Results 141 to 150 of about 652 (172)

Excess water dynamics in hydrotalcite: QENS study

Pramana, 2004
Results of the quasi-elastic neutron scattering (QENS) measurements on the dynamics of excess water in hydrotalcite sample with varied content of excess water are reported. Translational motion of excess water can be best described by random translational jump diffusion model.
S. Mitra, A. Pramanik, D. Chakrabarty, R. Mukhopadhyay   +3 more
openaire   +1 more source

QENS from polymer aggregates in supercritical CO2

Physica B: Condensed Matter, 2000
Abstract We report QENS measurements from PS-b-PFOA aggregates in supercritical CO2. Line shapes are dominated by localized diffusive modes and segmental dynamics of the anchored, finite-length PFOA chains. For Q⩽0.6 A−1, we obtain effective diffusion coefficients of ≅0.8 10−6 cm2/s.
R Triolo, V Arrighi, A Triolo, P Migliardo, S Magazu, J B McClain, D Betts, J M DeSimone, H D Middendorf   +8 more
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Dynamic scaling of QENS spectra of glassy water in aging cement paste

Physica A: Statistical Mechanics and its Applications, 2002
Abstract We propose a new method for the analysis of high-resolution incoherent quasi-elastic neutron scattering spectra of water in porous media and apply it, in particular, to a case of water in hydrated tricalcium silicate. We plot the normalized frequency-dependent susceptibility as a function of a scaling variable ω/ωp, where ωp is the peak ...
FRATINI, EMILIANO, A. FARAONE, BAGLIONI, PIERO, M. C. BELLISSENT FUNEL, S. H. CHEN   +4 more
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QENS/WINS Topical Discussions

Neutron News, 2021
Ross Stewart, Kristine Niss, Timmy Ramirez-Cuesta, Ken Herwig   +3 more
openaire   +1 more source

QENS and NMR studies of 3-picoline-water solutions

Applied Physics A: Materials Science & Processing, 2002
Quasi-elastic neutron scattering measurements were performed on aqueous solutions of 3-picoline (3-methyl- pyridine) at room temperature. H-D substitution on both the solute and the water was used to separate the dynamics of the two species. The analysis of the translational diffusive mo- tion at different concentrations shows that at high picoline ...
L. Alm�sy, P. B�nki, M.C. Bellissent-Funel, M. Bokor, L. Cser, G. Jancs�, K. Tompa, J.M. Zanotti   +7 more
openaire   +1 more source

Geometrical aspects of QENS experiments in case of anisotropic samples

The European Physical Journal Special Topics, 2007
Diffusion in anisotropic samples is often studied by quasi-elastic neutron scattering at time-of-flight (t-o-f) instruments. During the data analysis the measured dynamic structure factor S(Q,E) is fitted by a model function, which - reflecting the anisotropy of the sample - depends on the sample orientation.
F. Jurányi, F. González, S. Gvasaliya
openaire   +1 more source

Coherent QENS for the investigation of self-diffusion in intermetallic alloys

Physica B: Condensed Matter, 2001
Up to now, self-diffusion in intermetallic alloys has been successfully studied in various compounds containing strong incoherent scatterers, namely Ni and Co, by means of QENS. The range of accessible compounds could be significantly enlarged by using coherent scattering.
Kaisermayr, Martin, Sepiol, Bogdan, Vogl, Gero   +2 more
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Order-disorder transition in pyridinium iodide: QENS study

Applied Physics A: Materials Science & Processing, 2002
Reorientational motion of the pyridinium cation in pyridinium iodide as studied by the high-resolution, quasi-elastic neutron scattering (QENS) technique both above and below the order–disorder transition (Tc=247 K) temperature are reported. The pyridinium ion is found to undergo reorientational motion around the axis perpendicular to its plane and is ...
R. Mukhopadhyay, S. Mitra, P.S. Kumar, I. Tsukushi, S. Ikeda   +4 more
openaire   +1 more source

The use of Fourier transforms in the analysis of QENS data

Physica B: Condensed Matter, 1996
Abstract The traditional method of analysing QENS data has been to fit a model function to the S ( Q , ω ) taking into account the shape of the resolution function. The drawback of this method is the reliance on a model for S ( Q , ω ), for example, one (or more) Lorentzians.
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Molecular Dynamics in Nematic Phases: QENS and NMR Spectroscopy

1992
Molecular dynamics in liquid crystals (particularly smectic and to a lesser extent nematic phases) has been extensively studied by quasi elastic neutron scattering (QENS)1-11 as well as by magnetic relaxation12–17. Nevertheless, these two different techniques have never been combined, probably due to the fact that, quite often, the results obtained did
M. Riccò, M. P. Fontana
openaire   +1 more source