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Offset parameter cancellation produces countless coexisting attractors

CHAOS 2022年第12期32卷 121104-121104页

作者： Li, Chunbiao Lei, Tengfei Liu, Zuohua Nanjing Univ Informat Sci & Technol Sch Artificial Intelligence Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteorol Nanjing 210044 Peoples R China Qilu Inst Technol Collaborat Innovat Ctr Memrist Comp Applicat CICMC Jinan 250200 Peoples R China Chongqing Univ State Key Lab Coal Mine Disaster Dynam & Control Chongqing 400044 Peoples R China

The average value of a system variable determines the position of its attractor. When the offset parameters come together and get disappeared after an algebraic operation, the location of the attractor is then governed by an initial condition only. In this case, parameter-dominated offset control turns out to be the initial condition-defined coexisting attractors. In this Letter, a special mechanism for generating countless coexisting attractors is disclosed. Furthermore, a new regime of multistability is revealed, which explains where and how countless coexisting attractors are born and arranged. Published under an exclusive license by AIP Publishing.

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Mathematical modelling of axonal microtubule bundles under dynamic torsion

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Applied Mathematics and Mechanics(English Edition) 2018年第6期39卷 829-844页

作者： J.Y.WU Hong YUAN L.Y.LI MOE Key Laboratory of Disaster Forecast and Control in Engineering Institute of Applied MechanicsJinan University School of Engineering University of Plymouth

Owing to its viscoelastic nature, axon exhibits a stress rate-dependent me- chanical behavior. An extended tension-shear chain model with Kelvin-Voigt viscoelas- ticity is developed to illustrate the micromechanical behavior of the axon under dynamic torsional conditions. Theoretical closed-form expressions are derived to predict the de- formation, stress transfer, and failure mechanism between microtubule （MT） and tau protein while the axon is sheared dynamically. The results obtained from the present an- alytical solutions demonstrate how the MT-tau interface length, spacing between the tau proteins, and loading rate affect the mechanical properties of axon. Moreover, it is found that the MTs are more prone to rupture due to the contributions from the viscoelastic effects. Under the torsional force, the MTs are so long that the stress concentrates at the loaded end where axonal MTs will break. This MT-tau protein dynamics model can help to understand the underlying pathology and molecular mechanisms of axonal injury. Additionally, the emphasis of this paper is on the micromechanical behavior of axon, whereas this theoretical model can be equally applicable to other soft or hard tissues, owning the similar fibrous structure.

关键词： torsion biocomposite diffuse axonal injury （DAI） Kelvin-Voigt viscoelas-tic model dynamic response tension-shear chain model

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Stochastic harmonic function-based traffic load simulation method for fatigue damage assessment of concrete bridges

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PROBABILISTIC engineering MECHANICS 2022年 69卷 1页

作者： Gao, Ruofan He, Jingran Nie, Zhenhua Jinan Univ Sch Mech & Construct Engn 601 West Huangpu Ave Guangzhou 510632 Guangdong Peoples R China Minist Educ China Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Guangdong Univ Technol Guangzhou Higher Educ Mega Ctr Sch Civil & Transportat Engn Guangzhou 510006 Peoples R China South China Univ Technol Sch Civil Engn & Transportat 381 Wushan Rd Guangzhou 510641 Guangdong Peoples R China

A novel simulation method of the compound Poisson process based on the stochastic harmonic function (SHF) is proposed to represent the stochastic traffic load process, so that the fatigue damage of concrete bridges under traffic loading can be efficiently and accurately evaluated. To start with, the fundamental theory of simulation of the compound Poisson process via SHF is elucidated in detail with the application of the inverse transformation principle. Afterwards, the stochastic traffic load modelled by the compound Poisson process is reproduced by utilizing the SHF-based simulation method. Simultaneously, the Monte Carlo simulation (MCS) method is applied to simulate the traffic load, aiming to verify the superiority of the SHF-based method. By introducing a micro-meso stochastic fatigue damage constitutive model of concrete, integrated with the SHFbased simulation method of traffic load, the theoretical framework of estimating fatigue damage of concrete bridges under stochastic traffic loading is established. Finally, the fatigue damage assessment of a concrete bridge in practical engineering is implemented to validate the feasibility and advantage of the proposed SHF-based traffic load simulation method.

