Search results for " surface"
showing 10 items of 2838 documents
Nuclear levels of 183W studied with and reactions
2011
Abstract The level structure of 183 W has been studied using gamma–gamma coincidences from thermal neutron capture in 182 W accompanied with the reaction ( d → , p ) . From these data and those of previous studies a total of 76 levels and about 490 connecting γ -transitions have been established for energies below 2.4 MeV. An analysis based on the standard distorted-wave Born approximation (DWBA) provides the lj -angular momentum transfers and spectroscopic factors for 36 levels up to 2.2 MeV excitation energy. A large number of particle transitions indicate an influence of strong mixing between particle and probably hole states. The extra exchange of phonons across the Fermi surface leads …
Nuclear structure of 187W studied with (n,γ) and (d,p) reactions
2008
Abstract The level structure of 187 W has been studied using prompt and delayed gamma–gamma coincidences from thermal neutron capture in 186 W and also measuring the ( d , p ) reaction. From these data and those of previous studies a total of 170 levels (121 connected by γ transitions) have been established for energies below 2.35 MeV. Some of these levels have been grouped into rotational bands built on 14 intrinsic states of quasi-particle and quasi-particle plus phonon character. Of particular interest has been the identification of “quasi bands” with inverse spin sequence based on the newly established isomeric 11 / 2 + state at 410.1 keV. Although the DWBA analysis permitted definite s…
Low-spin mixed particle–hole structures in 185W
2005
Abstract The level structure of 185W has been studied using the prompt and delayed gamma–gamma coincidences from thermal neutron capture in 184W accompanied with the one-nucleon transfer reactions ( d , p ) and ( d , t ) with polarized beams. From these data and those of previous studies a total of 183 levels has been established for energies below 3 MeV. Many of these states have been grouped into rotational bands built on 28 intrinsic states of quasiparticle and quasiparticle-plus-phonon character. Although the DWBA analysis permitted definite spin–parity assignments for most of states a large number of particle transitions have ‘anomalous’ angular and asymmetry shapes with respect to the…
Inclination of Large Coronal Loops Observed by TRACE
2000
A TRACE field of view well inside the solar disk shows very well defined large loops, likely to be very inclined to the solar surface. On the other hand there is little evidence of large loops perpendicular to the solar surface. We show that this does not mean that most large loops have such large inclination but that perpendicular loops are much less visible to TRACE, because of density stratification. We quantitatively evaluate this effect by modeling in detail loops with different inclinations.
Quantum mechanical study of the 16O + 18O18O → 16O18O + 18O exchange reaction: Integral cross sections and rate constants
2018
The isotopic exchange reaction, 16O + 18O18O → 16O18O + 18O, involving excited ozone, O3*, as intermediate complex, was investigated by means of a time independent quantum mechanical approach using the TKTHS potential energy surface (PES) [V. G. Tyuterev et al., J. Chem. Phys. 139, 134307 (2013)] of ozone. State-to-state integral cross sections were calculated for collision energies lower than 0.4 eV. Then specific and thermal rate constants were computed between 10 K and 350 K using these cross sections. The full quantum thermal rate constant is found to be in better agreement with the most recent experimental data than with previous studies where other O3 PESs were employed, confirming th…
The Topological Phase Transitions Related to Fermion Condensate
2014
In this chapter, we consider so-called topological phase transitions, taking place in normal Fermi liquid. In other words, here we are dealing with different instabilities of normal Fermi liquids relative to several kinds of perturbations of initial quasiparticle spectrum \(\varepsilon (p)\) and occupation numbers \(n(p)\) associated with the emergence of a multi-connected Fermi surface. Depending on the parameters and analytical properties of the Landau interaction, such instabilities lead to several possible types of restructuring of initial Landau Fermi liquid ground state. This restructuring generates topologically distinct phases. One of them is the FC discussed above, another one belo…
Converting external potential fluctuations into nonzero time-average electric currents using a single nanopore
2015
The possibility of taking advantage of a fluctuating environment for energy and information transduction is a significant challenge in biological and artificial nanostructures. We demonstrate here directional electrical transduction from fluctuating external signals using a single nanopore of conical shape immersed in an ionic aqueous solution. To this end, we characterize experimentally the average output currents obtained by the electrical rectification of zero time-average input potentials. The transformation of external potential fluctuations into nonzero time-average responses using a single nanopore in liquid state is of fundamental significance for biology and nanophysics. This energ…
Coherence functions of the electrical and the optical noises in monomodal packaged vertical cavity surface emitting lasers
2006
Calculations of the frequency noise spectra and of the coherence functions between the electrical and the optical noises for a single-mode packaged vertical surface emitting laser (VCSEL) are reported.A rate-equation model for an index guided VCSEL is used, implemented with the electrical noise model including the intrinsic device, the package and external bias network.The extended model works up to the laser relaxation frequency. The amplitude optical noise and its correlation with the frequency and electrical noises are also analysed. The influence on the calculated quantities of some electrical and laser parameters is evaluated. The results show that generally the frequency noise is corr…
COMPARISON BETWEEN Mg IIkAND Ca II H IMAGES RECORDED BY SUNRISE/SuFI
2014
We present a comparison of high-resolution images of the solar surface taken in the Mg II k and Ca II H channels of the Filter Imager on the balloon-borne solar observatory SUNRISE. The Mg and Ca lines are sampled with 0.48 nm and 0.11 nm wide filters, respectively. The two channels show remarkable qualitative and quantitative similarities in the quiet Sun, in an active region plage and during a small flare. However, the Mg filtergrams display 1.4-1.7 times higher intensity contrast and appear more smeared and smoothed in the quiet Sun. In addition, the fibrils in a plage are wider. Although the exposure time is 100 times longer for Mg images, the evidence suggests that these differences ca…
Critical phenomena in polymer mixtures: Monte Carlo simulation of a lattice model
1987
A lattice model of a symmetrical binary (AB) polymer mixture is studied, modelling the polymer chains by self-avoiding walks withN A =N B =N steps on a simple cubic lattice. If a pair of nearest neighbour sites is taken by different monomersAB orBA, an energye ab is won; if the pair of sites is taken by anAA or aBB pair, an energye is won, while the energy is reduced to zero if at least one of the sites of the pair is vacant. To allow enough chain mobility, 20% of the lattice sites are vacancies. In addition to local motions of the chain segments we use a novel “grand-canonical” simulation technique:A chains are transformed intoB chains and vice versa, keeping the chemical potential differe…