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Nucleation and kinetics of defects at the atomic scale provide the most fundamental information about the mechanical response of materials and surfaces. Recent advances in experimental and computational analyses allow us to study this phenomenon in the context of nanoindentation and localized mechanical probing of surfaces. Here, we present an analytical(More)
Nanometre-scale contact experiments and simulations demonstrate the potential to probe incipient plasticity--the onset of permanent deformation--in crystals. Such studies also point to the need for an understanding of the mechanisms governing defect nucleation in a broad range of fields and applications. Here we present a fundamental framework for(More)
Recent advances in nanotechnology have stimulated novel applications in biomedicine where nanoparticles (NPs) are used to achieve drug delivery and photodynamic therapy. In chemotherapeutic cancer treatment, tumor-specific drug delivery is a topic of considerable research interest for achieving enhanced therapeutic efficacy and for mitigating adverse side(More)
We report the creation of a nanoscale electrochemical device inside a transmission electron microscope--consisting of a single tin dioxide (SnO(2)) nanowire anode, an ionic liquid electrolyte, and a bulk lithium cobalt dioxide (LiCoO(2)) cathode--and the in situ observation of the lithiation of the SnO(2) nanowire during electrochemical charging. Upon(More)
Nano-twinned copper exhibits an unusual combination of ultrahigh strength and high ductility, along with increased strain-rate sensitivity. We develop a mechanistic framework for predicting the rate sensitivity and elucidating the origin of ductility in terms of the interactions of dislocations with interfaces. Using atomistic reaction pathway calculations,(More)
We propose a method to induce microchannel ͑Poiseuille͒ flow in a molecular-dynamics simulation by introducing a partially reflecting ''membrane'' as a means of driving the fluid flow while conserving particle number and total energy. We also develop a method to estimate various continuous macroscopic fields from particle data, based on maximum likelihood(More)
Indentation is a remarkably flexible mechanical test due to its relative experimental simplicity. Coupled with advances in instrument development, ease of implementation has made indentation a ubiquitous research tool for a number of different systems across size scales (nano to macro) and scientific/engineering disciplines. However, the exploration of(More)
In this paper we discuss the transformation of a sheet of material into a wide range of desired shapes and patterns by introducing a set of simple cuts in a multilevel hierarchy with different motifs. Each choice of hierarchical cut motif and cut level allows the material to expand into a unique structure with a unique set of properties. We can(More)