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Computational Experiments for Complex Social Systems:Integrated Design of Experiment System

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1175-1189页

作者： xiao Xue Xiangning yu Deyu Zhou xiao Wang Chongke Bi Shufang Wang Fei-yue Wang College of Intelligence and Computing Tianjin UniversityTianjin 300350China School of Software Shandong UniversityJinan 250101China School of Artificial Intelligence Anhui UniversityHefei 230601China School of Geographic and Environmental Sciences Tianjin Normal UniversityTianjin 300387China Institute of Automation Chinese Academy of Sciences Beijing 100190China

Powered by advanced information industry and intelligent technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).And human factors have become crucial in the operations of complex social *** mechanical analysis and social simulations alone are powerless for analyzing complex social *** this backdrop,computational experiments have emerged as a new method for quantitative analysis of complex social systems by combining social simulation(e.g.,ABM),complexity science,and domain ***,in the process of applying computational experiments,the construction of experiment system not only considers a large number of artificial society models,but also involves a large amount of data and *** a result,how to integrate various data,model and knowledge to achieve a running experiment system has become a key *** paper proposes an integrated design framework of computational experiment system,which is composed of four parts:generation of digital subject,generation of digital object,design of operation engine,and construction of experiment ***,this paper outlines a typical case study of coal mine emergency management to verify the validity of the proposed framework.

关键词： artificial system operations

A Comparative Study on the Post-Buckling Behavior of Reinforced Thermoplastic Pipes(RTPs)Under External Pressure Considering Progressive Failure

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China Ocean Engineering 2024年第2期38卷 233-246页

作者： DING Xin-dong WANG Shu-qing LIU Wen-cheng YE xiao-han College of Engineering Ocean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China Department of Marine Technology Norwegian University of Science and Technology(NTNU)Trondheim NO-7491Norway

The collapse pressure is a key parameter when RTPs are applied in harsh deep-water *** investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are *** the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary *** for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with *** has been observed that the cross-section of the middle part collapses when it reaches the maximum *** collapse pressure obtained from the numerical simulations agrees well with that in the ***,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also *** has a relatively greater difference because of the ignorance of the progressive failure of *** the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.

关键词： reinforced thermoplastic pipes post-buckling behavior progressive failure of composites debonding initial ovality

Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research

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China Foundry 2024年第1期21卷 51-59页

作者： Dong Pan Qing-tao Guo Kai-lun Zhang Fu-zhi yu yu-ying Li yu-bao xiao State Key Laboratory of Metal Materials for Marine Equipment and Application Anshan 114009LiaoningChina Ansteel Beijing Research Institute Co. Ltd.Beijing 102200China

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting *** from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification *** this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring *** a comprehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 *** higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of *** experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element *** SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.Consequently,SWHS holds great promise as a potential approach for improving the quality of continuous casting billets.

关键词： billet electromagnetic stirring helical solidification element segregation numerical simulation

A Possible X-ray Quasi-periodic Oscillation in the Narrow-line Seyfert 1 Galaxy Mrk 142

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Research in Astronomy and Astrophysics 2024年第6期24卷 191-200页

作者： xiao-Gu Zhong Jian-Cheng Wang Yong-yun Chen xiao-Ling yu College of Physics and Electronic Engineering Qujing Normal UniversityQujing 655011China yunnan Observatories Chinese Academy of SciencesKunming 650216China

A possible quasi-periodic oscillation(QPO) at frequency 7.045 × 10^(-5) Hz is found in the narrow-line Seyfert 1galaxy Mrk 142 in the data of XMM-Newton collected on 2020 April *** find that the QPO signal is statistically significantly larger than the 5σ level and highly coherent with quality factor Q > 5 at the 0.3–10 keV band by using the method of the Lomb–Scargle Periodogram,the Weighted Wavelet Z-transform and the *** analyze the data in 0.3–0.6 keV,0.6–1 keV,1–3 keV and 3–10 keV energy bands,and find obvious QPO signals at 0.3–0.6 keV and 1–3 keV *** then analyze the time-average spectra and time variability at the QPO frequency of 7.045 × 10^(-5) Hz,and use a model to fit *** find that the QPO signal mainly comes from the X-ray hot corona.

