检索结果-南通市图书馆

L^(*)—An index for evaluating long range performance of autonomous underwater vehicles(AUVs)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第10期12卷 2205-2221页

作者： Manfu ZHU Liran MA Jianbin LUO State Key laboratory of tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

Autonomous underwater vehicles(AUVs)have various applications in both military and civilian fields.A wider operation area and more complex tasks require better overall range performance of ***,until recently,there have been few unified criteria for evaluating the range performance of *** the present work,a unified range index,i.e.,L^(*),considering the cruising speed,the sailing distance,and the volume of an AUV,is proposed for the first time,which can overcome the shortcomings of previous criteria using merely one single parameter,and provide a uniform criterion for the overall range performance of various *** constructing the expression of the L^(*)index,the relevant data of 49 AUVs from 12 countries worldwide have been collected,and the characteristics of the L^(*)range index in different countries and different categories were compared and ***,by analyzing the complex factors affecting the range index,methods to enhance the L^(*)range index value,such as efficiency enhancement and drag reduction,have been introduced and *** this condition,the work proposes a unified and scientific criterion for evaluating the range performance of AUVs for the first time,provides valuable theoretical insight for the development of AUVs with higher performance,and then arouses more attention to the application of the cutting-edge superlubricity technology to the field of underwater vehicles,which might greatly help to accelerate the coming of the era of the superlubricitive engineering.

关键词： autonomous underwater vehicles(AUVs) range performance range index superlubricity drag reduction

In situ probing of electron transfer at the dynamic MoS_(2)/graphene–water interface for modulating boundary slip

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 7513-7521页

作者： Yishu Han Dameng Liu State Key laboratory of tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

The boundary slip condition is pivotal for nanoscale fluid *** research has primarily focused on simulating the interaction mechanism between the electronic structure of two-dimensional materials and slip of water at the nanoscale,raising the possibility for ultralow friction flow of water at the ***,experimentally elucidating electronic interactions at the dynamic solid–liquid interface to control boundary slip poses a significant *** this study,the crucial role of electron structures at the dynamic solid–liquid interface in regulating slip length was ***,the slip length of water on the molybdenum disulfide/graphene(MoS_(2)/G)heterostructure(100.9±3.6 nm)significantly exceeded that of either graphene(27.7±2.2 nm)or MoS_(2)(5.7±3.1 nm)*** was also analyzed how electron transfer significantly affected interface *** electrons played a crucial role in determining the type and proportion of excitons at both MoS_(2)–water and MoS_(2)/G–water ***,by applying voltage,distinct photoluminescence(PL)responses at static and dynamic interfaces were discovered,achieving a 5-fold modulation in PL intensity and a 2-fold modulation in the trion to exciton intensity *** electrons transfer from the top graphene to the bottom MoS_(2)at the MoS_(2)/G–water interface,reducing surface charge ***,the reduction of electrostatic interactions between the solid and water leads to an increased slip length of water on the MoS_(2)/G *** process aids in comprehending the origin of frictional resistance at the subatomic *** work establishes a foundation for actively controlling and designing of fluid transport at the nanoscale.

关键词： two-dimensional materials solid-liquid interface photoluminescence excitons electron transfer slip length

Comparative analysis of frictional behavior and mechanism of molybdenum ditelluride with different structures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第1期12卷 110-119页

作者： Lina ZHANG Xinfeng TAN Jianguo JIAO Dan GUO Jianbin LUO State Key laboratory of tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

Two-dimensional(2D)transition metal dichalcogenides(TMDCs)have layered structures with excellent tribological *** the energy difference between hexagonal-molybdenum ditelluride(2H-MoTe_(2))and distorted octahedral-molybdenum ditelluride(1T′-MoTe_(2))is very small among the transition metal dichalcogenides(TMDCs),MoTe_(2) becomes one of the most promising candidates for phase *** our experiment,we found that the friction force and friction coefficient(COF)of 2H-MoTe_(2) were an order of magnitude smaller than those of 1T′-MoTe_(2) by the atomic force microscope(AFM)*** friction difference between 1T′-MoTe_(2) and 2H-MoTe_(2) was further verified in molecular dynamics(MD)*** density functional theory(DFT)calculations suggest that the friction contrast is related to the difference in sliding energy barrier of the potential energy surface(PES)for a tip sliding across the *** PES obtained from the DFT calculation indicates that the maximum energy barrier and the minimum energy path(MEP)energy barrier of 2H-MoTe_(2) are both smaller than those of 1T′-MoTe_(2),which means that less energy needs to be dissipated during the sliding *** difference in energy barrier of the PES could be ascribed to its larger interlayer spacing and weaker Mo–Te interatomic interactions within the layers of 2H-MoTe_(2) than those of 1T′-MoTe_(2).The obvious friction difference between 1T′-MoTe_(2) and 2H-MoTe_(2) not only provides a new non-destructive means to detect the phase transition by the AFM,but also provides a possibility to tune friction by controlling the phase transition,which has the potential to be applied in extreme environments such as space lubrication.

