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Adaptive output-feedback tracking for nonlinear systems with unknown control direction and generic inverse dynamics

Science China(Information Sciences) 2022年第8期65卷 134-149页

作者： Yuan Wang Yungang LIU School of Control Science and Engineering Shandong University

This paper studies adaptive output-feedback tracking for a class of typical uncertain nonlinear systems. In the context of unknown control direction, a generic uncertainty encountered inevitably in practice is adequately taken into consideration, i.e., the ISpS(input-to-state practically stable) inverse dynamics acting as the dynamic differences between the real plants and the models. Besides, the systems in question also permit two critical ingredients, i.e., unmeasured-state dependent nonlinearities and arbitrary functionof-output growth on unknown system nonlinearities. The three ingredients together largely challenge the feasibility/availability of practical tracking by means of output feedback. Nevertheless, a new control strategy is proposed by flexibly integrating the dynamic compensation based on Nussbaum-type gain, backstepping design technique together with the refined pseudo-sign and pseudo-dead-zone functions that were introduced for the first time in our previous studies. The two refined functions, which are sufficiently smooth, can moderately avoid the use of smooth domination/treatment in control design and can potentially render the attained control strategy tighter and less conservative. Moreover, to keep the order of the closed-loop system at a low level, an n-dimensional filter with a dynamic high gain is delicately devised instead of a2 n-dimensional one used in the relevant literature. It turns out that the proposed adaptive output-feedback controller is capable of guaranteeing the global boundedness of all states of the resulting closed-loop system,while steering the system tracking error to enter, in finite time, a prescribed λ-neighborhood of the origin and keeping it inside thereafter. A simulation example is provided to demonstrate the proposed approach.

关键词： nonlinear systems ISpS inverse dynamics unknown control direction practical output tracking global output feedback adaptive compensation

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Binary doping of nitrogen and phosphorus into porous carbon: A novel di-functional material for enhancing CO_(2) capture and super-capacitance

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Journal of Materials Science & Technology 2022年第4期99卷 73-81页

作者： Yuan Wang Jianfei Xiao Hanzhi wang Tian C.Zhang Shaojun yuan Low-carbon Technology&Chemical Reaction Engineering Lab College of Chemical EngineeringSichuan UniversityChengdu 610065China Civil&Environmental Engineering Department University of Nebraska-LincolnOmahaNE 68182-0178USA

Designing of hetero-atomic doped carbon-based systems through pyrolysis of abundant element organic precursors is a novel approach to construct rational porous carbon materials.Herein,a highly-cross-linked triazine polymer is employed to fabricate N,P co-doped porous carbon(A-TDP-12)with tunable active nitrogen in the carbon framework for simultaneous enhancement of CO_(2) capture capability and Supercapacitance(SC).The synthesized A-TDP-12 possesses a typical hierarchically porous framework(micro-pores and meso-pores)with a large surface area(1332 m^(2) g^(-1))and a rich content of N(7.89 at.%)and P(0.74 at.%).It delivers a CO_(2) adsorption capacity of 1.52 and 5.68 mmol g^(-1) at 1 and 5 bar,respectively,with almost no decay after successive 8 recycles.In 6 M KOH aqueous electrolyte,A-TDP-12 exhibits a superior specific capacitance of 172.7 F g^(-1) at a current density of 1 A g^(-1).Even at a high current density of 10 A g^(-1),80%of its initial capacity still remains.This work not only offers a novel strategy for fabricating promising adsorbents and electrodes for CO_(2) uptake and SCs,but also provides new insights into design of porous carbon material for related applications.

关键词： N,P co-doping Porous carbon CO_(2)capture Super-capacitors Bi-function

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Enhancing electrochemical performance of ultrasmall Fe_(2)O_(3)-embedded carbon nanotubes via combusting-induced high-valence dopants

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Journal of Materials Science & Technology 2023年第3期134卷 142-150页

作者： Yuan Wang Tao Zhang Jianfei Xiao Xiaobao Tian Shaojun yuan Low-carbon Technology and Chemical Reaction Engineering Lab College of Chemical EngineeringSichuan UniversityChengdu 610065China College of Architecture and Environment Sichuan UniversityChengdu 610065China

