A5040669675- Force Microscopy Techniques and Applications
- Surface Treatment and Residual Stress
- Mechanical and Optical Resonators
- Molecular Junctions and Nanostructures
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Graphene research and applications
- Aluminum Alloys Composites Properties
- Electromagnetic Effects on Materials
- Additive Manufacturing Materials and Processes
- High Entropy Alloys Studies
- Adhesion, Friction, and Surface Interactions
- Microstructure and mechanical properties
- Metallic Glasses and Amorphous Alloys
- Advanced Materials Characterization Techniques
- Thermal properties of materials
- Tribology and Wear Analysis
- Titanium Alloys Microstructure and Properties
- Laser Material Processing Techniques
- Lubricants and Their Additives
- Carbon Nanotubes in Composites
- High-pressure geophysics and materials
- Covalent Organic Framework Applications
- Advanced materials and composites
- Polymer crystallization and properties
Donghua University
2024-2025
University of Akron
2014-2023
First Affiliated Hospital of Xi'an Jiaotong University
2018-2022
Xidian University
2022
Purdue University West Lafayette
2009-2018
University of Calgary
2015
Harbin Institute of Technology
2012
The atomic stick-slip behavior of a Pt tip sliding on Au(111) surface is studied with force microscopy (AFM) experiments and accelerated (i.e., reduced speed) molecular dynamics (MD) simulations. MD AFM conditions are controlled to match, as closely possible, the geometry orientation, load, temperature, compliance. We observe clear without any damage. Comparison both results thermally activated Prandtl-Tomlinson model shows that at highest speeds not in regime. At lower speeds, within...
Molecular dynamics simulations are performed to study the frictional behavior of graphene. It is found that friction between a diamond tip and graphene decreases with increasing number layers. This also affected by sheet size; specifically, effect layers on becomes significant only when modeled sheets exceed critical length. We further show can be directly correlated height near-contact wrinkles resist sliding. These observations rationalized in terms ability multiple act as single material...
Owing to its intrinsically lubricious property, graphene has a high potential be an atomically thin solid lubricant for sliding interfaces. Despite ultrahigh breaking strength at the nanoscale, often fails maintain integrity when subjected macroscale tribological tests. To reveal true wear characteristics of graphene, nanoscale diamond tip was used scratch monolayer mechanically exfoliated SiO2 substrates. Our experimental results show that while exhibited extraordinary resistance in...
Atomic friction on hydrogenated graphene is investigated using molecular dynamics simulations. Hydrogenation found to increase significantly, and the atomic-level information provided by simulations reveals that atomic roughness induced hydrogenation primary cause of enhancement. Other proposed mechanisms, specifically adhesion rigidity, are excluded based simulation results analyses performed Prandtl-Tomlinson model. In addition, it does not monotonically with hydrogen coverage surface;...
Atomic force microscopy (AFM) and atomistic simulations of atomic friction with silicon oxide tips sliding on Au(111) are conducted at overlapping speeds. Experimental data unambiguously reveal a stick-slip plateau above critical scanning speed, in agreement the thermally activated Prandtl-Tomlinson (PTT) model. However, experiments is larger than simulations. PTT energetic parameters for two comparable, minor differences attributable to contact area's influence barrier slip. Recognizing...
Atomic force microscopy experiments and molecular dynamics simulations show that friction between a nanoscale tip atomically stepped surfaces of graphite is influenced by the environment. The presence small amount water increases at atomic steps, but does not strongly influence on flat terraces.
Molecular dynamics simulation and the two-temperature method are carried out to model effects of substrate roughness as well electron–phonon coupling on thickness-dependent friction graphene. It is found that can significantly enhance graphene, which orders magnitude larger than smooth due puckering effect. Additionally, adhesive force between graphene plays opposite roles for rough substrates. While a substrate, adhesion hinders wrinkle formation in therefore suppressing friction, helps...
Carbon nanotubes and graphene are promising materials for thermal management applications due to their high conductivities. However, properties anisotropic, the radial or cross-plane direction conductivity is low. A 3D nanotube (CNT)-graphene structure has previously been proposed address this limitation, direct molecular dynamics simulations have used predict associated conductivity. In work, by recognizing that resistance primarily comes from CNT-graphene junctions, a simple network model...
The debate regarding the possible molecular origins of Mullins effect has been ongoing since its discovery. Molecular dynamics (MD) simulations were carried out to elucidate underlying mechanism effect. For first time, key characteristics associated with effect, including (a) majority stress softening occurring in stretch, (b) continuous increase, (c) a permanent set, and (d) recovery heat treatment, are captured by modeling. It is discovered that irreversible disentanglement polymer chains...
Poor surface finish of 3D-printed metals significantly deteriorates their corrosion, wear and fatigue resistance. Ultrasonic nano-crystal modification (UNSM) is an innovative processing technique that utilizes low amplitude ultrasonic frequency vibrations superimposed on a static load to generate plastic deformation metal its improve properties performance. In this study, we investigate the effect UNSM metals. An aluminum AlSi10Mg alloy fabricated by direct laser sintering (DMLS) was used as...
Regenerated wool keratin fibers (RWKFs) featuring their ecofriendliness, ample resources, and intrinsic biocompatibility have attracted significant interest, while high-value-added applications are still severely limited by inadequate mechanical properties complex fabrication processes. Herein, a straightforward dry-jet wet spinning technique without post-treatment processes is proposed to prepare ultratoughness RWKFs. The as-spun achieve macroscale hierarchical structure due the...