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On the one hand, Graded Photonic Crystals (GPC) allow to efficiently control the flow of light thanks to the shape of their photonic bands, which we verified by demonstrating a “photonic mirage” at wavelength scale. On the other hand, GRaded INdex (GRIN) optics is undergoing a renewal because it allows downsizing optical systems, opening a new way to optical design. But GRIN optics was limited by a lack of easy to implement fabrication techniques. Nanotechnology enables to efficiently fabricate photonic crystals, which we will implement to fabricate GPC for GRIN optics. The main purpose of this Ph.D. topic is to explore graded photonic crystals and related gradient index optics in the near-infrared domain for applications on Silicon On Insulator (SOI) platforms. Gradient photonic crystals in the microwave band have been investigated by previous Ph.D. students in our group. This work then attempts to extend the application to the near-infrared field. According to the theory of subwavelength electromagnetism, the size of the device should be of the same order of magnitude as the operating wavelength. Thus, unlike the previous microwave field, a big challenge in the NIR field is the fabrication and characterization of the corresponding devices. A significant part of this work is focused on the fabrication and characterization process of gradient photonic crystals in the NIR field. We focus on nano-fabrication technology as well as SNOM characterization. SOI was chosen as the processing platform for this work, considering the good compatibility of the silicon-based platform with photonic devices and its ability to integrate well with nanofabrication techniques. In addition, another emphasized aspect of this work is to explore the effect of the variation of the photonic crystal parameters on its effective refractive index. Thus, the case of normalized frequencies in different photonic crystal energy bands is also a direction of the investigation. We attempt to manipulate the effective refractive index (even negative refractive index) of photonic crystals by changing their parameters. Experimental demonstration of negative refractive index gradient photonic crystal lens and related gradient photonic crystal devices will be highlighted. In summary, we have designed, fabricated and characterized gradient photonic crystal lens in the near-infrared domain., D'une part, les cristaux photoniques à gradient permettent de contrôler la propagation du champ électromagnétique grâce à la courbure de leur structure de bandes, ce que nous avons vérifié en démontrant un 'mirage photonique'. D'autre part, l'optique à gradient d'indice connaît un renouveau parce qu'elle offre de nouvelles possibilités pour la conception optique, notamment elle permet de miniaturiser les systèmes optiques. Les nanotechnologies permettent de fabriquer efficacement des cristaux photoniques ; nous les mettrons en œuvre pour fabriquer des cristaux photoniques à gradient. L'objectif principal de ce sujet de doctorat est d'explorer les cristaux photoniques à gradient et les optiques à gradient d'indice connexes dans le domaine du proche infrarouge pour des applications sur des plates-formes de silicium sur isolant (SOI). Les cristaux photoniques à gradient dans la bande des micro-ondes ont été étudiés par les précédents doctorants de notre groupe. Ce travail tente ensuite d'étendre l'application au domaine du proche infrarouge. Selon la théorie de l'électromagnétisme sub-longueur d'onde, la taille du dispositif doit être du même ordre de grandeur que la longueur d'onde de fonctionnement. Ainsi, contrairement au domaine précédent des micro-ondes, un grand défi dans le domaine du NIR est la fabrication et la caractérisation des dispositifs correspondants. Une partie importante de ce travail se concentre sur le processus de fabrication et de caractérisation des cristaux photoniques à gradient dans le domaine du proche infrarouge. Nous nous concentrons sur la technologie de nanofabrication ainsi que sur la caractérisation du SNOM. Le SOI a été choisi comme plateforme de traitement pour ce travail, compte tenu de la bonne compatibilité de la plateforme à base de silicium avec les dispositifs photoniques et de sa capacité à bien s'intégrer aux techniques de nanofabrication. De plus, un autre aspect mis en avant dans ce travail est d'explorer l'effet de la variation des paramètres du cristal photonique sur son indice de réfraction effectif. Ainsi, le cas des fréquences normalisées dans différentes bandes d'énergie de cristaux photoniques est également une direction d'investigation. Nous tentons de manipuler l'indice de réfraction effectif (voire l'indice de réfraction négatif) des cristaux photoniques en modifiant leurs paramètres. La démonstration expérimentale d'une lentille en cristal photonique à gradient d'indice de réfraction négatif et de dispositifs en cristal photonique à gradient connexes sera mise en évidence. En résumé, nous avons conçu, fabriqué et caractérisé une lentille à gradient de cristaux photoniques dans le domaine du proche infrarouge.

