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Achieving ultrafast superlubricity with layered double hydroxides

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Nano Research 2023年第5期16卷 6940-6950页

作者： Kunpeng wang Yuhong Liu hongdong wang Jianbin Luo State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechatronic Engineering Shanghai UniversityShanghai 200444China

Layered double hydroxides(LDHs)have the potential to be superlubricated materials due to their strong adsorption effect and weak internal ***,obtaining stable superlubricity during the ultrafast time(<10 s)is still a ***,we demonstrated macroscale superlubricity based on LDHs of multiple metal ions at high surface roughness,achieving superlow friction coefficients(0.006)and ultrafast wearing-in time(<7 s),which mainly originated from tribochemical reactions and the formation of nanostructured adsorption *** cross-sectional analysis and density functional theory,we revealed the properties of the protective tribofilm to achieve ultrafast *** strongly adsorbed on the surface of the bearing steel,the sliding interface transformed into a heterogeneous interface between the polytetrafluoroethylene and LDH,leading to macroscale *** findings demonstrate that tribochemical treatment of surfaces produces tribofilm that effectively reduces wearing-in time and promotes ultralow friction.

关键词： superlubricity ultrafast wearing-in time bearing steel LDH nanosheets sliding barrier

Hierarchical self-assembled structure and frictional response of phthalocyanine molecules

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Friction 2023年第3期11卷 354-368页

作者： Yijun QIAO Jian SONG Hongyu SHI hongdong wang Shizhu WEN Yuhong LIU State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Biomedical Engineering Sun Yat-sen UniversityGuangzhou 510006China School of Mechatronic Engineering Shanghai University Shanghai 200444China

Solid evidence is needed to demonstrate the effect of molecular orientation and structure on the frictional property of boundary *** this work,the frictional properties of phthalocyanine self-assembled monolayers(SAMs)with face-on(aromatic cores parallel to the substrate)and edge-on(aromatic cores stand on the substrate)orientations have been compared and the in situ structural variation of edge-on SAMs under frictional shear has been revealed by atomic force microscope(AFM).Face-on oriented SAMs show lower adhesion,lower friction,and stronger wear resistance,compared with edge-on oriented *** structures of edge-on oriented SAMs have been revealed by frictional topography,which are consisted of nanoscale columns,micron-scale stripes,and centimeter-scale *** column structure deforms under increasing load force,leading to a stepwise friction force curve and a transition among three friction states(ordered friction,collapsed friction,and worn friction).The structural deformation depends on both the order degree and anisotropic stiffness of *** in phthalocyanine SAMs show a larger stiffness when shearing against molecular plane than shearing along the molecular *** presented study on the interfacial structure and frictional mechanism promisingly supports the designing of novel boundary lubricants and their application in engineering.

关键词： hierarchical assembly molecular orientation frictional mechanism phthalocyanine

一种新型多旋翼无人机着舰装置及安全边界评估方法

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中国舰船研究 2024年第1期19卷 272-279页

作者：孔杰杰王检耀王鸿东上海交通大学海洋工程全国重点实验室上海200240 上海交通大学海洋智能装备与系统教育部重点实验室上海200240

[目的]为解决旋翼无人机在海上无人平台应用时的自主安全着舰问题,开展旋翼无人机着舰装置及其安全评估方法研究。[方法]以多旋翼无人机为对象,基于“鱼叉–格栅”式助降装置原理,设计一种新型的“V形足–网”式着舰装置。建立无人机和... 详细信息

[目的]为解决旋翼无人机在海上无人平台应用时的自主安全着舰问题,开展旋翼无人机着舰装置及其安全评估方法研究。[方法]以多旋翼无人机为对象,基于“鱼叉–格栅”式助降装置原理,设计一种新型的“V形足–网”式着舰装置。建立无人机和甲板的多刚体动力学模型,通过ADAMS在不同横摇幅值和周期条件下开展着舰过程仿真,得到无人机着舰的姿态变化过程、着舰临界周期和稳定时间。[结果]仿真结果显示,相比普通着舰装置,“V形足–网”装置具备更高的对接冗余度,可适应更小的横摇周期和更大的横摇幅值,并可更快达到姿态稳定。[结论]研究表明,所设计的装置相比普通装置安全性更优异,通过仿真得到的装置安全边界,可为无人机着舰控制提供参考依据,进而提高无人机在海上平台的自主着舰可靠性。

关键词：无人机着舰装置动力学仿真安全边界评估

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船舶操纵运动建模方法研究进展与展望

船舶工程 2024年第2期46卷 I0010-I0022页

作者：宋俊龙张靖扬董磊楼建坤王鸿东上海交通大学海洋智能装备与系统教育部重点实验室上海200240

建立精确的船舶操纵运动模型,是保障智能船舶自主航行和测试验证的关键。当前,船舶操纵运动建模方法主要为构建数学模型,并采用系统辨识法计算模型中的水动力系数。随着人工智能技术的发展,黑箱模型和灰箱模型也逐渐被用于船舶操纵运动... 详细信息

