Results 91 to 100 of about 1,372,895 (290)

Logarithm of the Discrete Fourier Transform

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2007
The discrete Fourier transform defines a unitary matrix operator. The logarithm of this operator is computed, along with the projection maps onto its eigenspaces. A geometric interpretation of the discrete Fourier transform is also given.
Michael Aristidou, Jason Hanson
doaj   +1 more source

2D Skeletal Muscle Thin Film Actuators Enhance Efficiency of Biohybrid Robots

open access: yesAdvanced Functional Materials, EarlyView.
2D skeletal muscle thin film actuators generate millinewton‐scale forces and millimeter‐scale strokes while remaining functional for over 30 days. Their force density is 20‐fold higher than 3D skeletal muscle actuators, enabling multi‐fin robots with tunable speed and multidirectional steering.
Maheera Bawa   +5 more
wiley   +1 more source

Sparse Fast Fourier Transform [PDF]

open access: yes, 2022
Analisi di un recente algoritmo in C++ per calcolare la Trasformata di Fourier Sparsa (SFT) di un segnale. L'algoritmo sfrutta la sparsità di un segnale nel dominio delle frequenze per calcolare la Trasformata Discreta di Fourier (DFT) in tempi ...
Turi, Leo
core  

Four Particular Cases of the Fourier Transform

open access: yesMathematics, 2018
In previous studies we used Laurent Schwartz’ theory of distributions to rigorously introduce discretizations and periodizations on tempered distributions.
Jens V. Fischer
doaj   +1 more source

Melanin's Role in Balancing Mechanical Strength and Reproductive Output in Environmentally Stressed Fungal Spores

open access: yesAdvanced Functional Materials, EarlyView.
Melanin content directly controls fungal spore mechanical properties, with pigmented spores achieving rupture forces two orders of magnitude higher than hyaline spores. Environmental stress drives this quantity‐quality tradeoff; stressed species invest energy in melanin‐reinforced, mechanically superior thick‐walled, super‐hydrophobic spores, while ...
Atul Agrawal, Steven E. Naleway
wiley   +1 more source

An Integrated Oxygen‐Supplying Device and Predictive Multiphysics Model for Extended Ambient Transport of Insulin‐Producing Cells

open access: yesAdvanced Functional Materials, EarlyView.
Cell therapies typically rely on cold‐chain logistics and cryopreservation, limiting access and compromising cell quality. Here, a dual‐chamber device separates an oxygen‐supplying chamber from a hyaluronic acid cargo chamber, sustaining oxygen delivery for over 70 h and enabling ambient‐temperature shipment.
Daniel A. Domingo‐Lopez   +9 more
wiley   +1 more source

Nanoscale Fourier-Transform Magnetic Resonance Imaging

open access: yesPhysical Review X, 2013
We report a method for nanometer-scale pulsed nuclear magnetic resonance imaging and spectroscopy. Periodic radio-frequency pulses are used to create temporal correlations in the statistical polarization of a solid organic sample.
John M. Nichol   +4 more
doaj   +1 more source

Electrically Induced Phase Transition and Synaptic Functionality in MoTe2/Graphene Memristors

open access: yesAdvanced Functional Materials, EarlyView.
An electrically induced reversible 2H ↔ 1T′ phase transition is demonstrated in a vertical Au/Ti/MoTe2/graphene memristor with a laterally contacted graphene electrode. Resistive switching proceeds through a compositionally invariant amorphous/2H ↔ amorphous/1T′ transformation, in which a self‐formed amorphous MoTe2 interfacial region is proposed to ...
Chien‐Hua Wang   +7 more
wiley   +1 more source

A visual approximation of a Fourier transforms operation using GeoGebra [PDF]

open access: yesITM Web of Conferences
Many engineering fields use the Fourier Transform. The purpose of the Fourier Transform is to decompose periodic signals into fundamental frequencies and harmonic frequencies.
Suwarno Djoko Untoro
doaj   +1 more source

Upcycling Keratin‐Based Textile Waste Into High‐Performance Hybrid Fibers Via Tuning the Interfacial Interactions

open access: yesAdvanced Functional Materials, EarlyView.
Keratin recovered from animal‐hair textile waste is fractionated and blended with cellulose to produce continuously spun hybrid fibers. Selecting the high‐molecular‐weight keratin fraction enables 30 wt.% keratin incorporation while maintaining high strength in dry and wet states.
Mian Zhai   +6 more
wiley   +1 more source

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