相关论文: Softening of ultra-nanocrystalline diamond at low …
Noble metal nanoparticles show specific optical properties due to the excitation of localized surface plasmons that make them attractive candidates for highly sensitive bionanosensors. The underlying physical principle is either an…
A nanocrystalline metal's strength increases significantly as its grain size decreases, a phenomenon known as the Hall-Petch relation. Such relation, however, breaks down when the grains become too small. Experimental studies have…
Dry granular materials such as sand, gravel, pills, or agricultural grains, can become rigid when compressed or sheared. At low density, one can distort the shape of a container of granular material without encountering any resistance.…
We report the studies of ultrafast electron nanocrystallography on size-selected Au nanoparticles (2-20 nm) supported on a molecular interface. Reversible surface melting, melting, and recrystallization were investigated with dynamical…
Scanning tunneling spectroscopies are performed below 100~mK on nano-crystalline boron-doped diamond films characterized by Transmission Electron Microscopy and transport measurements. We demonstrate a strong correlation between the local…
The widespread use of nanodiamond as a biomedical platform for drug-delivery, imaging, and sub-cellular tracking applications stems from their non-toxicity and unique quantum mechanical properties. Here, we extend this functionality to the…
An analytical mean field approach for describing the time evolution of film growth by seeding has been developed. The modeling deals with the generic case of anisotropic growth with different growth rates, respectively on -- and normal to…
Ultrananocrystalline Diamond Nanowire (UNCD NW) thin film was deposited on mirror polished silicon substrate (100) using Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) System with optimized deposition parameters in CH4 (6%)/N2…
Grain size engineering, particularly reducing grain size into the nanocrystalline regime, offers a promising pathway to further improve the strength-to-weight ratio of Al alloys. Unfortunately, the fabrication of nanocrystalline metals…
Nanostructures have the immense potential to supplant the traditional metallic structure as they show enhanced mechanical properties through strain hardening. In this paper, the effect of grain size on the hardening mechanism of Al-Cu…
Quantum-mechanical molecular-dynamics simulations are carried out to explore possible precursor states of nano-polycrystalline diamond, a novel ultra-hard material produced directly from graphite. Large-scale simulation with 10^5 atoms is…
Fluorescent nanodiamonds have been used to a large extent in various biological systems due to their robust nature, inert properties and the relative ease of modifying their surface for attachment to different functional groups. Within a…
The wear-driven structural evolution of nanocrystalline Cu was simulated with molecular dynamics under constant normal loads, followed by a quantitative analysis. While the microstructure far away from the sliding contact remains unchanged,…
Recent Raman data on diamond and crystalline Si nanopowders are analyzed with the use of a microscopic theory of Raman scattering in ensembles of disordered nonpolar nanocrystals. The large width of the Raman peak in nanoparticles as…
A correlation is established between the macro-scale friction regimes of metals and a transition between two dominant atomistic mechanisms of deformation. Metals tend to exhibit bi-stable friction behavior -- low and converging or high and…
Understanding and mastering the mechanical properties of metallic nanoparticles is crucial for their use in a wide range of applications. In this context, we use atomic-scale (Molecular Dynamics) and continuous (Finite Elements)…
Anisotropic core-shell model of a nano-grained polycrystal, proposed recently for nanocrystalline copper, is applied to estimate elastic effective properties for a set of crystals of cubic symmetry. Materials selected for analysis differ in…
Structural and mechanical properties of amorphous and nanocomposite carbon are investigated using tight-binding molecular dynamics and Monte Carlo simulations. In the case of amorphous carbon, we show that the variation of sp^3 fraction as…
It is now well established, both theoretically and experimentally, that very small changes in the size of isolated nanograins lead to substantial nonmonotonic variations, and sometimes enhancement, of the mean-field spectroscopic gap of…
In this work we investigated the time behavior of the polarization of bulk 13C nuclei in diamond above the thermal equilibrium. This nonthermal nuclear hyperpolarization is achieved by cross relaxation between two nitrogen related…