The increase of greenhouse gases concentration in the atmosphere leads to global warming, which has aroused widespread concern in society. Studying the earth's atmosphere and predicting future climate change are closely related to the accurate observation of greenhouse gas concentrations. At present, the high spectral resolution instruments used to observe column concentration of atmospheric greenhouse gases generally have large sizes and high costs, which are not conducive to monitor the greenhouse gases on a large scale. The laser heterodyne radiometer with high resolution can be made small, low-power consumption, compact and robust. It is conducive to the realization of the mobile observation of atmospheric greenhouse gases in the field. This thesis mainly focuses on infrared laser heterodyne detection technology and application. The main work and innovations of the thesis are as follows : An all-fiber dual-channel laser heterodyne radiometer was developed to detect CH₄ and CO₂ in the atmospheric simultaneously. In the device, a fiber optic switch and other fiber optic devices were used to improve the stability and reliability of the measurement system significantly. Continuous observation experiments were performed in Hefei, and the measurement results are approximately consistent with the GOSAT results. The integrated instrument also conducted field observations in Qinghai province. Then, an interband cascade laser based mid-infrared LHR has been demonstrated in an attractive atmospheric window of 3-5 μm, for the first time, in ground-based solar occultation mode. High-resolution (0.0033 cm⁻¹) spectra near 3.53 µm were obtained for simultaneous atmospheric observations of HDO and CH₄. Finally, an external cavity laser based laser heterodyne radiometer for the detection of ¹³CO₂ and ¹²CO₂ in the atmospheric was developed. The external cavity laser was used as the local oscillator to implement the continuous spectrum measurement in the range of 6248.5 cm⁻¹∼ 6256 cm⁻¹. And the atmospheric transmittance of ¹²CO₂ and ¹³CO₂ in the entire atmosphere was obtained., La mesure des profils de concentration verticale des gaz à effet de serre (GES) est extrêmement importante pour notre compréhension de la qualité de l’air régional et des tendances du changement climatique mondial. Dans ce contexte, la technique du radiomètre hétérodyne au laser (LHR) a été développée pour les mesures à distance au sol des GES dans la colonne atmosphérique. Le rayonnement solaire subissant une absorption par plusieurs espèces dans l'atmosphère est couplé à un instrument LHR dans lequel la lumière du soleil est mélangée à un oscillateur local (OL), généralement une source laser accordable, dans un photodétecteur rapide. Le battement de la note aux radiofréquences (RF) résultant de ce photomélange contient des informations sur l'absorption des molécules ciblées par LO. L'analyse de la fréquence LO sur les lignes d'absorption moléculaires cibles permet d'extraire les caractéristiques d'absorption correspondantes de l'absorption totale du rayonnement solaire par toutes les molécules de la colonne atmosphérique. Dans le présent travail, des instruments LHR fonctionnant dans le proches-IR (~ 1,5 µm) et la mi-IR (3,5 µm) ont été développées. Des campagnes de mesure sur le terrain ont été réalisées à Dunkerque en France et à Hefei en Chine. Les spectres du CH₄, du CO₂ (y compris ¹³CO₂ / ¹²CO₂), de la vapeur d'H₂O vapeur ainsi que son isotopologue HDO dans la colonne atmosphérique ont été mesurés.

This study examined the effects of long-term storage conditions on the chemical composition, pepsin-cellulase dry matter digestibility (PCDMD), and visible (VIS)/near infrared spectra (NIR) of forage. Eighteen samples of different whole-crop maize varieties originally harvested in 1987 were used. After drying, these samples were analyzed in the laboratory for ash, crude protein (CP), structural carbohydrates, total soluble carbohydrates (TSC), starch and PCDMD, and the remaining samples were stored frozen (at &minus, 20&deg, C) or at barn temperature (ambient temperatures ranged from &minus, 8.5 &deg, C to 27.1 &deg, C). In 2016, the samples were analyzed for ash, CP, structural carbohydrates, TSC, starch and PCDMD. The visible/NIR spectra of both storage methods were obtained. Chemical composition and PCDMD analyses revealed significant differences (p &lt, 0.05) between the storage methods for TSC but not for the other parameters (p &gt, 0.05). After sample harvesting in 1987, the analyses were compared with those in 2016. It was found that the post-harvest TSC and ash content were higher (p &lt, 0.05) and lower (p &lt, 0.05), respectively, during 2016. No significant differences were found for starch and PCDMD. Important differences between the VIS/NIR spectra of both storage methods were obtained in the VIS segment, particularly in the area between 630 and 760 nm. We concluded that storing dry forage samples at ambient temperature for a very long time (29 years) did not change their nutritive value compared to the values obtained before storage.

