Results 81 to 90 of about 104,752 (294)

Two fermion relativistic bound states: hyperfine shifts

open access: yes, 2006
We discuss the hyperfine shifts of the Positronium levels in a relativistic framework, starting from a two fermion wave equation where, in addition to the Coulomb potential, the magnetic interaction between spins is described by a Breit term.
Akhiezer A I   +18 more
core   +1 more source

End‐to‐End Sensing Systems for Breast Cancer: From Wearables for Early Detection to Lab‐Based Diagnosis Chips

open access: yesAdvanced Materials Technologies, EarlyView.
This review explores advances in wearable and lab‐on‐chip technologies for breast cancer detection. Covering tactile, thermal, ultrasound, microwave, electrical impedance tomography, electrochemical, microelectromechanical, and optical systems, it highlights innovations in flexible electronics, nanomaterials, and machine learning.
Neshika Wijewardhane   +4 more
wiley   +1 more source

Connecting fast-slow systems and Conley Index theory via transversality

open access: yesElectronic Journal of Differential Equations, 2010
Geometric Singular Perturbation Theory (GSPT) and Conley Index Theory are two powerful techniques to analyze dynamical systems. Conley already realized that using his index is easier for singular perturbation problems.
Christian Kuehn
doaj  

New spectral element method for the singular perturbation problem of second order

open access: yes上海师范大学学报. 自然科学版
As the solution of singular perturbation problem of second order has a boundary layer, it is difficult to obtain ideal approximation results for traditional numerical methods.
LIU Zhipeng, TAO Dongya
doaj   +1 more source

Transducers Across Scales and Frequencies: A System‐Level Framework for Multiphysics Integration and Co‐Design

open access: yesAdvanced Materials Technologies, EarlyView.
Transducers convert physical signals into electrical and optical representations, yet each mechanism is bounded by intrinsic trade‐offs across bandwidth, sensitivity, speed, and energy. This review maps transduction mechanisms across physical scale and frequency, showing how heterogeneous integration and multiphysics co‐design transform isolated ...
Aolei Xu   +8 more
wiley   +1 more source

Sliding mode control for permanent magnet synchronous motor of sensor-less considering time-varying disturbance

open access: yes机车电传动, 2023
To solve the degradation in control performance of permanent magnet synchronous motors (PMSMs) due to uncertainties from parameter perturbation, as well as the problems arising from the speed sensor, such as high cost, demanding environmental ...
LI Xiangfei   +5 more
doaj  

Highly Anisotropic Quasi‐Direct Organic Metal Halide Hybrids: A Platform for Polarization‐Sensitive Optoelectronics

open access: yesAdvanced Materials Technologies, EarlyView.
One‐dimensional C4N2H14PbBr4 is shown to have a quasi‐direct electronic band structure and strongly anisotropic transport with polarized broadband emission. A GW/Bethe–Salpeter excited‐state force formalism, supported by polarized Raman and temperature‐dependent photoluminescence, identifies low–frequency Pb–Br phonons that drive ultrafast exciton self‐
Rijan Karkee   +7 more
wiley   +1 more source

Collision‐Resilient Winged Drones Enabled by Tensegrity Structures

open access: yesAdvanced Robotics Research, EarlyView.
Based on structures of birds such as the woodpeck, this article presents the collision‐resilient aerial robot, SWIFT. SWIFT leverages tensegrity structures in the fuselage and wings which allow it to undergo large deformations in a crash, without sustaining damage. Experiments show that SWIFT can reduce impact forces by 70% over conventional structures.
Omar Aloui   +5 more
wiley   +1 more source

A singular perturbation problem

open access: yes, 2004
Consider the equation $-s^2 u_s+q(x)u_s=f(u_s)$ in $\R^3$, $|u(\infty)|0$. Under what assumptions on $q(x)$ and $f(u)$ can one prove that the solution $u_s$ exists and $\lim_{s\to 0} u_s=u(x)$, where $u(x)$ solves the limiting problem $q(x)u=f(u)$? These are the questions discussed in the paper.
openaire   +2 more sources

Multimodal Actuation and Environment Adaptive Strategies of Bio‐Inspired Micro/Nanorobots in Precision Medicine

open access: yesAdvanced Robotics Research, EarlyView.
An introduction for multidrive and environment‐adaptive micro/nanorobotics: design and fabrication strategies, intelligent actuation, and their applications. Various intelligent actuation approaches—magnetic, acoustic, optical, chemical, and biological—can be synergistically designed to enhance flexibility and adaptive behavior for precision medicine ...
Aiqing Ma   +10 more
wiley   +1 more source

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