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Temperature is one of the governing factors affecting friction of solids. Undesired high friction state has been generally reported at cryogenic temperatures due to the prohibition of thermally activated processes, following conventional Arrhenius equation. This has brought huge difficulties to lubrication at extremely low temperatures in industry. Here, the study uncovers a hydrogen-correlated sub-Arrhenius friction behavior in hydrogenated amorphous carbon (a-C:H) film at cryogenic temperatures, and a stable ultralow-friction over a wide temperature range (103-348 K) is achieved. This is attributed to hydrogen-transfer-induced mild structural ordering transformation, confirmed by machine-learning-based molecular dynamics simulations. The anomalous sub-Arrhenius temperature dependence of structural ordering transformation rate is well-described by a quantum mechanical tunneling (QMT) modified Arrhenius model, which is correlated with quantum delocalization of hydrogen in tribochemical reactions. This work reveals a hydrogen-correlated friction mechanism overcoming the Arrhenius temperature dependence and provides a new pathway for achieving ultralow friction under cryogenic conditions.
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http://dx.doi.org/10.1002/smll.202400083 | DOI Listing |
Anal Chim Acta
November 2025
Institute of Materials Science, Vietnam Academy of Science and Technology, Hanoi, 10000, Viet Nam. Electronic address:
Background: Recent advancements in cancer therapeutics have catalyzed the development of noninvasive treatment modalities, including the utilization of fluorescent chemotherapeutic agents. These agents offer dual functionality, enabling targeted drug delivery, real-time tumor imaging, and personalized therapy monitoring. Such capabilities are instrumental in the progression toward more precise and effective cancer interventions.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
September 2025
Institute of Functional Molecules, Shenyang University of Chemical Technology, Shenyang 110142, China.
A new variety of nitrogen-doped carbon dots (NCDs) was produced using a hydrothermal synthesis method, based on propanedioic acid and barbituric acid as the sources of carbon and nitrogen. The NCDs were analyzed by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Zeta Potential,X-ray Diffraction(XRD),Thermogravimetry-Derivative Thermogravimetry(TG-DTG),Fourier transform infrared spectroscopy (FTIR) and Fluorescence Lifetime. The characterization results indicate that NCDs possess an average diameter of approximately 2.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
September 2025
Research Center for Chinese Medicine Analysis and Transformation, Beijing University of Chinese Medicine, Beijing 100029, China; Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China. Electronic address:
The occurrence of isomeric dihydroflavone and chalcone, two important subfamilies of flavonoid class, extensively happens in herbal medicines. However, identical MS/MS spectra make the identity confirmation a tough job, the complexity will be further boosted in biological samples. Inspired by that isomers possess distinct inherent physicochemical parameters, optimal collision energy (OCE), which is positively correlated with the bond dissociation energies (BDEs), was evaluated towards differentiating isomeric dihydroflavone and chalcone.
View Article and Find Full Text PDFSci Adv
September 2025
Laboratory of Ultrafast Spectroscopy, SB-ISIC, and Lausanne Centre for Ultrafast Science (LACUS), Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland.
The electronic properties of correlated insulators are governed by the strength of Coulomb interactions, enabling the control of electronic conductivity with external stimuli. This work highlights that the strength of electronic correlations in nickel oxide (NiO), a prototypical charge-transfer insulator, can be coherently reduced by tuning the intensity of an optical pulse excitation. This weakening of correlations persists for hundreds of picoseconds and exhibits a recovery time independent of photodoping density across two orders of magnitude.
View Article and Find Full Text PDFFront Aging Neurosci
August 2025
Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.
Objective: The development of non-invasive clinical diagnostics is paramount for the early detection of Alzheimer's disease (AD). Neurofibrillary tangles in AD originate from the entorhinal cortex, a cortical memory area that mediates navigation via path integration (PI). Here, we studied correlations between PI errors and levels of a range of AD biomarkers using a 3D virtual reality navigation system to explore PI as a non-invasive surrogate marker for early detection.
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