关键词： Stochastic harmonic function Compound Poisson process Traffic load Fatigue damage Concrete bridge

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Collaborative mechanism of microbial fuel cell native bacteria and Sporosarcina pasteurii: Improving mineralization performance

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Chemical engineering Journal 2025年 515卷

作者： Liu, Jin-Di Cheng, Wei-Min Hu, Xiang-Ming Li, Xiao Feng, Yue Zhao, Yan-Yun Wu, Ming-Yue Rong, Hui Yu, Xiao-Niu Xiang, Yin-Bo Zhang, Zhi-Rong College of Safety and Environmental Engineering Shandong University of Science and Technology Qingdao 266590 Shandong China State Key Laboratory of Mine Lab Disaster Prevention and Control Co-found by Shandong Province and the Ministry of Science and Technology Shandong University of Science and Technology Shandong Qingdao266590 China School of Materials Science and Engineering Tianjin Chengjian University Tianjin Tianjin300384 China Jiangsu Key Laboratory of Construction Materials Southeast University Jiangsu Nanjing211189 China School of Civil and Environmental Engineering Nanyang Technological University 639798 Singapore College of Biology and Food Engineering Guangdong University of Petrochemical Technology Guangdong Maoming525000 China Anhui Provincial Key Laboratory of Photonic Devices and Materials Anhui Institute of Optics and Fine Mechanics Hefei Institute of Physical Sciences Chinese Academy of Sciences Anhui Hefei230031 China

Microbial mineralization is an important part of natural mineralization and diagenesis. The microbial mediated electron transfer in microbial fuel cell (MFC) may be a potential method for improving microbial mineralization performance. Therefore, in this paper, the effect of MFC effluent microorganisms on the mineralization performance of Sporosarcina pasteurii was investigated by co-culturing MFC effluent microorganisms with Sporosarcina pasteurii at different dilutions. The results showed that the highest mineralization extent of the experimental group could reach 93.94 %, which was 9.27 % higher than that of Sporosarcina pasteurii, when the dilution ratio was 10−8 and mineralized for 7 d. The increase in dilution was found to be beneficial in promoting the increase in crystal size and crystal type transformation of mineralization products (CaCO3) by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). High throughput sequencing showed that when MFC effluent microorganisms were co-cultured with Sporosarcina pasteurii, Sporosarcina pasteurii remained dominant as the dilution gradient increased. In addition, the competitive relationship between Sporosarcina pasteurii and other microorganisms promoted the evolution of microbial communities, increased species diversity. And the signal molecule transduction between microorganisms enhanced the mineralization performance of Sporosarcina pasteurii. This study provides a theoretical basis and new insights for improving the mineralization performance of Sporosarcina pasteurii. © 2025 Elsevier B.V.

关键词： Microbial fuel cells

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A unified simulation for effects of gellan polymer concentrations on large strain elastic behaviors of gellan gels

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MULTIDISCIPLINE MODELING IN MATERIALS AND STRUCTURES 2019年第5期15卷 859-870页

作者： Ding, Xie-Fei Zhan, Lin Xi, Hui-Feng Xiao, Heng Shanghai Univ Shanghai Inst Appl Math & Mech Shanghai Peoples R China Sch Mech & Construct Engn Guangzhou Guangdong Peoples R China MOE Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China

