Results 111 to 120 of about 5,889,360 (355)

Positive Definite $\ell_1$ Penalized Estimation of Large Covariance Matrices [PDF]

open access: yes, 2012
The thresholding covariance estimator has nice asymptotic properties for estimating sparse large covariance matrices, but it often has negative eigenvalues when used in real data analysis.
Ma, Shiqian, Xue, Lingzhou, Zou, Hui
core  

Cell Calcification Models and Their Implications for Medicine and Biomaterial Research

open access: yesAdvanced Healthcare Materials, EarlyView.
Calcification, is the process by which the tissues containing minerals are formed, occurring during normal physiological processes, or in pathological conditions. Here, it is aimed to give a comprehensive overview of the range of cell models available, and the approaches taken by these models, highlighting when and how methodological divergences arise,
Luke Hunter   +5 more
wiley   +1 more source

Characterization of quadratic growth of extended-real-valued functions

open access: yesJournal of Inequalities and Applications, 2016
This paper shows that the sharpest possible bound in the second-order growth condition of a proper lower semicontinuous function can be attained under some assumptions. We also establish a relationship among strong metric subregularity, quadratic growth,
Jin jiang Wang, Wen Song
doaj   +1 more source

A determinant characterization of moment sequences with finitely many mass-points

open access: yes, 2014
To a sequence (s_n)_{n\ge 0} of real numbers we associate the sequence of Hankel matrices \mathcal H_n=(s_{i+j}),0\le i,j \le n. We prove that if the corresponding sequence of Hankel determinants D_n=\det\mathcal H_n satisfy D_n>0 for ...
Berg, Christian, Szwarc, Ryszard
core   +1 more source

Recent Advances in Heterogeneous Frustrated Lewis Pair: Synthesis, Characterization, and Catalysis

open access: yesAdvanced Materials, EarlyView.
This review provides a concise analysis of heterogeneous frustrated Lewis pair (FLP) chemistry, focusing on their synthesis, characterization, and application in small‐molecule activation. It highlights current challenges in developing solid FLP systems and explores promising advancements through emerging technologies, offering critical insights into ...
Jiasi Li   +2 more
wiley   +1 more source

Néel Tensor Torque in Polycrystalline Antiferromagnets

open access: yesAdvanced Materials, EarlyView.
This work introduces a Néel tensor torque based on a rank‐two symmetric tensor capturing spin correlations in a polycrystalline antiferromagnet. It shows the Néel tensor can be shaped and reshaped through the spin‐orbit torque (SOT) technique, enabling field‐free SOT switching with a specific polarity of the adjacent ferromagnet. This discovery opens a
Chao‐Yao Yang   +4 more
wiley   +1 more source

Reliability and Quality of Complex Systems

open access: yesНадежность и качество сложных систем
Background. Mathematical modeling of processes of various physical and chemical nature is the most important stage in solving problems of design and operation of various physical and chemical systems.
I.E. Starostin
doaj   +1 more source

Artificial Intelligence‐Assisted Workflow for Transmission Electron Microscopy: From Data Analysis Automation to Materials Knowledge Unveiling

open access: yesAdvanced Materials, EarlyView.
AI‐Assisted Workflow for (Scanning) Transmission Electron Microscopy: From Data Analysis Automation to Materials Knowledge Unveiling. Abstract (Scanning) transmission electron microscopy ((S)TEM) has significantly advanced materials science but faces challenges in correlating precise atomic structure information with the functional properties of ...
Marc Botifoll   +19 more
wiley   +1 more source

Unveiling the Electrolyte and Solid Electrolyte Interphase in Sodium Ion Batteries: Mechanisms, Progress, and Perspectives

open access: yesAdvanced Materials, EarlyView.
This review summarizes the recent advances in sodium‐ion battery electrolytes (including organic, aqueous, gel, ionic liquid, and solid‐state types) and their influence on the solid electrolyte interphase (SEI). It discusses SEI formation, aging, and optimization, as well as cases where no SEI forms, providing insights into the critical relationship ...
Meng Li   +8 more
wiley   +1 more source

Equivalent definitions of positive definiteness [PDF]

open access: yesPacific Journal of Mathematics, 1984
Maserick, P. H., Szafraniec, F. H.
openaire   +2 more sources

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