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Novel concept of nano-additive design:PTFE@silica Janus nanoparticles for water lubrication

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Friction 2024年第2期12卷 258-270页

作者： Yanfei LIU Hailing HE Meng yang Ruize ZHANG Shengtao YU Tiantian yang Wenzhong WANG Fuxin LIANG School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Institute of Polymer Science&Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China MOE Key Laboratory of Bioinformatics Center for Plant BiologySchool of Life SciencesTsinghua UniversityBeijing 100084China Tsinghua-Peking Center for Life Sciences Beijing 100084China College of Biological Sciences China Agricultural UniversityBeijing 100193China

Polytetrafluoroethylene(PTFE)has been widely used as a lubrication additive for reducing friction and wear;however,the hydrophobic nature of PTFE restricts its application in eco-friendly water-based lubrication *** this study,for the first time,we designed novel PTFE@silica Janus nanoparticles(JNs)to meet the requirement for additives in water-based lubricants,which have excellent dispersion stability in water attributed to the unique amphiphilic *** introducing the lubrication of the aqueous dispersion of the JNs with a concentration of 0.5 wt%,the coefficient of friction(COF)and wear volume were reduced by 63.8%and 94.2%,respectively,comparing to those with the lubrication of pure ***,the JNs suspension also exhibits better lubrication and wear-resistance performances comparing to commercial silica and PTFE *** excellent tribological behaviors of PTFE@silica JNs as nano-additives could be attributed to the synergetic effect of the two components,where the PTFE provided lubrication through the formed tribofilms on the friction pairs,and the rigid silica further enhanced the wear-resistance *** importantly,the unique structure of JNs makes it possible to use PTFE as an additive in water-lubrication *** study shed light on the design and application of novel JNs nanomaterials as additives to meet the requirements of future industrial applications.

关键词： Janus nanoparticles(JNs) polytetrafluoroethylene(PTFE) nano-additives friction lubrication

Dynamic recrystallization behavior and strengthening mechanism of a novel Mo-Ti_(3)AlC_(2) alloy at ultrahigh temperature

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Rare Metals 2024年第8期43卷 3946-3960页

作者： Lu yang Xin-Yuan Zheng yang Zhao Xi-Ran Wang Fang-Nao Xiao Shi-Zhong Wei School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials Henan University of Science and TechnologyLuoyang 471003China Department of Applied Mechanics Univ.Bourgogne FrancheComteFEMTO-ST InstituteCNRS/UF/ENSMM/UTBM25000BesangonFrance

Increasing the recrystallization temperature to achieve better high-temperature performance is critical in the development of molybdenum alloys for ultrahightemperature applications,such as the newest generation of multitype high-temperature nuclear *** this study,an innovative strategy was proposed to improve the performance of molybdenum alloys at high temperature by using the two-dimensional MAX(where M is an early transition metal,A is an A-group element and X is C or N)ceramic material Ti_(3)AlC_(2).The relationships between flow stress,strain rate and temperature were *** microstructure,distribution of misorientation and evolution of dislocations in the Mo-Ti_(3)AlC_(2) alloy were *** microscopic mechanism of the Ti_(3)AlC_(2) phase in the molybdenum alloy at high temperatures was *** experimental results showed that the peak flow stress of Mo-Ti_(3)AlC_(2) at 1600℃ reached 155 MPa,which was161.8% greater than that of pure *** activation energy of thermal deformation of Mo-Ti_(3)AlC_(2) was as large as537 kJ·mol~(-1),which was 17.6% more than that of pure *** recrystallization temperature reached 1600℃ or even *** topological reaction of the Ti_(3)AlC_(2) phase consumed a large amount of energy at high temperatures,resulting in increases in the deformation activation *** structures of AlTi_3 and Ti-O Magneli-phase oxides(Ti_nO_(2n-1)) were formed in-situ,which relied on kink bands and interlayer slip,resulting in many dislocations during ***,the special two-dimensional of the structure Ti_(3)AlC_(2) ceramic inhibited the recrystallization behavior of the Mo *** results of this study can provide theoretical guidance for the development of a new generation of molybdenum alloys for use in ultrahigh-temperature environments.

