Formation of two-dimensional weak localization in conducting Langmuir-Blodgett films

We report the magnetotransport properties up to 7 T in the organic highly conducting Langmuir-Blodgett(LB) films formed by a molecular association of the electroactive donor molecule bis(ethylendioxy)tetrathiafulvalene (BEDO-TTF) and stearic acid CH$_3$(CH$_2$)$_{16}$COOH. We show the logarithmic decrease of dc conductivity and the negative transverse magnetoresistance at low temperature. They are interpreted in the weak localization of two-dimensional (2D) electronic system based on the homogeneous conducting layer with the molecular size thickness of BEDO-TTF. The electronic length with phase memory is given at the mesoscopic scale, which provides for the first time evidence of the 2D coherent charge transport in the conducting LB films.Comment: 5 pages, 1 Table and 5 figure

Pi-conjugated (co)polymers for organic electronics

International audienc

Devenir des élevages allaitants spécialisés de Midi-Pyrénées à l'horizon 2000. Premiers effets de la réforme de la PAC sur le revenu à l'échéance 1995. Eléments prospectifs 1995-2000

Cette étude tente d'apporter une meilleure connaissance du devenir des élevages allaitants spécialisés dans les zones défavorisées de la région Midi-Pyrénées, suite à la réforme de la PAC. La première partie est consacrée à la mesure des effets mécaniques de la réforme sur le revenu des éleveurs à horizon fin 1995, sur la base d'un échantillon de 60 comptabilités d'exploitations, où sont distingués les systèmes les mieux représentés en Midi-Pyrénées : naisseurs et veaux lourds du Ségala. La seconde partie intègre dans l'analyse les autres facteurs susceptibles d'influer sur le devenir de ces exploitations. Pour mener à bien cette réflexion, on s'est placé à horizon 2000, en utilisant un outil de prospective : l'analyse structurelle. Ces principaux déterminants de l'évolution du secteur viande (le marché, l'exode agricole, le progrès technique, la différenciation des produits) sont ensuite analysés, en vue d'établir des scénarios d'évolution, dont l'effet sur le revenu est estimé à partir de l'échantillon comptable

Devenir des élevages allaitants spécialisés de Midi-Pyrénées à l'horizon 2000. Premiers effets de la réforme de la PAC sur le revenu à l'échéance 1995. Eléments prospectifs 1995-2000

Cette étude tente d'apporter une meilleure connaissance du devenir des élevages allaitants spécialisés dans les zones défavorisées de la région Midi-Pyrénées, suite à la réforme de la PAC. La première partie est consacrée à la mesure des effets mécaniques de la réforme sur le revenu des éleveurs à horizon fin 1995, sur la base d'un échantillon de 60 comptabilités d'exploitations, où sont distingués les systèmes les mieux représentés en Midi-Pyrénées : naisseurs et veaux lourds du Ségala. La seconde partie intègre dans l'analyse les autres facteurs susceptibles d'influer sur le devenir de ces exploitations. Pour mener à bien cette réflexion, on s'est placé à horizon 2000, en utilisant un outil de prospective : l'analyse structurelle. Ces principaux déterminants de l'évolution du secteur viande (le marché, l'exode agricole, le progrès technique, la différenciation des produits) sont ensuite analysés, en vue d'établir des scénarios d'évolution, dont l'effet sur le revenu est estimé à partir de l'échantillon comptable

Simulation and optimization of the performance of organic photovoltaic cells based on capped copolymers for bulk heterojunctions

Recently many investigations have been done to improve the performance of solar cells photovoltaic. One of this devices developed is the Bulk Heterojunction (BHJ) solar cells based on poly (3-hexylthiophene) (P3HT)/[6, 6]-phenyl C-61-butyric acid methyl ester (PCBM) blend which have been fabricated by spin-coating. It is known that the nano structure of the active layer of this device has an important impact on the photovoltaic performances. In this work, we analyze the results obtained on solar cells using a copolymer P3HT-b-PS based on poly (3-hexylthiophene) (P3HT) as a donor block and polystyrene (PS) as a soft block, their compatibility with the blend of P3HT/PCBM at various weight percentages (0%-5%). The addition of this weight percentage is in order to improve the performance of polymer solar cells. It has been demonstrated that the addition of a small amount of P3HT-b-PS (from 0.5%-1.5%) led to an increase in photovoltaic efficiency compared to devices made from P3HT/PCBM only. To study the impact of the added amount of the P3HT-b-PS on the performances of the fabricated organic cells, we used an equivalent circuit model based on single diode model with five photovoltaic parameters. Then, we extracted these physical parameters of the organic photovoltaic cells such as the saturation current density, the series and shunt resistances, the ideality factor and the photogenerated current density from the experimental characteristics (J-V) in the dark and under illumination. We proposed and developed the used procedure based on this model and we resolved the analytic equations of the density-current using the Lambert W-function. A good agreement between the theoretical model and the experimental data of electrical characteristks is obtained illustrating the enhancement of the addition of a small amount of P3HT-b-PS (<1.5%) in the P3HT/PCBM blend on the characteristics of BHJ organic photovoltaic cells. (C) 2016 Elsevier Ltd. All rights reserved

Photovoltaic solar cells based on rod-coil block copolymers containing poly(3-hexylthiophene) and fullerene

International audienc

Controle de mosca doméstica em área de disposição de resíduos sólidos no Brasil House fly control in solid waste disposal area in Brazil

Desenvolveu-se uma metodologia de controle de Musca domestica (L.) em áreas de disposição de resíduos sólidos. Dois mosquicidas à base de azametifós foram aplicados em diferentes superfícies: nas verticais, a formulação pó molhável foi aplicada com rolos de pintura e, através de pulverização, na superfície de leiras; nas horizontais, foi empregado o mosquicida na formulação granulada. O nível de infestação de moscas foi avaliado por meio do monitoramento em placas (Scudder Fly Grill). Nas áreas das leiras, reduções de 98,5% e 100% foram atingidas em 18 e 30 dias, respectivamente, após a aplicação do produto. Na estação de transferência do lixo, observaram-se reduções de 85,6% e 98,7% no mesmo período de tempo. A aplicação de azametifós em diferentes formulações mostrou ser eficiente no controle da Musca domestica por um período de 30 dias.<br>A Musca domestica (L.) control method in solid waste disposal areas was developed. Two fly control products based on azamethiphos were applied to different surfaces: on vertical surfaces, the wettable powder was used as spray or paint-on and on windrows, as spray; on horizontal surfaces granular bait was used. Fly infestation was evaluated by Scudder Fly Grills. In the windrows areas, reductions of 98,5% and 100 % were achieved 18 and 30 days respectively after application. In the waste transfer station 85,6% and 98,7 % reductions were achieved over the same period of time. Application of azamethiphos in different formulations was effective against M. domestica for 30 days