关键词： friction two-dimensional(2D)materials distorted octahedral-molybdenum ditelluride(1T′-MoTe_(2)) hexagonal-molybdenum ditelluride(2H-MoTe_(2)) phase transition

Prediction of ball-on-plate friction and wear by ANN with data-driven optimization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第6期12卷 1235-1249页

作者： Alexander KOVALEV Yu TIAN Yonggang MENG State Key laboratory of tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

For training artificial neural network(ANN),big data either generated by machine or measured from experiments are used as input to"learn"the unspecified functions defining the *** experimental data are fed directly into the optimizer allowing training to be performed according to a predefined loss *** predict sliding friction and wear at mixed lubrication conditions,in this study a specific ANN structure was so designed that deep learning algorithms and data-driven optimization models can be *** ball-on-plate friction and wear data were analyzed using the specific training procedure to optimize the weights and biases incorporated into the neural layers of the ANN,and only two independent experimental data sets were used during the ANN optimization *** the training procedure,the ANN is capable to predict the contact and hydrodynamic pressure by adapting the output data according to the tribological condition implemented in the optimization algorithm.

关键词： machine learning deep learning artificial neural network mixed lubrication

In memoriam:Shizhu Wen(1932-2023)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第7期12卷 1341-1346页

作者： Jianbin LUO Yonggang MENG Yu TIAN State Key laboratory of tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

Professor Shizhu Wen,the winner of the 2015 tribology Gold Medal,passed away due to illness on November 3,2023,at the age of *** was a professor of Tsinghua University,an academician of the Chinese Academy of Sciences,and the Honorary President of the Chinese tribology Institute(CTI)from 1997 to *** Wen was born in 1932 in Jiangxi Province of China and graduated from Tsinghua University in 1955,where he was awarded the Outstanding Graduate Gold Medal and then remained as an assistant professor at the *** Wen was promoted to full professor in *** had undertaken tribology research at the Imperial College London in 1979 and *** 1985,he presided over the establishment of the State Key laboratory of tribology(SKLT)of Tsinghua University and served as the first director of the SKLT.

关键词： sided professor zhu

Hydration lubrication modulated by water structure at TiO2–aqueous interfaces

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 591-605页

作者： Pingsu MA Yuan LIU Ke HAN Yu TIAN Liran MA State Key laboratory of tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The nature of solid-liquid interfaces is of great significance in *** advances have been made in lubrication based on hydration ***,a detailed molecular-level understanding is still ***,we investigated water molecule behaviors at the TiO2-aqueous interfaces by the sum-frequency generation vibrational spectroscopy(SFG-VS)and atomic force microscope(AFM)to elucidate the fundamental role of solid-liquid interfaces in *** contributions of water structures and hydration effects were revealed,where water structures played the dominant role in lubrication for TiO2 surfaces of varying hydrophilicity,while hydration effects dominated with the increasing of ion *** lubrication is observed on the initial TiO2 surfaces with strongly H-bonded water molecules compared to the hydrophilic TiO2 surfaces with more disordered *** stable ordered water arrangement with strong hydrogen bonds and the shear plane occurring between the ordered water layer and subsequent water layer may play a significant role in achieving lower *** adsorbed hydrated molecules with the increasing ionic concentration perturb ordered water but lead to the enhancement of hydration effects,which is the main reason for the improved lubrication for both *** work provides more insights into the detailed molecular-level understanding of the mechanism of hydration lubrication.