建立精确的船舶操纵运动模型,是保障智能船舶自主航行和测试验证的关键。当前,船舶操纵运动建模方法主要为构建数学模型,并采用系统辨识法计算模型中的水动力系数。随着人工智能技术的发展,黑箱模型和灰箱模型也逐渐被用于船舶操纵运动建模。文章分别针对白箱模型和黑箱模型的关键技术研究现状进行梳理,总结当前操纵运动建模面临的六自由度耦合、模型迁移适用性、实测数据获取与构造等3个问题,并提出对应的3点展望:开展船舶六自由度耦合运动建模,结合先验知识的模型结构设计,船舶操纵试验设计及数据集构造。

关键词：六自由度耦合黑箱模型系统辨识船舶操纵

Macroscale superlubricity under ultrahigh contact pressure in the presence of layered double hydroxide nanosheets

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Nano Research 2022年第5期15卷 4700-4709页

作者： Kunpeng wang Lei Liu Aisheng Song Tianbao Ma hongdong wang Jianbin Luo Yuhong Liu State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechatronic Engineering Shanghai UniversityShanghai 200444China

It is difficult to achieve macroscale superlubricity under high contact pressures and high normal *** double hydroxide(LDH)nanoadditives were introduced into an ionic liquid alcohol solution(IL(as))with contact pressures up to 1.044 GPa,which resulted in a friction coefficient(COF)of 0.004 and a robust superlubricity state lasting for 2 *** with the LDH particles(LDH-Ps)with ca.90-nm widths and 18-nm thickness,micron-scale LDH nanosheet(LDH-N)additives with ca.1.5-pm width and 6-nm thickness increased the load-bearing capacity by approximately three times during *** lubricant film thickness and the ultrathin longitudinal dimension of the LDH-N additives did not influence the continuity of the fluid film on the contact *** improvements resulted from the protective adsorption layer and ion distribution formed on the contact interface,as revealed by detailed surface analyses and simulation *** particular,the sliding energy barrier and Bader charge calculation revealed that weak shear sliding between the nanosheet and the solid surface formed easily and the anions in the liquid adsorbed on the solid surface exhibited electrostatic repulsion forces,which generated stable tribological properties *** research provides a novel method for obtaining macroscale superlubricity for practical industrial applications.

关键词： macroscale superlubricity layered double hydroxide(LDH)nanosheets ionic liquid high pressure heterostructure

Construction and experimental verification research of a magnetic detection system for submarine pipelines based on a two-part towed platform

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Journal of Ocean Engineering and Science 2023年第2期8卷 169-180页

作者： Mianjin wang Shikun Pang Kefan Jin Xiaofeng Liang hongdong wang Hong Yi MOE Key Laboratory of Marine Intelligent Equipment and System Shanghai Jiao Tong UniversityShanghai 200240China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

With the acceleration of the investigation and development of marine resources,the detection and location of submarine pipelines have become a necessary part of modern marine *** pipelines are a typical weak magnetic anomaly target,and their magnetic anomaly detection can only be realized within a certain *** present,a towfish or an autonomous underwater vehicle(AUV)is mainly used as the platform to equip magnetometers close to the submarine pipelines for magnetic anomaly ***,the mother ship directly affects the towfish,thus causing control *** AUV cannot detect in real time,which affects the magnetic anomaly detection and creates problems regarding detection ***,a two-part towed platform has convenient control,thus reducing the interference of the towed mother ship and real-time *** the platform can maintain constant altitude sailing through the controller,the data accuracy in the actual magnetic anomaly detection can be *** the basis of a two-part towed platform,a magnetic detection system with constant altitude sailing ability for submarine pipelines was constructed in this *** addition,experimental verification was *** experimental verification research shows that the constant altitude sailing experiment of the two-part towed platform verifies that the platform has good constant altitude sailing ability in both a hydrostatic environment and the actual marine ***,the offshore magnetic anomaly detection experiment of submarine pipelines verifies the stable measurement function of the magnetic field and the function of the system to detect magnetic anomaly of submarine pipelines.

关键词： Submarine pipelines Two-part towed platform Constant altitude sailing Magnetic anomaly detection Stable measurement

Superlubricity achieved with two-dimensional nano-additives to liquid lubricants

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Friction 2020年第6期8卷 1007-1024页

作者： hongdong wang Yuhong LIU State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

The topic of superlubricity is attracting considerable interest around the world while humanity is facing an energy *** various liquid superlubricity systems can be commonly achieved on the macroscale in ambient conditions,it is considered an effective solution to reduce unnecessary energy and material ***,certain practical problems such as low load-bearing pressure,dependence on hydrogen ions,and relatively long running-in processes still limit its widespread ***-dimensional(2D)nano-additives with ultrathin longitudinal dimensions can lower the shear resistance between sliding solid surfaces,and thus further optimize the applied *** this review,the latest studies on 2D nano-additives with a combination of various water-based lubricants in the state of superlubricity are reported,typically including black phosphorus(BP),graphene oxide(GO),and layered double *** the sliding process,composite lubricants effectively improved the load capacity(up to 600 MPa),reduced wear,and accelerated the running-in period(within 1,000 s)of the liquid superlubricity *** macromechanical experiments and microscopic tests are conducted to precisely analyze various interactions at the interfaces of the nano-additives and solid *** interactions can be described as tribochemical reactions,physical protection,and adsorption enhancement,and improved wear *** review provides better guidance for applying 2D nanomaterials in liquid superlubricity systems.