Purpose A direct and unified approach is proposed toward simultaneously simulating large strain elastic behaviors of gellan gels with different gellan polymer concentrations. The purpose of this paper is to construct an elastic potential with certain parameters of direct physical meanings, based on well-designed invariants of Hencky's logarithmic strain. Design/methodology/approach For each given value of the concentration, the values of the parameters incorporated may be determined in the sense of achieving accurate agreement with large strain uniaxial extension and compression data. By means of a new interpolating technique, each parameter as a function of the concentration is then obtained from a given set of parameter values for certain concentration values. Findings Then, the effects of gellan polymer concentrations on large strain elastic behaviors of gellan gels are studied in demonstrating how each parameter relies on the concentration. Plane-strain (simple shear) responses are also presented for gellan gels with different polymer concentrations. Originality/value A direct, unified approach was proposed toward achieving a simultaneous simulation of large elastic strain behaviors of gellan gels for different gellan polymer concentrations. Each parameter incorporated in the proposed elastic potential will be derived as a function of the polymer concentration in an explicit form, in the very sense of simultaneously simulating large strain data for different concentrations.

关键词： Elastic potential Gellan gels Gellan polymer concentration Hencky strain Large elastic deformation Simultaneous simulation

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Variability and trends of near-surface wind speed over the Tibetan Plateau:The role played by the westerly and Asian monsoon

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Advances in Climate Change Research 2024年第3期15卷 525-536页

作者： Gang-Feng ZHANG Cesar AZORIN-MOLINA Deliang CHEN Tim RMCVICAR Jose AGUIJARRO Kai-Qiang DENG Lorenzo MINOLA Jaeyeon LEE Seok-Woo SON Heng MA Pei-Jun SHI State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Engineering Center of Desertification and Blown-Sand Control of Ministry of Education Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education Beijing Normal UniversityBeijing 100875China Centro de Investigaciones Sobre Desertificaci'on Consejo Superior de Investigaciones Cientı'ficas(CIDECSIC-UV-Generalitat alenciana)ClimateAtmosphere and Ocean Laboratory(Climatoc-Lab)Moncada 46113Spain Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg 40530Sweden CSIRO Environment CanberraACT 2600Australia Australian Research Council Centre of Excellence for Climate Extremes CanberraACT 2600Australia State Meteorological Agency Balearic Islands OfficePalma de Mallorca 07015Spain School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China Interuniversity Department of Regional and Urban Studies and Planning(DIST) Politecnico and University of TurinTurin 10125Italy School of Earth and Environmental Sciences Seoul National UniversitySeoul 08826South Korea Atmospheric and Oceanic Sciences Program Princeton UniversityPrinceton NJ 08544USA Geophysical Fluid Dynamics Laboratory NOAAPrinceton NJ 08544USA

Near-surface wind speed exerts profound impacts on many environmental issues,while the long-term(≥60 years)trend and multidecadal variability in the wind speed and its underlying causes in global high-elevation and mountainous areas(e.g.,Tibetan Plateau)remain largely ***,by examining homogenized wind speed data from 104 meteorological stations over the Tibetan Plateau for 1961-2020 and ERA5 reanalysis datasets,we investigated the variability and long-term trend in the near-surface wind speed and revealed the role played by the westerly and Asian *** results show that the homogenized annual wind speed displays a decreasing trend(-0.091 m s^(−1)per decade,p<0.05),with the strongest in spring(-0.131 m s^(−1)per decade,p<0.05),and the weakest in autumn(-0.071 m s^(−1)per decade,p<0.05).There is a distinct multidecadal variability of wind speed,which manifested in an prominent increase in 1961-1970,a sustained decrease in 1970-2002,and a consistent increase in *** observed decadal variations are likely linked to large-scale atmospheric circulation,and the correlation analysis unveiled a more important role of westerly and East Asian winter monsoon in modulating near-surface wind changes over the Tibetan *** potential physical processes associated with westerly and Asian monsoon changes are in concordance with wind speed change,in terms of overall weakened horizontal air flow(i.e.,geostrophic wind speed),declined vertical thermal and dynamic momentum transfer(i.e.,atmospheric stratification thermal instability and vertical wind shear),and varied Tibetan Plateau *** indicates that to varying degrees these processes may have contributed to the changes in near-surface wind speed over the Tibetan *** study has implications for wind power production and soil wind erosion prevention in the Tibetan Plateau.

