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C@Ag core‒shell structure as lubricating additives towards high efficient lubrication

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Friction 2024年第9期12卷 1991-2003页

作者： Dong AO Xiaoqiang fan Minhao zhu Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Efficient cooperative lubrication can be achieved via the introduction of core‒shell structure lubricant additives with hard core and soft shell,for obtaining the expected anti-wear performance from the structural changes in the friction *** this study,C@Ag microspheres with a core‒shell structure were prepared by the redox method with carbon spheres as the core and Ag nanoparticles as the *** tribological behaviors as base oil(G1830)additive with different concentrations were investigated in *** with base oil,the addition of C@Ag particles at 0.5 wt%can reduce the coefficient of friction(COF)and wear volume(Wv)up to 15.5%and 88%,*** importantly,C@Ag particles provide superior lubrication performance to single additive(like carbon sphere(CS)and Ag nanoparticle).C@Ag core‒shell particles contribute to the formation of tribo-film by melt bonding of flexible Ag and carbon sphere(CS)toward excellent self-repair performance and high-efficiency ***,core‒shell structural nanoparticles with hard-core and soft-shell hold bright future for high-performance lubrication application.

关键词： C@Ag microspheres tribo-film self-repair performance high-efficiency lubrication

A Note on Abelian Extensions

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wuhan University Journal of Natural Sciences 2008年第1期13卷 6-8页

作者： YU Chuxiong1,2. fan yun{2. school of {2. and statistics, wuhan University, wuhan 43.072. hubei, china 2. school of {2. and Computer Science, Jianghan University, wuhan 430056, {12., china 3. school of {2. and statistics, Huazhong Normal University, wuhan 430079, {12., china school of mathematics and {2. Wuhan University Wuhan 430072 Hubei China

Let K/Q be any abelian extension where Q is the field of rational numbers. By Galois theory and the Frobenius formula for induced characters, we prove that there exists a metabelian group G and an irreducible characte... 详细信息

关键词： abelian extensions metabelian groups induced characters Galois groups

Correlating dynamic relaxation and viscoelasticity in metallic glasses

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Science china(Physics,Mechanics & Astronomy) 2024年第5期67卷 81-90页

作者： GuangHui Xing Qi Hao fan zhu {2.-Jiang Wang Yong Yang Hidemi Kato Eloi Pineda Si Lan JiChao Qiao school of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China school of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Department of Mechanical Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Department of Materials Science and Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Department of Physics Institute of Energy TechnologiesUniversitat Politècnica de CatalunyaBarceona 9Spain school of Material Science and Engineering Herbert Gleiter Institute of NanoscienceNanjing University of Science and Technology.Nanjing 210094China State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Northwestern Polytechnical UniversityXi'an 710072China

Relaxation dynamics,essential for the structural evolution of non-equilibrium systems like glassy materials,remain ***,we explore relaxation dynamics and viscoelastic properties in three types of metallic glasses with distinctβrelaxation *** systems with significantβrelaxation,stress relaxation and creep experiments reveal a transition from two-step to one-step relaxation with rising ***,such a phenomenon is absent in systems with weakerβ*** model the two-step relaxation process using a double Kohlrausch-Williams-Watts equation,and the obtained relaxation times elegantly adhere to the Arrhenius *** combining fitted activation energies with theoretical analysis,we conclusively attribute these relaxation processes toβrelaxation andαrelaxation,***,we analyze the relaxation time spectra of two processes and establish a comprehensive picture linking dynamic relaxation with *** study provides new strategies for probing the complex relaxation behaviors of glasses from the perspective of viscoelasticity.

