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- Gvaramia, Manuchar, et al.
(author)
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Neutron spin echo spectroscopy with a moving sample
- 2023
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Journal article (peer-reviewed)abstract
- Neutron spin echo spectroscopy is a high resolution inelastic neutron scattering method probing nanosecond dynamics. It is well suited to study the atomistic motion in polymer systems and contributes to our understanding of viscoelasticity. However, for samples under shear, or moving samples in general, Doppler scattering has to be considered. We compare the measured phase shift and depolarisation due to Doppler scattering from a rotating graphite disk to numerical and analytical calculations and find excellent agreement. This allows to take into account Doppler scattering during the data processing and makes longer Fourier times as well as higher shear rates and Q ranges possible with neutron spin echo spectroscopy, enabling for example the study of polymers under high shear.
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| 2. |
- Kawecki, Maciej, et al.
(author)
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Direct measurement of topological interactions in polymers under shear using neutron spin echo spectroscopy
- 2019
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In: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Journal article (peer-reviewed)abstract
- We present in-situ neutron spin echo measurements on an entangled polydimethylsiloxane melt under shear and demonstrate the ability to monitor nano-scale dynamics in flowing liquids. We report no changes in the topological interactions of the chains for shear rates approaching the inverse longest relaxation time. Further experiments following along this line will allow to systematically test the predictions of theories, like e.g. convective constraint release.
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| 3. |
- Lundin, Filippa, 1992, et al.
(author)
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Ion Dynamics and Nanostructures of Diluted Ionic Liquid Electrolytes
- 2022
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In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 126:38, s. 16262-16271
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Journal article (peer-reviewed)abstract
- Diluted ionic liquid electrolytes are promising candidates in next-generation batteries enabling the implementation of lithium metal anodes. The diluent should fully mix with the ionic liquid while not interacting with the Li ions to preserve the ionic liquid character, which is beneficial for Li-metal electrode stability. We report on the influence of a hydrofluoroether (HFE) diluent on ion dynamics and nanostructure of an ionic liquid electrolyte. We show that the ionic liquid and the diluent are fully miscible and that the solvation structure of the Li ions is not affected by the presence of HFE. The increase in the conductivity by the addition of the diluent is directly related to a decrease in viscosity with faster dynamics of all ionic species. However, the relative increase in mobility is considerably larger for the ionic liquid cation as a result of a preferred interaction with HFE. On the microscopic scale, more complex local non-Gaussian diffusive dynamics are found, faster than what is expected from the self-diffusion coefficient. The relative change of the dynamics with the addition of HFE on macro- and microscopic length scales correlates well, which underlines the connection between the motions probed on different length and time scales.
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| 4. |
- Magazù, S., et al.
(author)
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Protein dynamics as seen by (quasi) elastic neutron scattering
- 2017
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In: Biochimica et Biophysica Acta - General Subjects. - : Elsevier BV. - 0304-4165. ; 1861:1, s. 3504-3512
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Journal article (peer-reviewed)abstract
- Background Elastic and quasielastic neutron scattering studies proved to be efficient probes of the atomic mean square displacement (MSD), a fundamental parameter for the characterization of the motion of individual atoms in proteins and its evolution with temperature and compositional environment. Scope of review We present a technical overview of the different types of experimental situations and the information quasi-elastic neutron scattering approaches can make available. In particular, MSD can crucially depend on the time scale over which the averaging (building of the “mean”) takes place, being defined by the instrumental resolution. Due to their high neutron scattering cross section, hydrogen atoms can be particularly sensitively observed with little interference by the other atoms in the sample. A few examples, including new data, are presented for illustration. Major conclusions The incoherent character of neutron scattering on hydrogen atoms restricts the information obtained to the self-correlations in the motion of individual atoms, simplifying at the same time the data analysis. On the other hand, the (often overlooked) exploration of the averaging time dependent character of MSD is crucial for unambiguous interpretation and can provide a wealth of information on micro- and nanoscale atomic motion in proteins. General significance By properly exploiting the broad range capabilities of (quasi)elastic neutron scattering techniques to deliver time dependent characterization of atomic displacements, they offer a sensitive, direct and simple to interpret approach to exploration of the functional activity of hydrogen atoms in proteins. Partial deuteration can add most valuable selectivity by groups of hydrogen atoms. “This article is part of a Special Issue entitled “Science for Life” Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo”.
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