This article presents a study of the poorly understood "shear-force" used in an important class of near-field instruments that use mechanical resonance feedback detection. In the case of a metallic probe near a metallic surface in vacuum, we show that in the 10-60 nm range there is no such a thing as a shear-force in the sense of the nonconservative friction force. Fluctuations of the oscillator resonance frequency, likely induced by local charge variations, could account for the reported effects in the literature without introducing a dissipative force.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/nl301618p | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Developmental and environmental effects on VTC2-dependent leaf ascorbate accumulation and functions.
J Exp Bot
January 2025
Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
In nature, environmental conditions strongly fluctuate, frequently subjecting plants to periods of immediate photo-oxidative stress. The small molecule ascorbate allows plants to cope with such stress conditions. Ascorbate scavenges reactive oxygen species and enables the rapid and full induction of photoprotective non-photochemical quenching (NPQ).
View Article and Find Full Text PDFReducing Nonradiative Recombination in Halide Perovskites through Appropriate Band Gaps and Heavy Atomic Masses.
J Phys Chem Lett
January 2025
State Key Laboratory of Organic Electronics and Information Displays, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
Halide perovskite optoelectronic devices achieve high energy conversion efficiencies. However, their efficiency decreases significantly with an increase in temperature. This decline is likely caused by changes in nonradiative recombination and electron-phonon coupling, which remain underexplored.
View Article and Find Full Text PDFStable Field Emissions from Zirconium Carbide Nanoneedle Electron Source.
Nanomaterials (Basel)
January 2025
Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255, USA.
In this study, a single zirconium carbide (ZrC) nanoneedle structure oriented in the <100> direction was fabricated by a dual-beam focused ion beam (FIB-SEM) system, and its field emission characteristics and emission current stability were evaluated. Benefiting from controlled fabrication with real-time observation, the ZrC nanoneedle has a smooth surface and a tip with a radius of curvature smaller than 20 nm and a length greater than 2 μm. Due to its low work function and well-controlled morphology, the ZrC nanoneedle emitter, positioned in a high-vacuum chamber, was able to generate a single and collimated electron beam with a current of 1.
View Article and Find Full Text PDFMorpho-functional characterisation of cœlomocytes in the aquacultivated sea cucumber Holothuria scabra: from cell diversity to transcriptomic immune response.
Fish Shellfish Immunol
January 2025
Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons (UMONS), 7000 Mons, Belgium; Laboratory of Cellular and Molecular Immunology, GIGA Research, University of Liège, 4000 Liège, Belgium.
Holothuria scabra is one of the most valuable species of sea cucumber owing to its exploitation as a seafood product. This study aims to describe the main molecular and cellular actors in the immunology of the holothuroid H. scabra.
View Article and Find Full Text PDFHydrogen Tunneling and Conformational Motions in Nonadiabatic Proton-Coupled Electron Transfer between Interfacial Tyrosines in Ribonucleotide Reductase.
J Am Chem Soc
January 2025
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
Ribonucleotide reductase (RNR) is essential for DNA synthesis and repair in all living organisms. The mechanism of RNR requires long-range radical transport through a proton-coupled electron transfer (PCET) pathway spanning two different protein subunits. Herein, the direct PCET reaction between the interfacial tyrosine residues, Y356 and Y731, is investigated with a vibronically nonadiabatic theory that treats the transferring proton and all electrons quantum mechanically.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!