The weak interlayer binding in two-dimensional layered materials such as graphite gives rise to poorly understood low-friction characteristics. Accurate measurements of the adhesion forces governing the overall mechanical stability have also remained elusive. We report on the direct mechanical measurement of line tension and friction forces acting in sheared mesoscale graphite structures. We show that the friction is fundamentally stochastic in nature and is attributable to the interaction between the incommensurate interface lattices. We also measured an adhesion energy of 0.227 ± 0.005 joules per square meter, in excellent agreement with theoretical models. In addition, bistable all-mechanical memory cell structures and rotational bearings have been realized by exploiting position locking, which is provided solely by the adhesion energy.
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PLoS One
January 2025
School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan, China.
In order to obtain proper speed limits in expressway work zones, CarSim and TruckSim software were used to determine the critical car and truck safe speeds and then VISSIM software was used to determine the traffic capacities and their corresponding speed limits under different upstream transition area lengths and road adhesion coefficients. The results show that critical car and truck safe speeds increase exponentially while traffic capacity and its corresponding speed limit increase logarithmically with rising road adhesion coefficient under a constant upstream transition area length, and critical car and truck safe speeds increase as a power function while traffic capacity and its corresponding speed limit increase exponentially with rising upstream transition area length under a constant road adhesion coefficient. Because Road Traffic Signs and Markings- Part 4: Work Zone (RTSM, GB 5768.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Sports Medicine of the Second Affiliated Hospital, and Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou 311113, China.
Joining heterogeneous materials in engineered structures remains a significant challenge due to stress concentration at interfaces, which often leads to unexpected failures. Investigating the complex, multiscale-graded structures found in animal tissue provides valuable insights that can help address this challenge. The human meniscus root-bone interface is an exemplary model, renowned for its exceptional fatigue resistance, toughness, and interfacial adhesion properties throughout its lifespan.
View Article and Find Full Text PDFCurr Genet
January 2025
Department of Medical Laboratory Sciences, Lovely Professional University, Phagwara, 144411, Punjab, India.
The Staphylococcus genus, composed of Gram-positive bacteria, includes several pathogenic species such as Staphylococcus aureus, S. epidermidis, S. haemolyticus, and S.
View Article and Find Full Text PDFJ Funct Biomater
January 2025
Restorative Dentistry Department, Faculty of Dentistry, Gazi University, 06510 Ankara, Turkey.
The aim of this study is to evaluate the shear bond strength of different universal adhesives applied to intact, demineralized, and remineralized enamel surfaces with total-etch and self-etch modes and to examine the effect of universal adhesives on the Ca/P mineral atomic and mass ratios of these enamel with FE-SEM/EDX (Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy) analysis. For this study, 264 bovine incisors were used. Samples in the demineralized and remineralized groups were kept in demineralization solution at 37 °C for 96 h to make an artificial initial carious lesion.
View Article and Find Full Text PDFBiomimetics (Basel)
January 2025
DENS-ia Research Group, Faculty of Health Sciences, Miguel de Cervantes European University, C/del Padre Julio Chevalier 2, 47012 Valladolid, Spain.
Treating the surfaces of dental implants in an alkaline medium allows us to obtain microstructures of sodium titanate crystals that favor the appearance of apatite in the physiological environment, producing osteoconductive surfaces. In this research, 385 discs made of titanium used in dental implants underwent different NaOH treatments with a 6M concentration at 600 °C and cooling rates of 20, 50, 75, and 115 °C/h. Using high-resolution electron microscopy, the microstructures were observed, and the different crystal sizes were determined and compared with control samples (those without biomimetic treatment).
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