Search results for "Sky"

Direct Imaging of Chiral Domain Walls and Néel‐Type Skyrmionium in Ferrimagnetic Alloys

2021

International audience; The evolution of chiral spin structures is studied in ferrimagnet Ta/Ir/Fe/GdFeCo/Pt multilayers as a function of temperature using scanning electron microscopy with polarization analysis (SEMPA). The GdFeCo ferrimagnet exhibits pure right-hand Néel-type domain wall (DW) spin textures over a large temperature range. This indicates the presence of a negative Dzyaloshinskii-Moriya interaction (DMI) that can originate from both the top Fe/Pt and the Co/Pt interfaces. From measurements of the DW width, as well as complementary magnetic characterization, the exchange stiffness as a function of temperature is ascertained. The exchange stiffness is surprisingly mostly const…

Chemical self-organization in self-assembling biomimetic systems

2009

Abstract Far-from-equillibrium oscillating chemical reactions are among the simplest systems showing complex behaviors and emergent properties. This class of reactions is often employed to mimic and understand the mechanisms of a great variety of biological processes. In this context, pattern formation due to the coupling between reaction and transport phenomena represent an active and promising research area. In this paper, we present results coming from experiments where we tried to blend the structural properties of self-assembled matrixes (sodium dodecyl sulphate micelles and phospholipid bilayers) together with the evolutive peculiarities of the Belousov–Zhabotinsky reaction. A series …

A Linear Cost Algorithm to Compute the Discrete Gabor Transform

2010

In this paper, we propose an alternative efficient method to calculate the Gabor coefficients of a signal given a synthesis window with a support of size much lesser than the length of the signal. The algorithm uses the canonical dual of the window (which does not need to be calculated beforehand) and achieves a computational cost that is linear with the signal length in both analysis and synthesis. This is done by exploiting the block structure of the matrices and using an ad hoc Cholesky decomposition of the Gabor frame matrix.

La conspiración anunciada

1998

Assessment and application of MODIS ocean and land algorithms for the characterization of aerosol properties over a Mediterranean coastal site

2015

Abstract The aerosol optical depth (AOD) and Angstrom exponent (α) obtained from MODIS Terra and Aqua over the coastal urban site of Burjassot (Spain) during the period 2002–2011 have been compared with retrievals from AERONET (AErosol RObotic NETwork) and ESR (European Skynet Radiometers) in order to investigate the performance of MODIS algorithms over land and ocean, respectively. The comparison of the MODIS aerosol products C051 over both land and ocean has been performed for a window size of 50 km × 50 km centred on the monitoring site. The correlation coefficients obtained from the comparison of the AOD from MODIS with that from ground-based measurements are 0.85 and 0.87 over land for…

An analysis of direct solar transmittance and atmospheric turbidity in the Mediterranean climatic belt

1989

Abstract The empirical model developed by King and Buckius for the direct transmission in clear sky is applied to hourly data of two Yugoslav locations exhibiting typical meteoclimatic characteristics common to the whole Mediterranean belt. The occurrence of “very clear”, “clear” and “very hazy” hours, after the usually accepted definitions, is determined and discussed. The degree of accuracy of the previsional model is investigated performing the comparison with the corresponding values obtained directly by energetic procedure. A general overestimate of the transmittance is experienced with notable deviations in meteorological conditions affected by the presence of dense clouds which behav…

A clear sky atmospheric model valid for the mediterranean zone

1988

Abstract The ASHRAE clear sky model in the version proposed by G.L. Powell has been applied to a set of clear days from two coastal locations of Yugoslavia. The results have provided further elements to confirm the existence of a clear sky atmospheric model valid for the whole Mediterranean zone. This model is characterized by values of the atmospheric extinction coefficient higher than the corresponding ASHRAE ones with upper limits defined by the regression curve derived by using data of Palermo.

Die Förderung der Mehrsprachigkeit und der Transkulturalität in der gymnasialen Oberstufe über ein internationales und fremdsprachiges Projekt : Fal…

2010

Tässä laadullisessa tapaustutkimuksessa tutkittiin 2008 kevään aikana suomalaisen Jyväskylän Normaalikoulun lukion ja saksalaisen Görres-Gymnasiumin (Koblenz) toteuttamaa kansainvälistä yhteistyöprojektia. Tavoitteena oli selvittää, kuinka osallistujien transkulturaalinen identiteetti kehittyy sekä toteutuuko monikielisyys tässä kansainvälisessä projektissa. Lisäksi haluttiin selvittää opettajien ja oppilaiden motivaatioita projektiin osallistumiseen sekä kieltenkäyttöä eri tilanteissa. Tutkimus toteutettiin vuonna 2007 projektiin osallistuneiden suomalaisten oppilaiden sekä vuonna 2008 mukana olevien suomalaisten ja saksalaisten opettajien ryhmähaastattelujen ja oppilaiden kyselylomakkeide…

Hyperspectral solar spectral measurements and applications

2007

Measurements of hyperspectral solar irradiance from aircraft and satellite are applied to a variety of cloud and aerosol remote sensing, and radiative energy budget applications.

An atmospheric model for computing direct and diffuse solar radiation

1979

Abstract This paper proposes an atmospheric model, which extends the computation of the direct radiation given by Cole's model to the cloudy sky and shows a method to calculate the diffuse radiation. Therefore the monthly average values of the global radiation incident on a horizontal surface at Palermo are computed by this method. These values are compared with the experimental data provided by the Istituto di Idraulica Agraria, Universita di Palermo and generally exhibit a mean deviation not more than 10 per cent. The deviations become lower than 8 per cent taking into account the effect of the underlying surface albedo. In order to better verify the validity of the proposed method, it sh…