Results 171 to 180 of about 87,748 (318)

Solid Harmonic Wavelet Bispectrum for Image Analysis

open access: yesAdvanced Science, EarlyView.
The Solid Harmonic Wavelet Bispectrum (SHWB), a rotation‐ and translation‐invariant descriptor that captures higher‐order (phase) correlations in signals, is introduced. Combining wavelet scattering, bispectral analysis, and group theory, SHWB achieves interpretable, data‐efficient representations and demonstrates competitive performance across texture,
Alex Brown   +3 more
wiley   +1 more source

Perspective: Hollow Core Optical Fibres for Ultraviolet and Visible Wavelengths

open access: yesAdvanced Science, EarlyView.
Hollow core optical fibres bypass material constraints that limit optical fibres at ultraviolet and visible wavelengths. However, their challenging fabrication has limited their development, and significant gains in performance remain possible. In this perspective we outline approaches to enable the next generation of fibres for shorter wavelengths ...
Robbie Mears   +5 more
wiley   +1 more source

HARMONIC MAPPINGS [PDF]

open access: yesProceedings of the National Academy of Sciences, 1954
openaire   +3 more sources

The Harmonic Scalpel [PDF]

open access: yesThe Journal of Obstetrics and Gynecology of India, 2016
Dilip Kumar, Dutta, Indranil, Dutta
openaire   +2 more sources

Effect of Alkyl Chain Length on the Bandgap, Ferroelectric, and Photoelectric Properties of Lead‐Based Molecular Ferroelectrics

open access: yesAdvanced Science, EarlyView.
This study develops a novel 2D molecular ferroelectric [C6N2H18]PbI4 with polarization enhanced photovoltaics. It systematically investigates the effect of alkylamine spacer cation chain lengths on the band gap, ferroelectric, and photoelectric properties, offering new design strategies.
Ganghua Zhang   +7 more
wiley   +1 more source

Photonic Time Crystals and Time‐Varying Electromagnetic Metamatter: A New Direction for Ultrafast Tunable Photonic and Microwave Materials and Devices

open access: yesAdvanced Science, EarlyView.
Photonic time crystals (PTCs) are systems in which electromagnetic parameters are modulated periodically in time, producing momentum bandgaps via temporal scattering rather than spatial Bragg processes. This review examines the theoretical frameworks, modeling, and computational tools for time‐varying media, and summarizes experimental demonstrations ...
Ranjan Kumar Patel   +3 more
wiley   +1 more source

3D Large‐Scale Subwavelength‐Resolution Sound Sheet Tomography Based on an Active and Programmable Circular Meta‐Array

open access: yesAdvanced Science, EarlyView.
A programmable 2048‐element circular ultrasound array combined with a compact acoustic lens produces a thin “sound sheet” over a large field of view, and records echoes with wide angular diversity across the ring aperture. Coherence‐enhanced beamforming converts full‐matrix data into high‐contrast tomographic slices, delivering near‐diffraction‐limited
Qiu‐De Zhang   +11 more
wiley   +1 more source

The Importance of Metal‐Organic Framework Linker Atoms for CO2 Reduction: A DFT Study

open access: yesAdvanced Science, EarlyView.
Using DFT, we examine the role of linker atoms in CO2 reduction on copper‐based metal organic frameworks (Cu MOFs). Our calculations reveal that linker atoms may serve as both CO2 and H‐shuttling sites and suggest linker electrostatics as a descriptor for linker activity. ABSTRACT Although the metal within the secondary building unit of a metal‐organic
Ugochukwu Nwosu, Samira Siahrostami
wiley   +1 more source

Eccentricity harmonics detection-based speed estimation approach in a sensorless induction motors

open access: yes, 2015
This paper presents an eccentricity harmonics detection-based speed estimation method in a sensorless efficient induction motors. Because of the influence of spectrum leakage, the motor current signature signals analysis method, which is based the stator
Hu JT(胡静涛)   +3 more
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