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Study on the tribological properties of metal rolling bearing under lubrication with diketone lubricants

Science China(Technological Sciences) 2024年第7期67卷 2003-2017页

作者： DU ShaoNan zhang ChenHui LUO zhi State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Beijing National Laboratory of Molecular Sciences CAS Key Laboratory of Engineering PlasticsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

In this article, 1-(4-ethylphenyl)-nonane-1,3-dione(0206) was prepared by Claisen condensation. By mixing 0206, chelate, and base oil in a ratio of 3.2:4.8:2, a diketone lubricant(PAO=14(20%)) that can achieve superlubricity was prepared and applied to bearing lubrication experiments. The experimental results show that when the bearing was lubricated by base oil, the friction coefficient(COF) and temperature rise decreased with the decrease of the viscosity of PAO. When PAO=14(20%) was used as the lubricant, the COF of the bearing was the lowest(0.001), and the wear morphology was comparable to that of the bearing lubricated with commercial lubricant. Compared with the base oil with the same viscosity, it is found that the COF and temperature rise of the bearing lubricated by PAO=14(20%) were lower under any experimental conditions. And when the amount of lubricant added was 10 μL, the COF of the bearing lubricated by PAO=14(20%) reached a very low value(0.0004).Bearing ball surface analysis identified the formation of diketone adsorption films. Combined with the previous PAO=14(20%)superlubricity mechanism, it was considered that the occurrence of tribochemical reaction and the bearing effect of chelates were the main reasons for the existence of ultra-low friction coefficient and low wear. In addition, when there were polar molecules in the lubricant, they were adsorbed on the metal surface through tribochemical reactions, resulting in many irregular pits on the surface.

关键词： superlubricity diketone chelate tribochemical recations bearing lubrication

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A lithium–tin fluoride anode enabled by ionic/electronic conductive paths for garnet-based solid-state lithium metal batteries

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Rare Metals 2024年第2期43卷 575-587页

作者： Lei zhang Qian-Kun meng Xiang-Ping Feng Ming Shen Yu-Qing zhang Quan-Chao Zhuang Run-Guo Zheng zhi-Yuan Wang Yan-Hua Cui Hong-Yu Sun Yan-Guo Liu School of Materials Science and Engineering Northeastern UniversityShenyang110819China School of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao066004China School of Materials and Physics China University of Mining&TechnologyXuzhou221116China Institute of Electronic Engineering China Academy of Engineering PhysicsMianyang621900China

The high energy density and stability of solid-state lithium metal batteries(SSLMBs)have garnered great ***-type oxides,especially Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO),with high ionic conductivity,wide electrochemical window,and stability to Li metal anode,are promising solid-state electrolyte(SSEs)materials for ***,Li/LLZTO interface issues including high interface resistance,inhomogeneous Li deposition,and Li dendrite growth have hindered the practical application of ***,a multi-functional Li–SnF_(2) composite anode with Li,LiF,and Li-Sn alloy was specifically designed and *** composite anode improves the wettability to LLZTO,constructing an intimate contact interface between it and ***,ionic/electronic conductive paths in situ formed at the interface can effectively uniform Li deposition and suppress Li *** solid-state symmetric cell exhibits low interface resistance(11Ω·cm^(2)) and high critical current density(1.3 mA·cm^(−2))at 25℃.The full SSLMB based on LiFePO_(4) or LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode also shows stable cycling performance and high rate *** work provides a new composite anode strategy for achieving high-energy density and high-safety SSLMBs.

