Search results for "diamant"

Preo : pépinière de revues en open access

2022

PREO est une plateforme de publication de revues et de collections portée par la MSH de Dijon. Son équipe assure un accompagnement à l'édition scientifique multisupports dans le contexte de la Science ouverte. Depuis sa création, PREO accompagne des projets de transition de l'imprimé vers le numérique ou de création au format numérique natif. Dès 2021, PREO s'associe aux presses universitaires de Bourgogne (EUD) et de Franche-Comté (PUFC) dans le développement de bonnes pratiques au sein d'un pôle éditorial régional.

Utilisation des minéraux lourds comme indicateurs de paléoplacers alluvionnaires diamantifères en République centrafricaine (RCA). Use of heavy miner…

2001

International audience; Le diamant est la première ressource minérale de la République Centrafricaine (RCA). Exclusivement exploité par plusieurs sociétés minières avant 1960, il l'est maintenant de façon artisanale. Avec une production annuelle d'envi-ron 500 000 carats (1 carat = 0,2 g), la RCA est le dixième producteur de diamant (en valeur) dans le monde. Les diamants gemmes (pierres de joaillerie, taillables) représentent 70 à 75 % de la production. Deux principales zones diamantifères présentant une relation spatiale évidente existent en RCA : la Formation de Mouka-Ouadda à l'Est et celle de Carnot à l'Ouest. Ces formations, représentant les 'roches magasins' du diamant, constituent a…

I giogali di diamanti ed oro dei Branciforti

2019

Si analizzano i preziosi monili elencati negli inventari dei Branciforti. Emergono svariate tipologie di "giogali" con i quali si ornavano i protagonisti dell'importante casato, da Ottavio ad Antonio, a Ercole e Giuseppe I, talora anche individuabili nei loro ritratti, custoditi dagli eredi. We analyze the precious jewels listed in the Branciforti inventories. Various types of "giogali" emerge with which the protagonists of the important family were adorned, from Octavius to Anthony, Hercules and Joseph I, sometimes also identifiable in their portraits, kept by their heirs.

Defying Stereotypes with Nanodiamonds: Stable Primary Diamondoid Phosphines

2016

International audience; Direct unequal C-H bond difunctionalization of phosphorylated diamantane was achieved in high yield from the corresponding phosphonates. Reduction of the functionalized phosphonates provides access to novel primary and secondary alkyl/aryl diamantane phosphines. The prepared primary diamantyl phosphines are quite air stable compared to their adamantyl and especially alkyl or aryl analogues. This finding is corroborated by comparing the singly occupied molecular orbital energy levels of the corresponding phosphine radical cations obtained by density functional theory computations.

Incenerimento elettrochimico di acido ossalico in presenza di NaCl

2008

Nanodiamonds: Emergence of Functionalized Diamondoids and Their Unique Applications

2015

Selective Preparation of Diamondoid Phosphonates

2014

We present an effective sequence for the preparation of phosphonic acid derivatives of the diamondoids diamantane, triamantane, [121]tetramantane, and [1(2,3)4]pentamantane. The reactions of the corresponding diamondoid hydroxy derivatives with PCl3 in sulfuric or trifluoroacetic acid give mono- as well as didichlorophosphorylated diamondoids in high preparative yields.

Conceptual design of the AGATA 1$\pi$ array at GANIL

2017

The Advanced GAmma Tracking Array (AGATA) has been installed at the GANIL facility, Caen-France. This setup exploits the stable and radioactive heavy-ions beams delivered by the cyclotron accelerator complex of GANIL. Additionally, it benefits from a large palette of ancillary detectors and spectrometers to address in-beam γ-ray spectroscopy of exotic nuclei. The set-up has been designed to couple AGATA with a magnetic spectrometer, charged-particle and neutron detectors, scintillators for the detection of high-energy γ rays and other devices such as a plunger to measure nuclear lifetimes. In this paper, the design and the mechanical characteristics of the set-up are described. Based on sim…

Senescence and longevity : from physiological mechanisms to evolutionary processes : studies in birds and mammals

2012

There is an incredible diversity of lifespan in the animal kingdom ranging from a few days for small gastrotrichs worms to several hundred of years for some bivalves or tortoises. This amazing diversity has long questioned biology researchers. The growing interest in the phenomenon of aging, mainly due to the increase in life expectancy in humans, has questioned researchers on processes that determine patterns of longevity and ageing. On the one hand, biomedical and biogerontological studies helped describe numerous cellular and physiological mechanisms related to aging. Among these mechanisms, oxidative stress has been identified as playing a major role, through life-time accumulation of d…

Diamondoids: functionalization and subsequent applications of perfectly defined molecular cage hydrocarbons

2014

The term “diamondoid” describes cage hydrocarbon molecules that are superimposable on the diamond lattice. Diamondoids that are formally built by face-fusing of adamantane units, namely diamantane, triamantane, tetramantane, etc., have fascinated chemists since the beginning of the last century. The functionalization of these perfectly defined (C,H)-molecules is described here. Thus, diamondoid halides and diamondoid alcohols are first rank precursors for amino and phosphine-substituted diamondoids that have proved to be highly useful in therapeutic applications and metal catalysis, respectively. The extent of functionalization and polyfunctionalization achieved for adamantane and diamantan…