Publications associées à Précession de Larmor

129Xe Dynamic Nuclear Polarization Demystified: The Influence of the Glassing Matrix on the Radical Properties

Rolf Gruetter, Andrea Capozzi, Jean-Noël Hyacinthe, Thanh Phong Kevin Lê, Emma Linnea Wiström

129Xe dissolution dynamic nuclear polarization (DNP) is a controversial topic. The gold standard technique for hyperpolarized xenon magnetic resonance imaging (MRI) is spin exchange optical pumping, which received FDA approval in 2022. Nevertheless, the ve ...

2024

A geometrically exact model for thin magneto-elastic shells

Pedro Miguel Nunes Pereira de Almeida Reis, Matteo Pezzulla, Dong Yan

We develop a reduced model for hard-magnetic, thin, linear-elastic shells that can be actuated through an external magnetic field, with geometrically exact strain measures. Assuming a reduced kinematics based on the Kirchhoff-Love assumption, we derive a r ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Hyperpolarization of inorganic solids

Snaedis Björgvinsdóttir

Solid-state NMR can provide information about the atomic level structure and dynamics of materials. It directly probes symmetry and structure at nuclear sites, and is especially useful for investigation of disordered or amorphous solids that lack long rang ...

EPFL2020

Multimodal Response to Copper Binding in Superoxide Dismutase Dynamics

David Lyndon Emsley

Copper/zinc superoxide dismutase (SOD) is a homodimeric metalloenzyme that has been extensively studied as a benchmark for structure-function relationships in proteins, in particular because of its implication in the familial form of the neurodegenerative ...

AMER CHEMICAL SOC2020

Weak Crystallization of Fluctuating Skyrmion Textures in MnSi

Dirk Grundler

We report an experimental study of the emergence of nontrivial topological winding and long-range order across the paramagnetic-to-skyrmion lattice transition in the transition metal helimagnet MnSi. Combining measurements of the susceptibility with small- ...

American Physical Society2019

High-Field C-13 Dynamic Nuclear Polarization in Nanodiamond

Stefano Alberti, Jean-Philippe Ansermet, Jérémy Genoud, Serguei Sekatski, Murari Soundararajan, Dongyoung Yoon

Hyperpolarization in diamond via dynamic nuclear polarization (DNP) has attracted a lot of interest for various applications as diamond exhibits extremely long C-13 spin relaxation times and has endogenous polarizing agents in the form of crystalline defec ...

2019

Prediction of hydro-acoustic resonances in hydropower plants by a new approach based on the concept of swirl number

François Avellan, Christophe Nicolet, Arthur Tristan Favrel, Christian Landry, Sébastien Alligné, Loïc Andolfatto, Joao Gomes Pereira Junior

Hydropower plant units operating in off-design conditions are subject to cavitation flow instabilities, potentially inducing hydro-acoustic resonances under certain conditions. They can be predicted by using one-dimensional numerical models of hydropower p ...

Taylor & Francis Ltd2019

New insight in Francis turbine cavitation vortex rope: role of the runner outlet flow swirl number

François Avellan, Christian Landry, Christophe Nicolet, Joao Gomes Pereira Junior, Arthur Tristan Favrel, Andres Müller

At part load operation, Francis turbines experience the development of a cavitation vortex rope in the draft tube, whose precession acts as a pressure excitation source. In case of resonance, the resulting pressure pulsations lead to unacceptable torque an ...

Taylor & Francis Ltd2018

Carbazole as Linker for Dinuclear Gadolinium-Based MRI Contrast Agents

Lothar Helm, Bibimaryam Mousavi, Anne-Sophie Chauvin, Loïck Moriggi

Ligands able to complex two gadolinium ions have been synthesized and characterized in view of the ability of the complexes to increase the spin relaxation of water protons. All ligands are based on the heptadentate diethylenetriaminetetraacetic acid (DTTA ...

Wiley-V C H Verlag Gmbh2017

Radio-frequency coils for ultra-high field magnetic resonance

Özlem Ipek

Radiofrequency (RF) coils are key components of magnetic resonance imaging (MRI) systems. The primary purpose of this review is to provide a basic theory of RF coil designs and their characterization by bench measurements, electromagnetic field simulations ...

