89 research outputs found
Magnetic and thermal properties of 4f-3d ladder-type molecular compounds
We report on the low-temperature magnetic susceptibilities and specific heats
of the isostructural spin-ladder molecular complexes L[M(opba)]_{3\cdot
xDMSOHO, hereafter abbreviated with LM (where L =
La, Gd, Tb, Dy, Ho and M = Cu, Zn). The results show that the Cu containing
complexes (with the exception of LaCu) undergo long range magnetic
order at temperatures below 2 K, and that for GdCu this ordering is
ferromagnetic, whereas for TbCu and DyCu it is probably
antiferromagnetic. The susceptibilities and specific heats of TbCu
and DyCu above have been explained by means of a model
taking into account nearest as well as next-nearest neighbor magnetic
interactions. We show that the intraladder L--Cu interaction is the predominant
one and that it is ferromagnetic for L = Gd, Tb and Dy. For the cases of Tb, Dy
and Ho containing complexes, strong crystal field effects on the magnetic and
thermal properties have to be taken into account. The magnetic coupling between
the (ferromagnetic) ladders is found to be very weak and is probably of dipolar
origin.Comment: 13 pages, 15 figures, submitted to Phys. Rev.
Oil pollution on coral reefs: a review of the state of knowledge and management needs
This paper reviews the current state of knowledge of the effects that oil pollution has on scleractinian corals. Areview of results obtained in laboratory as well as in field conditions are given and suitable management tools are discussed. Studies made in the 1970s and 1980s presented conflicting results regarding the impacts of oil on coral physiology, but later results confirmed the detrimental effect of oil on corals. The world's coral reefs are severely threatened by an array of factors, one of which is oil pollution. More laboratory and field work with current oils and dispersants is urgently needed in order to update our knowledge in this field and reduce impacts in case of a major oil spill on coral reefs
In situ reduction of core-shell Ag@In2O3 nanoparticles observed through environmental electronic microscopy
SSCI-VIDE+ECI2D+LPINational audienceNon
In situ environmental HRTEM study of the restructuration under reducing atmosphere of small oxidized silver-indium nanoparticles
International audienc
Comparaison de la tenue en oxydation cyclique de superalliages revêtus d'aluminiure
Cette étude porte sur la résistance à l'oxydation cyclique à 1100°C de deux revêtements d'aluminiure,
l'un obtenu par le procédé Codep, l'autre obtenu par le procédé APVS, sur trois superalliages (DSR142, N4 et N5)
ainsi que d'un revêtement d'aluminiure modifié par le palladium sur le DSR142. La caractérisation de l'état initial
des revêtements d'aluminiure étudiés montre que le procédé APVS garantit un revêtement d'épaisseur et de
composition plus régulières que le procédé Codep. Après 400 et 800 cycles d'oxydation, les revêtements APVS
développent un oxyde moins épais que les revêtements Codep, les échanges diffusionnels au sein des revêtements
APVS semblant concentrés dans la zone externe alors que la zone de diffusion des revêtements Codep évolue
notablement. Ceci semble associé à la répartition différente du chrome et des autres éléments d'alliage dans ces deux
types de revêtement. Nous constatons que le palladium favorise la formation d'un oxyde plus mince et plus continu
ainsi qu'il ralentit les modifications au sein du revêtement
In situ reduction of core-shell Ag@In2O3 nanoparticles observed through environmental electronic microscopy
International audienc
In situ environmental HRTEM study of the restructuration under reducing atmosphere of small oxidized silver-indium nanoparticles
International audienc
In situ environmental HRTEM study of the restructuration under reducing atmosphere of small oxidized silver-indium nanoparticles
International audienc
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