23,631 research outputs found
Effective models for charge transport in DNA nanowires
The rapid progress in the field of molecular electronics has led to an
increasing interest on DNA oligomers as possible components of electronic
circuits at the nanoscale. For this, however, an understanding of charge
transfer and transport mechanisms in this molecule is required. Experiments
show that a large number of factors may influence the electronic properties of
DNA. Though full first principle approaches are the ideal tool for a
theoretical characterization of the structural and electronic properties of
DNA, the structural complexity of this molecule make these methods of limited
use. Consequently, model Hamiltonian approaches, which filter out single
factors influencing charge propagation in the double helix are highly valuable.
In this chapter, we give a review of different DNA models which are thought to
capture the influence of some of these factors. We will specifically focus on
static and dynamic disorder.Comment: to appear in "NanoBioTechnology: BioInspired device and materials of
the future". Edited by O. Shoseyov and I. Levy. Humana Press (2006
Modeling molecular conduction in DNA wires: Charge transfer theories and dissipative quantum transport
Measurements of electron transfer rates as well as of charge transport
characteristics in DNA produced a number of seemingly contradictory results,
ranging from insulating behaviour to the suggestion that DNA is an efficient
medium for charge transport. Among other factors, environmental effects appear
to play a crucial role in determining the effectivity of charge propagation
along the double helix. This chapter gives an overview over charge transfer
theories and their implication for addressing the interaction of a molecular
conductor with a dissipative environment. Further, we focus on possible
applications of these approaches for charge transport through DNA-based
molecular wires
Asymmetries Between Strange and Antistrange Particle Production in Pion-Proton Interactions
Recent measurements of the asymmetries between Feynman distributions of
strange and antistrange hadrons in interactions show a strong effect
as a function of . We calculate strange hadron production in the context
of the intrinsic model and make predictions for particle/antiparticle
asymmetries in these interactions.Comment: version to be published in Nucl. Phys. A, 46 pages LaTeX, 15 .eps
figure
The role of contacts in molecular electronics
Molecular electronic devices are the upmost destiny of the miniaturization
trend of electronic components. Although not yet reproducible on large scale,
molecular devices are since recently subject of intense studies both
experimentally and theoretically, which agree in pointing out the extreme
sensitivity of such devices on the nature and quality of the contacts. This
chapter intends to provide a general theoretical framework for modelling
electronic transport at the molecular scale by describing the implementation of
a hybrid method based on Green function theory and density functional
algorithms. In order to show the presence of contact-dependent features in the
molecular conductance, we discuss three archetypal molecular devices, which are
intended to focus on the importance of the different sub-parts of a molecular
two-terminal setup.Comment: 17 pages, 8 figure
Stellar Population Challenge: analysis of M67 with the VO
In this poster we present the analysis of the CMD of M67 (proposed in the
Stellar Population Challenge) performed with VO applications. We found that,
although the VO environment is still not ready to perform a complete analysis,
its use provides highly useful additional information for the analysis. Thanks
to the current VO framework, we are able to identify stars in the provided CMD
that are not suitable for isochrone fitting. Additionally, we can complete our
knowledge of this cluster extending the analysis to IR colors, which were not
provided in the original data but that are available thanks to the VO. On the
negative side, we find it difficult to access theoretical data from VO
applications, so, currently, it is not possible to perform completely the
analysis of the cluster inside the VO framework. However it is expected that
the situation will improve in a near future.Comment: Stellar Populations as Building Blocks of Galaxies, Proceedings of
IAU Symposium #241. Edited by A. Vazdekis and R. F. Peletier. Cambridge:
Cambridge University Press, 2007, pp. 173-17
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