44 research outputs found
The summertime Boreal forest field measurement intensive (HUMPPA-COPEC-2010): an overview of meteorological and chemical influences
This paper describes the background, instrumentation, goals, and the regional influences on the HUMPPA-COPEC intensive field measurement campaign, conducted at the Boreal forest research station SMEAR II (Station for Measuring Ecosystem-Atmosphere Relation) in Hyytiälä, Finland from 12 July–12 August 2010. The prevailing meteorological conditions during the campaign are examined and contrasted with those of the past six years. Back trajectory analyses show that meteorological conditions at the site in 2010 were characterized by a higher proportion of southerly flow than in the other years studied. As a result the summer of 2010 was anomalously warm and high in ozone making the campaign relevant for the analysis of possible future climates. A comprehensive land use analysis, provided on both 5 and 50 km scales, shows that the main vegetation types surrounding the site on both the regional and local scales are: coniferous forest (Scots pine and/or Norway spruce); mixed forest (Birch and conifers); and woodland scrub (e.g. Willows, Aspen); indicating that the campaign results can be taken as representative of the Boreal forest ecosystem. In addition to the influence of biogenic emissions, the measurement site was occasionally impacted by sources other than vegetation. Specific tracers have been used here to identify the time periods when such sources have impacted the site namely: biomass burning (acetonitrile and CO), urban anthropogenic pollution (pentane and SO<sub>2</sub>) and the nearby Korkeakoski sawmill (enantiomeric ratio of chiral monoterpenes). None of these sources dominated the study period, allowing the Boreal forest summertime emissions to be assessed and contrasted with various other source signatures
Le savant et son époque à travers sa correspondance Seeger A. Bonebakker (1923-2005) et quelques notes sur Ḫalīl b. Aybak al-Ṣafadī (696-764/1297-1363)
This article proposes a survey of two great scholars’ in Arabic literature correspondences:
a European of the 20th century, Seeger Adrianus Bonebakker, who is of
special interest for us because he bequeathed all of his great library, personal notes and
correspondence to Università Ca’ Foscari, and a subject of study of the former, Ḫalīl b.
Aybak al-Ṣafadī, great littérateur and scholar of the first century of the Mamluk period.
Letters sent and received are preserved in both cases and are primary sources on their
network, but also on their personal life, personality and methodology
The RbSr <sup>2</sup>Σ<sup>+</sup> ground state investigated <i>via</i> spectroscopy of hot and ultracold molecules
We report on spectroscopic studies of hot and ultracold RbSr molecules, and
combine the results in an analysis that allows us to fit a potential energy
curve (PEC) for the X(1) ground state bridging the
short-to-long-range domains. The ultracold RbSr molecules are created in a
K sample of Rb and Sr atoms and probed by two-colour photoassociation
spectroscopy. The data yield the long-range dispersion coefficients and
, along with the total number of supported bound levels. The hot RbSr
molecules are created in a K gas mixture of Rb and Sr in a heat-pipe
oven and probed by thermoluminescence and laser-induced fluorescence
spectroscopy. We compare the hot molecule data with spectra we simulated using
previously published PECs determined by three different ab-initio theoretical
methods. We identify several band heads corresponding to radiative decay from
the B(2) state to the deepest bound levels of X(1). We
determine a mass-scaled high-precision model for X(1) by fitting
all data using a single fit procedure. The corresponding PEC is consistent with
all data, thus spanning short-to-long internuclear distances and bridging an
energy gap of about 75% of the potential well depth, still uncharted by any
experiment. We benchmark ab-initio PECs against our results, and give the PEC
fit parameters for both X(1) and B(2) states. As first
outcomes of our analysis, we calculate the -wave scattering properties for
all stable isotopic combinations and corroborate the locations of Fano-Feshbach
resonances between alkali Rb and closed-shell Sr atoms recently observed
[Barb\'e et al., Nat. Phys., 2018, DOI:10.1038/s41567-018-0169-x]. These
results should greatly contribute to the generation of ultracold
alkalialkaline-earth dimers, whose applications range from quantum
simulation to quantum chemistry.Comment: 24 pages, 13 figures, 10 table