关键词： Mo alloy Two-dimensional reinforcement Dynamic recrystallization behavior Hot deformation Mechanical properties

Built defects of homogeneous junction to enhance the lithium storage capacity of niobium pentoxide materials

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Journal of Energy Chemistry 2024年第5期92卷 730-737页

作者： Huibin Ding yang Luo Zihan Song Cong Chen Kai Feng Xiaofei yang Hongzhang Zhang Xianfeng Li Division of Energy Storage National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina University of Chinese Academy of Sciences Beijing 100049China College of Chemistry&Engineering Yantai UniversityYantai 264005ShandongChina

Niobium pentoxide(Nb_(2)O_(5))is deemed one of the promising anode materials for lithium-ion batteries(LIBs)for its outstanding intrinsic fast Li-(de)intercalation *** specific capacity,however,is still limited,because the(de)intercalation of excessive Li-ions brings the undesired stress to damage Nb_(2)O_(5) *** increase the capacity of Nb_(2)O_(5) and alleviate the lattice distortion caused by stress,numerous homogeneous H-and M-phases junction interfaces were proposed to produce coercive stress within theNb_(2)O_(5)*** interfaces bring about rich oxygen vacancies with structural shrinkage tendency,which pre-generate coercive stress to resist the expansion stress caused by excessive Li-ions ***,the synthesized Nb_(2)O_(5) achieves the highest lithium storage capacity of 315 mA h g−1 to date,and exhibits high-rate performance(118 mA h g^(-1) at 20 C)as well as excellent cycling stability(138 mA h g^(-1) at 10 C after 600 cycles).

关键词： Niobiumpent oxide Homojunction polycrystalline Defects Oxygen vacancy

Stress-assisted corrosion mechanism of 3Ni steel by using gradient boosting decision tree machining learning method

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1311-1321页

作者： Xiaojia yang Jinghuan Jia Qing Li Renzheng Zhu Jike yang Zhiyong Liu Xuequn Cheng Xiaogang Li Institute of Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China AECC Key Laboratory of Advanced Corrosion and Protection of Aeronautical Materials AECC Beijing Institute of Aeronautical MaterialsBeijing 100095China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China

Traditional 3Ni weathering steel cannot completely meet the requirements for offshore engineering development,resulting in the design of novel 3Ni steel with the addition of microalloy elements such as Mn or Nb for strength enhancement becoming a *** stress-assisted corrosion behavior of a novel designed high-strength 3Ni steel was investigated in the current study using the corrosion big data *** information on the corrosion process was recorded using the galvanic corrosion current monitoring *** gradi-ent boosting decision tree(GBDT)machine learning method was used to mine the corrosion mechanism,and the importance of the struc-ture factor was *** exposure tests were conducted to verify the calculated results using the GBDT *** indic-ated that the GBDT method can be effectively used to study the influence of structural factors on the corrosion process of 3Ni ***-ferent mechanisms for the addition of Mn and Cu to the stress-assisted corrosion of 3Ni steel suggested that Mn and Cu have no obvious effect on the corrosion rate of non-stressed 3Ni steel during the early stage of *** the corrosion reached a stable state,the in-crease in Mn element content increased the corrosion rate of 3Ni steel,while Cu reduced this *** the presence of stress,the increase in Mn element content and Cu addition can inhibit the corrosion *** corrosion law of outdoor-exposed 3Ni steel is consistent with the law based on corrosion big data technology,verifying the reliability of the big data evaluation method and data prediction model selection.

关键词： weathering steel stress-assisted corrosion gradient boosting decision tree machining learning

Self-derivation and reconstruction of silver nanoparticle reinforced cobalt-nickel bimetallic hydroxides through interface engineering for overall water splitting

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Journal of Energy Chemistry 2024年第3期90卷 590-599,I0013页

