Search results for "rake"
showing 10 items of 866 documents
Electronic Structures of Main-Group Carbene Analogues
2007
The electronic structures of 15 group 13−16 carbene analogues are analyzed using various quantum chemical methods and compared to the data obtained for the parent N-heterocyclic carbene (NHC), imidazol-2-ylidene. The results of this study present a uniform analysis of the similarities and differences in the electronic structures of p-block main-group carbene analogues. Though all systems are formally isovalent, the theoretical analyses unambiguously indicate that their electronic structures run the gamut from CC localized (group 13) to CN localized (group 16) via intermediate, more delocalized, systems. In particular, neither the stibenium ion nor any of the chalcogenium dications is a dire…
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…
Surface Coordination of Multiple Ligands Endows N‐Heterocyclic Carbene‐Stabilized Gold Nanoclusters with High Robustness and Surface Reactivity
2020
Deciphering the molecular pictures of the multi-component and non-periodic organic-inorganic interlayer is a grand technical challenge. Here we show that the atomic arrangement of hybrid surface ligands on metal nanoparticles can be precisely quantified through comprehensive characterization of a novel gold cluster, Au 44 ( i Pr 2 -bimy) 9 (PA) 6 Br 8 , which features three types of ligands, namely, carbene (1,3-diisopropylbenzimidazolin-2-ylidene, i Pr 2 -bimy), alkynyl (phenylacetylide, PA), and halide (Br), respectively. The delicately balanced stereochemical effects and bonding capabilities of the three ligands give rise to peculiar geometrical and electronic structures. Remarkably, des…
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…
Low-spin excitations in the 109Tc nucleus
2012
Monoisotopic samples of ${}^{109}$Mo nuclei, produced in the deuteron-induced fission of ${}^{238}$U and separated using the IGISOL mass separator coupled to a Penning trap, were used to perform $\ensuremath{\beta}$- and $\ensuremath{\gamma}$-coincidence spectroscopy of ${}^{109}$Tc. Spin and parity 5/2${}^{+}$ for the ground state of ${}^{109}$Mo, proposed earlier, are supported in the present work. Three new low-energy levels observed in ${}^{109}$Tc are interpreted as bandheads of the $\ensuremath{\pi}3/{2}^{\ensuremath{-}}$[301], $\ensuremath{\pi}5/{2}^{\ensuremath{-}}$[303], and $\ensuremath{\pi}1/{2}^{+}$[431] configurations, respectively. A further three levels observed around 0.4 Me…
High-accuracy mass spectrometry of fission products with Penning traps
2012
Mass measurements of fission products based on Penning-trap technique are reviewed in this article. More than 300 fission products have been measured with JYFLTRAP, ISOLTRAP, CPT, LEBIT and TITAN Penning traps with a typical precision of δm/m ≈ 10−7 − 10−8. In general, the results agree well with each other. The new data provide a valuable source of information and a challenge for the future development of theoretical mass models as well as for obtaining a deeper insight into microscopic properties of atomic nuclei as measured, for example, via key mass differentials. Shape transitions around N = 60, subshell closure at N = 40 and shell closures at N = 50 and N = 82 have been investigated i…
Precision measurement of the magnetic octupole moment in 45Sc as a test for state-of-the-art atomic- and nuclear-structure theory
2020
We report on measurements of the hyperfine $A, B$ and $C$-constants of the $3d4s^2 ~^2D_{5/2}$ and $3d4s^2 ~^2D_{3/2}$ atomic states in $^{45}$Sc. High-precision atomic calculations of the hyperfine fields of these states and second-order corrections are performed, and are used to extract $C_{5/2}=-0.06(6)$ kHz and $C_{3/2}=+0.04(3)$ kHz from the data. These results are one order of magnitude more precise than the available literature. From the combined analysis of both atomic states, we infer the nuclear magnetic octupole moment $\Omega = -0.07(53) \mu_N b$, including experimental and atomic structure-related uncertainties. With a single valence proton outside of a magic calcium core, scan…
Weight loss induces changes in adaptive thermogenesis in female and male physique athletes
2023
Physique athletes lose substantial weight preparing for competitions, potentially altering systemic metabolism. We investigated sex differences in body composition, resting energy expenditure (REE), and appetite-regulating and thyroid hormone changes during a competition preparation among drug-free physique athletes. The participants were female (10 competing (COMP) and 10 nondieting controls (CTRL)) and male (13 COMP and 10 CTRL) physique athletes. COMP were tested before they started their diet 23 weeks before competing (PRE), during their diet one week before competing (MID), and 23 weeks after competing (POST), whereas CTRL were tested at similar intervals but did not diet. Measurement…
XML-pohjaiset toimistodokumenttistandardit julkishallinnossa
2010
Self-organised structures in the field of ICT : challenges for employees’ workplace learning
2021
PurposeThe purpose of this study is to identify the challenges of low hierarchy and self-organised structures for employees’ learning and competency development at work. In the past decade, interest in employees’ and organisations’ self-directedness has increased. Self-organised structures are perceived as better able to answer to the quickly changing requirements of clients and business environments. Within these structures, employees are expected to take on more responsibility and maintain more control over their workplace learning, which means they must be self-directed and autonomous. An important question for this approach is how can workplace learning and employee competence developme…