A single transistor preamplifier circuit was designed to facilitate electrical detection of mechanical oscillations in nanoelectromechanical systems (NEMSs) at low temperatures. The amplifier was integrated in the close vicinity of the nanowire inside the cryostat to minimize cabling load and interference. The function of the circuit was impedance conversion for current flow measurements in NEMSs with a high internal resistance. The circuit was tested to operate at temperatures as low as 5 K and demonstrated the ability to detect oscillations in double-clamped bismuth selenide nanowires upon excitation by a 0.1 MHz-10 MHz AC signal applied to a mechanically separated gate electrode. A strong resonance frequency dependency on temperature was observed. A relatively weak shift in the oscillation amplitude and resonance frequency was measured when a DC bias voltage was applied to the gate electrode at a constant temperature.
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http://dx.doi.org/10.3390/mi14101910 | DOI Listing |
Nano Lett
January 2025
Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027 Zhejiang, China.
Chiral vortices and their phase transition in ferroelectric/dielectric heterostructures have drawn significant attention in the field of condensed matter. However, the dynamical origin of the chiral phase transition from achiral to chiral polar vortices has remained elusive. Here, we develop a phase-field perturbation model and discover the softening of out-of-plane vibration mode of polar vortices in [(PbTiO)/(SrTiO)] superlattices at a critical epitaxial strain or temperature.
View Article and Find Full Text PDFClin Ther
January 2025
Department of Mechanical, Energy and Materials Engineering, School of Industrial Engineering, University of Extremadura, Badajoz, Spain.
Purpose: The aim of this study was to propose a lateral oscillating device for the prevention of pressure ulcers by understanding the mechanisms of tissue protection in healthy individuals during prolonged decubitus. We also sought to determine the optimal time interval for oscillation, considering peak pressure peaks and tolerable pressure limits as a function of individual characteristics such as age, weight, height, gender, and BMI.
Methods: A quasi-experimental, descriptive and analytical observational study was conducted between January 2022 and June 2023 with a sample of 25 healthy volunteers.
Biomaterials
January 2025
Prometheus Division of Skeletal Tissue Engineering, KU Leuven, O&N1, Herestraat 49, PB 813, 3000, Leuven, Belgium; Skeletal Biology and Engineering Research, KU Leuven, ON1 Herestraat 49, PB 813, 3000, Leuven, Belgium. Electronic address:
Self-assembled cartilaginous microtissues provide a promising means of repairing challenging skeletal defects and connective tissues. However, despite their considerable promise in tissue engineering, the mechanical response of these engineered microtissues is not well understood. Here we examine the mechanical and viscoelastic response of progenitor cell aggregates formed from human primary periosteal cells and the resulting cartilaginous microtissues under large deformations as might be encountered in vivo.
View Article and Find Full Text PDFISA Trans
January 2025
Leuphana University of Lueneburg, Universitaetsallee 1, 21335 Lueneburg, Germany. Electronic address:
This paper addresses a non-interacting torque control strategy to decouple the d- and q-axis dynamics of a permanent magnet synchronous machine (PMSM). The maximum torque per ampere (MTPA) method is used to determine the reference currents for the desired torque. To realize the noninteracting control, knowledge concerning the inductances L and L of the electrical machine is necessary.
View Article and Find Full Text PDFSensors (Basel)
January 2025
School of Mechanical, Aerospace & Civil Engineering, University of Sheffield, Sheffield S1 3JD, UK.
Stress wave dispersion can result in the loss or distortion of critical high-frequency data during high-strain-rate material tests or blast loading experiments. The purpose of this work is to demonstrate the benefits of correcting stress wave dispersion in split-Hopkinson pressure bar experiments under various testing situations. To do this, an innovative computational algorithm, SHPB_Processing.
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