Search results for "elements"
showing 10 items of 799 documents
Fission Barrier of Superheavy Nuclei and Persistence of Shell Effects at High Spin: Cases of 254No and 220Th
2014
We report on the first measurement of the fission barrier height in a heavy shell-stabilized nucleus. The fission barrier height of 254No is measured to be Bf=6.0±0.5 MeV at spin 15ℏ and, by extrapolation, Bf=6.6±0.9 MeV at spin 0ℏ. This information is deduced from the measured distribution of entry points in the excitation energy versus spin plane. The same measurement is performed for 220Th and only a lower limit of the fission barrier height can be determined: Bf(I)8 MeV. Comparisons with theoretical fission barriers test theories that predict properties of superheavy elements.
On the adsorption and reactivity of element 114, flerovium
2022
Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly v…
Rotational properties of nuclei around 254 No investigated using a spectroscopic-quality Skyrme energy density functional
2014
Abstract. Background: Nuclei in the Z≈100 mass region represent the heaviest systems where detailed spectroscopic information is experimentally available. Although microscopic-macroscopic and self-consistent models have achieved great success in describing the data in this mass region, a fully satisfying precise theoretical description is still missing. Purpose: By using fine-tuned parametrizations of the energy density functionals, the present work aims at an improved description of the single-particle properties and rotational bands in the nobelium region. Such locally optimized parametrizations may have better properties when extrapolating towards the superheavy region. Methods: Skyrme H…
Ca-48+Bk-249 Fusion Reaction Leading to Element Z=117: Long-Lived alpha-Decaying (270)Db and Discovery of Lr-266
2014
The superheavy element with atomic number Z=117 was produced as an evaporation residue in the 48Ca+249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope 294117 and its decay products. A hitherto unknown α-decay branch in 270Db (Z=105) was observed, which populated the new isotope 266Lr (Z=103). The identification of the long-live…
The Synthesis of Quinoline‐based Tin Complexes with Pendant Schiff Bases
2019
Whilst pursuing the synthetic utility of quinoline‐based tin complexes, Me2Sn(Quin‐NO2)2 (1) and Ph2Sn(Quin‐NO2)2 (2) (Quin‐NO2 = 5‐nitroquinolino‐8‐oate) were synthesized bearing coordinatively inert nitro groups. Conventional reduction methodologies successfully converted 1 to Me2Sn(Quin‐NH2)2 (3) and 2 to Ph2Sn(Quin‐NH2)2 (4) (Quin‐NH2 = 5‐aminoquinolino‐8‐oate). The synthetically useful amine groups proved difficult to exploit in the presence of the central tin atom, however, a complete Schiff base functionalized Sn complex of the dimethyltin pro‐ligand Me2Sn(Quin‐py)2 (6) was successfully synthesized from 5‐[(pyridin‐2‐ylmethylene)amino]quinolin‐8‐ol (HQuin‐py; 5) in good yield via an …
Honey Bee Pollen in Meagre (Argyrosomus regius) Juvenile Diets: Effects on Growth, Diet Digestibility, Intestinal Traits, and Biochemical Markers Rel…
2020
This research aimed to evaluate the effects of the inclusion of honey bee pollen (HBP) in meagre (Argyrosoumus regius) juveniles&rsquo
The cycle of major and trace elements in a volcanic environment
2010
Atmospheric Deposition Of Volcanogenic Major And Trace Elements On Mt. Etna (Italy)
2009
There are a variety of natural and anthropogenic sources of trace elements into the environment, and human activity has drastically changed the biogeochemical cycles and balance of several elements. In the last twenty years many efforts have been spent by the scientific community to better outline the levels of pollutants in the environment on a long-term basis, and to evaluate global large-scale changes. It is generally accepted that volcanic emissions are an important source of gases and particles to the atmosphere, contributing significantly to the natural geochemical cycles of all elements (Nriagu, 1989; Hinkley et al., 1999; Oppenheimer, 2003). Many studies have been carried out on the…
Trace elements in thermomineral waters in Greece
2020
Trace elements have a fundamental role in natural and anthropogenic systems. In waters, they present a great variability of concentrations that mostly depends on the degree of gas-water-rock interactions and geochemical conditions such as pH, temperature, redox and/or exchange reactions, etc. Even though, they are present in very low contents in host-rocks, elevated concentrations in ground or surface waters may have a hazardous impact on human health and thus, it is important to both quantify and understand their behavior in natural systems. Here we present the results of about 300 cold and thermal mineral waters collected along the entire Hellenic territory. Physicochemical parameters (te…