نتایج جستجو برای: samarium

تعداد نتایج: 1033  

Journal: :Physical review letters 2013
C Özen Y Alhassid H Nakada

Heavy nuclei exhibit a crossover from vibrational to rotational collectivity as the number of neutrons or protons increases from shell closure towards midshell, but the microscopic description of this crossover has been a major challenge. We apply the shell model Monte Carlo approach to families of even-even samarium and neodymium isotopes and identify a microscopic signature of the crossover f...

The mass transfer performance of a pulsed disc and doughnut column for extraction of samarium and gadolinium from aqueous nitrate solution with D2EHPA was investigated. The effects of operating parameters such as pulsation intensity, continuous and dispersed phase velocities on column performance were investigated. The axial dispersion model was used to obtain the overall mass transfer coef...

Journal: :Journal of Nuclear and Radiochemical Sciences 2003

Katreddi Reddy, Sriramula Vidya Sagar Babu

Five rare earth complexeslanthanum(III),praseodymium(III),neodymium(III), samarium(III) and europium(III) have been synthesized from Schiff base ligand (N,N-bis (2-hydroxy-1-naphthylidene) acetylhydrazone). The complexes were characterized based on elemental analysis, molar conductance, ultraviolet, infrared, mass, thermogravimetric and powder X-ray diffraction studies. Infrared spectra sug...

2011
E. May M. Thoennessen

Currently, thirty-four samarium, thirty-four europium, thirty-one gadolinium, and thirty-one terbium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented. ∗Corresponding author. Email address: [email protected] (M. Thoennessen...

2002
Alena Novoselova Vladimir Khokhlov Vladimir Shishkin

The formal standard redox potentials of samarium (III)/(II) (EZmi+/ Smi+) and europium (III)/(II) (•£,£u3+/eu2+ ) *n molten alkali metal chlorides were measured potentiometrically against a reference chlorine electrode. The Gibbs energy changes and equilibrium constants for the reaction LnCl2(D + V2 Cl2(g) LnCl3(I) were calculated for the salt systems studied. The effect of the cationic composi...

Journal: :Organic & biomolecular chemistry 2014
Marco Buccini Kathryn A Punch Belinda Kaskow Gavin R Flematti Brian W Skelton Lawrence J Abraham Matthew J Piggott

An improved synthesis of the anti-inflammatory natural product antrocamphin A (2), involving a key Castro-Stephens reaction, is presented, along with the first total synthesis of its congener antrocamphin B (3). Approaches towards the more complex co-metabolite antrodioxolanone (4) were unsuccessful, but a samarium diiodide-mediated pinacol coupling of antrocamphin B did provide the chiral epim...

Journal: :European Journal of Organic Chemistry 2021

A series of (S)-proline-based enantiopure phosphorus triamide derivatives were prepared and evaluated as HMPA alternative in samarium diiodide cyclization reactions N-acylated indole derivatives. The expected tricyclic indoline generally obtained good to excellent yields, however, the induced enantioselectivities at best moderate. In our model reaction, derivative with a (dimethyl)hydroxymethyl...

2017
F. H. Spedding T. A. Butler

An ion-exchange process was developed for the separation of spectrographically pure praseodymium salts in kilogram amounts from commercially available concentrates. The application of either 0.5% or 0.1% citrate solutions as eluting agents was show to result in excellent separations of praseodymium from samarium, neodymium, and lanthanum when the mixed rare earths were eluted from Amberlite IR-...

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