关键词： superlubricity two-dimensional(2D)nanomaterial lubricant additive water-based tribological property

Enhancing leaching efficiency of ion adsorption rare earths by ameliorating mass transfer effect of rare earth ions by applying an electric field

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Journal of Rare Earths 2024年第1期42卷 172-180,I0006页

作者： Lingbo Zhou Jie Yang Shijie Kang Xiaojun wang hongdong Yu Yinhua Wan Rare Earth Institute University of Science and Technology of ChinaHefei230000China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341000China Jiangxi Institute of Rare Earths Chinese Academy of SciencesGanzhou341000China School of Resources and Environment Engineering Jiangxi University of Science and TechnologyGanzhou341000China

Improving the seepage of leaching solution in the ore body and strengthening the mass transfer process of rare earth ions during in-situ leaching are two critical methods to improve the leaching efficiency of rare *** this study,2 wt%MgSO_(4)solution was used for the indoor simulated column leaching experiment on rare earth samples and an electric field was applied at both ends of the *** the effects of different intensities,initial application time and duration of the electric field on the rare earth leaching system and its mechanism were *** results show that compared with the single MgSO_(4)solution leaching,applying an electric field with a strength of 6 V/cm can save the leaching time of 30 min and increase the flow velocity of the rare earth leachate by 26.98%.Under the optimal conditions of applying an electric field with a strength of 6 V/cm for 20 min to the leaching system after10 min of the rare earth leachate flowing out,the leaching efficiency of sample increases from 81.20% to 86.05% with the increase of 4.85%.The mechanism analysis shows that when a direct current electric field is applied to the rare earth leaching system,rare earth ions rapidly change from disorderly movement with the seepage into faster and directional *** addition,the seepage of the leaching solution is also improved due to the increase of the cross-sectional area of the seepage channel,the polarized water molecules migrate directionally by force from the negative pole,and the movement of the hydrogen is generated by the electrolytic *** impo rtantly,based on the principle of in-situ leaching process,the layout of injection holes and deflector holes in this process provides a natural site for the electrode layout of the electric *** the simple equipme nt and the ope ration,the rare earth leaching process with the applied electric field has high feasibility in industrial application.

关键词： Ion adsorption rare earths Leaching system Electric field Mass transfer process Seepage

Acidic electroreduction CO_(2)to formic acid via interfacial modification of Bi nanoparticles at industrial-level current

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Nano Research 2024年第7期17卷 5817-5825页

作者： Tian Dong hongdong Li Zhenhui wang Yanling Geng Rui Chang Xiaofeng Tian Jianping Lai Shouhua Feng Lei wang Key Laboratory of Eco-Chemical Engineering International Science and Technology Cooperation Base of Eco-Chemical Engineering and Green ManufacturingCollege of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042China Shandong Engineering Research Center for Marine Environment Corrosion and Safety Protection College of Environment and Safety EngineeringQingdao University of Science and TechnologyQingdao 266042China

Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in acidic media is a promising approach to overcome the unavoidable formation of carbonates in alkaline or neutral ***,the proton-rich environment near the catalyst surface favors hydrogen evolution reactions(HER),leading to lower energy efficiency of the desired products,especially in industrial-level current ***,quaternary ammonium cationic surfactant(cetyltrimethylammonium bromide(CTAB))was introduced into acidic electrolyte to modulate the interfacial microenvironment,which greatly enhanced CO_(2)electroreduction to formic acid(HCOOH)at the Bi/C nanoparticles *** a Bi/C nanoparticles electrode with CTAB added,constant production of formic acid was enabled with a cathodic energy efficiency of>40%and maximum FEHCOOH(FE=Faradaic efficiency)of 86.2%at−400 mA·cm^(−2)over 24 *** with in-situ attenuated total reflection Fourier transform infrared spectroscopy,the concentration of*OCHO intermediates significantly increased after CTAB modification,confirming that the hydrophobic interface microenvironment formed by dynamic adsorption of positively charged long alkyl chains on Bi/C nanoparticle electrodes inhibited HER and improved the selectivity of CO_(2)RR to HCOOH.

关键词： acidic media CO_(2)electrolysis electrolyte additive hydrophobic interfacial microenvironment industrial-level current