作者： Yan Li Jie Han Weiwei Bao Junjun Zhang Taotao Ai Mameng yang Chunming yang Pengfei Zhang National and Local Joint Engineering Laboratory for Slag Comprehensive Utilization and Environmental Technology School of Materials Science and EngineeringShaanxi University of TechnologyHanzhong 723000ShaanxiChina State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering College of Chemistry&Chemical EngineeringNingxia UniversityYinchuan 750021NingxiaChina College of Chemistry&Chemical Engineering Yan’an UniversityYan’an 716000ShaanxiChina School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Designing efficient and long-lasting non-metal electrocatalysts is an urgent task for addressing the issue of kinetic hysteresis in electrochemical oxidation *** bimetallic hydroxides,catalyzing the oxygen evolution reaction(OER),have significant research potential because hydroxide reconstruction to generate an active phase is a remarkable ***,the complete reconstruction of ultrathin CoNi(OH)_(2) nanosheets was achieved by embedding Ag nanoparticles into the hydroxide to induce a spontaneous redox reaction(SRR),forming heterojunction Ag@CoNi(OH)_(2) for bifunctional *** calculations and in situ Raman and ex situ characterizations revealed that the inductive effect of the Ag cation redistributed the charge to promote phase transformation to highly activate Ag-modified *** Co-Ni dual sites in Co/NiOOH serve as novel active sites for optimizing the intermediates,thereby weakening the barrier formed by OOH^*.Ag@CoNi(OH)_(2) required a potential of 1.55 V to drive water splitting at a current density of 10 mA cm^(-2),with nearly 98.6% Faraday *** ion induction and triggering of electron regulation in the OER via the synergistic action of the heterogeneous interface and surface reconstruction,this strategic design can overcome the limited capacity of bimetallic hydroxides and bridge the gap between the basic theory and industrialization of water decomposition.

关键词： Surface reconstruction Bimetallic hydroxides Ag nanoparticle Operando Raman Overall water splitting

Mechanically driven assembly of biomimetic 2D-material microtextures with bioinspired multifunctionality

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Nano Research 2024年第2期17卷 663-678页

作者： yang Li Lin Jing Joshua M.Little Haochen yang Tsai-Chun Chung Po-Yen Chen Department of Chemical and Biomolecular Engineering University of MarylandCollege ParkMD 20740USA Maryland Robotics Center University of MarylandCollege ParkMD 20742USA School of Materials Science and Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

Nature provides a wealth of bio-inspiration for advanced material *** various nanomaterials into biomimetic microtextures with bioinspired functionalities has spurred increasing research interests and facilitated technological advances in various *** recent years,two-dimensional materials(2DMs)have emerged as important building block units in the biomimicry field due to their distinct chemical,physical,electrical,electrochemical,and catalytic *** this review article,various mechanically driven assembly approaches are summarized to fabricate various genealogies of biomimetic 2DM microtextures with bio-inspired ***,sequential deformation strategies are discussed to programmably construct higher dimensional 2DM microtextures,ranging from wrinkles/crumples(one-time deformation)to multiscale hierarchies(multiple deformations).Next,the current progress using higher dimensional 2DM microtextures to imitate different biological structures and/or induce bio-inspired multifunctionality is systematically *** showcases of bio-inspiration and biomimicry using different 2DM nanosheets are highlighted:(1)wrinkle patterns of an earthworm that spur the design of strain sensors with programmable working ranges and sensitivities,(2)wrinkle appearance of a Shar-Pei dog that motivates the fabrication of stretchable energy storage devices,(3)hierarchical scale textures of a desert lizard that inspire cation-induced gelation platforms for 2DM aerogels,and(4)wrinkle skin of an elephant that influences the development of 2DM protective skin for soft ***,challenges and future opportunities of adopting 2DM nanosheets to assemble biomimetic microstructures with synergistic functionalities are discussed.

关键词： two-dimensional(2D)materials mechanically driven assembly biomimetic microtextures functional nanocomposite bio-inspired multifunctionality

From common biomass materials to high-performance tissue engineering scaffold: Biomimetic preparation, properties characterization, in vitro and in vivo evaluations

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Journal of Bioresources and Bioproducts 2024年第2期9卷 185-196页

作者： Zongpu Xu Fang He Jing Yu Zhangze yang Yu Zhu Rong Liao Ruyin Lyu Mei yang Liangjun Zhu Mingying yang Institute of Applied Bioresources College of Animal SciencesZhejiang UniversityHangzhou 310058China Key Laboratory of Silkworm and Bee Resource Utilization and Innovation of Zhejiang Province Zhejiang UniversityHangzhou 310058China Department of Neurosurgery the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China

Converting common biomass materials to high-performance biomedical products could not only reduce the environmental pressure associated with the large-scale use of synthetic materials,but also increase the economic *** as a very promising candidate has drawn considerable attention owing to its abundant sources and remarkable ***,pure chitosan materials usually exhibit insufficient mechanical properties and excessive swelling ratio,which seriously affected their in vivo stability and integrity when applied as tissue engineering ***,simultaneously improving the mechanical strength and biological compatibility of pure chitosan(CS)scaffolds becomes very ***,inspired by the fiber-reinforced con-struction of natural extracellular matrix and the porous structure of cancellous bone,we built silk microfibers/chitosan composite scaffolds via ice-templating *** biomimetic strategy achieved 500%of mechanical improvement to pure chitosan,and meanwhile still maintaining high porosity(>87%).In addition,the increased roughness of chitosan pore walls by embedded silk microfibers significantly promoted cell adhesion and *** importantly,after subcutaneous implantation in mice for four weeks,the composite scaffold showed greater struc-tural integrity,as well as better collagenation,angiogenesis,and osteogenesis abilities,suggesting its great potential in biomedicine.