India and Belgium have jointly established two 4-meter class optical telescopes at Devasthal located in Nainital, India. After successful installation of the 3.6-m modern new technology Devasthal Optical Telescope (DOT) in 2015, it was technically activated by premiers of both countries from Brussels on March 30, 2016. Since then, the 3.6-m DOT has been used for both optical and near-Infrared (NIR) observations for a number of research proposals. The best angular resolution achieved is 0″.4 indicating that the optics of the 3.6-m DOT is good and capable of providing images of celestial bodies with sub-arc-second resolution. The observations provide proof that the care taken in the construction of the telescope dome building has paid a rich dividend as their thermal mass is so low that it has not degraded the natural atmospheric seeing at Devasthal measured about two decades ago during 1997 to 1999 using differential image motion monitor. A few preliminary scientific results obtained from recent observations are presented along with performance and global potential of the 3.6-m DOT in the field of galactic astronomy. The 3.6-m DOT is capable of providing internationally competitive science once high resolution spectrograph and other planned modern back-end instruments become operational. Geographical location of the observatory has global importance for time domain and multi-wavelength astrophysical studies.

International audience; In this article, a set of 50 turbid liquid samples with different levels of absorption and scattering properties were prepared and measured at various orientations of polarizers and analyzers to obtain the 16 elements of the complete Muller matrix. Partial Least Square (PLS) was used to build calibration models in order to assess the potential of polarization spectroscopy through the elements of Muller matrix to predict chemical and physical parameters.

International audience; The potential of multispectral VIS-NIR imaging to discriminate beef meat muscles in relation with their type and animal origin was examined in the present study. Two hundred and forty muscles of three types (Longissimus thoracis, Biceps femoris and Semimembranosus) were obtained from the carcasses of three types of animals, two late-maturing cattle types of animals (Limousin and Blond d'Aquitaine) that grow slowly and deposit more muscles and less fat, compared to one early-maturing cattle types of animals (Angus) which tends to have muscles richer in collagen and in intramuscular fat. Two hundred and forty cube images were collected with nineteen emitting LEDs (405 to 1050 nm) using the Videometer Lab2 device. The image cubes were processed in order to extract image mean spectra and image shape features from co-occurrence and difference of histogram matrices. The results of the PLSDA performed on image texture features and spectral data show a maximum ranging from 63.5 to 83% of good classification depending on the muscle and breed considered. This study demonstrated the promising potential of the VIS-NIR multispectral imager to characterize beef meat muscles based on muscle type and its animal origin.

International audience; The combination of aerial images acquired in the visible and near infrared spectral ranges is particularly relevant for agricultural and environmental survey. In unmanned aerial vehicle (UAV) imagery, such a combination can be achieved using a set of several embedded cameras mounted close to each other, followed by an image registration step. However, due to the different nature of source images, usualregistration techniques based on feature point matching are limited when dealing with blended vegetation and bare soil patterns. Here, another approach is proposed based on i mage spatial frequency analysis. This approach, which relies on the Fourier-Mellin transform, has been adapted to homographic registration and distortion issues. It has been successfully tested on various aerial image sets, and has proved to be particularly robust and accurate, providing a registration error below 0.3 pixels in most cases.

