Noncontact friction between a Au(111) surface and an ultrasensitive gold-coated cantilever was measured as a function of tip-sample spacing, temperature, and bias voltage using observations of cantilever damping and Brownian motion. The importance of the inhomogeneous contact potential is discussed and comparison is made to measurements over dielectric surfaces. Using the fluctuation-dissipation theorem, the force fluctuations are interpreted in terms of near-surface fluctuating electric fields interacting with static surface charge.
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http://dx.doi.org/10.1103/PhysRevLett.87.096801 | DOI Listing |
Mater Horiz
January 2025
School of Materials Science and Engineering, Energy Materials and Devices Key Lab of Anhui Province for Photoelectric Conversion, Anhui University, Hefei, Anhui 230601, China.
The triboelectric nanogenerator (TENG) has been proved to be a very promising marine energy harvesting technology. Herein, we have developed a high-performance triboelectric nanogenerator (SD-TENG) with low friction, high durability, swing-induced counter-rotating motion mechanism (SICRMM) and dual potential energy storage and release strategy (DPESRS). The unique counter-rotating motion mechanism enabled SD-TENG to convert the external linear and swing motion energy into rotation motion energy of the inner and outer cylinders, and then converted it into a controllable power output.
View Article and Find Full Text PDFJ Chem Phys
November 2024
Department of Materials Science and Engineering, Saarland University, 66123 Saarbrücken, Germany.
The split-charge equilibration method is extended to describe dissipative charge transfer similarly as the Drude model, whereby the complex-valued frequency-dependent dielectric permittivities or conductivities of dielectrics and metals can be mimicked at non-zero frequencies. To demonstrate its feasibility, a resistor-capacitor circuit is simulated using an all-atom representation for the resistor and capacitor. The dynamics reproduce the expected charging process and Nyquist noise, the latter resulting from the thermal voltages acting on individual split charges.
View Article and Find Full Text PDFCardiovasc Eng Technol
December 2024
Department of Cardiovascular and Thoracic Surgery, University of Louisville, 302 E. Muhammad Ali Blvd, Room 411, Louisville, KY, 40202, USA.
Purpose: CoRISMA MCS Systems Inc (Hamden CT) is developing an innovative mechanical circulatory support system (CMCS) as a durable therapeutic option for heart failure (HF) patients. The CMCS system is comprised of an axial flow pump, non-contacting hydrodynamic bearings, and integrated DC motor designed to be fully implantable in a left atrial (LA) to aortic (Ao) configuration; this unloading strategy may be particularly beneficial for HF patients with preserved ejection fraction (HFpEF). The small (5.
View Article and Find Full Text PDFMaterials (Basel)
June 2024
Department of Materials Science, Faculty of Mechanical Engineering and Aeronautics, Rzeszów University of Technology, 12 Powstancow Warszawy Ave., 35-959 Rzeszow, Poland.
Single point incremental forming (SPIF) is becoming more and more widely used in the metal industry due to its high production flexibility and the possibility of obtaining larger material deformations than during conventional sheet metal forming processes. This paper presents the results of the numerical modeling of friction stir rotation-assisted SPIF of commercially pure 0.4 mm-thick titanium sheets.
View Article and Find Full Text PDFNanotechnology
April 2024
School of Mechanical and Electrical Engineering, Lanzhou University of Technology, Lanzhou, 730050, People's Republic of China.
Herein, we employ molecular dynamics simulations to decode the friction properties and phonon energy dissipation between black phosphorus layers. The observations reveal the influence of three factors, temperature, velocity, and normal load, on the friction force of monolayer/bilayer black phosphorus. Specifically, friction is negatively correlated with layer thickness and temperature, and positively correlated with velocity and normal load.
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