关键词： creep relaxation glasses

An Overview on Wavelet Software Packages

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wuhan University Journal of Natural Sciences 2001年第Z1期6卷 593-600页

作者： fan Qi\|bin 1, Li Hong 2.1. school of {2. and {2., wuhan University, wuhan 43.072. china 2. school of Electronic Information, wuhan University, wuhan 43.072. china school of mathematics and {2. Wuhan University Wuhan China school of Electronic Information Wuhan University Wuhan China

Wavelet analysis provides very powerful problem\|solving tools for analyzing, encoding, compressing, reconstructing, and modeling signals and images. The amount of wavelets\|related software has been constantly multiplying. Many wavelet analysis tools are widely available. This overview represents a significant survey for many currently available packages. It will be of great benefit to engineers and researchers for using the toolkits and developing new software. The beginner to learning wavelets can also get a great help from the review. If you browse around at some of the Internet sites listed in the reference of this paper, you may find more plentiful wavelet resources.

关键词： wavelet transforms image compression matching pursuit lifting MATLAB

Airflow Analytical Toolkit(AAT):A MATLAB-based analyzer for holistic studies on the dynamic characteristics of airflows

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Building Simulation 2024年第7期17卷 1137-1159页

作者： Zuoyu Xie Junhui fan Bin Cao Yingxin zhu Department of Building Science School of ArchitectureTsinghua UniversityBeijingChina Key Laboratory of Eco Planning&Green Building Ministry of Education(Tsinghua University)BeijingChina

The dynamic characteristics of different airflows on micro-scales have been explored from many perspectives since the late *** the one hand,most analytical tools and research subjects in previous contributions vary significantly:some only focus on fluctuant velocity features,while others pay attention to directional *** the other hand,despite the wide variety of existing analytical methods,they are not systematically classified and *** paper aims to establish a system including state-of-the-art tools for airflow analysis and to further design a holistic toolkit named Airflow Analytical Toolkit(AAT).The AAT contains two tools,responsible for analyzing the velocity and direction characteristics of airflows,each of which is integrated with multiple analytical *** assess the performance of the developed toolkit,we further take typical natural and mechanical winds as cases to show its excellent analytical *** the help of this toolkit,the great differences in velocity and directional characteristics among different airflows are *** comparative results reveal that not only is the velocity of natural wind more fluctuating than that of mechanical wind,but its incoming flow direction is also more *** AAT,serving as a powerful and user-friendly instrument,will hopefully offer great convenience in data analysis and guidance for a deeper understanding of the dynamic characteristics of airflows,and further remedy the gap in airflow analytical tools.

关键词： airflow analysis dynamic characteristic wind velocity wind direction thermal comfort wind comfort

Evaluation of transmission risk of respiratory particles under different ventilation strategies in an elevator

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Building Simulation 2024年第5期17卷 771-784页

作者： Liangyu zhu Xian Li Bujin Feng fan Liu school of Civil Engineering and Architecture Linyi UniversityLinyi276000China College of Agriculture Shandong Agricultural UniversityTaian271018China school of Environment and Architecture University of Shanghai for Science and TechnologyShanghai200093China

People in elevators are at risk of respiratory infection because the elevator cabin is crowded and has poor *** exhaled particles may be inhaled by the susceptible person,deposited on the surface and suspended in the elevator,which can result in direct and indirect ***,whether the air vent designs adopted in the elevator can effectively reduce the transmission risk of respiratory particles remains *** this study,the dispersion of particles under four common ventilation strategies used in the commercial elevator was investigated by proven computational fluid dynamics(CFD)*** flow field was simulated with the RNG κ-ξ turbulence model and the Lagrangian method was adopted to track particle *** effects of air vent layout and airflow rate on particle transmission were *** found that more than 50% of exhaled particles(average value)were suspended in the cabin and difficult to discharge under the investigated ventilation *** deposited fraction of particles on the susceptible person reached up to 39.14% for infiltration ventilation,which led to a high risk of contact *** the ventilation rate could not significantly reduce the inhalation proportion of particles due to the poor airflow distribution inside the elevator.A more proper ventilation strategy should be explored for the elevator to control transmission risk.

