Auswahl der wissenschaftlichen Literatur zum Thema „Écorces – Surfaces“
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Zeitschriftenartikel zum Thema "Écorces – Surfaces"
Périot, Gaëlle. „Le boeuf écorché (Rembrandt – Soutine – Bacon)“. Figures de l'Art. Revue d'études esthétiques 8, Nr. 1 (2004): 239–56. http://dx.doi.org/10.3406/fdart.2004.1347.
Der volle Inhalt der QuelleDesRochers, Pierre, Nicolas Nadeau-Thibodeau, Louis Bernier und Danny Rioux. „La réaction au dégagement et les caractéristiques individuelles du noyer cendré favorisant la résistance au chancre causé par l’Ophiognomonia clavigignenti-juglandacearum“. Forestry Chronicle 96, Nr. 02 (Juli 2020): 100–110. http://dx.doi.org/10.5558/tfc2020-015.
Der volle Inhalt der QuelleBalint-Babos, Adina. „Imaginer, monter : la mémoire inachevée d’Auschwitz selon Georges Didi-Huberman“. Voix Plurielles 11, Nr. 2 (03.12.2014): 20–31. http://dx.doi.org/10.26522/vp.v11i2.1097.
Der volle Inhalt der QuelleDissertationen zum Thema "Écorces – Surfaces"
Nguyen, Van Tho. „Estimation de la qualité de bois ronds et d'arbres sur pied par Lidar terrestre“. Electronic Thesis or Diss., Paris, AgroParisTech, 2018. http://www.theses.fr/2018AGPT0007.
Der volle Inhalt der QuelleTerrestrial Laser Scanning (TLS) technology is booming in forestry applications. It generates a cloud of tens of millions of 3D points corresponding to the obstacles encountered by a laser beam scanning a scene from several points of view. Its advantage lies in its ability to describe a forest plot or an individual tree by a point cloud with a high level of detail unusual for such a large object. This level of detail allows a fine analysis of the trunk surface to detect the defects that play an essential role in wood quality. In fact, several studies have shown that 80% of internal defects correspond to traces on the trunk surface, for example, branch scars.The objective of the thesis is to develop a method to automatically quantify defects on trunks of standing trees or logs, using TLS data. The defects included branches, branch scars, burls, bud cluster, and picots.The development is completed through 3 steps: (1) defect detection, (2) defect identification and (3) defect characterization.The detection of defects is based on an analysis of the bark roughness using an estimation of the reference distance to the trunk centerline. The principle of centerline computation is to find the points where the surface normal vectors converge. The reference distance of each point from the surface to this centerline is computed from the distribution of its neighboring points belonging to the elongated patch along the main axis of the trunk. The detection of defects is based on the idea that, for one point belonging to a defect, the difference between the real distance and the reference distance to the centerline exceeds a certain threshold value. The reference distance computation takes also into account the local roughness of the bark. The points supposed to correspond to a defect are obtained by an automatic thresholding of the statistical distribution of the differences. The defect detection method can take into account a large variety of shapes of the trunk or log; it uses a small number of parameters not sensitive to the nature of the bark.Then, the identification of defects is based on a machine learning approach using the Random Forests classifier, which not only classifies defects by type but also reduces the number of false positives resulting from the first step.The characterization of defects includes the estimation of their position and dimensions associated with their type.Experiments on logs or trunks of different species such as oak, beech, wild cherry, pine, fir, and spruce showed that we can detect defects with a size as small as 5 mm with sufficiently dense TLS data. When compared at the surface element level, the results were well consistent with the data observed visually on the meshes created from the TLS point cloud. The criterion chosen to evaluate the classification performance is the F1 score, which is the harmonic mean of the precision and the recall, two variables calculated from the false and true positives. Concerning the detection step, F1 was 0.76. The second step correctly classified 163 defects out of 185 but induced 75 false identifications of mostly small defects. The F1 score was 0.84.The latest experiments on oaks and beeches, designed to automatically evaluate the quality of standing trees, showed that the proposed method was robust and promising for these two species with very different bark structures.Compared to previous work on the use of TLS data for similar objectives, the developed tool considerably improves the automatic quantification of external defects and estimation of standing tree quality. The main perspectives of this work are: improve the variability of the defects contained in the training set and possibly separate the training set by species, and extend this tool to take into account other types of external defects, such as cracks, and the global attributes of the trunk or log to estimate log quality on the wood yard or in the forest
Bauer, Rodolphe. „La modélisation du volume des compartiments riches en composés chimiques extractibles (écorce et nœud) dans six essences d'intérêt des régions Grand-Est et Bourgogne Franche-Comté“. Electronic Thesis or Diss., Paris, AgroParisTech, 2021. http://www.theses.fr/2021AGPT0025.
