Results 81 to 90 of about 79,804 (306)

Random Rearrangements of Fourier Coefficients [PDF]

The Annals of Mathematics, 1976
In [2] and [3] Hardy and Littlewood gave (1) necessary and sufficient conditions that numbers on, -0 should be, for every variation of their arguments and arrangement, the Fourier coefficients of a function in LP (2 < p < c), and (2) necessary and sufficient conditions that such numbers should be, for some variation of their arguments and arrangement ...
openaire   +3 more sources

Dual‐Salt Carbothermal Shock Strategy Enabling Ultrafast and Sustainable Regeneration of Spent LiFePO4 Cathode Materials

Advanced Functional Materials, EarlyView.
Lithium iron phosphate (LFP) accounts for over 50% of the global cathode market, underscoring the need for efficient recycling and regeneration. We propose a dual‐salt carbothermal shock (CTS) strategy using LiI and NaI to in situ repair Li vacancies.
Yanjuan Li, Zhongou Yang, Junhui Cai, Yiran Li, Zhenzhen Wu, Zhouyang Long, Xiao Yan, Shanqing Zhang   +7 more
wiley   +1 more source

Binder Engineering Suppresses Jahn–Teller‐Driven Mn Dissolution and Enables High‐Loading MnO2 Cathodes for Aqueous Zn‐Ion Batteries

Advanced Functional Materials, EarlyView.
A Zn2+‐coordinated poly(vinylidene fluoride) binder is shown to suppress Jahn–Teller‐driven Mn dissolution while improving dispersion, wettability, and structural integrity in thick MnO2 cathodes. This simple binder‐engineering strategy enables high‐loading aqueous Zn‐ion batteries with enhanced areal capacity, cycling stability, and practical promise ...
Insung Jang, Geun Yoo, Geon−Hyoung An
wiley   +1 more source

Fourier coefficients-based stepwise Bayesian inversion for elastic and fracture parameters using azimuthal seismic data

Frontiers in Earth Science
The inversion of elastic and fracture parameters from azimuthal seismic data plays a critical role in charactering naturally fractured reservoirs. We propose a Fourier coefficients-based stepwise Bayesian inversion method to estimate these reservoir ...
Jingkun Sui, Haowen Xu, Sheng Chen, Xiaodong Zheng, Xinpeng Pan   +4 more
doaj   +1 more source

FOURIER COEFFICIENTS OF CONTINUOUS FUNCTIONS WITH RESPECT TO LOCALIZED HAAR SYSTEM

Проблемы анализа, 2017
We construct a nontrivial example of a continuous function f* on [0, 1]² which is orthogonal to tensor products of Haar functions supported on intervals of the same length.
E. S. Belkina, Yu. V. Malykhin
doaj   +1 more source

Dipole‐Engineered Conductive Additives for Ultrastable Interphase Evolution in High‐Areal‐Capacity Silicon Anodes

Advanced Functional Materials, EarlyView.
In the work reported herein, dipole‐engineered sulfonated carbon nanofibers enable conductive additives to actively regulate interphase formation in silicon anodes. Polar sulfonyl groups guide electrolyte decomposition to form a compact LiF‐rich interphase while promoting robust integration with silicon.
Song Kyu Kang, Hyeonju Kim, Jeongbin Cho, Minseon Park, Taehun Kim, Seonghun Sin, Won Bae Kim   +6 more
wiley   +1 more source

On summation of Fourier series in finite form

Discrete and Continuous Models and Applied Computational Science
The problem of summation of Fourier series in finite form is formulated in the weak sense, which allows one to consider this problem uniformly both for classically convergent and for divergent series. For series with polynomial Fourier coefficients \(a_n,
Mikhail D. Malykh, Ksaverii Yu. Malyshev
doaj   +1 more source

In Situ Crystalline‐Amorphous Composite Oxide Structure Suppressing Thermal Wear Instability for Refractory Multi‐Principal Element Alloy

Advanced Functional Materials, EarlyView.
An effective strategy is developed to overcome the medium temperatures wear resistance degradation in refractory multi‐principal element alloys. By utilizing chemical short‐range ordering to trigger oxygen‐induced amorphization, a composite oxide structure is formed, which combines high hardness with robust stiffness.
Xuhui Pei, Jianbao Zhang, Hanming Wang, Yin Du, Tao Yang, Ji‐Jung Kai, Benyebka Bou‐Saïd, Haifeng Wang   +7 more
wiley   +1 more source

Functions of Minimal Norm with the Given Set of Fourier Coefficients

Mathematics, 2019
We prove the existence and uniqueness of the solution of the problem of the minimum norm function ∥ · ∥ ∞ with a given set of initial coefficients of the trigonometric Fourier series c j , j = 0 , 1 , … , 2 n ...
Pyotr Ivanshin
doaj   +1 more source

Spectroscopic Investigation of Polysulfide Redox Evolution in Catholyte Solutions for Potassium–Sulfur Batteries

Advanced Functional Materials, EarlyView.
Potassium–sulfur batteries are investigated using UV–vis spectroscopy to track the evolution of potassium polysulfide species at elevated temperature. The study reveals sulfur radical anions as key intermediates and shows how solvent composition and cell design influence polysulfide stability, redox behavior, and cycling performance, providing insights
Chiara Morini, Dawid Kasprzak, Lincoln Crowe, Cecilia Spedalieri, Johannes Baller, Naiyu Qi, Fariza Kalyk, Gustav Graeber   +7 more
wiley   +1 more source