Doping is a reasonable solution to improve the electronic structure and surface properties of nanomaterials.Herein,we propose a rapid and simple methodology,flame synthesis,as an effective preparation strategy for incorporating high-valence metal ions(Ti^(4+),Sn^(4+),and Zr^(4+))into ultrasmall Fe_(2)O_(3)on carbon nanotube support(i.e.,M-FeO-CNT).The resulting materials exhibit not only a boosted Na+adsorption as shown by density functional theory(DFT)calculations,but also display an increased oxygen deficiency.The electrochemical activity and charge transfer efficiency of Fe 2 O 3 can be improved by reasonably sub-stituting Fe 3+with Ti^(4+),Sn^(4+),and Zr^(4+).The electrochemical investigation of Ti-doped Fe 2 O 3(Ti-FeO-CNT)electrode demonstrates a splendid specific capacitance of 1.25 F cm^(−2)at 1 mA cm^(−2)in 1 M Na_(2)SO_(4).This is significantly higher as compared to the capacitance of 0.48 F cm^(−2).Flexible solid-state asymmetric su-percapacitor Ti-FeO-CNT//MnO_(2)is verified with operating voltage of 2.0 V and stability over 3000 cycles,and delivers a high energy density of 2.14 mWh cm^(−3)at power density of 25 mW cm−3.The flame synthesis is expected to be widely applicable for the preparation of high-valence metal ions doped nanosized Fe_(2)O_(3)functionalized materials,thus opening up new avenues for energy and catalysis research.

关键词： Ultrasmall Fe_(2)O_(3)nanoparticles Doping Flame synthesis Flexible supercapacitor DFT calculations

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A stimuli responsive lanthanide-based hydrogel possessing tunable luminescence by efficient energy transfer pathways

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Journal of Rare Earths 2022年第5期40卷 696-701,I0001页

作者： Yuan Wang Jinglei Chen yuan Shang Peng Li Huanrong Li Tianjin Key Laboratory of Chemical Process Safety School of Chemical Engineering and TechnologyNational-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources UtilizationHebei University of TechnologyTianjin 300130China

Energy transfer as an important component in light-harvesting antenna systems can mimic effectively natural photosynthesis processes,showing great potential in optoelectronic devices.Herein,we report a responsive polymeric hydrogel based on the combination of excited state intramolecular proton transfer(ESIPT) molecule(Salicylic acid,Sal) and terbium(Ⅲ)(Tb^(3+)),as enabled by external stimuli to construct artificial light-harvesting antenna systems.Benefiting from unique photophysical properties of Sal,the synthesized hydrogel displays a temperature-dependent reversible opaque?transparent states transition,accompanied with an interesting photoluminescence behavior.Moreover,by further incorporating europium(Ⅲ)(Eu^(3+)) into the hydrogel,we demonstrate well-defined cascades of energy transfer that provides a tunable optical output from the collection of lanthanides by the excitation of a common sensitizer(Sal) upon base vapor stimulation.Efficient energy transfer efficiency from Tb^(3+) to Eu^(3+),as high as 97.8%,was also obtained as established by the time-resolved fluorescence spectroscopy analysis.

关键词： Energy transfer Lanthanides Stimuli-responsive hydrogel Luminescence Rare earths

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A dynamic large-deformation particle finite element method for geotechnical applications based on Abaqus

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第7期15卷 1859-1871页

作者： Weihai yuan Jinxin Zhu Neng wang Wei Zhang Beibing Dai yuanjun Jiang Yuan Wang College of Mechanics and Materials Hohai UniversityNanjing210098China Hunan Provincial Communications Planning Survey and Design Institute CoLtdChangsha410200China College of Water Conservancy and Civil Engineering South China Agricultural UniversityGuangzhou510642China School of Civil Engineering Sun Yat-Sen UniversityGuangzhou510275China Institute of Mountain Hazards and Environment IMHE Chinese Academy of SciencesChengdu610041China College of Water Conservancy and Hydropower Hohai UniversityNanjing210098China

In this paper,the application of Abaqus-based particle finite element method(PFEM)is extended from static to dynamic large deformation.The PFEM is based on periodic mesh regeneration with Delaunay triangulation to avoid mesh distortion.Additional mesh smoothing and boundary node smoothing techniques are incorporated to improve the mesh quality and solution accuracy.The field variables are mapped from the old to the new mesh using the closest point projection method to minimize the mapping error.The procedures of the proposed Abaqus-based dynamic PFEM(Abaqus-DPFEM)analysis and its implementation in Abaqus are detailed.The accuracy and robustness of the proposed approach are examined via four illustrative numerical examples.The numerical results show a satisfactory agreement with published results and further confirm the applicability of the Abaqus-DPFEM to solving dynamic large-deformation problems in geotechnical engineering.

