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Simple and effective:Superlubricity behaviour of the G-quadruplex hydrogel with high selectivity for K+ions based on the ocular environment

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Friction 2024年第11期12卷 2548-2562页

作者： hongdong wang Jian WU Kunpeng wang Yunjuan SU Xiacong ZHANG Yuhong LIU Jianhua ZHANG School of Mechatronic Engineering and Automation and Key Laboratory of Advanced Display and System Application Ministry of EducationShanghai UniversityShanghai 200444China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Department of Polymer Materials School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

Hydrogels have been the subject of significant research in the field of friction due to their exceptional lubricating *** this study,the G-quadruplex hydrogel with high selectivity for K+ions was formed by introducing a mixture of G,2-formylphenylboronic acid,and polyethylene glycol diamine into simulated artificial tears solution with high transparency,and an ultra-low coefficient of friction(COF)of about 0.004 was obtained based on the simulated ocular environment,thus achieving macroscopic *** friction pairs simulating the ocular environment,to assess the frictional performance of the G-quadruplex hydrogel as both a lubricant and a friction pair based on the simulated ocular environment,we conducted experiments considering various factors such as concentration,sliding speed,and *** these experiments,it was found that superlubricity was achieved when the G-quadruplex hydrogel was applied as lubricant or friction *** effect was attributed to the three-dimensional network structure and hydrophilicity of the hydrogel,which facilitated the formation of a highly bearing and flowing hydration layer,promoting macroscopic *** to the G-quadruplex hydrogel with low concentration,the high concentration hydrogel(75 mM)exhibited increased mechanical strength and robustness in *** with biocompatibility experiments,our synthesized G-quadruplex hydrogel has excellent biocompatibility and offers a novel approach to achieve superlubricity in ocular drug delivery.

关键词： superlubricity ocular environment G-quadruplex hydrogel bio-compatibility

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

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

Adjustable superlubricity system using polyalkylene glycol with various acid aqueous solutions

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Friction 2023年第7期11卷 1138-1149页

作者： Wenrui LIU hongdong wang Yuhong LIU State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechatronic Engineering and Key Laboratory of Advanced Display and System Application Ministry of EducationShanghai UniversityShanghai 200444China

Polyalkylene glycol(PAG)aqueous solutions have recently been demonstrated to exhibit an ultralow friction coefficient(COF,μ<0.01).However,the prolonged running-in period and low bearing capacity have limited its widespread *** this study,we determined that the running-in period can be decreased by more than 75%when the pH value of the lubricant is controlled at 3 by introducing various acid ***,less time was required to realize stable superlubricity with inorganic acid at lower pH *** was mainly attributed to the acceleration effect of hydrogen ions around the contact *** case of PAG aqueous solution with organic acid,the wear loss between sliding solid surfaces was reduced,and thus the bearing pressure during the superlubricity period was significantly improved from approximately 30 to 160 ***,the organic acid molecules were considered to form strong hydrogen bonds with PAG macromolecules and solid *** in turn strengthened the structure of the adsorption *** unique effect of different acids in aqueous polymer lubrication can potentially significantly aid in advancing the study of polymer tribology and broadening industrial applications.

关键词： superlubricity running-in time bearing pressure organic acid hydrogen bond

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

Tribological properties of novel palygorskite nanoplatelets used as oil-based lubricant additives

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Friction 2021年第2期9卷 332-343页

作者： Kunpeng wang Huaichao WU hongdong wang Yuhong LIU Lv YANG Limei ZHAO School of Mechanical Engineering Guizhou UniversityGuiyang 550025China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

Layered palygorskite(PAL),commonly called attapulgite,is a natural inorganic clay mineral composed of magnesium *** this study,an aqueous miscible organic solvent treatment method is adopted to prepare molybdenum-dotted palygorskite(Amo-PMo)nanoplatelets,which greatly improved the specific surface area of PAL and the dispersion effect in an oil-based lubricant *** layered structure and size were confirmed using transmission electron microscopy(TEM)and atomic force *** a tribological test lubricated with three additives(PAL,organic molybdenum(SN-Mo),and Amo-PMo),it was found that the sample of 0.5 wt%Amo-PMo exhibited the best tribological properties with a coefficient of friction of ***,the resulting wear scar diameter and wear volume of the sliding ball surface were 63%and 49.6%of those lubricated with base oil,*** excellent lubricating performance and self-repairing ability were mainly attributed to the generated MoS2 adsorbed on the contact surfaces during the tribochemical reaction,thereby effectively preventing the direct collision between asperities on sliding solid ***,as-prepared Amo-PMo nanoplatelets show great potential as oil-based lubricant additives,and this study enriches the existing application of PAL in industry.

关键词： palygorskite(PAL) layered material lubricant additive wear tribofilm

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

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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

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上海航运安全保障智慧化创新方向研究

船舶工程 2024年第7期46卷 103-110,135页

作者：谭星查伊倩赵丽莉陈姝怡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 中国舰船研究设计中心上海分部上海201108

航运业作为我国经济社会发展重要的基础产业,其存在的航运安全问题不容忽视。为了探究航运安全保障的潜在智慧化创新方向,以上海航运安全保障为例,梳理并提出航运安全保障概念与内涵,对航运安全保障体系国内外现状进行归纳总结,从智能... 详细信息

航运业作为我国经济社会发展重要的基础产业,其存在的航运安全问题不容忽视。为了探究航运安全保障的潜在智慧化创新方向,以上海航运安全保障为例,梳理并提出航运安全保障概念与内涵,对航运安全保障体系国内外现状进行归纳总结,从智能港口、智慧航道2个方面剖析航运安全相关技术的研究进展。在总结分析航运安全保障现存问题和主要差距的基础上,对智能技术在航运安全保障领域的应用进行展望,即大力发展数字孪生与大数据应用和推动无人驾驶与智能船舶技术结合。

关键词：航运安全保障智能港口智慧航道