Search results for "Density"
showing 10 items of 4402 documents
Chalcogen‐Bonding Interactions in Telluroether Heterocycles [Te(CH2)m]n (n=1-4; m=3-7)
2020
The Te…Te secondary bonding interactions (SBI) in solid heterocyclic telluroethers were explored by preparing and structurally characterizing a series of [Te(CH2)m]n (n = 1‐4; m = 3‐7) species. The SBIs in 1,7‐Te2(CH2)10, 1,8‐Te2(CH2)12, 1,5,9‐Te3(CH2)9, 1,8,15‐Te3(CH2)18, 1,7,13,19‐Te4(CH2)20, 1,8,15,22‐Te4(CH2)24, and 1,9,17,25‐Te4(CH2)28 led to the tubular packing of the molecules, as has been observed previously for related thio‐ and selenoether rings. The nature of the intermolecular interactions was explored by solid‐state PBE0‐D3/pob‐TZVP calculations involving periodic boundary conditions. The packing of molecules in 1,7,13,19‐Te4(CH2)20, 1,8,15,22‐Te4(CH2)24, and 1,9,17,25‐Te4(CH2)…
Impact of Nonlinear Inductor on Efficiency and Power Losses in a SMPS: a Case Study
2022
This paper proposes a comparative analysis focused on losses in two Switched Mode Power Supplies, adopting a linear inductor and an inductor operated up to saturation, respectively. The use of the nonlinear inductor saves weight and cost on the magnetic material, which is of great interest for automotive applications; however, it increases the peak current and can increase losses. The analysis aims to compare, by simulations, the impact on the efficiency of the different current waveforms throughout the converter. The losses are discussed in detail and calculated for each component of the converters.
Multipactor radiation analysis within a waveguide region based on a frequency-domain representation of the dynamics of charged particles
2009
[EN] A technique for the accurate computation of the electromagnetic fields radiated by a charged particle moving within a parallel-plate waveguide is presented. Based on a transformation of the time-varying current density of the particle into a time-harmonic current density, this technique allows the evaluation of the radiated electromagnetic fields both in the frequency and time domains, as well as in the near- and far-field regions. For this purpose, several accelerated versions of the parallel-plate Green's function in the frequency domain have been considered. The theory has been successfully applied to the multipactor discharge occurring within a two metal-plates region. The proposed…
β and γ bands in N = 88, 90, and 92 isotones investigated with a five-dimensional collective Hamiltonian based on covariant density functional theory…
2019
A comprehensive systematic study is made for the collective β and γ bands in even-even isotopes with neutron numbers N=88 to 92 and proton numbers Z=62(Sm) to 70 (Yb). Data, including excitation energies, B(E0) and B(E2) values, and branching ratios from previously published experiments are collated with new data presented for the first time in this study. The experimental data are compared to calculations using a five-dimensional collective Hamiltonian (5DCH) based on the covariant density functional theory (CDFT). A realistic potential in the quadrupole shape parameters V(β,γ) is determined from potential energy surfaces (PES) calculated using the CDFT. The parameters of the 5DCH are fixe…
Gas phase behavior of radical cations of perfluoroalkyl-1,2,4-triazines: an experimental and theoretical study
2009
Electron ionization mass spectrometry and low-energy collision-induced decomposition reactions occurring in a tridimensional ion trap, together with density functional theory (DFT) calculations on neutrals, even- and odd-electron cations, have been used to study the gas-phase ion chemistry of a series of perfluoroalkyl-1,2,4-triazines. Loss of oxygen, due to thermal degradation occurring before ionization, likely involving the hydroxylamino group, has been observed. Compounds having a carbonyl group at position 6 of the triazine ring fragment in the source by elimination of NO followed by HF or CO. The decomposition pathways occurring due to CID experiments have shown interesting features d…
Structure of superheavy nuclei along decay chains of element 115
2014
[Introduction] A recent high-resolution α , X -ray, and γ -ray coincidence-spectroscopy experiment offered the first glimpse of excitation schemes of isotopes along α -decay chains of Z = 115. To understand these observations and to make predictions about shell structure of superheavy nuclei below 288 115, we employ two complementary mean-field models: the self-consistent Skyrme energy density functional approach and the macroscopic-microscopic Nilsson model. We discuss the spectroscopic information carried by the new data. In particular, candidates for the experimentally observed E 1 transitions in 276 Mt are proposed. We find that the presence and nature of low-energy E 1 transitions in w…
A Tunable, Fullerene‐Based Molecular Amplifier for Vibrational Circular Dichroism
2019
Abstract Vibrational circular dichroism (VCD) studies are reported on a chiral compound in which a fullerene C60 moiety is used as an electron acceptor and local VCD amplifier for an alanine‐based peptide chain. Four redox states are investigated in this study, of which three are reduced species that possess low‐lying electronic states as confirmed by UV/Vis spectroelectrochemistry. VCD measurements in combination with (TD)DFT calculations are used to investigate (i) how the low‐lying electronic states of the reduced species modulate the amplification of VCD signals, (ii) how this amplification depends on the distance between oscillator and amplifier, and (iii) how the spatial extent of the…
Nuclear receptor NR5A2 and bone: gene expression and association with bone mineral density
2011
El pdf del artículo es el manuscrito de autor (PMCID: PMC3682472).-- et al.
Effect of digitonin on membrane-bound and chitosomal chitin synthetase activity in protoplasts from yeast cells ofCandida albicans
1993
The effect of digitonin on chitin synthetase present in membrane (MMF) and cytoplasmic fractions (chitosomes) (CF) from C. albicans yeast protoplasts has been determined. The zymogen is preferentially, but not exclusively, solubilized by digitonin from MMF. Centrifugation of distinct solubilized preparations, containing either zymogen, in vivo active enzyme and/or trypsin activated enzyme, on linear sucrose gradients suggests that both zymogen and trypsin activated enzyme sediment slightly slower than the active enzyme, pointing out differences between the activation processes in vivo and in vitro or, alternatively, that both enzyme activities (active in vivo and zymogenic) correspond to di…
Katalizatory i proces koordynacyjnej polimeryzacji etylenu - eksperyment i teoria
2004
Badania eksperymentalne i teoretyczne koordynacyjnej polimeryzacji etylenu przeprowadzono wobec katalizatorów otrzymanych z prekursorów - kompleksów halogenków Ti, Zr, Hf, V z organicznymi zasadami Lewisa, nośnika magnezowego [MgCl2(THF)2] i związków glinoorganicznych. Określono zależnosć pomiędzy rodzajem halogenków w prekursorze a aktywnością katalizatora wanadowego. Ustalono profile energetyczne reakcji insercji i terminacji (beta-eliminacji) oraz przeniesienia atomu wodoru beta. Obliczone wartości barier insercji, a także energii wiązania etylenu do centrum aktywnego dobrze korelują z wynikami polimeryzacji. Stwierdzono występowanie w centrach aktywnych oddziaływań agostycznych, które o…