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State estimate for stochastic systems with dual unknown interference inputs

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Chinese Journal of Aeronautics 2020年第9期33卷 2395-2407页

作者： Xiaoxue feng Shuhui LI feng pan School of Automation Beijing Institute of TechnologyBeijing 100081China Kunming-BIT Industry Technology Research Institute INC Kunming 650106China

Stochastic system state estimation subject to the unknown interference input widely exists in many fields,such as the control,communication,signal processing,and fault diagnosis.However,the research results are mostly limited to the stochastic system in which only the dynamic state model or the measurement model concerns the individual unknown interference input,and the state model and the measurement model are both with the same unknown interference input.State estimate of the stochastic systems where the state model and the measurement model contain dual Unknown Interference inputs(dual-UI)with different physical meanings and mathematical definitions is concerned here.Firstly,the decoupling condition with the Unknown Interference input in the State model(S-UI)is shown,which introduces the decoupled system with the adjacent Measurement concerned Unknown Interference inputs(M-UI)appearing in the state model and the measurement model.Then,through defining the Differential term of the adjacent M-UI(M-UID),the equivalent system with only M-UID in the state model is obtained.Finally,considering the design freedom of the equivalent system,the decoupling filter in the minimum mean square error sense and the adaptive minimum upper filter with different applicable conditions are represented to obtain the optimal and sub-optimal state estimate,respectively.Two simulation cases verify the effectiveness and superiority compared with the traditional methods.

关键词： Adaptive filter Decoupling filter State estimate Stochastic system Unknown interference input

'Structure units' as material genes in cathode materials for lithium-ion batteries

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National Science Review 2020年第2期7卷 242-245页

作者： Jiaxin Zheng Yaokun Ye feng pan School of Advanced Materials Peking University Shenzhen Graduate School

The basic structure unit of crystals is the lattice atom and its coordination environment. They are arranged periodically in certain combinations (e.***.space group) to form crystals. Generally speaking, the bonding interaction and electronic structure in the structure unit determine the intrinsic physical and chemical properties of crystals [1],similar to the key role of genes in life.

关键词： as material genes in cathode materials for lithium-ion batteries Structure units

Monotonic uplift behavior of anchored pier foundations in soil overlying rock

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第7期24卷 569-583页

作者： Yizhou SUN Honglei SUN Chong TANG Yuanqiang CAI feng pan College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China College of Civil Engineering Zhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Zhejiang Electric Power Design Institute Co.Ltd. China Energy Engineering GroupHangzhou 310012China

Rock-embedded foundations with good uplift and bearing capacity are often used in mountains or hilly areas.However,there are soil layers with a certain thickness on the rocks in these mountainous areas,and the utilization of those soil layers is a problem worthy of attention in foundation construction.Considering construction-and cost-related factors,traditional single-form foundations built on such sites often cannot provide sufficient resistance against uplift.Therefore,an anchored pier foundation composed of anchors and belled piers,specifically constructed for such conditions,can be invaluable in practice.This paper introduces an experimental and analytical study to investigate the uplift capacity and the uplift mobilization coefficients(UMCs)of the anchored pier foundation.In this study,three in-situ monotonic pullout tests were carried out to analyze the load–displacement characteristics,axial force distribution,load transfer mechanism,and failure mechanism.A hyperbolic model is used to fit the load–displacement curves and to reveal the asynchrony of the ultimate limit states(ULSs)of the anchor group and the belled pier.Based on the results,the uplift capacity can be calculated by the UMCs and the anchor group and pier uplift capacities.Finally,combined with the estimation of the deformation modulus of the soil and rock,the verification calculation of the uplift capacity and UMC was carried out on the test results from different anchored pier foundations.

