Denis Petermann

Denis Petermann
Université Paris-Sud 11 | Paris 11 · Laboratoire de Physique des Solides

Research Engineer

About

17
Publications
1,686
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506
Citations
Citations since 2017
0 Research Items
137 Citations
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2017201820192020202120222023010203040
2017201820192020202120222023010203040
2017201820192020202120222023010203040
Introduction
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Publications

Publications (17)
Article
Le même formalisme est utilisé pour expliquer la diffraction par l’ADN et par les nanotubes de carbone ou leurs analogues d’oxydes métalliques, les nanotubes d’imogolite. La diffraction permet à la fois de déterminer la structure et l’organisation des nanotubes. De la diffraction électronique à celle des rayons X, nous discutons des propriétés indi...
Conference Paper
Full-text available
We present long term site testing statistics based on DIMM and GSM data obtained at Dome C, Antarctica. These data have been collected on the bright star Canopus since the end of 2003. We give values of the integrated turbulence parameters in the visible (wavelength 500 nm). The median value we obtained for the seeing are 1.2 arcsec, 2.0 arcsec and...
Article
A stroboscopic X-ray diffraction machine is described that allows studying kinetics aspects of strain-induced crystallization in natural rubber. Besides conventional mechanical cycling in extension, samples may be submitted to periodic extension cycling over a 0.05 Hz–30 Hz frequency range and for various amplitudes of elongation. Pertinent paramet...
Article
We study the influence of nanoparticle doping on the lyotropic liquid crystalline phase of the industrial surfactant Brij®30 (C₁₂E₄) and water, doped with spherical polyoxometalate nanoparticles smaller than the characteristic dimensions of the host lamellar phase. We present viscometry and in situ rheology coupled with small-angle X-ray scattering...
Article
We discuss the application of in-situ rheological small angle X-ray scattering experiments to the study of complex fluids under shear, implemented using custom Couette cylinder rheometers mounted on the SWING beamline of the SOLEIL Synchrotron. We discuss several applications of this technique to the study of phase transitions in nanoparticle doped...
Article
Full-text available
The aim of the LUCAS program is to observe chlorophyll and atmospheric molecules in the Earthshine spectrum in order to prepare the detection of life in terrestrial extrasolar planets to be discovered. Actually, observations from Antarctica offer a unique possibility to study the variations of Earthshine spectrum during Earth rotation while various...
Article
A prototype instrument has been developed which allows the simultaneous acquisition of both X-ray diffraction and X-ray fluorescence data at a microscopic length scale for mapping studies on materials. The instrument takes full advantage of the performance of recently developed optics and detectors to optimize the detection of low-intensity signals...
Article
Full-text available
So as to prepare future observations of terrestrial extrasolar planets liable to shelter life, we attempt to detect the life on the Earth seen as a dot. We use the Moon Earthshine, in which any place reflects the totality of the enlightened part of Earth facing the Moon. Observing from OHP and from ESO, we detected terrestrial chlorophyll in the ne...
Article
A new series of mesomorphic side chain polysiloxane networks has been recently synthesized in which the chemical nature of the linkage and the mesogenic group have been varied and the gelation conditions during the chemical reaction have been studied. This paper presents an X-ray diffraction study of the mesogenic group orientation in stretched sam...
Article
Full-text available
In 1902, Majorana reported the magneto-optical properties of aqueous colloidal suspensions of mixed iron oxides. Oddly enough, the magnetic-field induced birefringence displayed a non-monotonic dependence upon field intensity. This behaviour was later interpreted as due to the existence in these sols of at least two different chemical species. Duri...
Article
Full-text available
Depending on volume fraction, aqueous suspensions of goethite (alpha-FeOOH) nanorods form a liquid-crystalline nematic phase (above 8.5%) or an isotropic liquid phase (below 5.5%). In this article, we investigate by small-angle X-ray scattering, magneto-optics, and magnetometry the influence of a magnetic field on the isotropic phase. After a brief...
Article
Full-text available
At volume fractions larger than 8.5%, aqueous suspensions of lath-like goethite (alpha-FeOOH) nanorods form a lyotropic nematic phase. In this article, we first discuss the nematic ordering within statistical-physics models of the isotropic/nematic phase transition. We then describe the influence of a magnetic field on the nematic phase. Because th...
Article
Small angle X-ray scattering (SAXS) studies have been performed in the columnar hexagonal and nematic mesophases of a 1,3-diacylaminobenzene. In both mesophases the molecules are self-assembled into columns by hydrogen bonds. The SAXS experiments confirm the existence of point defects in both phases. The generic π defect is the point where a single...
Article
Full-text available
A family of mesomorphic bis(alkoxystilbazole) silver(I) dodecylsulphate and octylsulphate complexes has been studied by X-ray scattering in their various mesophases. In particular, many of the complexes exhibit a thermotropic cubic mesophase and, for one example, a monodomain was obtained allowing the space group to be unequivocally identified. A m...
Article
Full-text available
This paper reviews and extends the procedure used to measure the nematic order parameter by X-ray scattering. We show that the well-known integral equation derived by Leadbetter and coworkers, relating the scattered intensity $I(\theta)$ to the orientational distribution function $f(\beta)$, can be analytically simplified both in the general case a...

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