关键词： Tibetan Plateau Wind speed Decadal change Atmospheric circulation Physical processes

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Machine learning to optimize climate projection over China with multi-model ensemble simulations

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ENVIRONMENTAL RESEARCH LETTERS 2021年第9期16卷

作者： Li, Tong Jiang, Zhihong Treut, Herve Le Li, Laurent Zhao, Lilong Ge, Lingling Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Joint Int Res Lab Climate & Environm Change Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Minist Educ Key Lab Meteorol Disaster Nanjing 210044 Peoples R China Sorbonne Univ Ecole Normale Super Ecole Polytech Lab Meteorol DynamIPSLCNRS F-75005 Paris France Nanjing Univ Informat Sci & Technol Sch Informat & Control Jiangsu Key Lab Big Data Anal Technol Nanjing 210044 Peoples R China

The multi-model ensemble approach is generally considered as the best way to explore the advantage and to avoid the weakness of each individual model, and ultimately to achieve the best climate projection. But the design of an optimal strategy and its practical implementation still constitutes a challenge. Here we use the random forest (RF) algorithm (from the category of machine learning) to explore the information offered by the multi-model ensemble simulations within the Coupled Model Intercomparison Project Phase 6. Our objective is to achieve a more reliable climate projection (mean climate and extremes) over China. RF is furthermore compared to two other ensemble-processing strategies of different nature, one is the basic arithmetic mean (AM), and another is the linear regression across the ensemble members. Our results indicate that RF effectively enhances the capability in capturing spatial climate characteristics. Regions with complex topography, such as the Tibetan Plateau and its periphery, show the most significant improvements. RF projects less future warming but enhanced wet conditions across China. It also produces larger spatial variability and more small-scale features. The most obvious increase of precipitation is in the northern part and the periphery of the Tibetan Plateau. The projected changes in RF for strong precipitation are almost twice higher than in AM, while in the northwestern area, weaker increases of precipitation are projected by RF, which indicates larger spatial inhomogeneity of its projection.

关键词： ensemble-processing strategy climate extremes observational constraint random forest China regional climate

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Simultaneous strength-ductility enhancement in as-cast Ti6Al4V alloy by trace Ce

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MATERIALS & DESIGN 2022年 215卷

作者： Li, K. M. Liu, Y. J. Liu, X. C. Wu, X. Zhou, S. F. Zhang, L. C. Li, W. Zhang, W. C. Changsha Univ Sci & Technol Inst Met Coll Mat Sci & Engn 9602 Sect Changsha 410004 Hunan Peoples R China Jinan Univ Inst Adv Wear & Corros Resistance & Funct Mat Key Lab Disaster Forecast & Control Engn MOE Guangzhou 510632 Guangdong Peoples R China Edith Cowan Univ Sch Engn 270 Joondalup Dr Perth WA 6027 Australia Jinan Univ Affiliated Hosp 1 Guangzhou 510632 Guangdong Peoples R China

Impurity elements always play a major role in hindering mechanical property improvement in Ti6Al4V, and specifically most of them e.g. O, P, Cl, and S dissolved in the matrix deteriorate the mechanical properties of Ti6Al4V. This work presents a strategy of enhancing the mechanical performance of as-cast Ti6Al4V alloy by adding a small amount of rare earth (i.e. 0.1 wt% Ce), where deleterious elements could be absorbed from the crystalline lattice during solidification process, forming uniformly distributed Cerich oxides or precipitates with-200 nm in size. The Ce-rich precipitates in turn refine the beta phase lamellae by introducing more nucleation in the cast alloy, which further enhances the strength. As such, the cast Ti6Al4V with Ce addition exhibits a tensile strength of 957 +/- 47 MPa and elongation of 12.3%, which exhibits a simultaneous strength-ductility enhancement compared with the Ti6Al4V counterpart (787 +/- 65 MPa and 8.8%). In addition, the Ce-rich precipitates also pin dislocation motions, which effectively shields the stress concentration at the crack tip and deflects the crack propagation during fracture process.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://***/licenses/by/4.0/).

