The amplitude and phase evolution of the oscillations of a cantilever after a single tip-sample impact are investigated using a cross-correlation wavelet analysis. The excitation of multiple flexural modes is evidenced and the instantaneous amplitude and phase evolution is extracted from the experimental data at all frequencies simultaneously. The instantaneous total force acting on the tip during a single impact is reconstructed. This method has general relevance for the development of an atomic force spectroscopy of single tip-sample interactions, that develop in a few oscillation cycles of the interacting cantilever eigenmodes and their harmonics.
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http://dx.doi.org/10.1088/0957-4484/24/50/505716 | DOI Listing |
Sci Rep
December 2024
Department of Physics, Shahid Beheshti University, Tehran, 1983969411, Iran.
Machine learning interatomic potentials, as a modern generation of classical force fields, take atomic environments as input and predict the corresponding atomic energies and forces. We challenge the commonly accepted assumption that the contribution of an atom can be learned from the short-range local environment of that atom. We employ density functional theory calculations to quantify the decay of the induced electron density and electrostatic potential in response to local perturbations throughout insulating, semiconducting and metallic samples of different dimensionalities.
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December 2024
Department of Biophysics, Faculty of Environmental Biology, University of Life Sciences in Lublin, Akademicka 13, Lublin, 20-950, Poland.
Physical and photophysical properties of starch-based biopolymer films containing 5-(4-nitrophenyl)-1,3,4-thiadiazol-2-amine (NTA) powder as a nanofiller were examined using atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), stationary UV-Vis and fluorescence spectroscopy as well as resonance light scattering (RLS) and time-resolved measurements, and where possible, analyzed with reference to pristine NTA solutions. AFM studies revealed that the addition of NTA into the starch biopolymer did not significantly affect surface roughness, with all examined films displaying similar Sq values ranging from 70.7 nm to 79.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
School of Agriculture and Bioengineering, Heze University, Heze 274500, China. Electronic address:
Herin, the successful synthesis of a bis Schiff base (L) has been achieved using 2-hydroxy-1-naphthaldehyde and 1,3-diaminoguanidine as raw materials, which was further characterized by infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance hydrogen spectrum. Moreover, spectroscopic experiments demonstrated that the probe L showed good selectivity and visual detectability for Al. Its detection limit (DL) is 2.
View Article and Find Full Text PDFVestn Oftalmol
December 2024
Institute of Regenerative Medicine of the Sechenov University, Moscow, Russia.
Unlabelled: The scientific and practical interest in studying the biomechanical characteristics of the lens capsule, on the one hand, is associated with its anatomical significance in modern microinvasive phaco surgery, and on the other hand, with investigation of the mechanisms of lens curvature changes during accommodation. Selective study of the biomechanical properties of the lens capsule aims to identify characteristics of various regions and surfaces of the capsule.
Purpose: This study is a comparative analysis of age-related changes in the biomechanical properties of the anterior (AC) and posterior (PC) lens capsules in humans.
Sci Rep
December 2024
Department of Mathematics, Payame Noor University, Tehran, Iran.
In the realm of petroleum extraction, well productivity declines as reservoirs deplete, eventually reaching a point where continued extraction becomes economically unfeasible. To counteract this, artificial lift techniques are employed, with gas injection being a prevalent method. Ideally, unrestricted gas injection could maximize oil output.
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