Results 51 to 60 of about 626 (221)

The Automorphism Group of the Infinite-Rank Free Group is Coarsely Bounded

open access: yes, 2022
We prove that the full automorphism group and the outer automorphism group of the free group of countably infinite rank are coarsely bounded. That is, these groups admit no continuous actions on a metric space with unbounded orbits, and have the quasi ...
Kwak, Sanghoon   +2 more
core  

Rapid Fabrication of Self‐Propelled and Steerable Magnetic Microcatheters for Precision Medicine

open access: yesAdvanced Materials, EarlyView.
A rapid Joule heating fabrication method for the production of self‐propelling, adaptive microcatheters, with tunable stiffness and integrated microfluidic channels is presented. Demonstrated through three microrobotic designs, including a steerable guiding catheter, an untethered wave‐crawling TubeBot, and a distal‐end propelled microcatheter, it was ...
Zhi Chen   +5 more
wiley   +1 more source

Atomistic Mechanisms Triggered by Joule Heating Effects in Metallic Cu‐Bi Nanowires for Spintronics

open access: yesAdvanced Materials, EarlyView.
Bi doped metallic Cu nanowires are promising for spintronics thanks to the stabilization of a giant spin Hall effect. However, heat resulting from current injection forces Bi to leave solution, forcing segregation into monoatomic decorations which evolve into coherent crystalline aggregates.
Alejandra Guedeja‐Marrón   +6 more
wiley   +1 more source

Tough, Ductile, and Strong Hard‐Soft Cementitious Composite Enabled by Multi‐Material Additive Manufacturing

open access: yesAdvanced Materials, EarlyView.
Drawing inspiration from the layered hard‐soft architecture found in sea sponges, this work establishes a new framework for architected cementitious composites (ACC) through multi‐material additive manufacturing (MMAM) process. The integration of mortar and elastomer phases into layered architectures enables synergistic toughening mechanisms, including
Aimane Najmeddine   +5 more
wiley   +1 more source

On the Splitting of Modules and Abelian Groups

open access: yes, 1974
In a fundamental paper on torsion-free abelian groups, R. Baer [1] proved that the group P of all sequences of integers with respect to componentwise addition is not free. This means precisely that P is not a direct sum of infinite cyclic groups. However,
Paul Hill
core   +1 more source

Topology and Material Optimization in Ultra‐Soft Magneto‐Active Structures: Making Advantage of Residual Anisotropies

open access: yesAdvanced Materials, EarlyView.
Residual magnetization induces pronounced mechanical anisotropy in ultra‐soft magnetorheological elastomers, shaping deformation and actuation even without external magnetic fields. This study introduces a computational‐experimental framework integrating magneto‐mechanical coupling into topology optimization for designing soft magnetic actuators with ...
Carlos Perez‐Garcia   +3 more
wiley   +1 more source

Groups with positive rank gradient and their actions

open access: yes, 2018
We show that given a finitely generated LERF group G with positive rank gradient, and finitely generated subgroups A, B ≤ G of infinite index, one can find a finite index subgroup B 0 of B such that [G : 〈A ∪ B 0〉] = ∞.
Mark Shusterman
core   +1 more source

New‐Era Polymer Thermoelectrics: Material Innovations, Doping Frontiers, Decoupling Strategies, and Unconventional Applications

open access: yesAdvanced Materials, EarlyView.
The field of polymer thermoelectrics is entering a new era, featuring breakthroughs in addressing the conventional performance disparity between p‐type and n‐type polymers, pioneering doping frontiers, and sophisticated decoupling strategies. This review explores innovations in molecular design and superior stabilities, bridging the gap from ...
Suhao Wang
wiley   +1 more source

Residual Properties of Free Groups

open access: yes, 1993
In this paper the following is proved: If X is an infinite class of finite simple groups of Lie-type such that the corresponding set of Lie-ranks is unbounded, then free groups of rank at least 2 are residually X.
Weigel, T.S.
core   +1 more source

Miniature Soft Robot With Magnetically Reprogrammable Surgical Functions

open access: yesAdvanced Materials, EarlyView.
Miniature soft robots have great prospects to revolutionize minimally invasive treatments. Here we present a miniature soft robot, which can be reprogrammed to perform five surgical functionalities with six‐degrees‐of‐freedom motions. This soft robot can prospectively make minimally invasive surgery considerably safer and painless, and enable ...
Chelsea Shan Xian Ng   +4 more
wiley   +1 more source

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