关键词： Chitosan Biomimetic strategy Fiber-reinforced composite Mechanical property Biocompatibility

Flow Loss Mechanism in a Supercritical Carbon Dioxide Centrifugal Compressor at Low Flow Rate Conditions

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Journal of Thermal Science 2024年第1期33卷 114-125页

作者： yang Zimu JIANG Hongsheng ZHUGE Weilin CAI Ruikai yang Mingyang CHEN Haoxiang QIAN Yuping ZHANG yangjun State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

With the advantages of high efficiency and compact structure,supercritical carbon dioxide(sC02)Brayton cycles have bright prospects for development in energy conversion *** one of the core components of the power cycle,the centrifugal compressor tends to operate near the critical point(304.13 K,7.3773 MPa).Normally,the compressor efficiency increases as the inlet temperature *** the inlet temperature is close to the critical point,the density increases sharply as the temperature decreases,which results in quickly decreasing of volume flow rate and efficiency *** flow loss mechanism of the sCO_(2) compressor operating at low flow rate is studied in this *** fluid dynamics(CFD) simulations for sCO_(2)compressor were carried out at various inlet temperatures and various mass flow *** the sCO_(2)compressor operates at low volume flow rate,the flow loss is generated mainly on the suction side near the trailing edge of the *** flow loss is related to the counterclockwise vortexes generated on the suction side of the main *** vortexes are caused by the flow separation in the downstream region of the impeller passage,which is different from air compressors operating at low flow *** reason for this flow separation is that the effect of Coriolis force is especially severe for the sCO_(2) fluid,compared to the viscous force and inertial *** lower flow rates,with the stronger effect of Coriolis force,the direction of relative flow velocity deviates from the direction of radius,resulting in its lower radial *** lower radial relative flow velocity leads to severe flow separation on the suction side near the trailing edge of the main blade.

关键词： supercritical CO_(2) centrifugal compressor flow loss mechanism Coriolis force

Photochemical Production of Methyl Halides with Guaiacol as the Precursor

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Journal of Ocean University of China 2024年第5期23卷 1275-1286页

作者： yang Fan ZHANG Yan WU Guanyu HE Zhen yang Guipeng Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Laboratory of Marine Chemistry Theory and TechnologyMinistry of EducationOcean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Qingdao Marine Science and Technology CenterQingdao 266237China Institute of Marine Chemistry Ocean University of ChinaQingdao 266100China

Methyl halides are crucial trace greenhouse gases in the atmosphere,playing a significant role in global climate change and the atmospheric *** study investigated the photochemical production of methyl halides in an artificial seawater system using guaiacol as a precursor through laboratory simulation *** influences of various environmental factors,including illumination time,radiation wavebands,illumination intensity,concentrations of guaiacol and halide ions(X^(-)),Fe^(3+),salinity,dissolved oxygen(DO),and pH value on the photochemical production of methyl halides were *** demonstrated that increased illumination intensity and duration promote the photochemical production of methyl halides,with a notable enhancement under UV-B *** and halide ions were identified as key precursors,and their high concentrations facilitated the formation of methyl ***,different types of halide ions exhibited a competitive relationship in producing methyl *** study found that an increase in pH inhibited the photochemical formation of CH_(3)I due to the reaction between OH^(-)and·CH_(3).Dissolved oxygen was found to inhibit the photochemical formation of CH3I while promoting the formation of CH_(3)***,an appropriate concentration of Fe^(3+)enhanced the photochemical production of methyl *** observations indicated a high photochemical production of methyl halides in the natural waters near Qingdao’s coastal area,likely due to the high concentration of dissolved organic matter(DOM),which supports photochemical ***,the photochemical production of methyl halides in natural seawater was significantly higher than in dark conditions,underscoring the importance of illumination in promoting these photochemical processes in seawater.

关键词： methyl halides photochemical production dissolved organic matter guaiacol