Metric remote sensing experiments in preparation for Spacelab flights

Aerial and ground photographs of Wallis mountains and of Dolomiti di Cortina d'Ampezzo in Italy were made using spectrozonal emulsions and optical multichannel filters. A metric camera was used in the perspective of the first Spacelab flight aboard the space shuttle. Elementary forms of alpine geomorphology and ice or snow phenomena are detectable on these metric scenes

Anthropologie fictionnelle et anthropologie de la fiction : Un exemple d’« ethnologie à domicile »

La contribution à une anthropologie historique que nous proposons s’appuie sur l’utilisation de diverses sources écrites et orales et un recueil de nouvelles littéraires produites par un habitant du village de Corse du Sud objet de notre étude. Nous retraçons ainsi le processus de (re)production de la vie quotidienne en donnant accès de façon privilégiée aux représentations et aux modes de connaissance d’un acteur se faisant l’observateur de sa propre société. Ainsi s’amorce une anthropologie de la quotidienneté et de l’homme ordinaire qui permet entre autres de revisiter les rapports entre l’anthropologie et la fiction.The anthropological utilisation of a Corsican novel contributes to the comprehension of the daily life of a village community, through the representations of an actor who is both actor and observer of his own society. This documentation is a means for anthropologists to construct an anthropology of the ordinary man and his daily life. It also questions the relations between anthropology and fiction.La contribución a la antropología histórica que proponemos, se apoya en la utilización de diversas fuentes escritas y orales y en una selección de novelas cortas escritas por un habitante de un pueblo de Córcega del sur, objeto de nuestro estudio. Rastreamos el proceso de (re)producción de la vida cotidiana dando un acceso privilegiado a las representaciones y a las formas de conocimiento de un actor que se vuelve observador de su propia sociedad. Se inicia así una antropología de la cotidianeidad y del hombre común que permite, entre otras cosas, revisar las relaciones entre la antropología y la ficción

X-ray structures of dinuclear copper(I) and polynuclear copper(II) complexes with the 2,4-bis(cyanamido)cyclobutane-1,3-dione dianion

From the 2,4-bis(cyanamido)cyclobutane-1,3-dione dianion (2,4-NCNsq2−), two copper complexes [Cu2(PPh3)4(PhCN)2(μ-2,4-NCNsq)] · PhCN (1) and [Cu(dien)(μ-2,4-NCNsq) · H2O]n (2) have been synthesized and characterized by IR and electronic absorption spectroscopies. Their structures have been determined by X-ray crystallography. Complex 1 is a dinuclear copper(I) compound with a 2,4-NCNsq2− ligand bridging two copper atoms through the nitrile nitrogen atoms. Complex 2 appears as a 3D network constituted of copper(II) atoms bridged by 2,4-NCNsq2− dianions. This complex presents an unexpected coordination mode of the bis(cyanamido) ligands which are both coordinated via the nitrile functions and via the amido nitrogen atoms of the NCN groups

Evidence of magnetic field quenching of phosphorous-doped silicon quantum dots

We present data on the electrical transport properties of highly-doped silicon-on-insulator quantum dots under the effect of pulsed magnetic fields up to 48 T. At low field intensities, B<7 T, we observe a strong modification of the conductance due to the destruction of weak localization whereas at higher fields, where the magnetic field length becomes comparable to the effective Bohr radius of phosphorous in silicon, a strong decrease in conductance is demonstrated. Data in the high and low electric field bias regimes are then compared to show that close to the Coulomb blockade edge magnetically-induced quenching to single donors in the quantum dot is achieved at about 40 T.Comment: accepted for publication at Current Applied Physic

Double-walled carbon nanotube dispersion via surfactant substitution

A new approach for the stabilisation of double-walled carbon nanotubes in aqueous media was developed. A low molecular weight surfactant was used in the first stage for the debundling of the nanotubes followed by substitution with a higher molecular weight surfactant or non-ionic surfactants. Dispersions were characterized by optical density measurements, SEM and DLS. The presence of remaining low molecular weight surfactant was investigated by FT-IR. Double walled carbon nanotube dispersions showed good dispersion stability and non-detectable amounts of the initial surfactant, which was completely removed. Such a method could be useful for preparation of stable aqueous dispersions of carbon nanotubes with low concentration of surfactants, which is especially important for toxicity studies

Electron Transport in the Assemblies of Multiwall Carbon Nanotubes

The assemblies (films) of carbon nanotubes (CNTs) possess very stable, reproducible, and extraordinary electronic properties. These films have been considered as attractive materials for various nanosensors and as electrodes of electrochemical energy storage devices, like supercapacitors, with low equivalent series resistance and highly developed internal surface. In order to develop CNT devices operating at the room temperature, it was necessary to determine the assembled films’ properties, such as the mechanism of conductivity, carrier concentration, and mobility. In this study, we are focused on the assemblies (monolayers, arrays, and films) of multiwall carbon nanotubes (MWCNT). We applied a wide temperature range resistance and magnetoresistance as a tool to determine the transport characteristics of MWCNT films. The measurements of the electrical transport (temperature dependence of the resistance) in the assemblies of nanotubes were tested in the temperature range T = 1.5–300 K, and the magnetoresistance measurements were carried out in pulsed magnetic fields up to 35 tesla in the temperature range 1.5–300 K. The mechanisms responsible for the transport in these systems, including weak localization, antilocalization, Luttinger liquid, Shubnikov–de Haas oscillations, and intertube coupling, were observed

Study and characterization by magnetophonon resonance of the energy structuring in GaAs/AlAs quantum-wire superlattices

We present the characterization of the band structure of GaAs/AlAs quantum-wire 1D superlattices performed by magnetophonon resonance with pulsed magnetic fields up to 35 T. The samples, generated by the "atomic saw method" from original quantum-well 2D superlattices, underwent substantial modifications of their energy bands built up on the X-states of the bulk. We have calculated the band structure by a finite element method and we have studied the various miniband structures built up of the masses m_t and m_l of GaAs and AlAs at the point X. From an experimental point of view, the main result is that in the 2D case we observe only resonances when the magnetic field B is applied along the growth axis whereas in the 1D case we obtain resonances in all magnetic field configurations. The analysis of the maxima (or minima for B // E) in the resistivity rho_xy as a function of B allows us to account, qualitatively and semi-quantitatively, for the band structure theoretically expected