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International audience; Chirality is found at all length scales in nature, and chiral metasurfaces have recently attracted attention due to their exceptional optical properties and their potential applications. Most of these metasurfaces are fabricated by top-down methods or bottom-up approaches that cannot be tuned in terms of structure and composition. By combining grazing incidence spraying of plasmonic nanowires and nanorods and Layer-by-Layer assembly, we show that nonchiral 1D nano-objects can be assembled into scalable chiral Bouligand nanostructures whose mesoscale anisotropy is controlled with simple macroscopic tools. Such multilayer helical assemblies of linearly oriented nanowires and nanorods display very high circular dichroism up to 13 000 mdeg and giant dissymmetry factors up to g ≈ 0.30 over the entire visible and near-infrared range. The chiroptical properties of the chiral multilayer stack are successfully modeled using a transfer matrix formalism based on the experimentally determined properties of each individual layer. The proposed approach can be extended to much more elaborate architectures and gives access to template-free and enantiomerically pure nanocomposites whose structure can be finely tuned through simple design principles.

Ecosystem services have been described as the direct and indirect benefits people obtain from ecological systems.Maintenance and conservation of functioning ecosystem services is the basis for achieving sustainable development.This anthropocentric view has led to increased efforts to identify,quantify,and place a monetary value on ecosystem services.In recent years,with the gradual deepening of this field of study as well as the development of 3S technology,more research has begun to focus on spatial ecosystem patterns and factors influencing the value of ecosystem services while achieving a series of impressive results.However,most previous studies lack quantitative analysis which includes the study of how accumulation rules,association patterns of the value of ecosystem services vary spatially,and few studies focus on the how the intensity of land use effects the value of ecological services.Studying the spatial variation of the value of ecosystem services and factors affecting the value helps us to gain an in-depth understanding of the characteristics of regional ecosystems and reveal the mechanisms driving changes in the value of the ecosystem services they provide. Exploring the spatio-temporal variations in the value of ecosystem services is critical to a thorough understanding of typical urbanized watersheds.The Jiuxiang River watershed in the city of Nanjing is used here as a case study to estimate the spatial distribution and dynamics of ecosystem services,based on QuickBird imagery collected in 2003 and 2009,a spatial autocorrelation model and geographic information system technology.A study of the impacts of how urbanization changes land use patterns and the effect on the value of ecosystem services was conducted.Results show a decline in the value of ecosystem services from 0.230 to 0.224 billion yuan from 2003 to 2009,respectively,in the study watershed,which indicated the value of the watershed′s ecosystem services decreased 2.59% because of land use change caused by urbanization.Also,a trend toward spatial clustering of ecosystem service values was enhanced;the areas of high value ecosystem service were mainly concentrated in the upstream portions of the watershed and the low value areas were mainly concentrated in Xianlin University City in the downstream areas;the change of spatial distribution of ecosystem service value was significant in the Jiuxiang River watershed.The low value area has experienced rapid expansion around Xianlin University City in the downstream portion of the watershed,and the high value area increased only in local areas of the Jiuxiang River headwaters and upstream areas.The spatial autocorrelation of watershed ecosystem service value showed significant scale effects;the value of ecosystem services gradually increased as the scale increased.The spatial distribution and the corresponding change in the value of ecosystem services were mainly caused by land development and use patterns;the higher levels of land use in the watershed had a significantly negative effect on value of ecological services,which shows the ecological service value decreased as the intensity of land use increased.Therefore,we should consider appropriate land use options to adapt future land use patterns in light of impacts to ecological services,based on past and present land use changes.Most importantly,land use planners should strive to protect water bodies,wetlands,vegetation,and environmentally sensitive areas.Also,the density of construction land should be restrained,and appropriate engineering and mitigation measures should be initiated to repair degraded areas,including urban afforestation,pollution control,and so on.

This thesis work describes the spray-alignment of silver nanowires (AgNWs) at solid interfaces in the form of mono- and multilayer films. The technique allows to control the in-plane density of nanowires over macroscopic areas with the best nematic order parameters reaching > 0.90 in monolayer films. Repeated deposition cycles using layer-by-layer assembly yield multilayer films in which for example uniaxial or helically twisted superstructures can be prepared by choosing appropriate spraying directions for each individual monolayer. Uniaxial systems are strong wavelength dependent polarizers (due to the orthogonality of the transversal and longitudinal plasmons of the AgNWs) and they show anisotropic in-plane conductivitiy. Helically twisted systems show very high circular dichroism which can be tuned for example through the in-plane density of AgNWs or through the distance between individual monolayers. Müller Matrix measurements confirm that the observed circular dichroism arises from the helically twisted superstructure of the AgNW multilayers.; Ce travail de thèse décrit l’alignement par pulvérisation de nanofils d'argent (AgNWs) aux interfaces solides sous la forme de films mono- et multicouches. Cette technique permet de contrôler la densité de nanofils dans le plan sur des zones macroscopiques avec des paramètres d'ordre nématique atteignant des valeurs > 0,90 dans les films monocouches. La répétition des cycles de dépôt en utilisant l’assemblage couche-par-couche produit des films multicouches dans lesquels par exemple des superstructures uniaxiales ou hélicoïdales peuvent être préparées en choisissant les directions de pulvérisation appropriées pour chaque monocouche individuelle. Les systèmes uniaxiaux sont des polariseurs fortement dépendant de la longueur d'onde (en raison de l'orthogonalité des plasmons transversaux et longitudinaux des AgNWs) et montrent une conductivité anisotrope dans le plan. Les systèmes hélicoïdaux montrent un dichroïsme circulaire très élevé qui peut être ajusté par exemple par le biais de la densité des AgNWs dans le plan ou de la distance entre les monocouches individuelles. Les mesures de la matrice Müller confirment que le dichroïsme circulaire observé découle de la superstructure hélicoïdale des multicouches à base d’AgNWs.

Urban wetland as a semi-natural ecosystem plays significant roles in flood storage and regulation, climatic regulation, water conservation and purification, maintenance of biological diversity. At the same time, wetlands in urban areas are prone to be influenced by human activities compared to nature wetlands. In this study, we collected 40 urban wetlands, and monitored their water qualities monthly from September 2009 to August 2010. And then, we built an index named Water Quality Score Index (WQSI) based on the principle components analysis (PCA) and analysis of variance. Next human Disturbance Index (HDI) was put forward to reveal the relationships between human activities and the water quality. Results showed that (1) strong ties existed between land uses and the water quality of adjacent aquatic systems within a watershed. The forest area showed significant (P