关键词： particle dispersion transmission risk elevator ventilation strategy computational fluid dynamics(CFD)

A theorem of Fong's type for graded algebras

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Science china mathematics 2005年第5期48卷 577-582页

作者： fan yun & {2. ping school of {2. and statistics, Central china Normal University, wuhan 430079, china school of Mathematical Science, Nankai University, Tianjin 300071, china 1. school of mathematics and {2. Central China Normal University 430079 Wuhan China 2. school of Mathematical Science Nankai University 300071 Tianjin China

Let G be a finite p-solvable group and k be an algebraic closed field of characteristic p. It is proved that any projective indecomposable module of a G-graded k-algebra is an induced module of a module of the subalgebra graded by a Hall p′-subgroup. A necessary and sufficient condition for the indecomposability of an induced module from a Hall p′-subgroup is obtained.

关键词： group graded algebra indecomposable induced module primitive idempotent.

Study on the preparation and fretting behavior of bonded oriented MoS_(2.solid lubricant coating

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Friction 2024年第11期12卷 2505-2518页

作者： Liangliang XIONG Mengxue WU Xiaoqiang fan Minhao zhu Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

The bonded MoS_(2.solid lubricant coating is an effective measure to mitigate the fretting wear of AISI 1045 *** this work,the amino functionalized MoS_(2.was protonated with acetic acid to make the MoS_(2.positively *** directional arrangement of protonated MoS2.in the coating was achieved by electrophoretic deposition under the electric field *** bonded directionally aligned MoS_(2.solid lubricant coating showed high adaptability to various loads and excellent lubrication performance under all three working *** a load of 10 N,the friction coefficient and wear volume of the coating with 5 wt%protonated MoS_(2.decreased by 2..0%and 37.2.compared to the pure epoxy coating,respectively,and by 0.07%and 16.8%than the randomly arranged MoS_(2.sample,*** remarkable lubricating properties of MoS_(2.with directional alignment were attributed to its effective load-bearing and mechanical support,barrier effect on longitudinal extension of cracks,and the formation of a continuous and uniform transfer film.

关键词： bonded solid lubricant coating MoS_(2. fretting oriented alignment

Quantitative assessment of the supply,demand and flows of ecosystem services in the Yangtze River Basin,china

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Frontiers of Earth Science 2024年第2期18卷 422-445页

作者： Dongjie GUAN Xiaofeng fan Lilei ZHOU Kangwen zhu school of Smart City Institute Chongqing Jiaotong UniversityChongqing 400074China

Ecosystem service flow is essential for transporting,transforming,and maintaining ecosystem services and connecting supply and *** study attempted to quantitatively assess the supply and demand flows of ecosystem services in the Yangtze River Basin in 2.00,2.10,and 2.2.;assess the evolution of the spatial patterns of ecosystem service flow at the provincial,watershed and urban agglomeration scales;and design a zoning standard for ecosystem service *** results showed as follows.1)Between 2.00 and 2.2.,the Yangtze River had a progressive drop in its freshwater supply,water conservation service and carbon sequestration service *** decline rates for these services were measured at 10.90%,11.11%,and 5.17%,*** climate regulation service flow exhibited a pattern of initial fall followed by a subsequent increase,characterized by a decline rate of 35.53%.2.The lowest was the ecosystem service flow in the lower reaches of the Yangtze River and the Yangtze River Delta urban *** supply service flow and water conservation service flow were the highest in the upper reaches of the Yangtze River and the Chengdu-Chongqing urban *** sequestration service flow and climate regulation service flow were the highest in the middle reaches of the Yangtze River Basin and the urban agglomeration in the middle reaches of the Yangtze River.3)From 2.00 to 2.2.,the change ratios of the area proportion of the confluence,flow,and outflow areas in the Yangtze River Basin were 1.06,3.1.,and 0.86,*** results of this research could offer decision support for regulating ecosystem services in the Yangtze River Basin,promoting sustainable regional development and achieving rational use of the basin resources.

关键词： Yangtze River Basin ecosystem services supply and demand service flow quantitative assessment spatial matching