关键词： Solid-state lithium metal batteries(SSLMBs) Lithium-tin fluoride anode Ionic/electronic conductive Interface resistance Lithium dendrite

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Towards designing high mechanical performance low-alloyed wrought magnesium alloys via grain boundary segregation strategy:A review

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Journal of Magnesium and Alloys 2024年第5期12卷 1774-1791页

作者： zhi zhang Jinshu Xie Jinghuai zhang Xu-Sheng Yang Ruizhi Wu Key Laboratory of Superlight Material and Surface Technology Ministry of EducationCollege of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China State Key Laboratory of Ultra-Precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518060China

Low-alloyed magnesium(Mg)alloys have emerged as one of the most promising candidates for lightweight ***,their further application potential has been hampered by limitations such as low strength,poor plasticity at room temperature,and unsatisfactory *** address these challenges,grain refinement and grain structure control have been identified as crucial factors to achieving high performance in low-alloyed Mg *** effective way for regulating grain structure is through grain boundary(GB)*** review presents a comprehensive summary of the distribution criteria of segregated atoms and the effects of solute segregation on grain size and growth in Mg *** analysis encompasses both single element segregation and multi-element co-segregation behavior,considering coherent interfaces and incoherent ***,we introduce the high mechanical performance low-alloyed wrought Mg alloys that utilize GB segregation and analyze the potential impact mechanisms through which GB segregation influences materials *** upon these studies,we propose strategies for the design of high mechanical performance Mg alloys with desirable properties,including high strength,excellent ductility,and good formability,achieved through the implementation of GB *** findings of this review contribute to advancing the understanding of grain boundary engineering in Mg alloys and provide valuable insights for future alloy design and optimization.

关键词： Magnesium alloys Grain boundary segregation High strength High plasticity High formability

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The connection of phytoplankton biomass in the Marguerite Bay polynya of the western Antarctic Peninsula to the Southern Annular Mode

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Acta Oceanologica Sinica 2024年第1期43卷 35-47页

作者： Ning Jiang Zhaoru zhang Ruifeng zhang Chuning Wang meng Zhou School of Oceanography Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory for Polar Science Polar Research Institute of ChinaMinistry of Natural ResourcesShanghai 200136China

Antarctic coastal polynyas are biological hotspots in the Southern Ocean that support the abundance of hightrophic-level predators and are important for carbon cycling in the high-latitude *** this study,we examined the interannual variation of summertime phytoplankton biomass in the Marguerite Bay polynya(MBP)in the western Antarctic Peninsula area,and linked such variability to the Southern Annular Mode(SAM)that dominated the southern hemisphere extratropical climate *** satellite data,atmosphere reanalysis products and numerical simulations,we found that the interannual variation of summer chlorophyll-a(Chl-a)concentration in the MBP is significantly and negatively correlated with the spring SAM index,and weakly correlated with the summer SAM *** negative relation between summer Chl-a and spring SAM is due to weaker spring vertical mixing under a more positive SAM condition,which would inhibit the supply of iron from deep layers into the surface euphotic *** negative relation between spring mixing and spring SAM results from greater precipitation rate over the MBP region in positive SAM phase,which leads to lower salinity in the ocean surface *** coupled physical-biological mechanisms between SAM and phytoplankton biomass revealed in this study is important for us to predict the future variations of phytoplankton biomasses in Antarctic polynyas under climate change.

关键词： Marguerite Bay polynya phytoplankton biomass Southern Annular Mode mixed layer depth interannual variation

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Output Feedback Stabilization of High-Order Nonlinear Time-Delay Systems With Low-Order and High-Order Nonlinearities

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1304-1306页

作者： meng-meng Jiang Kemei zhang Xue-Jun Xie School of Mathematics Science Liaocheng UniversityLiaocheng 252059China School of Mathematics Science Qufu Normal UniversityQufu 273165China Institute of Automation Qufu Normal UniversityQufu 273165China

Dear Editor,to This letter deals with the output feedback stabilization of a class of high-order nonlinear time-delay systems with more general low-order and high-order *** constructing reduced-order observer,based on homogeneous domination theory together with the adding a power integrator method,an output feedback controller is developed guarantee the equilibrium of the closed system globally uniformly asymptotically stable.