Der volle Inhalt der QuelleIn a context of renewal of the chemical industry and the search for new outlets for forestry, extractives are becoming increasingly interesting molecules, both ecologically and financially speaking. In order to evaluate the relevance of these molecules as a new resource for the chemical industry and a potential outlet for forestry, it is necessary to make a preliminary evaluation of the resource. This requires knowledge of the volume of compartments rich in extractable material, particularly bark and knots. The present study therefore focuses on modeling bark and knot volumes. It focuses specifically on two French regions, the Grand Est and the Bourgogne-Franche-Comté, and on six important species, Abies alba, Picea abies, Pseudotsuga menziesii, Quercu robur, Quercus patraea, and Fagus sylvatica.This study is made possible, on one hand, by the use of a large database including numerous measurements of bark thickness made at different heights on the stems of many trees. On the other hand, new samplings have been made to allow X-ray scanning of nodes all along the stem and thus to determine precisely the volume on a computer picture.In order to model the available amount of bark, three types of models were built, models predicting the volume of bark, models predicting the surface area of bark along the stem and models predicting the thickness of bark at 1m30. The former achieved a relative root mean square error (RMSErel) of 16.7% to 27.5% depending on the species.The study of bark area models showed that it was possible to use a model independent of diameter-over-bark but that model using this variable are more accurate. The RMSErel achieved by these bark area models varied between 23 and 38% depending on the species and model considered.This work showed the importance of using the bark thickness at 1m30 as an input data. As it is rarely measured today, it was also modelled using the DBH. This allowed us to show the influence of altitude on bark thickness at 1.30 m for three species: Abies alba, Picea abies, Fagus sylvatica. The models obtained RMSErel of the models ranged from 26.8 to 36 % of RMSErel depending on the species considered.Finally, knot volumes have started to be studied. Although this work has not been fully completed, it already shows the importance of producing new models in order to fit the predicted knot patterns as closely as possible to reality. Moreover, the quantity of these compounds in the wood seems, at this stage of the study, to be too small to provide a large extractable resource, despite their great intrinsic richness. Their interest could therefore be more in the extraction of specific molecules
Trenque, Isabelle. „Synthèse et caractérisation d’oxydes métalliques ZnO au bénéfice de nouvelles stratégies d’élaboration d’absorbeurs IR“. Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14905/document.
Der volle Inhalt der QuelleThanks to its absorption / reflexion properties limited to the UV and the IR range, n-doped zinc oxide is a promising candidate for the elaboration of transparent and insulating films in smart windows. Nanostructured particles of Ga-doped zinc oxide were elaborated by polyol process. Polyol process was used in order to control the size and the morphology of the particles. Both experimental and theoretical data show that a maximum of IR absorption efficiency is obtained for a doping rate of 2.6 molar percent. Colloidal suspensions with high transmission in the visible range combined with significant absorption of the near infrared range were obtained using two strategies. The first one is the encapsulation of the Ga-doped ZnO particles by a fluoride shells with an intermediate refractive index between ZnO and the dispersion medium. The second one is the optimization of the dispersion state of nano-colloidal suspensions thanks to the adsorption of thioalkanes on the Ga-doped ZnO crystallite surfaces
Maritaud, Karl. „Rendu réaliste d'arbres vus de près en images de synthèse“. Limoges, 2003. http://aurore.unilim.fr/theses/nxfile/default/26d2f3b6-ee12-4232-956d-706abdfbda53/blobholder:0/2003LIMO0049.pdf.
Der volle Inhalt der QuelleMost of the research in the rendering of trees in Computer Graphics has focused on methods designed for viewpoints at a certain distance where the details of the bark and leaves are not perceptible. Rendering realistic trees at a short distance remains an open and difficult problem, essentially due to the visual complexity of bark textures. Here, image-based methods are proposed to extract the relief and color from a single photograph of real bark texture, without any complicated manipulations, and then to automatically synthesize realistic 3D bark textures. A method is proposed to apply these textures, with neither repetition nor discontinuities on the texture, onto branches modeled by displacement-mapped implicit surfaces, which are blended without bulge. Moreover, a technique for extracting the relief of leaf veins is proposed. Together, these methods allow us to achieve a high degree of visual realism for rendering close-up views of trees
Artiomenco, Mitcova Liubov. „Dendritic functionalization of core-shell magnetic nanoparticles for biotechnology“. Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0025/document.
