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High temperature lubrication performance of chlorophenyl silicone oil

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Friction 2024年第8期12卷 1716-1727页

作者： yan meng Xiangli WEN Jie CHENG Pengpeng BAI Yonggang meng Yu TIAN School of Mechanical and Electrical Engineering China University of Mining and Technology-BeijingBeijing 100083China Department of Mechanical Engineering State Key Laboratory of Tribology in Advanced EquipmentTsinghua UniversityBeijing 100084China

Most studies of liquid lubricants were carried out at temperatures below 200°***,the service temperature of lubricants for aerospace and aeroengine has reached above 300°*** order to investigate the friction mechanism and provide data for high temperature lubrication,the friction and wear properties of chlorophenyl silicone oil(CPSO)-lubricated M50 steel and Si3N4 friction pairs were investigated ***-on-disk experimental results show that the lubrication performance of CPSO varies significantly with *** 150°C,coefficient of friction(COF)remains at 0.13–0.15 after the short running-in stage(600 s),while the COF in the running-in stage is 0.2–*** 200°C and above,the running-in time is much longer(1,200 s),and the initial instantaneous maximum COF can reach *** this condition,the COF gradually decreases and finally stabilizes at around 0.16–0.17 *** phenomenon is mainly due to the different thickness of boundary adsorption *** importantly,the wear rate of M50 steel increases significantly with the temperature,while the wear rate barely changes at temperatures above 200°*** anti-wear mechanism is explained as tribochemical reactions are more likely to occur between CPSO and steel surface with the increased temperature,generating the FeCl2 protective film on the metal ***,FeCl2 tribochemical film improves the lubrication and anti-wear capacity of the *** high temperatures(200–350°C),FeCl2 film becomes thicker,and the contact region pressure becomes lower due to the larger wear scar size,so the wear rate growth of M50 steel is much smaller compared with that of low temperatures(22–150°C).The main findings in this study demonstrate that CPSO lubricant has good anti-wear and lubrication capacity,which is capable of working under temperatures up to 350°C.

关键词： chlorophenyl silicone oil(CPSO) liquid lubricant anti-wear high temperature

Structural regulation of coal-derived hard carbon anode for sodium-ion batteries via pre-oxidation

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Rare Metals 2024年第6期43卷 2585-2596页

作者： meng-Yuan Su Kai-Yang Zhang Edison Huixiang ang Xue-Li Zhang yan-Ning Liu Jia-Lin Yang Zhen-Yi Gu Faaz A.Butt Xing-Long Wu Faculty of Chemistry Northeast Normal UniversityChangchun 130024China MOE Key Laboratory for UV Light-Emiting Materials and Technology.Northeast Normal University.Ministry of Education Changchun 130024China Natural Sciences and Science Education National Institute of EducationNanyang Technological UniversitySingapore 637616Singapore Materials Engineering Department NED University of Engineering and TechnologyKarachi 75300Pakistan

Hard carbon(HC)is broadly recognized as an exceptionally prospective candidate for the anodes of sodium-ion batteries(SIBs),but their practical implementation faces substantial limitations linked to precursor factors,such as reduced carbon yield and increased ***,a cost-effective approach is proposed to prepare a coal-derived HC anode with simple pre-oxidation followed by a post-carbonization process which effectively expands the d_(002)layer spacing,generates closed pores and increases defect *** these modifications,the resulting HC anode attains a delicate equilibrium between plateau capacity and sloping capacity,showcasing a remarkable reversible capacity of 306.3 mAh·g^(-1)at 0.03 A·g^(-1).Furthermore,the produ ced HC exhibits fast reaction kinetics and exceptional rate performance,achieving a capacity of 289 mAh·g^(-1)at 0.1 A·g^(-1),equivalent to~94.5%of that at 0.03 A·g^(-1).When implemented in a full cell configuration,the impressive electrochemical performance is evident,with a notable energy density of 410.6 Wh·kg^(-1)(based on cathode mass).In short,we provide a straightforward yet efficient method for regulating coal-derived HC,which is crucial for the widespread use of SIBs anodes.

关键词： Sodium-ion batteries Hard carbon Anode Coal Pre-oxidation

Restoring cosmological concordance with axion-like early dark energy and dark matter characterized by a constant equation of state?

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Communications in Theoretical Physics 2024年第7期76卷 74-82页

作者： yan-Hong Yao Xin-He meng School of Physics and Astronomy Sun Yatsen University 2 Daxue RoadTangjiaZhuhaiChina School of Physics Nankai University 94 Weijin RoadNankaiTianjinChina

The Hubble tension persists as a challenge in *** early dark energy(EDE)models,initially considered the most promising for alleviating the Hubble tension,fall short of addressing the issue without exacerbating other tensions,such as the S_(8)*** that a negative dark matter(DM)equation of state(EoS)parameter is conducive to reduce the value of the σ_(8)parameter,we extend the axion-like EDE model in this paper by replacing the cold dark matter(CDM)with DM characterized by a constant EoS w_(dm)(referred to as WDM hereafter).We then impose constraints on this axion-like EDE extension model,along with three other models:the axion-like EDE model,ΛWDM,and Λ*** constraints are derived from a comprehensive analysis incorporating data from the Planck 2018 cosmic microwave background,baryon acoustic oscillations,and the Pantheon compilation,as well as a prior on H_(0)(i.e.H_(0)=73.04±1.04,based on the latest local measurement by Riess et al)and a Gaussianized prior on S_(8)(i.e.S_(8)=0.766±0.017,determined through the joint analysis of KID1000+BOSS+2dLenS).We find that although the new model maintains the ability to alleviate the Hubble tension to~1.4σ,it still exacerbates the S_(8)tension to a level similar to that of the axion-like EDE model.

