Search results for "Alite"
showing 10 items of 446 documents
Plasmon-Induced Direct Hot-Carrier Transfer at Metal-Acceptor Interfaces.
2019
Plasmon-induced hot-carrier transfer from a metal nanostructure to an acceptor is known to occur via two key mechanisms: (i) indirect transfer, where the hot carriers are produced in the metal nanostructure and subsequently transferred to the acceptor, and (ii) direct transfer, where the plasmons decay by directly exciting carriers from the metal to the acceptor. Unfortunately, an atomic-level understanding of the direct-transfer process, especially with regard to its quantification, remains elusive even though it is estimated to be more efficient compared to the indirect-transfer process. This is due to experimental challenges in separating direct from indirect transfer as both processes o…
Stability limits of elemental 2D metals in graphene pores
2019
Two-dimensional (2D) materials can be used as stabilizing templates for exotic nanostructures, including pore-stabilized, free-standing patches of elemental metal monolayers. Although these patches represent metal clusters under extreme conditions and are thus bound for investigations, they are poorly understood as their energetic stability trends and the most promising elements remain unknown. Here, using density-functional theory simulations and liquid drop model to explore the properties of 45 elemental metal candidates, we identify metals that enable the largest and most stable patches. Simulations show that pores can stabilize patches up to $\sim 8$ nm$^2$ areas and that the most promi…
Noise identification and sampling frequency determination for precise Pb isotopic measurements by quadrupole-based Inductively Coupled Plasma Mass Sp…
2000
Analytical precision of the isotope ratios measured by quadrupole-based ICP-MS is drastically controlled by the low- frequency noises which originate from nebulisation and vaporisation processes, and from sample introduction systems. The unde- sirable influence of these latter can be however reduced by choosing efficiently the operating parameters. In the present study , the choice of the stabilisation time necessary in peak jump mode, and the one of the number of sweeps are discussed in the light of noise power spectra obtained with various speeds of the peristaltic pump used as sample introduction system. Obviously, the settings proposed are probably efficient only on our own ICP-MS, but …
Universal trend of charge radii of even-even Ca-Zn nuclei
2021
Radii of nuclear charge distributions carry information about the strong and electromagnetic forces acting inside the atomic nucleus. While the global behavior of nuclear charge radii is governed by the bulk properties of nuclear matter, their local trends are affected by quantum motion of proton and neutron nuclear constituents. The measured differential charge radii $\delta\langle r^2_c\rangle$ between neutron numbers $N=28$ and $N=40$ exhibit a universal pattern as a function of $n=N-28$ that is independent of the atomic number. Here we analyze this remarkable behavior in even-even nuclei from calcium to zinc using two state-of-the-art theories based on quantified nuclear interactions: t…
Mirror and triplet displacement energies within nuclear DFT: : numerical stability
2017
Isospin-symmetry-violating class II and III contact terms are introduced into the Skyrme energy density functional to account for charge dependence of the strong nuclear interaction. The two new coupling constants are adjusted to available experimental data on triplet and mirror displacement energies, respectively. We present preliminary results of the fit, focusing on its numerical stability with respect to the basis size.
Impact of the surface energy coefficient on the deformation properties of atomic nuclei as predicted by Skyrme energy density functionals
2018
Background: In the framework of nuclear energy density functional (EDF) methods, many nuclear phenomena are related to the deformation of intrinsic states. Their accurate modeling relies on the correct description of the change of nuclear binding energy with deformation. The two most important contributions to the deformation energy have their origin in shell effects that are correlated to the spectrum of single-particle states, and the deformability of nuclear matter, that can be characterized by a model-dependent surface energy coefficient asurf. Purpose: With the goal of improving the global performance of nuclear EDFs through the fine-tuning of their deformation properties, the purpose …
Beta-Decay Studies in N ≈ Z Nuclei Using No-Core Configuration-Interaction Model
2015
The no-core configuration-interaction model based on the isospin- and angular-momentum projected density functional formalism is introduced. Two applications of the model are presented: (i) determination of spectra of 0+ states in 62Zn and (ii) determination of isospin-symmetry-breaking corrections to superallowed β-decay between isobaric-analogue 0+ states in 38Ca and 38K. It is shown that, without readjusting a single parameter of the underlying Skyrme interaction, in all three nuclei, the model reproduces the 0+ spectra surprisingly well. peerReviewed
Layer formation on silicon steel by processing in H2/H2O at elevated temperatures
1992
Silicon steel (Fe-3wt%Si), as used for transformers and generators, has been annealed in wet hydrogen at elevated temperatures. The composition, sequence, and thicknesses of the layers found by conversion electron Mossbauer spectroscopy (CEMS) and Auger electron spectroscopy (AES) depth profiling for a 10 minutes anneal in different atmospheres are reported. In the range from 500°C to 720°C we observed carbide formation, indicating that the decarburization is hindered. Above 800°C, the layers consist of fayalite or of fayalite and iron oxides, depending on the oxygen potentialaO. At 843°C, the onset of iron oxide formation was found ataO=0.33.
Quantitative determination of fayalite layers on iron by CEMS
1990
In the processing of silicon iron (Fe-3%) Si), so-called ‘fayalite layers’ are formed. By CEMS, they were found to consist of an outer Fe3+-oxide layer and an inner Fe2SiO4 (fayalite) layer. Sometimes an additional wustite contribution was found. Thef-factor of fayalite was determined experimentally (ffayalite/fα-Fe=0.47±0.04) and, by use of it, the thicknesses of the layers on some silicon iron samples could be calculated from CEMS data.
Model nuclear energy density functionals derived from ab initio calculations
2020
We present the first application of a new approach, proposed in [Journal of Physics G: Nuclear and Particle Physics, 43, 04LT01 (2016)] to derive coupling constants of the Skyrme energy density functional (EDF) from ab initio Hamiltonian. By perturbing the ab initio Hamiltonian with several functional generators defining the Skyrme EDF, we create a set of metadata that is then used to constrain the coupling constants of the functional. We use statistical analysis to obtain such an ab initio-equivalent Skyrme EDF. We find that the resulting functional describes properties of atomic nuclei and infinite nuclear matter quite poorly. This may point out to the necessity of building up the ab init…