关键词： hydration lubrication interfacial water structures hydration effects titanium dioxide(TiO2)

AFM probe with the U-shaped cross-sectional cantilever for measuring the ultra-low coefficient of friction of 10^(–6)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第8期12卷 1707-1715,F0004页

作者： Yushan CHEN Liang JIANG Linmao QIAN tribology Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu 610031China

Accurately measuring the coefficient of friction(COF)is the fundamental prerequisite of superlubricity *** study aimed to reduce the COF measurement resolutionΔμof atomic force microscopy(AFM).Based on the theoretical model,a distinctive strategy was adopted to reduceΔμby optimizing the cantilever’s cross-section of the AFM probe,inspired by civil engineering.Δμcan be reduced by decreasing the width of the horizontal side wR and the wall thickness t and increasing the width of the vertical side ***,the I-shape demonstrates the highest reduction inΔμ,followed by the *** the processability,the AFM probe with the U-shaped cross-sectional cantilever was investigated further,and the dimensions are 35μm wR,3.5μm wH,0.5μm t,50μm l(cantilever length),and 23μm htip(tip height).The finite element analysis results confirm its *** being fabricated and calibrated,the AFM probe achieves the minimalΔμof 1.9×10^(–6)under the maximum normal force so ***,the friction detection capability of the fabricated AFM probe improves by 78 times compared to the commercial tipless-force modulation mode(TL-FM)AFM probe with the conventional solid rectangular cross-sectional *** study provides a powerful tool for measuring 10^(–6)COF.

关键词： atomic force microscopy superlubricity coefficient of friction probe cantilever

A novel UHMWPE composite with low friction coefficient for long-term ice sliding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第11期12卷 2480-2490页

作者： Yacong HOU Lei CHEN Zheng ZHANG Jinlin CHANG Ding WENG Yuan MA Jiadao WANG State Key laboratory of tribology in Advanced Equipment School of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Low friction ice sliding interfaces were critical for ski performance *** fluorinated ski waxes have attracted considerable attention for enhancing the hydrophobicity,anti-wearing,and oxidation resistance of ski–ice ***,the toxicity and complexity of the waxing process limited batch manufacturing of low-cost and non-toxic ski–ice base,what is more,the wax covering on the base wore and failed during skiing due to the friction between ski and ***,we demonstrated a novel ultra-high molecular weight polyethylene(UHMWPE)composite that could maintain a low coefficient of friction(COF)with about 0.026 for at least 160 min when skiing on the ***(MS)could release liquid(liquid paraffin(LP)).The released LP further enhanced the hydrophobicity of UHMWPE’s surfaces when friction occurred,which would maintain the stability and durability of the water film,and achieved superior and long-lasting friction *** with other microcapsules with lower hydrophobic core,microcapsules with LP performed the best in reducing the friction of ski base from 0.126 to ***,the COF of the surface kept at about 0.02 even after 12 rapid temperature *** presented UHMWPE composite of encapsulated liquids showed great potential and broad application owing to its simplicity and efficiency in winter sports.

关键词： microcapsule(MS) ice friction ski liquid paraffin self-lubrication water film

A review of ultrafast laser micro/nano fabrication:Material processing,surface/interface controlling,and devices fabrication

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第7期17卷 6212-6230页

作者： Heng Guo Jiawang Xie Guangzhi He Dezhi Zhu Ming Qiao Jianfeng Yan Jiachen Yu Jiaqun Li Yuzhi Zhao Ma Luo Haoze Han State Key laboratory of tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Ultrafast laser processing technology has offered a wide range of opportunities in micro/nano fabrication and other fields such as nanotechnology,biotechnology,energy science,and photonics due to its controllable processing precision,diverse processing capabilities,and broad material *** processing abilities and applications of the ultrafast laser still need more *** the field of material processing,controlling the atomic scale structure in nanomaterials is *** effects exist in ultrafast laser surface/interface processing,making it difficult to modulate the nanostructure and properties of the surface/interface as *** the ultrafast laser fabrication of micro functional devices,the processing ability needs to be ***,we review the research progress of ultrafast laser micro/nano fabrication in the areas of material processing,surface/interface controlling,and micro functional devices *** useful ultrafast laser processing methods and applications in these areas are *** various processing effects and abilities,the ultrafast laser processing technology has demonstrated application values in multiple fields from science to industry.

关键词： ultrafast laser micro/nano fabrication material processing surface/interface controlling devices fabrication