关键词： Hubble tension early dark energy noncold dark matter S8 tension

Fuzzy-Model-Based Finite Frequency Fault Detection Filtering Design for Two-Dimensional Nonlinear Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第10期11卷 2099-2110页

作者： meng Wang Huaicheng yan Jianbin Qiu Wenqiang Ji Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationSchool of Information Science and EngineeringEast China University of Science and TechnologyShanghai 200237China Research Institute of Intelligent Control and Systems School of AstronauticsHarbin Institute of TechnologyHarbin 150080China School of Artificial Intelligence Hebei University of TechnologyTianjin 300401China IEEE

This article studies the fault detection filtering design problem for Roesser type two-dimensional(2-D)nonlinear systems described by uncertain 2-D Takagi-Sugeno(T-S)fuzzy ***,fuzzy Lyapunov functions are constructed and the 2-D Fourier transform is exploited,based on which a finite frequency fault detection filtering design method is proposed such that a residual signal is generated with robustness to external disturbances and sensitivity to *** has been shown that the utilization of available frequency spectrum information of faults and disturbances makes the proposed filtering design method more general and less conservative compared with a conventional nonfrequency based filtering design ***,with the proposed evaluation function and its threshold,a novel mixed finite frequency H_(∞)/H_(-)fault detection algorithm is developed,based on which the fault can be immediately detected once the evaluation function exceeds the ***,it is verified with simulation studies that the proposed method is effective and less conservative than conventional non-frequency and/or common Lyapunov function based filtering design methods.

关键词： Fault diagnosis finite frequency specifications mixed H_(∞)/H_(-)performance two-dimensional nonlinear systems

Research status and perspectives of MXene-based materials for aqueous zinc-ion batteries

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Rare Metals 2024年第5期43卷 1867-1885页

作者： Xiao-Yu Wang Qi-Hang Yang Xin-yan meng meng-meng Zhen Zhen-Zhong Hu Bo-Xiong Shen School of Energy and Environmental Engineering Hebei University of TechnologyTianjin 300071China

Aqueous zinc-ion batteries(AZIBs)as green battery systems have attracted widespread attention in large-scale electrochemical energy storage devices,owing to their high safety,abundant Zn materials,high theoretica specific capacity and low redox *** there are some thorny issues in AZIBs that hinder their practical application,such as low intrinsic electron conductivity,slow ion migration kinetics,zinc dendrites and side ***-based materials with superior conductivity,large polar surface and abundant active sites can simultaneously serve as cathode materials,electrolyte additive and protection layer of anode to regulate redox reactions of *** various materials have been used to improve electrochemical performances of AZIBs there is a lack of in-depth discussion on the regulation mechanism of MXene-based materials for *** this review,we elaborate the research progress of MXenebased materials in AZIBs,including their application in cathode materials and inhibition of zinc *** the future prospects and development directions of MXenebased materials that may improve performance of AZIBs are prospected.

关键词： MXene Aqueous zinc-ion batteries Composite materials Zinc dendrites

Research on casing deformation prevention technology based on cementing slurry system optimization

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Petroleum Science 2024年第2期21卷 1231-1240页

作者： yan yan meng Cai Wen-Hai Ma Xiao-Chuan Zhang Li-Hong Han Yong-Hong Liu State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials CNPC Tubular Goods Research InstituteXi©an710077ShaanxiChina College of Mechanical and Electrical Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Gas Evaluation and Exploitation Key Laboratory of Sichuan Province Chengdu610095SichuanChina CNPC Daqing Oilfield Company Daqing163453HeilongjiangChina

The casing deformation prevention technology based on the optimization of cement slurry is proposed to reduce the casing deformation of shale oil and gas wells during hydraulic fracturing. In this paper, the fracture mechanism of hollow particles in cement sheath was firstly analyzed by discrete element method, and the effect of hollow particles in cement on casing deformation was investigated by laboratory experiment method. Finally, field test was carried out to verify the improvement effect of the casing deformation based on cement slurry modification. The results show that the formation displacement can be absorbed effectively by hollow particles inside the cement transferring the excessive deformation away from casing. The particles in the uncemented state provide deformation space during formation slipping. The casing with diameter of 139.7 mm could be passed through by bridge plug with the diameter of 99 mm when the mass ratio of particle/cement reaches 1:4. According to the field test feedback, the method based on optimization of cement slurry can effectively reduce the risk of casing deformation, and the recommended range of hollow microbeads content in the cement slurry is between 15% and 25%.

