Results 61 to 70 of about 471,906 (281)

From Fourier to Gegenbauer: Dimension walks on spheres [PDF]

open access: yes, 2014
We show that the even- resp. odd-dimensional Schoenberg coefficients in Gegenbauer expansions of isotropic positive definite functions on the d-sphere can be expressed as linear combinations of Fourier resp. Legendre coefficients, and we give closed form
Fiedler, Jochen
core  

Unassisted Photoelectrochemical Hydrogen Production Coupled with Selective Glucose Oxidation Using Metal Halide Perovskite Photoanodes

open access: yesAdvanced Functional Materials, EarlyView.
A metal halide perovskite‐based photoanode integrated with a CoNiFe layered double hydroxide (LDH) cocatalyst is reported for selective glucose oxidation reaction (GOR), achieving simultaneous and unassisted photoelectrochemical hydrogen production. This system delivers high photocurrent density, excellent Faradaic efficiency of GOR, and strong techno ...
Shujie Zhou   +12 more
wiley   +1 more source

Almost Periodic Solutions for Some Convolution Equations

open access: yesAnalele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2013
We use the theory of Fourier series for almost periodic functions to looking for complex-valued functions f which are almost periodic on R and satisfy the following ...
Corduneanu Silvia-Otilia
doaj   +1 more source

FOURIER COEFFICIENTS FOR THE LIGHT CURVES OF 62 MIRA-TYPE STARS

open access: yesOdessa Astronomical Publications, 2017
For 62 Mira-type stars the values of periods have been redetermined; the mean curves have   been fitted by a trigonometric polynomial with an optimal number of harmonics; a number of the parameters of the light curve have been calculated (amplitude of ...
L. S. Kudashkina, I. L. Andronov
doaj   +1 more source

Near‐Infrared Emitting Lanthanide Catecholate Giant Single Crystals – Morphology Control and Photon Down‐Conversion

open access: yesAdvanced Functional Materials, EarlyView.
Controlled syntheses of lanthanide coordination polymers based on the dihydroxybenzoquinone (DHBQ) organic linker afforded large single crystals of Ln‐DHBQ CPs (Ln = Yb, Nd). A novel structural variant of Yb‐DHBQ is identified by means of single crystal diffraction analysis.
Marina I. Schönherr   +7 more
wiley   +1 more source

Laguerre-Volterra Filters Optimization Based on Laguerre Spectra

open access: yesEURASIP Journal on Advances in Signal Processing, 2005
New batch and adaptive methods are proposed to optimize the Volterra kernels expansions on a set of Laguerre functions. Each kernel is expanded on an independent Laguerre basis. The expansion coefficients, also called Fourier coefficients, are estimated
Hassani Moha M   +2 more
doaj   +1 more source

Reconstruction of Piecewise Smooth Multivariate Functions from Fourier Data

open access: yesAxioms, 2020
In some applications, one is interested in reconstructing a function f from its Fourier series coefficients. The problem is that the Fourier series is slowly convergent if the function is non-periodic, or is non-smooth. In this paper, we suggest a method
David Levin
doaj   +1 more source

Defect Analysis of the β– to γ–Ga2O3 Phase Transition

open access: yesAdvanced Functional Materials, EarlyView.
The role of defects at all the relevant stages of the β$\beta$‐ to γ$\gamma$‐Ga2O3 polymorph transition is investigated using a multi method approach. The positron annihilation spectroscopy based results show that the defect density decreases after the transition, and that changes in defect configuration within the γ phase occur with increasing ...
Umutcan Bektas   +9 more
wiley   +1 more source

Constrained and Vanishing Expressivity of Quantum Fourier Models [PDF]

open access: yesQuantum
In this work, we highlight an unforeseen behavior of the expressivity of Parameterized Quantum Circuits (PQCs) for machine learning. A large class of these models, seen as Fourier series whose frequencies are derived from the encoding gates, were thought
Hela Mhiri   +5 more
doaj   +1 more source

Emergence of Light‐Transforming Layered Hybrid Halide Perovskites

open access: yesAdvanced Functional Materials, EarlyView.
The emerging class of light‐transforming layered halide perovskite materials is reviewed, outlining challenges for their development and perspectives toward application in the future. Abstract Layered hybrid halide perovskites (LHPs) have attracted considerable attention in optoelectronics.
Ghewa AlSabeh, Jovana V. Milić
wiley   +1 more source

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