Search results for "Uranium"
showing 10 items of 260 documents
Resonant laser–SNMS for spatially resolved and element selective ultra-trace analysis of radionuclides
2018
The newly developed resonant laser–SNMS system at the IRS Hannover combines the high spatial and decent mass resolution of a TOF-SIMS instrument with the element-selective process of resonant laser ionization. This setup was characterized by use of synthetic uranium, plutonium and technetium samples to prepare and demonstrate the performance for measurements on environmental samples. The laser–SNMS system will be applied for the detection, visualization and ultra-trace analysis of radionuclide containing nanoparticles in environmental samples with strongly reduced or even completely omitted chemical preparation. The necessary suppression of isobaric contamination was demonstrated as well as…
Magnetic order in UCu4+xAl8−x
1992
Abstract A neutron diffraction study has been performed on UCu4+xAl8−x. The compound was chosen as an example of a uranium-based system, which goes from a magnetically ordered state to a pure heavy-fermion state. In the range x = 0.25–1, UCu4+xAl8−x orders in a simple collinear antiferromagnetic structure. With increasing concentration of Cu, the ordering temperature decreases and moment compensation develops due to the increasing hybridization of the 5f electrons.
Fayans functional for deformed nuclei. Uranium region
2016
Fayans energy density functional (EDF) FaNDF^0 has been applied to the nuclei around uranium region. Ground state characteristics of the Th, U and Pu isotopic chains, up to the two-neutron drip line, are found and compared with predictions from several Skyrme EDFs. The two-neutron drip line is found for FaNDF^0, SLy4 and SkM^* EDFs for a set of elements with even proton number, from Pb up to Fm.
Contribution of recently measured nuclear data to reactor antineutrino energy spectra predictions
2013
This paper attempts to summarize the actual problematic of reactor antineutrino energy spectra in the frame of fundamental and applied neutrino physics. Nuclear physics is an important ingredient of reactor antineutrino experiments. These experiments are motivated by neutrino oscillations, i.e. the measure of the θ 13 mixing angle. In 2011, after a new computation of the reactor antineutrino energy spectra, based on the conversion of integral data of the beta spectra from 235 U, and 239;241 Pu, a deficit of reactor antineutrinos measured by short baseline experiments was pointed out. This is called the “reactor anomaly”, a new puzzle in the neutrino physics area. Since then, numerous new ex…
Sequestering ability of polyaminopolycarboxylic ligands towards dioxouranium(VI) cation
2006
Abstract In the present paper, some results of an investigation (at t = 25 °C by potentiometry, ISE-H+ glass electrode) on the sequestering ability of five different polyaminopolycarboxylic ligands [Nitrilotriacetate (NTA), ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetate (EGTA), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA), triethylenetetraamine-N,N,N′,N″,N′′′,N′′′-hexaacetate (TTHA)] towards dioxouranium(VI) cation in sodium chloride aqueous solutions, at I = 0.7 mol L−1 are reported. Calculations performed on potentiometric data gave evidence of the formation of the following species (log β in parenthesis): UO2(NTA)H0 (12…
Efficiency of dihydroxamic and trihydroxamic siderochelates to extract uranium and plutonium from contaminated soils
2021
International audience; Actinide-based mineral phases occurring in contaminated soils can be solubilized by organic chelators excreted by plants, such as citrate. Herein, the efficiency of citrate towards U and Pu extraction is compared to that of siderophores, whose primary function is the acquisition of iron(III) as an essential nutrient and growth factor for many soil microorganisms. To that end, we selected desferrioxamine B (DFB) as an emblematic bacterial trishydroxamic siderophore and a synthetic analog, abbreviated (LCy,Pr)H2, of the tetradentate rhodotorulic acid (RA) produced by yeasts. Firstly, the uranyl speciation with both ligands was assessed in the pH range 2–11 by potentiom…
Modular Metal Chalcogenide Chemistry: Secondary Building Blocks as a Basis of the Silicate-Type Framework Structure of CsLiU(PS4)2
2011
The novel uranium thiophosphate CsLiU(PS4)2 has been synthesized by reacting uranium metal, Cs2S, Li2S, S, and P2S5 at 700 °C in an evacuated silica tube. The crystal structure was determined by single-crystal X-ray diffraction techniques. CsLiU(PS4)2 crystallizes in the rhombohedral space group Rc (a = 15.2797(7) A; c = 28.778(2) A, V = 5818.7(5) A3, Z = 18). The structure ofCsLiU(PS4)2 is a unique three-dimensional U(PS4)22– framework with large tunnels with an approximate diameter of 6.6 A running parallel to the crystallographic c axis. The tunnels are filled with Cs+ cations. The smaller Li+ cations are located at tetrahedral sites at the periphery of the channels. In the structure of …
CCDC 652541: Experimental Crystal Structure Determination
2008
Related Article: H.Sopo, A.Lehtonen, R.Sillanpaa|2008|Polyhedron|27|95|doi:10.1016/j.poly.2007.08.047
CCDC 1439186: Experimental Crystal Structure Determination
2016
Related Article: Toni Mäkelä, Miia-Elina Minkkinen, and Kari Rissanen|2016|Inorg.Chem.|55|1339|doi:10.1021/acs.inorgchem.5b02780
CCDC 619714: Experimental Crystal Structure Determination
2006
Related Article: M.Cametti, M.Nissinen, A.D.Cort, K.Rissanen, L.Mandolini|2006|Inorg.Chem.|45|6099|doi:10.1021/ic060251u