Search results for "Raphe"
showing 10 items of 839 documents
Simulation de scénarios d’urbanisation pour estimer l’impact écologique du développement résidentiel et des évolutions de trafic associées
2015
National audience; La maîtrise de l’étalement urbain repré¬sente actuellement une préoccupation ma¬jeure en aménagement face au nombre im¬portant de nuisances induites par le phénomène. Sur le plan paysager, la croissance des villes se produit aux dépens des milieux naturels et agricoles, ce qui contribue à la fragmentation et à la réduction des habitats de la faune sauvage. Il est donc souhaitable de trouver un compromis entre les implantations résidentielles et la connectivité des habitats écologiques afin d’assurer la durabilité des populations animales. La recherche de ce compromis suppose une concertation entre les différents acteurs de l’aménagement du territoire et de l’environnement…
Unexpected Scholl Reaction of 6,7,13,14-Tetraarylbenzo[k]tetraphene: Selective Formation of Five-Membered Rings in Polycyclic Aromatic Hydrocarbons
2016
Cyclodehydrogenation is a versatile reaction that has enabled the syntheses of numerous polycyclic aromatic hydrocarbons (PAHs). We now describe a unique Scholl reaction of 6,7,13,14-tetraarylbenzo[k]tetraphene, which "unexpectedly" forms five-membered rings accompanying highly selective 1,2-shift of aryl groups. The geometric and optoelectronic nature of the resulting bistetracene analogue with five-membered rings is comprehensively investigated by single-crystal X-ray, NMR, UV-vis absorption, and cyclic voltammetry analyses. Furthermore, a possible mechanism is proposed to account for the selective five-membered-ring formation with the rearrangement of the aryl groups, which can be ration…
Certain doping concentrations caused half-metallic graphene
2017
This work is supported by National Natural Science Foundation of China (Grant No. 21173096).
Design and preparation of core-shell structured magnetic graphene oxide@MIL-101(Fe): Photocatalysis under shell to remove diazinon and atrazine pesti…
2020
Abstract A magnetically separable support with core-shell morphology comprising amine-functionalized Fe3O4 wrapped with graphene oxide (AFG) was successfully prepared and used to support MIL-101(Fe). The ternary AFG@MIL-101(Fe) composite was investigated as a photo-Fenton catalyst for the degradation of recalcitrant diazinon (DIZ) and atrazine (ATZ) pesticides. After 105 min visible light irradiation, the AFG@30MIL-101(Fe) photocatalyst achieved 100 ± 1% and 81 ± 1% photocatalytic degradation efficiency for DIZ and ATZ pollutants, respectively. The recorded data indicated superior photocatalytic ability of the nanocomposite as compared to AF@30MIL-101(Fe) and MIL-101(Fe) photocatalysts for …
Fabrication of graphene ruthenium-complex heterostructures
2015
The aim of this study is to understand the photoresponse of a Ruthenium-complex/graphene heterostructure. Early work demonstrated that light detection by graphene field effect devices was enhanced by dropcasting Ruthenium Complex molecules. Here we proposed to fabricate a new class of devices where the Ruthenium-complex molecules are embedded between two layer of CVD monolayer graphene.
Shedding Light on Graphene Quantum Dots: Key Synthetic Strategies, Characterization Tools, and Cutting-Edge Applications
2021
During the last 20 years, the scientific community has shown growing interest towards carbonaceous nanomaterials due to their appealing mechanical, thermal, and optical features, depending on the specific nanoforms. Among these, graphene quantum dots (GQDs) recently emerged as one of the most promising nanomaterials due to their outstanding electrical properties, chemical stability, and intense and tunable photoluminescence, as it is witnessed by a booming number of reported applications, ranging from the biological field to the photovoltaic market. To date, a plethora of synthetic protocols have been investigated to modulate the portfolio of features that GQDs possess and to facilitate the…
Electrochemical and spectroscopic studies of poly(diethoxyphosphoryl)porphyrins
2011
Abstract The synthesis and electrochemical characterization of two related series of porphyrins bearing diethoxyphosphoryl groups are reported. One group of compounds is represented as (T( p -R)PP)M where R = phos = P(O)(OEt) 2 and M = Zn(II) or H 2 while the other is represented as (di( p -R)Pdi(phos)P)M where R = P(O)(OEt) 2 , H or CH 3 and M = Zn(II) or H 2 . Each porphyrin was investigated by electrochemistry and thin-layer spectroelectrochemistry in CH 2 Cl 2 , CDCl 3 , CHCl 3 or PhCN containing tetra- n -butylammonium perchlorate (TBAP) as supporting electrolyte. The highly electron-withdrawing P(O)(OEt) 2 groups lead to easier reductions and harder oxidations than the two comparison …
One-pot synthesis of graphene quantum dots and simultaneous nanostructured self-assembly via a novel microwave-assisted method: impact on triazine re…
2018
One-step methods for fabricating green materials endowed with diverse functions is a challenge to be overcome in terms of reducing environmental risk and cost. We report a fast and easy synthesis of multifunctional materials composed of only fluorescent dots with structural flexibility and high sorption capability. The synthesis consists of a one-pot microwave-assisted reaction for the simultaneous formation of graphene quantum dots (GQDs) from organic precursors and their spontaneous self-assembly forming porous architectures. The GQD-assemblies are robust and no signs of degradation were observed with most organic solvents. The ensuing GQDs and their porous solids were fully characterized…
Bayesian Modelling of Confusability of Phoneme-Grapheme Connections
2007
Deficiencies in the ability to map letters to sounds are currently considered to be the most likely early signs of dyslexia. This has motivated the use of Literate, a computer game for training this skill, in several Finnish schools and households as a tool in the early prevention of reading disability. In this paper, we present a Bayesian model that uses a student's performance in a game like Literate to infer which phoneme-grapheme connections student currently confuses with each other. This information can be used to adapt the game to a particular student's skills as well as to provide information about the student's learning progress to their parents and teachers. We apply our model to …
Functionalization of Graphene with Molecules and/or Nanoparticles for Advanced Applications
2019
Graphene is considered the material of the third millennium, due to its extraordinary electronic and mechanical properties, and due to the possibility to modulate its conductivity, flexibility, elasticity, transparency, and biocompatibility by bottom-up approach. The possibility to gather the proper- ties of graphene and graphene oxide with those of functional moieties or nanoparticles is herein reviewed. The synthetic approaches proposed, either covalent or noncovalent, are aimed to tune appropriately graphene’s properties for the realization of materials for advanced uses, such as bio- medical applications, sensors, catalysis, and energy devices. In particular, methods based on covalent l…