No abstract

Uranium, along with other actinides and lanthanides, forms a large group of ternary intermetallic compounds of stoichiometry UTX (T = transistion metal, X = p-electron metal). These compounds am formed in several structure types and the occurence and stability of particular structures with respect to the transition metal content suggests reasonable systematics. We have also investigated the, magnetic structures of selected u'rx compounds and it is revealing to relate the crystallographic and magnetic structures, because of the relationship between the magnetic symmetry and that of the U-atom environment produced by the Sf-ligand hybridisation, and the consequent anisotropic exchange. Those of ZrNiAI structure type are collinear, with moments along the hexagonal c-axis. In the orthorhombic NiSiTi structure type, the moments are confined to the b-c plane (perpendicular to the uranium chains) and the structures are often incommensurate. In the hexagonal Cain2 (or GaGeLi) structure type, the magnetic structures form in an orthorhombic cell, and at least in the disordered centric group, again the moments lie perpendicular to the nearest-neighbour uranium spacing.

Magnetization, ac and dc susceptibility of a UCoGa single crystal are presented. Magnetic ordering was detected below 47 K. The complicated magnetization behavior at low temperatures does not allow us to conclude unambiguously about the type of ground state. The observed strong uniaxial anisotropy is consistent with the behavior of other isostructural UTX compounds. The anisotropy field exceeds by far the highest field of 35 T applied in the experiments.

-This paper presents a review on all available analytical methods for 90 Sr and 89 Sr determination in milk. Special attention was focused on the parameter of the performing time in order to assess the rapid measurement of milk contamination, especially in the case of emergency situations such as a nuclear plant accident. Preliminarily, a short description of the milk matrix and radiostrontium transfer from soil to milk and its derivatives is given. Then analytical procedures are examined step by step. 90 Sr and 89 Sr can be separately determined in less than 2 days by a rapid sample pretreatment and the use of a liquid scintillation detector.Strontium / radioactivity / analytical method / milk Résumé -Revue des méthodes de dosage du radiostrontium dans le lait. Cet article présente l'ensemble des méthodes analytiques disponibles pour le dosage du 90 Sr et du 89 Sr dans le lait. Cette étude attache une importance toute particulière à la durée d'analyse dans le but d'une estimation rapide de la contamination du lait telle qu'elle est rendue nécessaire dans le cas de situations d'urgences comme l'accident d'une centrale nucléaire. En préliminaires, une rapide description de la matrice lait et du transfert du radiostrontium du sol au lait et ses dérivés est donnée. Puis, les procédures analytiques sont examinées étape par étape. Les isotopes 90 et 89 du strontium peuvent être déterminés séparément en moins de 2 jours par un traitement rapide de l'échantillon et l'utilisation d'un détecteur à scintillation liquide. Strontium / radioactivité / méthode d'analyse / lait

Structure, transport and thermal properties of UCoGaPurwanto, A.; Robinson, R.A.; Prokes, K.; Nakotte, H.; de Boer, F.R.; Havela, L.; Sechovsky, V.; Tuan, N.C.; Kergadallan, Y.; Spirlet, J.C.; Rebizant, J. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 11 May 2018Structure, transport and thermal properties of By means of neutron powder diffraction, we find that UCoGa crystallizes in the hexagonal ZrNiAl structure and orders ferromagnetically at low temperatures with magnetic moments stacked along the c axis. The magnetic-ordering temperature is reflected in anomalies in the temperature dependencies of the electrical resistivity and the specific heat at Tc =47 K. Furthermore, the strong anisotropy in the electrical resistivity for illc and ilc indicates a significant contribution of the magnetic anisotropy to the electrical resistivity.