Results 51 to 60 of about 16,885,510 (241)

Extremal estimates of the Wiener index for weakly connected directed graphs

open access: yesМоделирование и анализ информационных систем
The article considers the Wiener index for weakly connected directed graphs. For such graphs, the distance $d(u,v)$ between vertices $u$ and $v$ is not always defined, which requires a correction for the Wiener index to be meaningful.
Dmitry Y. Chalyy
doaj   +1 more source

When Poor Exciton Dissociation Limits Photocurrents in Organic Solar Cells: Why Low Offset Non‐Fullerene Acceptor Blends Can't Be Efficient

open access: yesAdvanced Materials, EarlyView.
The energetic offset between the donor and the acceptor components in organic photoactive layers is central to the tradeoff between photovoltage and photocurrent losses. This Perspective covers the most important issues surrounding this topic in non‐fullerene acceptor blends, from the difficulty of accurately determining state energies and driving ...
Dieter Neher, Manasi Pranav
wiley   +1 more source

On a relation between Szeged and Wiener indices of bipartite graphs [PDF]

open access: yesTransactions on Combinatorics, 2012
Hansen et. al., using the AutoGraphiX software package, conjectured that the Szeged index Sz(G) and the Wiener index W(G) of a connected bipartite graph G with n ≥ 4 vertices and m ≥ n edges, obeys the relation Sz(G) − W(G) ≥ 4n − 8. Moreover, this bound
Ivan Gutman   +3 more
doaj  

Bioengineered Interfaces for Peripheral Nerve Sensory Restoration

open access: yesAdvanced Materials, EarlyView.
Half of amputees abandon their prosthetics for lack of feeling. This review charts the full path from peripheral nerve injury to restored sensation, through surgical, regenerative, noninvasive, and implanted approaches, and shows how injury type and interface material properties determine which strategy can deliver naturalistic feedback, and why ...
Sydney Swedick   +4 more
wiley   +1 more source

Inverse Problem on the Steiner Wiener Index

open access: yesDiscussiones Mathematicae Graph Theory, 2018
The Wiener index W(G) of a connected graph G, introduced by Wiener in 1947, is defined as W(G) =∑u,v∈V (G)dG(u, v), where dG(u, v) is the distance (the length a shortest path) between the vertices u and v in G. For S ⊆ V (G), the Steiner distance d(S) of
Li Xueliang, Mao Yaping, Gutman Ivan
doaj   +1 more source

Topological Spin‐Texture Transitions in van der Waals Magnets Revealed by X‐Ray Fourier Transform Holography

open access: yesAdvanced Materials, EarlyView.
Applied here for the first time to a 2D material, high‐resolution synchrotron x‐ray Fourier transform holography directly images topological spin textures in Fe3GeTe2. Combined with atomistic tight‐binding simulations including itinerant electrons and Rashba spin‐orbit coupling, the approach reveals labyrinth, skyrmion, and mixed phases, and uncovers ...
Sourav Chowdhury   +16 more
wiley   +1 more source

Biodiversity of butterflies in endosulfan-affected areas of Kerala, India

open access: yesJournal of Basic and Applied Zoology, 2020
Background Butterflies are considered as bio-indicators of a healthy and diversified ecosystem. Endosulfan was sprayed indiscriminately in large plantations of Kasaragod district, Kerala which had caused serious threats to the ecosystem.
K. N. Raghavendra   +3 more
doaj   +1 more source

The Wiener-Hopf solution of the isotropic penetrable wedge problem: diffraction and total field [PDF]

open access: yes, 2011
The diffraction of an incident plane wave by an isotropic penetrable wedge is studied using generalized Wiener-Hopf equations, and the solution is obtained using analytical and numerical-analytical approaches that reduce the Wiener-Hopf factorization to ...
Vito Daniele   +3 more
core   +1 more source

Elasticity‐Driven Periodic Polarization Patterns in a Chiral Ferroelectric Nematic Fluid

open access: yesAdvanced Materials, EarlyView.
Chiral polar ferroelectric nematic fluids exhibit spontaneous formation of stripe, square, and hexagonal polarization textures under confinement. Controlled by thickness and anchoring, these patterns produce spatially modulated nonlinear optical responses.
Anej Sterle   +11 more
wiley   +1 more source

A Weak Convergence to Hermite Process by Martingale Differences

open access: yesAdvances in Mathematical Physics, 2014
We consider the weak convergence to general Hermite process ZH,k of order k with index H. By applying martingale differences we construct a sequence {ZH,kn ,  n=1,2,…} of multiple Wiener-Itô stochastic integrals such that it converges in distribution to ...
Xichao Sun, Ronglong Cheng
doaj   +1 more source

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