关键词： X-rays:galaxies galaxies:Seyfert accretion accretion disks radiation mechanisms:general

Hydration lubrication modulated by water structure at TiO2–aqueous interfaces

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Friction 2024年第4期12卷 591-605页

作者： Pingsu MA yuan LIU Ke han yu TIAN Liran MA State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The nature of solid-liquid interfaces is of great significance in *** advances have been made in lubrication based on hydration ***,a detailed molecular-level understanding is still ***,we investigated water molecule behaviors at the TiO2-aqueous interfaces by the sum-frequency generation vibrational spectroscopy(SFG-VS)and atomic force microscope(AFM)to elucidate the fundamental role of solid-liquid interfaces in *** contributions of water structures and hydration effects were revealed,where water structures played the dominant role in lubrication for TiO2 surfaces of varying hydrophilicity,while hydration effects dominated with the increasing of ion *** lubrication is observed on the initial TiO2 surfaces with strongly H-bonded water molecules compared to the hydrophilic TiO2 surfaces with more disordered *** stable ordered water arrangement with strong hydrogen bonds and the shear plane occurring between the ordered water layer and subsequent water layer may play a significant role in achieving lower *** adsorbed hydrated molecules with the increasing ionic concentration perturb ordered water but lead to the enhancement of hydration effects,which is the main reason for the improved lubrication for both *** work provides more insights into the detailed molecular-level understanding of the mechanism of hydration lubrication.

关键词： hydration lubrication interfacial water structures hydration effects titanium dioxide(TiO2)

Non-isothermal kinetics and characteristics of calcium carbide nitridation reaction with calcium-based additives

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 49-61页

作者： Zhihan Zhang Mengxiao yu xiaoyu Zhang Jinli Zhang You han School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

The nitridation reaction of calcium carbide and N_(2) at high temperatures is the key step in the production of ***,the challenges faced by this process,such as high energy consumption and poor product quality,are mainly attributed to the lack of profound understanding of the *** study aimed to improve this process by investigating the non-isothermal kinetics and reaction characteristics of calcium carbide nitridation reaction at different heating rates(10,15,20,and 30℃·min^(-1))using thermogravimetric *** kinetic equation for the nitridation reaction of additive-free calcium carbide sample was obtained by combining model-free methods and model-fitting *** effect of different calcium-based additives(CaCl_(2) and CaF_(2))on the reaction was also *** results showed that the calcium-based additives significantly reduced reaction temperature and activation energy E_(a) by about 40% with CaF_(2) and by 55%-60% with CaCl_(2).The reaction model f(α)was also changed from contracting volume(R3)to 3-D diffusion models with D3 for CaCl_(2) and D4 for CaF_(2).This study provides valuable information on the mechanism and kinetics of calcium carbide nitridation reaction and new insights into the improvement of the lime-nitrogen process using calcium-based additives.

关键词： lime-nitrogen calcium carbide calciumbased additive thermogravimetric analysis nonisothermal kinetics

Growth of Ag/g-C_(3)N_(4) nanocomposites on nickel foam to enhance photocatalytic degradation of formaldehyde under visible light

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Journal of Environmental Sciences 2024年第3期137卷 432-442页

作者： Ze Wang Zhi Huang Jiang yu xiao Shao Weidong Peng Jie yu Yinying Jiang Department of Environmental Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Institute of New Energy and Low Carbon Technology Sichuan UniversityChengdu 610065China School of Agriculture and Environment University of Western AustraliaPerth 6907Western AustraliaAustralia Yibin Institute of Industrial Technology Sichuan UniversityYibin 644000China