关键词： Rare earth Ce Titanium Mechanical properties Geometrically-necessary dislocations Slip systems

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Impact of late spring Siberian snow on summer rainfall in South-Central China

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CLIMATE DYNAMICS 2020年第7-8期54卷 3803-3818页

作者： Shen, Haibo Li, Fei He, Shengping Orsolini, Yvan J. Li, Jingyi Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Key Lab Meteorol Disaster Minist Educ Nanjing Peoples R China China Southern Power Grid Co Ltd Power Dispatching Control Ctr Guangzhou Peoples R China Univ Bergen Geophys Inst Bergen Norway Bjerknes Ctr Climate Res Bergen Norway NILU Norwegian Inst Air Res Kjeller Norway

Located in the Yangtze River Valley and surrounded by mountains, South-Central China (SCC) frequently suffered from natural disasters such as torrential precipitation, landslide and debris flow. Here we provide corroborative evidence for a link between the late spring (May) snow water equivalent (SWE) over Siberia and the summer (July-August, abbr. JA) rainfall in SCC. We show that, in May, anomalously low SWE over Siberia is robustly related to a large warming from the surface to the mid-troposphere, and to a stationary Rossby wave train from Siberia eastward toward the North Atlantic. On the one hand, over the North Atlantic there exhibits a tripole pattern response of sea surface temperature anomalies in May. It persists to some extent in JA and in turn triggers a wave train propagating downstream across Eurasia and along the Asian jet, as the so-called Silk Road pattern (SRP). On the other hand, over northern Siberia the drier soil occurs in JA, accompanied by an overlying anomalous anticyclone through the positive feedback. This anomalous anticyclone favors the tropospheric cooling over southern Siberia, and the meridional (northward) displacement of the Asian jet (JMD) due to the change in the meridional temperature gradient. The combination of the SRP and the JMD facilitates less water vapor transport from the tropical oceans and anomalous descending motion over SCC, and thus suppresses the precipitation. These findings indicate that May Siberian SWE can be exploited for seasonal predictability of SCC precipitation.

关键词： Siberian snow water equivalent Precipitation in South-Central China Sea surface temperature over the North Atlantic Siberian soil moisture The Silk Road pattern The meridional displacement of the Asian jet

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Ill-Posedness Determination of Moving Force Identification and Parameters Selection for Regularization Methods

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INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS 2021年第8期21卷

作者： Chen, Zhen Sun, Pudong Chan, Tommy H. T. Yu, Ling North China Univ Water Resources & Elect Power Sch Civil Engn & Commun Zhengzhou 450045 Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Queensland Univ Technol QUT Sch Civil & Environm Engn Brisbane Qld 4000 Australia

Moving force identification (MFI) from dynamic responses of bridges is a typical inverse problem with ill-posedness. Under the efforts of researchers, some regularization methods have been presented to solve the ill-posed problem, but there still lacks an effective index to reveal the ill-posedness of the vehicle-bridge dynamic system such that it can be utilized as a guidance for the regularization parameter selection. In this paper, an ill-posedness indicator (IPI) defined as the ratio of the Fourier coefficient to the singular value is adopted to reveal the ill-posedness in the MFI problem. Simulation results show that the larger the IPI value is, the more obvious the ill-posedness of the vehicle-bridge system equation, namely, the intrinsic factor of ill-posedness in MFI is attributed to very large IPI value. The maximum IPI value increases with the increasing noise level, which leads directly to the ill-posedness of the vehicle-bridge system equation. In addition, a relative percentage error (RPE) is used to select the optimal regularization parameters, while evaluating the ill-posedness existing in the MFI. Using the proposed IPI value, the influence of ill-posedness on identified results is evaluated in this study, which can assist qualitatively and quantitatively in selecting optimal regularization parameters and proper regularization methods.

关键词： Vehicle bridge moving force identification Fourier coefficient ill-posedness indicator relative percentage error

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