1,778 research outputs found
Two-speed deflection system for electron micropattern generator
Development of dual speed deflection system for electron beam micropattern generator system is discussed. Factors affecting application of electron beam lithography are analyzed. Procedure for using two speed deflection system is described
Dual field alignment display and control for electron micropattern generator
Application of electron beam lithography to replace photolithography process in fabrication of integrated circuits is discussed. Procedure for using electron beam lithography equipment is described. Diagram of electron micropattern generator is provided
Interpolating fields of carbon monoxide data using a hybrid statistical-physical model
Atmospheric Carbon Monoxide (CO) provides a window on the chemistry of the
atmosphere since it is one of few chemical constituents that can be remotely
sensed, and it can be used to determine budgets of other greenhouse gases such
as ozone and OH radicals. Remote sensing platforms in geostationary Earth orbit
will soon provide regional observations of CO at several vertical layers with
high spatial and temporal resolution. However, cloudy locations cannot be
observed and estimates of the complete CO concentration fields have to be
estimated based on the cloud-free observations. The current state-of-the-art
solution of this interpolation problem is to combine cloud-free observations
with prior information, computed by a deterministic physical model, which might
introduce uncertainties that do not derive from data. While sharing features
with the physical model, this paper suggests a Bayesian hierarchical model to
estimate the complete CO concentration fields. The paper also provides a direct
comparison to state-of-the-art methods. To our knowledge, such a model and
comparison have not been considered before.Comment: Published in at http://dx.doi.org/10.1214/08-AOAS168 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
The role of cluster evolution in disrupting planetary systems and disks: the Kozai mechanism
We examine the effects of dynamical evolution in clusters on planetary
systems or protoplanetary disks orbiting the components of binary stars. In
particular, we look for evidence that the companions of host stars of planetary
systems or disks could have their inclination angles raised from zero to
between the threshold angles (39.23 degrees and 140.77 degrees) that can induce
the Kozai mechanism. We find that up to 20 per cent of binary systems have
their inclination angles increased to within the threshold range. Given that
half of all extrasolar planets could be in binary systems, we suggest that up
to 10 per cent of extrasolar planets could be affected by this mechanism.Comment: 5 pages, 4 figures, accepted for publication in MNRAS. References
update
Polarons and Solitons in Jahn-Teller Systems
Using a semiclassical continuum model of an electron in a deformable
molecular crystal, some properties of multicomponent generalizations of the
polaron--``vector polarons''-- are elucidated. Analytical solutions for the
case of two electronic bands coupled to two vibrational modes are given in
detail. Within the model considered, the vector polaron can be classified by
its wavefunction into several types and can have features that include: (1) a
spatial variation in the electronic and vibrational character, and (2)
low-energy internal degrees of freedom. For the case of electronic and
vibrational degeneracy, local Jahn-Teller interactions can also lead to a novel
spatiotemporal soliton, a long-lived excited state of the many-electron system
stabilized by the conservation law resulting from degeneracy.Comment: 10 pages, 0 figures. International Symposium on Jahn-Teller Effects,
ICTP, Trieste, Ital
The origin of very wide binary systems
The majority of stars in the Galactic field and halo are part of binary or
multiple systems. A significant fraction of these systems have orbital
separations in excess of thousands of astronomical units, and systems wider
than a parsec have been identified in the Galactic halo. These binary systems
cannot have formed through the 'normal' star-formation process, nor by capture
processes in the Galactic field. We propose that these wide systems were formed
during the dissolution phase of young star clusters. We test this hypothesis
using N-body simulations of evolving star clusters and find wide binary
fractions of 1-30%, depending on initial conditions. Moreover, given that most
stars form as part of a binary system, our theory predicts that a large
fraction of the known wide 'binaries' are, in fact, multiple systems.Comment: 4 pages, 1 figure, to appear in the proceedings of IAU Symposium 266,
eds. R. de Grijs & J.R.D. Lepin
Host-based identification is not supported by morphometrics in natural populations of Gyrodactylus salaris and G. thymalli (Platyhelminthes, Monogenea)
Gyrodactylus salaris is a serious pest of wild pre-smolt Atlantic salmon (Salmo salar) in Norway. The closely related G. thymalli, originally described from grayling (Thymallus thymallus), is assumed harmless to both grayling and salmon. The 2 species are difficult to distinguish using traditional, morphometric methods or molecular approaches. The aim of this study was to explore whether there is a consistent pattern of morphometrical variation between G. salaris and G. thymalli and to analyse the morphometric variation in the context of ‘diagnostic realism’ (in natural populations). Specimens from the type-material for the 2 species are also included. In total, 27 point-to-point measurements from the opisthaptoral hard parts were used and analysed by digital image processing and uni- and multivariate morphometry. All populations most closely resembled its respective type material, as expected from host species, with the exception of G. thymalli from the Norwegian river Trysilelva. We, therefore, did not find clear support in the morphometrical variation among G. salaris and G. thymalli for an a priori species delineation based on host. The present study also indicates an urgent need for more detailed knowledge on the influence of environmental factors on the phenotype of gyrodactylid populations
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