关键词： Nonlinear stabilization guarantee

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Failure characteristics and fracture mechanism of overburden rock induced by mining:A case study in China

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International Journal of Coal Science & Technology 2024年第3期11卷 241-255页

作者： Jiawei Li meng zhang Changxiang Wang Changlong Liao Baoliang zhang Department of Energy and Power Engineering College of Mechanical and Transportation EngineeringChina University of Petroleum(Beijing)BeijingChina Department of Energy and Power Engineering Tsinghua UniversityBeijingChina College of Safety Science and Engineering Anhui University of Science and TechnologyHuainan232000China School of Architecture and Civil Engineering Liaocheng UniversityLiaocheng252000China

This study employs similar simulation testing and discrete element simulation coupling to analyze the failure and deformation processes of a model coal seam's *** caving area of the overburden rock is divided into three zones:the delamination fracture zone,broken fracture zone,and compaction *** caving and fracture zones'heights are approximately 110 m above the coal seam,with a maximum subsidence of 11 *** delamination fracture zone's porosity range is between 0.2 and 0.3,while the remainder of the roof predominantly exhibits a porosity of less than *** addition,the numerical model's stress analysis revealed that the overburden rock's displacement zone forms an'arch-beam'structure starting from 160 m,with the maximum and minimum stress values decreasing as the distance of advancement *** the stress beam interval of the overburden rock,the maximum value changes periodically as the advancement distance *** on a comparative analysis between observable data from on-site work and numerical simulation results,the stress data from the numerical simulation are essentially consistent with the actual results detected on-site,indicating the validity of the numerical simulation results.

关键词： Fracture development characteristics Similar simulation experiment Layer porosity Discrete element numerical simulation

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Enhanced photocatalytic performance by regulating the Ce^(3+)/Ce^(4+)ratio in cerium dioxide

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 75-87页

作者： zhi Li Dongsheng Jia Wei zhang Ying Li Mitang Wang Dongliang zhang School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai200093China

Cerium dioxide(CeO_(2))photocatalysts are used in treating environmental pollution and addressing the energy crisis due to their excellent oxygen storage capacities and abundant oxygen *** this paper,CeO_(2)precursors were synthesized with different water-alcohol ratios via a solvothermal method,and CeO_(2)photocatalysts with different Ce^(3+)/Ce^(4+)ratios were obtained by changing the precursor calcination atmospheres(air,Ar)as well as the calcination *** effects of CeO_(2)with different Ce^(3+)/Ce^(4+)ratios in photocatalytic degradations of methylene blue under visible light were investigated.X-ray photoelectron spectroscopy results showed that the surfaces of the samples calcined under Ar had higher Ce^(3+)/Ce^(4+)ratios and oxygen vacancy concentrations,which reduced the band gaps of the catalysts and improved their utilization of visible *** addition,the many Ce^(3+)/Ce^(4+)redox centers and oxygen vacancies on the sample surfaces improved the separation and transfer efficiencies of the photogenerated *** sample C2-Ar calcined under Ar showed a high adsorption capacity and excellent photocatalytic activity by removing 96%of the methylene blue within 120 min,which was more than twice the degradation rate of the sample(C2-air)prepared via calcination under *** experiments showed that photogenerated holes played a key role in the photocatalytic *** addition,a synergistic photocatalytic mechanism for the Ce^(3+)/Ce^(4+)redox centers and oxygen vacancies was elucidated in detail,and the sensitization of cerium dioxide by dyes aided the degradation of methylene blue.

关键词： CeO_(2) oxygen vacancies Ce^(3+)/Ce^(4+)ratios photocatalytic dye-sensitization

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Enrichment and reconfiguration of titanium-bearing phase in vortex smelting reduction process of vanadium-titanium magnetite

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Journal of Iron and Steel Research(International) 2024年第7期31卷 1582-1589页

作者： Yong-chao Han zhi-he Dou Rui zhang Ting-an zhang Shuai Fang Key Laboratory for Ecological Metallurgy of Multimetallic Ores(Ministry of Education) Shenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