关键词： Uplift capacity Anchored pier foundation Belled pier Rock anchor Uplift mobilization coefficient(UMC)

Fluidization thermal decomposition of sodium fluosilicate

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Chinese Journal of Chemical Engineering 2023年第5期57卷 329-337页

作者： feng pan Sugang Ma Yu Ge Chuanlin Fan Qingshan Zhu State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences(CAS)Beijing 100190China College of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

To break through the thermodynamic limitation that sodium fluosilicate only can be completely decomposed at high temperature,the technology of pre-decomposition under SiF_(4) atmosphere and deep decomposition under air condition at lower temperature was developed.The hydrolysis reaction of sodium fluosilicate can be effectively restrained when drying under vacuum or low temperature.Thermal decomposition results of sodium fluosilicate indicate that temperature has a very significant effect on its decomposition.The decomposition ratio can reach 79.4%at 600℃ for 1 h,and 99.6% at 700℃ for 1 h under air condition,respectively.Gas velocity and the type of inert gas have no significant effect on its decomposition.Fine particles affect its decomposition performance due to agglomeration,while coarse particles have good thermal decomposition performance without significant differences.The decomposition reaction process in fluidized bed satisfies the classical Avrami Erofe'EV model,with the reaction order of 1.5 and the activation energy of 61.35 kJ·mol^(-1).

关键词： Sodium hexafluorosilicate Preparation Silicon tetrafluoride Absorption Fluidized bed

Vision-based aerial image mosaicking algorithm with object detection

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Journal of Systems Engineering and Electronics 2022年第2期33卷 259-268页

作者： HAN Jun LI Weixing feng Kai pan feng School of Automation Beijing Institute of TechnologyBeijing 100081China

Aerial image sequence mosaicking is one of the chal-lenging research fields in computer vision.To obtain large-scale orthophoto maps with object detection information,we propose a vision-based image mosaicking algorithm without any extra location data.According to object detection results,we define a complexity factor to describe the importance of each input ima-ge and dynamically optimize the feature extraction process.The feature points extraction and matching processes are mainly guided by the speeded-up robust features(SURF)and the grid motion statistic(GMS)algorithm respectively.A robust refer-ence frame selection method is proposed to eliminate the trans-formation distortion by searching for the center area based on overlaps.Besides,the sparse Levenberg-Marquardt(LM)al-gorithm and the heavy occluded frames removal method are ap-plied to reduce accumulated errors and further improve the mo-saicking performance.The proposed algorithm is performed by using multithreading and graphics processing unit(GPU)accel-eration on several aerial image datasets.Extensive experiment results demonstrate that our algorithm outperforms most of the existing aerial image mosaicking methods in visual quality while guaranteeing a high calculation speed.

关键词： image mosaicking object detection grid motion statistic(GMS) mapping

Seismic performance of HWBBF considering different design methods and structural heights

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Frontiers of Structural and Civil Engineering 2023年第12期17卷 1849-1870页

作者： Yulong feng Zhi ZHANG Zuanfeng pan School of Civil Engineering Hefei University of TechnologyHefei 230009China Thornton Tomasetti New YorkNY 10271USA College of Civil Engineering Tongji UniversityShanghai 200092China

Previous research has shown that using buckling-restrained braces(BRBs)at hinged wall(HW)base(HWBB)can effectively mitigate lateral deformation of steel moment-resisting frames(MRFs)in earthquakes.Forcebased and displacement-based design methods have been proposed to design HWBB to strengthen steel MRF and this paper comprehensively compares these two design methods,in terms of design steps,advantages/disadvantages,and structure responses.In addition,this paper investigates the building height below which the HW seismic moment demand can be properly controlled.First,3-story,9-story,and 20-story steel MRFs in the SAC project are used as benchmark steel MRFs.Secondly,HWs and HWBBs are designed to strengthen the benchmark steel MRFs using force-based and displacement-based methods,called HWFs and HWBBFs,respectively.Thirdly,nonlinear time history analyses are conducted to compare the structural responses of the MRFs,HWBBFs and HWFs in earthquakes.The results show the following.1)HW seismic force demands increase as structural height increases,which may lead to uneconomical HW design.The HW seismic moment demand can be properly controlled when the building is lower than nine stories.2)The displacement-based design method is recommended due to the benefit of identifying unfeasible component dimensions during the design process,as well as better achieving the design target displacement.