Elsevier2017

Collisional cross-section of water molecules in vapour studied by means of H-1 relaxation in NMR

Geoffrey Bodenhausen, Lothar Helm, Pascal Miéville, Daniele Mammoli, Roberto Buratto, Estel Canet Martinez

In gas phase, collisions that affect the rotational angular momentum lead to the return of the magnetization to its equilibrium (relaxation) in Nuclear Magnetic Resonance (NMR). To the best of our knowledge, the longitudinal relaxation rates R-1 = 1/T-1 of ...

Nature Research2016

Anomalous thermal decoherence in a quantum magnet measured with neutron spin echo spectroscopy

Thomas Keller, Felix Groitl

The effect of temperature dependent asymmetric line broadening is investigated in Cu(NO3)(2)center dot 2.5D(2)O, a model material for a one-dimensional bond alternating Heisenberg chain, using the high resolution neutron-resonance spin echo (NRSE) techniqu ...

Amer Physical Soc2016

Low frequency terahertz-induced demagnetization in ferromagnetic nickel

Christoph Peter Hauri, Mostafa Shalaby

A laser stimulus at terahertz (THz) frequency is expected to offer superior control over magnetization dynamics compared to an optical pulse, where ultrafast demagnetization is mediated by heat deposition. As a THz field cycle occurs on a timescale similar ...

Amer Inst Physics2016

The upgraded cold neutron triple-axis spectrometer FLEXX - enhanced capabilities by new instrumental options

Felix Groitl

The upgrade of the cold neutron triple axis spectrometer FLEXX, a work-horse instrument for inelastic neutron scattering matching the sample environment capabilities at Helmholtz-Zentrum Berlin, has been successfully accomplished. Experiments confirmed an ...

E D P Sciences2015

Spin Noise Detection of Nuclear Hyperpolarization at 1.2K

Geoffrey Bodenhausen, Aurélien Bornet, Sami Jannin, Jonas Milani, Basile Vuichoud

We report proton spin noise spectra of a hyperpolarized solid sample of commonly used DNP (dynamic nuclear polarization) juice containing TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxide) and irradiated by a microwave field at a temperature of 1.2K ...

Wiley-Blackwell2015

Neutron resonance spin-echo upgrade at the three-axis spectrometer FLEXX

Thomas Keller, Felix Groitl

We describe the upgrade of the neutron resonance spin-echo setup at the cold neutron triple-axis spectrometer FLEXX at the BER II neutron source at the Helmholtz-Zentrum Berlin. The parameters of redesigned key components are discussed, including the radio ...

American Institute of Physics2015

Hydro-acoustic resonance behavior in presence of a precessing vortex rope: observation of a lock-in phenomenon at part load Francis turbine operation

François Avellan, Christian Landry, Arthur Tristan Favrel, Andres Müller, Keita Yamamoto

Francis turbines operating at part load condition experience the development of a cavitating helical vortex rope in the draft tube cone at the runner outlet. The precession movement of this vortex rope induces local convective pressure fluctuations and a s ...

IOP science2014

Hydro-acoustic resonance behavior in presence of a precessing vortex rope: observation of a lock-in phenomenon at part load Francis turbine operation

François Avellan, Arthur Tristan Favrel, Christian Landry, Andres Müller, Keita Yamamoto

Francis turbines operating at part load condition experience the development of a cavitating helical vortex rope in the draft tube cone at the runner outlet. The precession movement of this vortex rope induces local convective pressure fluctuations and a s ...

Iop Publishing Ltd2014

Structure and Properties of the Precursor/Successor Complex and Transition State of the CrCl2+/Cr2+ Electron Self-Exchange Reaction via the Inner-Sphere Pathway

François Rotzinger

The electron self-exchange reaction CrCl(OH2)5(2+) + Cr(OH2)6(2+) -> Cr(OH2)(6)(2+) + CrCl(OH2)(5)(2+), proceeding via the inner-sphere pathway, was investigated with quantum-chemical methods. Geometry and vibrational frequencies of the precursor/successor ...

American Chemical Society2014

Nanosecond Time Scale Motions in Proteins Revealed by High-Resolution NMR Relaxometry

Geoffrey Bodenhausen, Fabien Ferrage

Understanding the molecular determinants underlying protein function requires the characterization of both structure and dynamics at atomic resolution. Nuclear relaxation rates allow a precise characterization of protein dynamics at the Larmor frequencies ...

American Chemical Society2013