International audience; Visible and Near-infrared (Vis-NIR) spectroscopy is now a common analytical method to measure different physical and chemical properties of soils, including carbon content. However, prediction model accuracy is insufficient for Vis-NIR spectroscopy to replace routine laboratory analysis. One of the main issues of this technique is facing up to is light scattering due to soil particles. It causes departure in the assumed linear relationship between the absorbance spectrum and the concentration of the chemical components as stated by Beer-Lambert's law, which underpins the linear calibration models.Therefore, it is essential to improve the quality of the measured signal in order to optimize the calibration results. Optics can help to mitigate scattering effect on the signal.The aims of this study were to test the feasibility of a new optical setup, names PoLiS, coupling linearly polarized light with a Vis-VNIR (350-800 nm) spectrometer to free the measured spectra from multiscattering effect. The measured signals were used to model the chemical absorbance of the soil samples using Dahm's equation in the frame of the Representative Layer Theory (RLT).The study was conducted using a set of 52 soil samples collected in France (in the French calcareous Prealps) to predict soil total organic carbon (TOC) content. The PoLiS absorbance signal tended to be more linearly related to the concentration of organic carbon, which is an important pre-requisite to perform linear multivariate modeling. In a second step, the PLS models achieved for TOC performed appreciably better than models based on classical reflectance spectra. The standard errors of cross validation decreased from 20.8 to 17.6 g kg−1 and the coefficient of determination R2 improved from 0.82 to 0.87 on ground samples. To compare the added-value of the PoLiS method, we benchmarked the PoLiS prediction models against models built from empirically preprocessed spectra. Again, the PoLiS method showed better performances.This work confirmed that by optical means, it is possible to significantly improve the quality of a spectroscopic signal and as a consequence, improve also the quality of the linear model.

International audience; In the dataset presented in this article, 36 sludge samples were characterized. Rheological parameters were determined and near infrared spectroscopy measurements were realized. In order to assess the potential of near infrared spectroscopy to predict rheological parameters of sludge, Partial Least Square algorithm was used to build calibration models.

International audience; The combination of aerial images acquired in the visible and near infrared spectral ranges is particularly relevant for agricultural and environmental survey. In unmanned aerial vehicle (UAV) imagery, such a combination can be achieved using a set of several embedded cameras mounted close to each other, followed by an image registration step. However, due to the different nature of source images, usualregistration techniques based on feature point matching are limited when dealing with blended vegetation and bare soil patterns. Here, another approach is proposed based on i mage spatial frequency analysis. This approach, which relies on the Fourier-Mellin transform, has been adapted to homographic registration and distortion issues. It has been successfully tested on various aerial image sets, and has proved to be particularly robust and accurate, providing a registration error below 0.3 pixels in most cases.

International audience; Hyperspectral imaging has become an interesting non-destructive way to spatially characterize various materials such as vegetation. Because several leaf biochemical compounds affect the visible and near-infrared reflectance, they can potentially be retrieved from the measured spectral profile. At leaf scale, usual methods are either statistically- or physically-based. On the one hand, statistical methods aim at extracting a statistical relationship between spectral data and targeted variable(s), thus potentially requiring the construction of a large calibration database to get to an acceptable robustness. On the other hand, physically-based methods use the knowledge of leaf optical properties to retrieve the targeted variables without any calibration. Although being highly effective in ideal laboratory conditions, these methods do not scale well to the close range remote sensing case because they require the signal to be measured in every direction using an integrating sphere. In this study, we propose an improvement of a physically -based model that overcomes the need for multi-angle measurements. This model is then applied to the retrieval of water and dry matter contents from NIR hyperspectral images. This method is based on the PROSPECT radiative transfer model that has been much used to characterize the relationship between the directional-hemispherical reflectance of monocotyledon and dicotyledon species and their biochemical content at leaf level. However, because PROSPECT simulates the sum of both specular and diffuse reflected fluxes over the whole hemisphere, it cannot directly be applied to hyperspectral images of leaves. Using a single light source assumed to be directional, we show that adding two parameters to the PROSPECT model enables the model to be used with hyperspectral measurements. The first parameter is a multiplicative term that is related to local leaf angle and illumination zenith angle. The second parameter is an additive specular-related term that models surface bidirectional effects. The resulting enhanced PROSPECT-based model can therefore be inverted from hyperspectral measurements to retrieve the foliar content, surface effects and leaf local topography. We tested this method on seven leaf species with images acquired in laboratory using a SWIR (1-2.5 µm) hyperspectral camera. Each leaf was imaged in three positions corresponding to average incident angles of 10°, 30° and 50°. Lighting was provided by a collimated halogen source positioned close to the camera. After each image acquisition, water and dry matter contents were evaluated using destructive measurements as these PROSPECT variables have the greatest influence on reflectance in this spectral range. When tested on horizontal leaves, our model accurately retrieved water (R²=0.98,RMSE=24%) and dry matter (R²=0.85,RMSE=16%) contents. Results obtained with both flat and tilted leaves did not show significant decrease in performance, either for water (R²=0.95,RMSE=28%) or dry matter (R²=0.84,RMSE=17%) contents. These results were better than those obtained with PROSPECT alone, i.e., R²=0.79 and RMSE=28% for water content, and R²=0.67 and RMSE=26% for dry matter content. In addition, the estimated spatial distribution of model parameters was clearly not affected by variable surface effects and leaf local topography, thus proving the relevance of the proposed model for hyperspectral imaging compared to original PROSPECT.

