59 research outputs found
An Efficient Molecular Dynamics Scheme for the Calculation of Dopant Profiles due to Ion Implantation
We present a highly efficient molecular dynamics scheme for calculating the
concentration depth profile of dopants in ion irradiated materials. The scheme
incorporates several methods for reducing the computational overhead, plus a
rare event algorithm that allows statistically reliable results to be obtained
over a range of several orders of magnitude in the dopant concentration.
We give examples of using this scheme for calculating concentration profiles
of dopants in crystalline silicon. Here we can predict the experimental profile
over five orders of magnitude for both channeling and non-channeling implants
at energies up to 100s of keV.
The scheme has advantages over binary collision approximation (BCA)
simulations, in that it does not rely on a large set of empirically fitted
parameters. Although our scheme has a greater computational overhead than the
BCA, it is far superior in the low ion energy regime, where the BCA scheme
becomes invalid.Comment: 17 pages, 21 figures, 2 tables. See: http://bifrost.lanl.gov/~reed
Early-Age-Related Changes in Proteostasis Augment Immunopathogenesis of Sepsis and Acute Lung Injury
adult) mechanisms that augment immunopathogenesis of sepsis and acute lung injury. model to standardize the efficacy of salubrinal (inhibitor of eIF2α de-phosphorylation) in controlling the accumulation of ubiquitinated proteins and the NFÎșB levels. Finally, we evaluated the therapeutic efficacy of salubrinal to correct proteostasis-imbalance in the adult mice based on its ability to control CLP induced IL-6 secretion or recruitment of pro-inflammatory cells.Our data demonstrate the critical role of early-age-related proteostasis-imbalance as a novel mechanism that augments the NFÎșB mediated inflammation in sepsis and ALI. Moreover, our data suggest the therapeutic efficacy of salubrinal in restraining NFÎșB mediated inflammation in the adult or older subjects
Absence of a Crystal Direction Regime in which Sputtering Corresponds to Amorphous Material
Erosion of material by energetic ions, i.e., sputtering, is widely used in industry and research. Using experiments and simulations that, independently of each other, obtain the sputter yield of thousands of individual grains, we demonstrate here that the sputter yield for heavy keV ions on metals changes as a continuous function of the crystal direction. Moreover, we show that polycrystalline metals with randomly oriented grains do not sputter with the same yield as the amorphous material. The key reason for this is attributed to linear collision sequences rather than channeling.Peer reviewe
EFFICIENT SIMULATION OF 3âD STRESS DISTRIBUTIONS AT TRENCH STRUCTURES CAUSED BY THERMAL MISMATCH OF TRENCH FILLING AND SILICON SUBSTRATE
Colonial Housing Reform and Transitions in Architecture in the Bella Coola Area of British Columbia
- âŠ