Formaldehyde is a pollutant that significantly affects the indoor air ***,conventional remediation approaches can be challenging to deal with low-concentration formaldehyde in an indoor *** this study,Photocatalysts of Ag/graphitic carbon nitride(g-C_(3)N_(4))/Ni with 3D reticulated coral structure were prepared by thermal polymerization and liquid phase photo-deposition,using nickel foam(NF)as the *** demonstrated that when the Ag concentration was 3%,and the relative humidity was 60%,the Ni/Ag/g-C_(3)N_(4)showed the maximum degradation rate of formaldehyde at 90.19%under visible light irradiation,and the formaldehyde concentration after degradation was lower than the Hygienic standard stated by the Chinese *** porous structure of Ni/Ag/g-C_(3)N_(4)and the formation of Schottky junctions promoted the Adsorption efficiency and degradation of formaldehyde,while the nickel foam carrier effectively promoted the desorption of degradation ***,the degradation rate was only reduced by3.4%after 16 recycles,the three-dimensional porous structure extended the lifetime of the *** study provides a new strategy for the degradation of indoor formaldehyde at low concentrations.

关键词： Graphitic carbon nitride(g-C_(3)N_(4)) Nickel foam(NF) Ag Formaldehyde Photocatalysis

Effect of Mn addition on microstructure and mechanical properties of GX40CrNiSi25-12 austenitic heat resistant steel

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China Foundry 2024年第3期21卷 205-212页

作者： Guan-yu Jiang Meng-wu Wu xiao-guang Yang Hui Wang yu-yuan Zhu Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000HubeiChina Wescast Industries(China)Co. Ltd.Wuhan 430100China

Three types of steels were designed on the basis of GX40CrNiSi25-12 austenitic heat resistant steel by adding different Mn contents(2wt.%,6wt.%,and 12wt.%).Thermodynamic calculation,microstructure characterization and mechanical property tests were conducted to investigate the effect of Mn addition on the microstructure and mechanical properties of the austenitic heat resistant *** show that the matrix structure in all the three types of steels at room temperature is completely *** NbC and M_(23)C_(6)precipitate at grain boundaries of austenite *** the increase of Mn content,the number of carbides increases and their distribution becomes more *** the Mn content increases from 1.99%to 12.06%,the ultimate tensile strength,yield strength and elongation increase by 14.6%,8.0%and 46.3%,*** improvement of the mechanical properties of austenitic steels can be explained by utilizing classic theories of alloy strengthening,including solid solution strengthening,precipitation strengthening,and grain *** increase in alloy strength can be attributed to solid solution strengthening and precipitation strengthening caused by the addition of *** improvement of the plasticity of austenitic steels can be explained from two aspects:grain refinement and homogenization of precipitated phases.

关键词： austenitic heat resistant steel manganese microstructure mechanical properties

Meta label associated loss for fine-grained visual recognition

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Science China(Information Sciences) 2024年第6期67卷 230-247页

作者： Yanchao LI Fu xiao Hao LI Qun LI Shui yu School of Computer Science Nanjing University of Posts and Telecommunications School of Network Engineering Zhoukou Normal University School of Computer Science University of Technology Sydney

Recently, intensive attempts have been made to design robust models for fine-grained visual recognition, most notably are the impressive gains for training with noisy labels by incorporating a reweighting strategy into a meta-learning framework. However, it is limited to up or downweighting the contribution of an instance for label reweighting approaches in the learning process. To solve this issue, a novel noise-tolerant method with auxiliary web data is proposed. Specifically, first, the associations made from embeddings of well-labeled data with those of web data and back at the same class are measured. Next, its association probability is employed as a weighting fusion strategy into angular margin-based loss, which makes the trained model robust to noisy datasets. To reduce the influence of the gap between the well-labeled and noisy web data, a bridge schema is proposed via the corresponding loss that encourages the learned embeddings to be coherent. Lastly, the formulation is encapsulated into the meta-learning framework, which can reduce the overfitting of models and learn the network parameters to be noise-tolerant. Extensive experiments are performed on benchmark datasets, and the results clearly show the superiority of the proposed method over existing state-of-the-art approaches.

关键词： label associated loss weighting noisy samples fine-grained visual recognition noise-tolerant learning meta-learning