Der volle Inhalt der QuelleThe purpose of this work is to design stable, water-dispersible, maleimide functionalized magneticnanoparticles (MNPs) that will ensure selective covalent immobilization of biomolecules. While, a largechoice of MNPs is now commercially available, the surface modification of MNPs remains an indispensablestep in the elaboration of such MNPs. A precise control over the surface functionalization of MNPs iscrucial, because it governs their physicochemical properties, their colloidal stability, and their biologicalbehaviour. In this work with the aim to increase the number of functional groups on MNPs’ surfaces, it wasproposed to functionalize MNPs with dendritic coupling agents and to compare their efficiency with thosefunctionalized with a linear analogue. Moreover, it was decided to investigate the “dendritic effect” of thesurface functionalization on two types of core-shell MNPs (300 nm) that consist of a maghemite (γ-Fe2O3)ferrofluid core coated with: (I) polymer shell or (II) silica shell. Therefore, three types of coupling agents(that possess an amino or silane anchoring site) were synthesized: linear coupling agents (containing onemaleimide functional group); two-branched coupling agents (containing two maleimide functional groups)and four-branched dendritic coupling agents (containing four maleimide functional groups). Then, thecapacity of MNPs functionalized with dendritic or linear coupling agents to immobilize biomolecules ormodels of biomolecules was investigated. This study proved the efficiency of the surface functionalizationwith dendritic structures for the immobilization of biomolecules
Siurdyban, Elise. „Immobilisation de dérivés du cryptophane-A sur des surfaces planes SiO2/or et or ainsi que sur des nanoparticules magnétiques“. Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0149/document.
Der volle Inhalt der QuelleCryptophanes are spherical molecules that can encapsulate neutral molecules(halogenomethanes, xenon), and ionic species like cesium and thallium cations in their lipophiliccavity. Our objective was to covalently immobilize these molecular cages onto solid substrates tocreate a material able to extract toxic cations such as thallium in aqueous media. Different strategieswere considered to optimize the immobilization of cryptophane-A derivatives onto silica and goldsurfaces (flat surfaces and core-shell magnetic nanoparticles). Mono-acid cryptophane-A (1) andhexa-acid cryptophane-A (2) were immobilized onto silica surfaces that were functionalized by aminogroups beforehand. Alcanethiols cryptophane-A (3), 1 and 2 modified by cysteamine (cryptophanes 4and 5 ,respectively) were immobilized onto gold surfaces. Flat surfaces were characterized bypolarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS) to estimate thesurface coverage of different cryptophane monolayers and to evaluate the most effective method. Asurface coverage close to 100% was obtained for the cryptophane 3 immobilized onto gold surfaces.This compound has been also immobilized efficiently onto magnetic nanoparticles (γ-Fe2O3/SiO2)coated with gold nano-shell. These results allow to consider the synthesis of cryptophane bearing fivehydroxyl and one thiol functions to create materials able to extract toxic cations
Bousquet, Cathel. „Chimie en milieux fluides supercritiques pour l'élaboration de céramiques ferroélectriques nonostructureées“. Bordeaux 1, 2008. http://www.theses.fr/2008BOR13576.
Der volle Inhalt der QuelleFerrie, Mélanie. „Design de particules plasmoniques pour le contrôle de l’absorption et de l’émission de lumière“. Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14410/document.
Der volle Inhalt der QuelleDuring this work, we were interested in the design of plasmonic particles for the control of the absorption and the emission of light. Our strategy was to synthesize core@shell nanoparticles made of a gold core and a silica shell containing fluorescent organic molecules. We have varied the distance between the emitters and the core in order to tune their coupling with the plasmons of gold. We thus tuned the optical properties of the particles. We were also interested in the assembly of these nanoparticles to get supra-particles or organized two-dimensional networks. The study of optical properties of these new materials showed that the exaltation of the fluorescence is maximal when the core@shell particles are confined between two gold boundaries, this situation corresponding to a strong cavity mode. We also worked on the synthesis of particles consisting of a silica core and either a gold shell with bare patches or a titanium dioxide shell with patches covered with gold nanoparticles
Trenque, Isabelle. „Synthèse et caractérisation d'oxydes métalliques ZnO au bénéfice de nouvelles stratégies d'élaboration d'absorbeurs IR“. Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-01017168.
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