关键词： Cement slurry Hollow ceramsite Casing deformation Formation slip Field test

Exploring the transformative impact of traditional Chinese medicine on depression:Insights from animal models

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World Journal of Psychiatry 2024年第5期14卷 607-623页

作者： yan Yang yan-Kun Chen meng-Zhou Xie School of Nursing Hunan University of Chinese MedicineChangsha 410200Hunan ProvinceChina Precision Medicine R&D Center Zhuhai Institute of Advanced TechnologyChinese Academy of SciencesZhuhai 519000Guangdong ProvinceChina School of Chinese Medicine Hunan University of Chinese MedicineChangsha 410200Hunan ProvinceChina Hunan Engineering Technology Research Center for Medicinal and Functional Food Hunan University of Chinese MedicineChangsha 410200Hunan ProvinceChina Key Laboratory of TCM Heart and Lung Syndrome Differentiation and Medicated Diet and Dietotherapy Hunan University of Chinese MedicineChangsha 410200Hunan ProvinceChina

Depression,a prevalent and complex mental health condition,presents a significant global health *** is one of the most frequent mental disorders;deaths from it account for 14.3%of people *** recent years,the integration of complementary and alternative medicine,including traditional Chinese medicine(TCM),has gained attention as a potential avenue for addressing *** comprehensive review critically assesses the efficacy of TCM interventions in alleviating depressive *** in-depth look at different research studies,clinical trials,and meta-analyses is used in this review to look into how TCM practices like herbal formulations,acupuncture,and mindbody practices *** review looks at the quality of the evidence,the rigor of the methods,and any possible flaws in the current *** gives us an idea of where TCM stands right now in terms of treating *** comprehensive review aims to assess the efficacy of TCM interventions in alleviating depressive *** order to learn more about their possible healing effects,the study also looks into how different types of TCM work,such as herbal formulas,acupuncture,and mind-body practices.

关键词： Traditional Chinese medicine Depression Efficacy Treatment Holistic approach

Predicting submerged vegetation drag with a machine learning-based method

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Journal of Hydrodynamics 2024年第3期36卷 534-545页

作者： meng-yang Liu Hong-wu Tang Sai-yu Yuan Jing yan College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China Key Laboratory of Hydrologic-Cycle and Hydrodynamic-System of Ministry of Water Resources Hohai UniversityNanjing210098China

Accurate estimation of the drag forces generated by vegetation stems is crucial for the comprehensive assessment of the impact of aquatic vegetation on hydrodynamic processes in aquatic *** coupling relationship between vegetation layer flow velocity and vegetation drag makes precise prediction of submerged vegetation drag forces particularly *** present study utilized published data on submerged vegetation drag force measurements and employed a genetic programming(GP)algorithm,a machine learning technique,to establish the connection between submerged vegetation drag forces and flow and vegetation *** using the bulk velocity,U,as the reference velocity scale to define the drag coefficient,C_(d),and stem Reynolds number,the GP runs revealed that the drag coefficient of submerged vegetation is related to submergence ratio(H^(*)),aspect ratio(d^(*)),blockage ratio(ψ^(*)),and vegetation density(λ).The relation between vegetation stem drag forces and flow velocity is implicitly embedded in the definition of C_(d).Comparisons with experimental drag force measurements indicate that using the bulk velocity as the reference velocity,as opposed to using the vegetation layer average velocity,U_(v),eliminates the need for complex iterative processes to estimate U_(v)and avoids introducing additional errors associated with U_(v)*** approach significantly enhances the model’s predictive capabilities and results in a simpler and more user-friendly formula expression.

关键词： Drag coefficient genetic programming algorithm submerged vegetation flow resistance cylinder array

Warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography

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Defence Technology（防务技术） 2024年第7期37卷 162-172页

作者： Pengyu Hu Jiangpeng Wu Zhengang yan meng He Chao Liang Hao Bai Xi'an Modern Control Technology Research Institute Xi'an710065China Xi'an OET Science and Technology Co. LtdXi'an710076China

High speed photography technique is potentially the most effective way to measure the motion parameter of warhead fragment benefiting from its advantages of high accuracy,high resolution and high ***,it faces challenge in dense objects tracking and 3D trajectories reconstruction due to the characteristics of small size and dense distribution of fragment *** address these challenges,this work presents a warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo ***,background difference algorithm is utilized to extract the center and area of each fragment in the image ***,a multi-object tracking(MOT)algorithm using Kalman filtering and Hungarian optimal assignment is developed to realize real-time and robust trajectories tracking of fragment *** reconstruct 3D motion trajectories,a global stereo trajectories matching strategy is presented,which takes advantages of epipolar constraint and continuity constraint to correctly retrieve stereo correspondence followed by 3D trajectories refinement using polynomial ***,the simulation and experimental results demonstrate that the proposed method can accurately track the motion trajectories and reconstruct the spatio-temporal distribution of 1.0×10^(3)fragments in a field of view(FOV)of 3.2 m×2.5 m,and the accuracy of the velocity estimation can achieve 98.6%.

关键词： Warhead fragment measurement High speed photography Stereo vision Multi-object tracking Spatio-temporal reconstruction