Bulletin 2024年第12期69卷 1852-1856页

作者：张伟张鹏飞赵静汪峰尚昱竹方培薛文博张鹏岩宋玲玲蒋洪强王金南李佳硕 State Environmental Protection Key Laboratory of Environmental Planning and Policy Simulation Chinese Academy of Environmental PlanningBeijing 100041China The Center for Beijing-Tianjin-Hebei Regional Environment and Ecology Chinese Academy of Environmental PlanningBeijing 100041China Institute of Blue and Green Development Shandong UniversityWeihai 264209China School of Business Nanjing University of Information Science&TechnologyNanjing 210044China Institute of Climate Economy and Low-carbon Industry Nanjing University of Information Science&TechnologyNanjing 210044China Center of Air Quality Simulation and System Analysis Chinese Academy of Environmental PlanningBeijing 100041China School of Urban Economics and Public Administration Capital University of Economics and BusinessBeijing 100070China

Bulk coal combustion in rural households is a major contributor to PM_(2.5)pollution in Northern China[1,2].To promote the energy transition and reduce bulk coal combustion for heating in rural areas,China initiated the Winter Clean Heating Action Plan in Rural Northern China in 2017,hereinafter referred to as rural clean heating(RCH)[3].The 2+26 region,comprising beijing,Tianjin,and 26 other municipalities in the surrounding area(Fig.S1 online),is the key implementation area for the RCH.

关键词：华北农村 Rural 成本收益

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Erratum to: Depth estimation using an improved stereo network (Frontiers of Information technology & Electronic Engineering, (2022), 23, 5, (777-789), 10.1631/FITEE.2000676)

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Frontiers of Information technology and Electronic Engineering 2023年 1-1页

作者： Xu, Wanpeng Zou, Ling Wu, Lingda Qi, Yue Qian, Zhaoyong Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing101416 China Peng Cheng Laboratory Shenzhen518055 China Digital Media School Beijing Film Academy Beijing100088 China

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Temperature fluctuations and heat transport in partitioned supergravitational thermal turbulence

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Acta Mechanica Sinica 2024年第6期40卷 20-30页

作者： Dongpu Wang Jing Liu Rushi Lai Chao Sun Beijing Key Laboratory of Space Thermal Control Technology Beijing Institute of Spacecraft System EngineeringBeijing100094China Center for Combustion Energy Key Laboratory for Thermal Science and Power Engineering of MoEand Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China Department of Engineering Mechanics School ofAerospace EngineeringTsinghua UniversityBeijing100084China

We report an experimental study of the local temperature fluctuationsδT and heat transport in a partitioned supergravitational turbulent convection *** to the dynamics of zonal flow in the normal system without partition walls,the probability density function(PDF)at a position in the mixing zone exhibits a downward bending shape,suggesting that the multi-plume clustering effect plays an important *** partitioned system,zonal flow is suppressed and the PDFs indicate that the single-plume effect is ***,statistical analysis shows that the PDF ofδT is sensitive to ***,the thermal spectra follow P(f)∼f^(-5) in the normal system,which is relevant to the zonal *** absolute value of the scaling exponent of P(f)and the scaling range become small in the partitioned system,which provides another evidence for the influence of zonal flow on the energy ***,heat transfer enhancement is found in the partitioned system,which may result from zonal flow being restricted and then facilitating the radial movement of thermal plumes to the opposite conducting *** work may provide insights into the flow and heat transport control of some engineering and geophysical flows.

关键词： Partitioned turbulent convection Supergravity Probability density function Power spectra Heat transfer

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A LSTM-based method for simulation execution validity evaluation 33

A LSTM-based method for simulation execution validity evalua...

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33rd European Modeling and simulation Symposium, EMSS 2021

作者： Wang, YuLun Li, Wei Li, Jing Control and Simulation Center Harbin Institute of Technology Harbin150080 China Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing100074 China

This paper improves the concept of simulation execution validity and a methodology to assess the complex simulation system. As the complexity of the simulation system gradually rises, the magnitude of the simulation data obtained continues to increase, which makes it extremely difficult for experts to provide expert knowledge to evaluate the execution validity of the simulation system. More precisely, the essence of execution validity is to dig out the hidden relationships in the simulation time series data and complete the classification task whether it is valid. Considering that machine learning can better complete the two tasks of mining data features and classification, this paper adopts long short-term memory, a neural network used to process time series data, to evaluate the execution validity. Finally, an experiment is conducted on a simulation system, and the results show that the evaluation method based on LSTM can accurately evaluate the validity of the simulation system, and can greatly improve the efficiency of evaluation. © 2021 The Authors.

关键词： Long short-term memory

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Cross-Polarization suppression by Comb-Shaped slots in Microstrip Patch 13

Cross-Polarization suppression by Comb-Shaped slots in Micro...

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13th International Conference on Microwave and Millimeter Wave technology, ICMMT 2021

作者： Ma, Jing Tan, Shi-Li Ni, Si-Yuan Wang, Chen Sun, Kai Luo, Yong-Yuan Peng, Lin Beijing Simulation Center Science And Technology On Special System Simulation Laboratory Beijing100854 China 95972 Troops Of PLA Jiuquan735018 China Guilin University Of Electronic Technology Guangxi Key Laboratory Of Wireless Wideband Communication And Signal Processing Guangxi Guilin541004 China

ISBN: (纸本)9781665434379

Cross-polarization (XP) of the microstrip antenna was suppressed by etching comb-shaped slots in the patch. By cutting longitudinal comb-shaped slots on the rectangular patch, the transverse current at the patch edges that lead to cross-polarization was dammed up. Then, the co-to cross-polarization (CP-XP) ratio over entire angular range around the broadside direction was increased from 20 dB of the rectangular microstrip antenna (RMA) to 35 dB of the defected patch structure (DPS). Moreover, as the longitudinal current was little affected by the slots, the proposed structure has little effect on the other performances of the antenna (including gain, directivity, radiant principle and impedance bandwidth). As the presented structure is achieved by simple adding slots to the rectangular patch, it is very easy to be fabricated. © 2021 IEEE.

