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991.
We study projectively self-dual polygons and curves in the projective plane. Our results provide a partial answer to problem No 1994-17 in the book of Arnold’s problems (2004). 相似文献
992.
Clavel G Marichy C Willinger MG Ravaine S Zitoun D Pinna N 《Langmuir : the ACS journal of surfaces and colloids》2010,26(23):18400-18407
CoFe(2)O(4)-TiO(2) and CoFe(2)O(4)-ZnO nanoparticles/film composites were prepared from directed assembly of colloidal CoFe(2)O(4) in a Langmuir-Blodgett monolayer and atomic layer deposition (ALD) of an oxide (TiO(2) or ZnO). The combination of these two methods permits the use of well-defined nanoparticles from colloidal chemistry, their assembly on a large scale, and the control over the interface between a ferrimagnetic material (CoFe(2)O(4)) and a semiconductor (TiO(2) or ZnO). Using this approach, architectures can be assembled with a precise control from the Angstrom scale (ALD) to the micrometer scale (Langmuir-Blodgett film). The resulting heterostructures present well-calibrated thicknesses. Electron microscopy and magnetic measurement studies give evidence that the size of the nanoparticles and their intrinsic magnetic properties are not altered by the various steps involved in the synthesis process. Therefore, the approach is suitable to obtain a layered composite with a quasi-monodisperse layer of ferrimagnetic nanoparticles embedded in an ultrathin film of semiconducting material. 相似文献
993.
Benjamin Isare Dr. Mathieu Linares Dr. Loussiné Zargarian Dr. Serge Fermandjian Dr. Motofumi Miura Shigeyasu Motohashi Prof. Nicolas Vanthuyne Dr. Roberto Lazzaroni Dr. Laurent Bouteiller Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(1):173-177
Amplification of chirality has been reported in polymeric systems. It has also been shown that related effects can occur in polymer‐like dynamic supramolecular aggregates, if a subtle balance between noncovalent interactions allows the coupling between a chiral information and a cooperative aggregation process. In this context, we report a strong majority‐rules effect in the formation of chiral dynamic nanotubes from chiral bisurea monomers. Furthermore, similar helical nanotubes (with the same circular dichroism signature) can be obtained from racemic monomers in a chiral solvent. Competition experiments reveal the relative strength of the helical bias induced by the chiral monomer or by the chiral solvent. The nanotube handedness is imposed by the monomer chirality, whatever the solvent chirality. However, the chirality of the solvent has a significant effect on the degree of chiral induction. 相似文献
994.
Serge Cosnier Andrew J. Gross Fabien Giroud Michael Holzinger 《Current Opinion in Electrochemistry》2018
After a short comparison of biofuel cells based on enzymes and microorganisms, several important developments and applications of enzymatic fuel cells (EFCs) are discussed. This discussion emphasizes how to evaluate the performance of EFCs, and highlights the influence of temperature and how it must be carefully considered for practical use of EFCs as power sources. Some of the latest and most important innovations in EFC design using buckypapers and redox nanoparticles are briefly reviewed. 相似文献
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Guocan Li Ke Hu Kiyoshi C. D. Robson Prof. Serge I. Gorelsky Prof. Gerald J. Meyer Prof. Curtis P. Berlinguette Prof. Michael Shatruk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):2173-2181
Two novel tris‐heteroleptic Ru–dipyrrinates were prepared and tested as sensitizers in the dye‐sensitized solar cell (DSSC). Under AM 1.5 sunlight, DSSCs employing these dyes achieved power conversion efficiencies (PCEs) of 3.4 and 2.2 %, substantially exceeding the value achieved previously with a bis‐heteroleptic dye (0.75 %). As shown by electrochemical measurements and DFT calculations, the improved PCEs stem from the synthetically tuned electronic structure, which affords more negative excited state redox potentials and favorable electron injection into the TiO2 conduction band. Electron injection was quantified by nanosecond transient absorption spectroscopy, which revealed that the highest injection yield is achieved with the dye that acts as the strongest photoreductant. 相似文献
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Françoise Provencher Maciej Sakowicz Colin‐Nadeau Brosseau Gianluca Latini Serge Beaupré Mario Leclerc Luke X. Reynolds Saif A. Haque Richard Leonelli Carlos Silva 《Journal of Polymer Science.Polymer Physics》2012,50(20):1395-1404
We explore charge recombination dynamics at electron donor‐acceptor heterojunctions, formed between a semiconductor polymer (PCDTBT) and a fullerene derivative (PC70BM), by means of combined time‐resolved photoluminescence and transient absorption spectroscopies. Following prompt exciton dissociation across the heterojunction, a subset of bound electron‐hole pairs recombines with a temperature‐independent rate distribution spanning submicrosecond timescales to produce luminescent charge‐transfer excitons (CTX). At 14 K, this slow mechanism is the dominant geminate charge recombination pathway, whereas we also observe CTX emission on subnanosecond timescales at 293 K. We thus find that at these temperatures, a fraction of the initial charge‐pair population is trapped deeply such that they only recombine slowly over a broad distribution of timescales by quantum tunneling. We identify geminate polaron pairs (GPP) as a reservoir of long‐lived localized states that repopulate the CTX up to microsecond timescales. The observation of such distributed geminate‐charge recombination highlights the importance of the molecular nature of specific donor–acceptor electronic interactions in defining the relaxation pathways of trapped GPP. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献