关键词： Abaqus Collapse of granular materials Dynamics Large deformation Particle finite element method(PFEM) Rigid strip footing

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Collective Molecular Machines: Multidimensionality and Reconfigurability

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NANO-MICRO LETTERS 2024年第1期16卷 1-32页

作者： wang, Bin Lu, yuan Tsinghua Univ Dept Chem Engn Beijing 100084 Peoples R China Tsinghua Univ Key Lab Ind Biocatalysis Minist Educ Beijing 100084 Peoples R China

Recent advances and design strategies for molecular machines working as collectives in building smart responsive materials and micro/nanoscale operations are summarized in this review.The modulation of collective behaviors characteristics and properties is summarized in focus, including reversibility, amplification, anisotropy and reconfigurability of smart materials, as well as reconfigurability, orthogonality and logical control of swarming.Experiences and paradigms in the field of micro/nanorobotics in collective construction, control strategies, and model transformations are expected to provide guidance for molecular machines to build reconfigurable, multi-dimensional, and multi-modularity advanced collectives. Molecular machines are key to cellular activity where they are involved in converting chemical and light energy into efficient mechanical work. During the last 60 years, designing molecular structures capable of generating unidirectional mechanical motion at the nanoscale has been the topic of intense research. Effective progress has been made, attributed to advances in various fields such as supramolecular chemistry, biology and nanotechnology, and informatics. However, individual molecular machines are only capable of producing nanometer work and generally have only a single functionality. In order to address these problems, collective behaviors realized by integrating several or more of these individual mechanical units in space and time have become a new paradigm. In this review, we comprehensively discuss recent developments in the collective behaviors of molecular machines. In particular, collective behavior is divided into two paradigms. One is the appropriate integration of molecular machines to efficiently amplify molecular motions and deformations to construct novel functional materials. The other is the construction of swarming modes at the supramolecular level to perform nanoscale or microscale operations. We discuss design strategies for both modes and focus on the modulation of features a

关键词： Molecular machines Collective control Collective behaviors DNA Biomolecular motors UNIDIRECTIONAL ROTARY MOTION SUPRAMOLECULAR POLYMERS INTERLOCKED MOLECULES MICROTUBULES DRIVEN INTEGRATED MOTION NOBEL-PRIZE LIGHT MUSCLE MOTOR TRANSPORT

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Event-triggered finite-time command-filtered tracking control for nonlinear time-delay cyber physical systems against cyber attacks

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Frontiers of Information Technology & Electronic Engineering 2024年第2期25卷 225-236页

作者： Yajing MA Yuan Wang Zhanjie LI Xiangpeng XIE School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210003China Institute of Advanced Technology for Carbon NeutralityNanjing University of Posts and TelecommunicationsNanjing210023China

This article addresses the secure finite-time tracking problem via event-triggered command-filtered control for nonlinear time-delay cyber physical systems(CPSs)subject to cyber attacks.Under the attack circumstance,the output and state information of CPSs is unavailable for the feedback design,and the classical coordinate conversion of the iterative process is incompetent in relation to the tracking task.To solve this,a new coordinate conversion is proposed by considering the attack gains and the reference signal simultaneously.By employing the transformed variables,a modified fractional-order command-filtered signal is incorporated to overcome the complexity explosion issue,and the Nussbaum function is used to tackle the varying attack gains.By systematically constructing the Lyapunov-Krasovskii functional,an adaptive event-triggered mechanism is presented in detail,with which the communication resources are greatly saved,and the finite-time tracking of CPSs under cyber attacks is guaranteed.Finally,an example demonstrates the effectiveness.

关键词： Cyber physical systems Finite-time tracking Event-triggered Command-filtered control Attacks

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The Forced Secondary Circulation of the Mei-yu Front

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Advances in Atmospheric Sciences 2020年第7期37卷 766-780页

作者： Zipeng yuan Xiaoyong ZHUGE Yuan Wang School of Atmospheric Sciences and Key Laboratory of Mesoscale Severe Weather of Ministry of EducationNanjing UniversityNanjing 210023China Liaoning Provincial Meteorological Information Center Shenyang 110160China

Using National Centers for Environmental Prediction reanalysis data for the period 28 June to 12 July during 2001 to2013,the secondary circulation(SC)associated with the mei-yu front was quantitatively diagnosed by numerically solving a primitive version of the Sawyer-Eliassen equation.Results demonstrate that a direct SC exists near the mei-yu front zone during mid-summer and the synoptic-scale geostrophic deformations are the main factors determining SC structures.About94%of the sinking strength and 61%of the ascending strength in the SC are induced by the geostrophic deformations.Other terms,such as diabatic heating,ageostrophic dynamical forcing,and frictional forcing,mainly influence the fine flow pattern of the SC.The forced SC produces a frontogenesis area tilting to the north with altitude.Further diagnosis clarifies the positive feedback involving the geostrophic shear forcing and vorticity frontogenesis in the upper-level mei-yu front zone.Furthermore,statistical results indicate that all 34 deep convection cases that occurred in the warm region of the meiyu front over the period 2004-2013 experienced high-level frontogenesis associated with along-jet cold advection.The cyclonic shear forcing"moved"the monsoon SC’s subsidence branch to the warm side of the mei-yu front and caused the subsidence branch to extend downwards to the lower troposphere,conducive to the initiation of deep convection in the warm region of the mei-yu front.

