1,170 research outputs found
Divisia monetary services indexes for Switzerland: are they useful for monetary targeting?
Monetary policy - Switzerland ; Switzerland
Orbital parameters of extrasolar planets derived from polarimetry
Polarimetry of extrasolar planets becomes a new tool for their investigation,
which requires the development of diagnostic techniques and parameter case
studies. Our goal is to develop a theoretical model which can be applied to
interpret polarimetric observations of extrasolar planets. Here we present a
theoretical parameter study that shows the influence of the various involved
parameters on the polarization curves. Furthermore, we investigate the
robustness of the fitting procedure. We employ the physics of Rayleigh
scattering to obtain polarization curves of an unresolved extrasolar planet.
Calculations are made for two cases: (i) assuming an angular distribution for
the intensity of the scattered light as from a Lambert sphere and for
polarization as from a Rayleigh-type scatterer, and (ii) assuming that both the
intensity and polarization of the scattered light are distributed according to
the Rayleigh law. We show that the difference between these two cases is
negligible for the shapes of the polarization curves. In addition, we take the
size of the host star into account, which is relevant for hot Jupiters orbiting
giant stars
Hanle effect in the CN violet system with LTE modeling
Weak entangled magnetic fields with mixed polarity occupy the main part of
the quiet Sun. The Zeeman effect diagnostics fails to measure such fields
because of cancellation in circular polarization. However, the Hanle effect
diagnostics, accessible through the second solar spectrum, provides us with a
very sensitive tool for studying the distribution of weak magnetic fields on
the Sun. Molecular lines are very strong and even dominate in some regions of
the second solar spectrum. The CN system is
one of the richest and most promising systems for molecular diagnostics and
well suited for the application of the differential Hanle effect method. The
aim is to interpret observations of the CN
system using the Hanle effect and to obtain an estimation of the magnetic field
strength. We assume that the CN molecular layer is situated above the region
where the continuum radiation is formed and employ the single-scattering
approximation. Together with the Hanle effect theory this provides us with a
model that can diagnose turbulent magnetic fields. We have succeeded in fitting
modeled CN lines in several regions of the second solar spectrum to
observations and obtained a magnetic field strength in the range from 10--30 G
in the upper solar photosphere depending on the considered lines.Comment: Accepted for publication in Astronomy and Astrophysic
Real-time monitoring of stress evolution during thin film growth by in situ substrate curvature measurement
Strain engineering is the art of inducing controlled lattice distortions in a
material to modify specific physicochemical properties. Strain engineering is
applied for basic fundamental studies of physics and chemistry of solids but
also for device fabrication through the development of materials with new
functionalities. Thin films are one of the most important tools for strain
engineering. Thin films can in fact develop large strain due to the crystalline
constrains at the interface with the substrate and/or as the result of specific
morphological features that can be selected by an appropriate tuning of the
deposition parameters. Within this context, the in situ measurement of the
substrate curvature is a powerful diagnostic tool allowing a real time
monitoring of the stress state of the growing film. This manuscript reviews a
few recent applications of this technique and presents new measurements that
point out the great potentials of the substrate curvature measurement in strain
engineering. Our study also shows how, due to the high sensitivity of the
technique, the correct interpretation of the results can be in certain cases
not trivial and require complementary characterizations and an accurate
knowledge of the physicochemical properties of the materials under
investigation
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