To comprehensively utilize the low-iron high-vanadium-titanium magnetite,a new method of vortex smelting reduction of vanadium-titanium magnetite was proposed,and the enrichment and reconstitution regularity of Ti-bearing phases in the slag was investigated through X-ray fluorescence spectrometry,X-ray photoelectron spectroscopy,X-ray diffraction analysis,and optical *** phase diagram revealed that the preferential crystallization of MgTi_(2)O_(5) can be achieved by adjusting the CaO,MgO,and TiO_(2) contents of *** predominant Ti-bearing phases in the slag obtained from the reduction process are MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3).FeTiO_(3) is present at carbon-iron ratio(CR)=1.3,while MgTi_(2)O4 and TiC are formed at CR=*** enrichment of TiO_(2) in the slag increases first and then decreases as the CR increases,and at CR=1.1,the enrichment of TiO_(2) in the slag reaches 51.3 wt.%.Additionally,the concentrations of MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3) in the slag,along with the grain width of MgxTi_(3_x)O_(5)(0≤x≤1),decrease with the increase in CR.

关键词： Vanadium-titanium magnetite Vortex smelting reduction Phase reconfiguration TiO_(2)enrichment

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Intermittent disturbance mechanical behavior and fractional deterioration mechanical model of rock under complex true triaxial stress paths

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International Journal of Mining Science and Technology 2024年第1期34卷 117-136页

作者： zhi Zheng Hongyu Xu Kai zhang Guangliang Feng Qiang zhang Yufei Zhao State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100080China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensional high-stress and even causing ***,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is *** triaxial static compression and intermittent disturbance tests are carried out on *** effects of intermediate principal stress and amplitude on the strength characteristics,deformation characteristics,failure characteristics,and precursors of monzogabbro are analyzed,intermediate principal stress and amplitude increase monzogabbro strength and tensile fracture *** increases in microseismic parameters during rock loading can be precursors for intermittent rock *** on the experimental result,the new damage fractional elements and method with considering crack initiation stress and crack unstable stress as initiation and acceleration condition of intermittent disturbance irreversible deformation are proposed.A novel three-dimensional disturbance fractional deterioration model considering the intermediate principal stress effect and intermittent disturbance damage effect is established,and the model predicted results align well with the experimental *** sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are *** study provides valuable theoretical bases for the stability analysis of deep mining engineering under dynamic loads.

关键词： True triaxial static and disturbance test Mechanical properties Failure mechanism and precursor Intermittent disturbance effect Fractional mechanical model

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Insight into structure evolution of carbon nitrides and its energy conversion as luminescence

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Carbon Energy 2024年第2期6卷 37-60页

作者： Hao zhang Jingwei zhang Wenjie Chen Minjia Tao Xianguang meng Yuanjian zhang Guifu Zuo Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials College of Materials Science and EngineeringNorth China University of Science and TechnologyTangshanHebeiChina College of Clinical Medicine North China University of Science and TechnologyTangshanHebeiChina Hebei Iron and Steel Laboratory TangshanHebeiChina Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical ResearchState Key Laboratory of BioelectronicsSchool of Chemistry and Chemical EngineeringMedical SchoolSoutheast UniversityNanjingJiangsuChina

A series of carbon nitride(CN)materials represented by graphitic carbon nitride(g-C_(3)N_(4))have been widely used in bioimaging,biosensing,and other fields in recent years due to their nontoxicity,low cost,and high luminescent quantum *** is more attractive is that the luminescent properties such as wavelength and intensity can be regulated by controlling the structure at the molecular ***,it is time to summarize the related research on CN structural evolution and make a prospect on future *** this review,we first summarize the research history and multiple structural evolution of ***,the progress of improving the luminescence performance of CN through structural evolution was ***,the relationship between CN structure evolution and energy conversion in the forms of photoluminescence,chemiluminescence,and electrochemiluminescence was ***,key challenges and opportunities such as nanoscale dispersion strategy,luminous efficiency improving methods,standardization evaluation,and macroscopic preparation of CN are highlighted.

关键词： carbon nitride chemiluminescence electrochemiluminescence energy conversion photoluminescence structural evolution

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