关键词： hinged wall moment-resisting frame seismic design displacement-based design nonlinear time-history analysis

Event-triggered robust control for networked control systems with actuator failures and time-varying transmission delays

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International Journal of Intelligent Computing and Cybernetics 2015年第2期8卷 172-186页

作者： Peng pan Shun Jiang feng pan Key Laboratory of Advanced Process Control for Light Industry(Ministry of Education) Jiangnan UniversityWuxiChina

Purpose–The purpose of this paper is with robust control problem for event-triggered networked control systems(NCSs)with actuator failures and time-varying transmission delays.Design/methodology/approach–A random sequence is introduced to describe the actuator faults,and a novel event-triggering communication scheme is adopted in the sensor-to-controller channel.By taking the event-triggered mechanism and network transmission delay into consideration,a delay system model is constructed.Findings–Based on Lyapunov stability theory and free weighting matrix method,the feasibility criteria for co-designing both the controller gain and the trigger parameters are derived.Finally,a simulation example is exploited to demonstrate the effectiveness of the proposed linear matrix inequalities(LMIs)approach.Originality/value–The introduced approach is interesting for NCSs with actuator failures and timevarying transmission delays.

关键词： Robust control Networked control Actuator failure Event-triggering scheme

Anomalous displacement reaction for synthesizing above-room-temperature and air-stable vdW ferromagnet PtTe2Ge1/3

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National Science Review 2023年第1期10卷 236-245页

作者： Wenxuan Zhu Cheng Song Qian Wang Hua Bai Siqi Yin feng pan Key Laboratory of Advanced Materials School of Materials Science and Engineering Beijing Innovation Center for Future Chips Tsinghua University

Emerging van der Waals(vdW) magnets provide a paradise for the exploration of magnetism in the ultimate two-dimensional(2D) limit,and the construction of integrated spintronic devices,and have become a research frontier in the field of low-dimensional materials.To date,prototypical vdW magnets based on metals of the first transition series(e.g.V,Cr,Mn and Fe) and chalcogen elements suffer from rapid oxidation restricted by the Hard-Soft-Acid-Base principle,as well as low Curie temperatures(TC),which has become a generally admitted challenge in 2D spintronics.Here,starting from air-unstable Cr2Ge2Te6vdW thin flakes,we synthesize Ge-embedded PtTe2(namely PtTe2Ge1/3) with superior air stability,through the displacement reaction in the Cr2Ge2Te6/Pt bilayer.In this process,the anomalous substitution of Cr with Pt in the thermal diffusion is inverse to the metal activity order,which can be attributed to the compatibility between soft-acid(Pt) and soft-base(Te) elements.Meanwhile,the layered uniform insertion of Ge unbalances Pt-Te bonds and introduces long-range ordered ferromagnetism with perpendicular magnetic anisotropy and a Curie temperature above room temperature.Our work demonstrates the anti-metal-activity-order reaction tendency unique in 2D transition-metal magnets and boosts progress towards practical 2D spintronics.

关键词： vdW magnets room-temperature ferromagnetism air stability HSAB PtTe2Ge1/3

Quasi-exactly solvable decatic model description of nuclei near the X(5) critical point

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Communications in Theoretical Physics 2022年第1期74卷 46-56页

作者： Hadi Sobhani Hassan Hassanabadi Dennis Bonatsos feng pan Jerry P Draayer Department of Physics Liaoning Normal UniversityDalian 116029China Faculty of Physics Shahrood University of TechnologyShahroodIran Institute of Nuclear and Particle Physics National Centre for Scientific Research‘Demokritos’GR-15310 Aghia ParaskeviAttikiGreece Department of Physics and Astronomy Louisiana State UniversityBaton RougeLA 70803-4001United States of America

The Bohr Hamiltonian with axially deformed shape confined in a quasi-exactly solvable decatic β-part potential is studied.It is shown that the decatic model can well reproduce the X(5)model results as far as the energy ratios in the ground and beta band and related B(E2)values are concerned.Fitting results to the low-lying energy ratios and relevant B(E2)values of even-even X(5)candidates ^(150)Nd,^(156)Dy,^(164)Yb,^(168)Hf,^(174)Yb,^(176,178,180)Os,and ^(188,190)Os show that the decatic model provides the best fitting results for the energy ratios,while the X(5)model is the best at reproducing the B(E2)values of these nuclei,in which the beta-bandhead energy is lower than that of the gamma band.While for even-even nuclei,such as ^(154,156,158)Gd,with bandhead energies of the beta and gamma bands more or less equal within the X(5)critical point to the axially deformed region,our numerical analysis indicates that the decatic model is better than the X(5)model in describing both the low-lying level energies and related B(E2)values.

关键词： Bohr Hamiltonian the decatic potential X(5)critical point