关键词： forcing subsidence altitude

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Conodont Biostratigraphic Constraint on the Lower Taiyuan Formation in Southern North China and Its Paleogeographic Implications

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Journal of Earth Science 2022年第6期33卷 1480-1493页

作者： Yuan Wang Jianghai Yang Dong-Xun yuan Jia Liu Rui Ma School of Earth Sciences China University of GeosciencesWuhan430074China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan430074China School of Resources and Geosciences China University of Mining and TechnologyXuzhou221116China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of SciencesNanjing210008China

The Late Paleozoic Taiyuan Formation in North China is mainly composed of a mixed shallow-marine carbonate and terrigenous clastic deposits.Its basal limestones have been constrained in the late Pennsylvanian to Early Permian.To further constrain the age of the lowest Taiyuan Formation,we obtained two genera and 16 species of conodonts from the bottom limestones of the Taiyuan Formation in two sections in Henan Province,southern North China.The fauna includes Idiognathodus hebeiensis,Streptognathodus isolatus,S.elongatus,S.cf.longus,S.acuminatus,S.cf.recreatus,S.cf.cristellaris,S.bellus,S.invaginatus,S.wabaunsensis,S.glenisteri,S.conjunctus,S.binodosus,S.fuchengensis,S.nodulinearis,and S.sp.A genus of Streptognathodus dominated conodont assemblage with some Idiognathodus elements.It indicates a late Gzhelian(latest Pennsylvanian)age for the lowest Taiyuan Formation in southern North China.This is consistent with recently published high-precision zircon U-Pb ages from ash layers.Based on conodont biostratigraphy,the basal limestones of the Taiyuan Formation in Henan Province(southern North China)can be correlated with the upper part of Miaogou limestones of the Taiyuan Formation in Shanxi Province(northern North China).This correlation might reflect a significant sea-level rise in North China,possibly corresponding to a deglaciation event at the Permo-Carboniferous transition.

关键词： Taiyuan Formation conodonts Gzhelian southern North China biostratigraphy

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Track-Pattern-Based Characteristics of Extratropical Transitioning Tropical Cyclones in the Western North Pacific

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Advances in Atmospheric Sciences 2024年第6期41卷 1251-1263页

作者： Hong HUANG Dan WU Yuan Wang Zhen wang Yu LIU College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410000China No.31631 Army of PLA Huizhou 516000China School of Atmospheric Sciences and Key Laboratory of Mesoscale Severe Weather/Ministry of Education Nanjing 210023China No.93721 Army of PLA Shuozhou 038300China

Based on the Regional Specialized Meteorological Center(RSMC)Tokyo-Typhoon Center best-track data and the NCEP-NCAR reanalysis dataset,extratropical transitioning(ET)tropical cyclones(ETCs)over the western North Pacific(WNP)during 1951–2021 are classified into six clusters using the fuzzy c-means clustering method(FCM)according to their track patterns.The characteristics of the six hard-clustered ETCs with the highest membership coefficient are shown.Most tropical cyclones(TCs)that were assigned to clusters C2,C5,and C6 made landfall over eastern Asian countries,which severely threatened these regions.Among landfalling TCs,93.2%completed their ET after landfall,whereas 39.8%of ETCs completed their transition within one day.The frequency of ETCs over the WNP has decreased in the past four decades,wherein cluster C5 demonstrated a significant decrease on both interannual and interdecadal timescales with the expansion and intensification of the western Pacific subtropical high(WPSH).This large-scale circulation pattern is favorable for C2 and causes it to become the dominant track pattern,owning to it containing the largest number of intensifying ETCs among the six clusters,a number that has increased insignificantly over the past four decades.The surface roughness variation and three-dimensional background circulation led to C5 containing the maximum number of landfalling TCs and a minimum number of intensifying ETCs.Our results will facilitate a better understanding of the spatiotemporal distributions of ET events and associated environment background fields,which will benefit the effective monitoring of these events over the WNP.

关键词： Western North Pacific tropical cyclone extratropical transition fuzzy c-means clustering method

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