关键词： Etching

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Electrical resistivity-temperature characteristics enhancement of insulating cross-linked polyethylene composites by incorporating positive temperature coefficient particles with different Curie temperatures

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High Voltage 2023年第1期8卷 1-11页

作者： Guimin Jiang Yuanxiang Zhou Chenyuan Teng Yunxiao Zhang Xin Huang Lei Xue Luming Zhou The Wind Solar Storage Division of State Key Laboratory of Control and Simulation of Power System and Generation Equipment Xinjiang UniversityUrumqiChina State Key Laboratory of Power System and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijingChina College of Information Engineering Zhejiang University of TechnologyHangzhouChina School of Electronics and Computer Science University of SouthamptonSouthamptonUK

Incorporating positive temperature coefficient(PTC)ceramic particles into polymers provides a prospective alternative solution for suppressing severe electric field distortions caused by negative temperature coefficient(NTC)of electrical resistivity within polymer insulation in high voltage direct current *** effect of the Curie temperature of PTC particles on the inhibition of the NTC effect of cross-linked polyethylene(XLPE)is investigated in this *** temperature coefficient particles with varied Curie temperatures are surface-modified and melt blending with *** modified particles are dispersed on averagely in the *** electrical resistivity,space charge behaviour,and direct current(DC)electrical breakdown strength of the samples are investigated at different temperatures,exploring the effect of the Curie temperature of PTC particles on suppressing the NTC effect of *** is demonstrated that the reduction in Curie temperature can further suppress the NTC effect of XLPE,enhance the DC strength at elevated temperatures,and inhibit the internal space charge *** reduction in the Curie temperatures means that the initiation of the PTC effect advances,exhibiting a higher potential barrier and inhibiting the NTC effect more *** work may give a reference for improving the temperature stability of DC properties for XLPE cable insulation.

关键词： coefficient resistivity insulation

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A dislocation-based model for cyclic plastic response of lath martensitic steels

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Acta Mechanica Sinica 2022年第2期38卷 110-118,I0004页

作者： Long Yu Wenbin Liu Haonan Sui Ying Liu Huiling Duan State Key Laboratory for Turbulence and Complex System Department of Mechanics ami Engineering ScienceBeijing Innovation Center for Engineering Science and Advanced Technology(BIC-ESAT)College of EngineeringPeking UniversityBeijing 100871China Key Laboratory of High Energy Density Physics Simulation(HEDPS) Center for Applied Physics and Technology(CAPT)and IFSACollaborative Innovation Center of MoEPeking UniversityBeijing 100871China

Softening behavior of lath martensitic steels is related to the coarsening of laths and dislocation evolution during cyclic *** the physical mechanism,we developed a dislocation-based model to study the cyclic plastic response for lath martensitic *** a block,we proposed an interfacial dislocation evolution model to physically present the interaction between mobile dislocations in the block and interfacial dislocations by considering the coarsening mechanism of the ***,the evolution behavior of backstress caused by dislocation pile up at the block boundary has been ***,a hierarchical model based on the elastic-viscoplastic self-consistent(EVPSC)theory is developed,which can realize the scale transition among representative volume element(RVE),prior austenite grains(PAGs)and *** to the proposed model,the effective mechanical responses including the cyclic hysteretic loop and peak stress at different cycles for lath martensitic steel have been theoretically predicted and investigated.

关键词： Lath martensitic steel Cyclic softening Hierarchical microstructure Lath coarsening Crystal plasticity

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Miniaturization Design of TEM Horn Antenna for Ground-Penetrating Radar

Miniaturization Design of TEM Horn Antenna for Ground-Penetr...

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International Conference on Microwave and Millimeter Wave technology Proceedings

作者： Zhi-Hao Li Jing Ma Jin Wu Jia-Jia Huang Yong-Han Lu Lin Peng Key Laboratory of Cognitive Radio and Information Processing (Ministry of Education) Guilin University of Electronic Technology Guilin China Education Department of Guangxi Zhuang Autonomous Region Key Laboratory of Microwave and Optical Wave Application Technology (Guilin University of Electronic Technology) Guilin China Science and Technology on Special System Simulation Laboratory Beijing Simulation Center Beijing China

This paper presents a miniaturized TEM horn antenna for ground penetrating radar (GPR). First, an exponential gradient horn antenna is designed with a low cut-off frequency of 0.45 GHz. Then, the low cut-off frequency is decreased to 0.19 GHz through curve structural loading and lens loading without increasing the size of the horn. The antenna size is 378.49 mm × 359.07 mm × 386.06 mm, corresponding to 0.226 λ 1 × 0.238 λ 1 × 0.243 λ 1 ( λ 1 is the wavelength corresponding to the lowest frequency of the antenna). The results show that the working bandwidth of the antenna is 0.19-3GHz, and it has a good radiation pattern in the band, with a peak gain of 12.4dBi, which would be a good candidate for GPR.

关键词：

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