International audience; Most methods for retrieving foliar content from hyperspectral data are well adapted either to remote-sensing scale, for which each spectral measurement has a spatial resolution ranging from a few dozen centimeters to a few hundred meters, or to leaf scale, for which an integrating sphere is required to collect the spectral data. In this study, we present a method for estimating leaf optical properties from hyperspectral images having a spatial resolution of a few millimeters or centimeters. In presence of a single light source assumed to be directional, it is shown that leaf hyperspectral measurements can be related to the directional hemispherical reflectance simulated by the PROSPECT radiative transfer model using two other parameters. The first one is a multiplicative term that is related to local leaf angle and illumination zenith angle. The second parameter is an additive specular-related term that models BRDF effects.Our model was tested on visible and near infrared hyperspectral images of leaves of various species, that were acquired under laboratory conditions. Introducing these two additional parameters into the inversion scheme leads to improved estimation results of PROSPECT parameters when compared to original PROSPECT. In particular, the RMSE for local chlorophyll content estimation was reduced by 21% (resp. 32%) when tested on leaves placed in horizontal (resp. sloping) position. Furthermore, inverting this model provides interesting information on local leaf angle, which is a crucial parameter in classical remote-sensing.

International audience; In the context of the RHEA European project addressing site-specific weeding on arable crops, a complete aerial image acquisition chain has been developed, providing a geo-referenced multispectral image of a total parcel with 1 cm spatial resolution. Robust automatic ground control point detection and near infrared - visible sensor image registration modules have been implemented and associated with the MicMac photogrammetric software suite to provide a fully automatized mosaicking procedure. This procedure has been successfully applied on various maize and wheat crops for weed patch detection, but could be extended to other precision agriculture applications, especially those requiring a very high spatial resolution.

International audience; In the context of the RHEA European project addressing site-specific weeding on arable crops, a complete aerial image acquisition chain has been developed, providing a geo-referenced multispectral image of a total parcel with 1 cm spatial resolution. Robust automatic ground control point detection and near infrared - visible sensor image registration modules have been implemented and associated with the MicMac photogrammetric software suite to provide a fully automatized mosaicking procedure. This procedure has been successfully applied on various maize and wheat crops for weed patch detection, but could be extended to other precision agriculture applications, especially those requiring a very high spatial resolution.

International audience; Sugar beet is the second biggest world contributor to sugar production and the only one grown in Europe. Great efforts are currently being made to preserve and enhance its competitiveness. Within this context, one of the main bottlenecks identified is the lack of effective tools for assessing sugar content in unprocessed sugar beet roots. In the sugar industry, NIRS has been long used to monitor product quality on sugar processing lines in both sugar beet and cane industrial processes. The main work have been performed on beet brei although some authors studied the feasability of predicting sucrose content of intact and sliced beets. The results are of very good quality, however the beet peel is still a real problem to acquire signals of sufficient quality. Optical fibers are an essential component for remote optical measurements and have been extensively used to deliver and collect light in optical setups. By invasive but non destructive measurement, the fiber-optic probe could be an effective tools for rapid assessment of sugar content of intact beets and deal with the problem caused by the presence of beet peel. The objective of this work is to evaluate the use of a self-designed fiber-optic probe for the estimation of Soluble Solid Content (SSC) in intact sugar beets. Two geometries were tested : a single-fiber probe and a multiple-fiber probe. The impact of different components of the probe were analyzed, such as fiber diameter, distance between illumination and collection fiber in order to optimize optical setup of the probe. Total reflectance over the [400-2500 nm] spectral range, of 180 sugar beet samples, were measured with the two probes. Immediately after spectrum acquisition, Soluble Solids Content measurements were achieved for each sample. Partial Least Square (PLS) algorithm was used to calibrate the SSC estimation of the sugar beets With the single-fiber probes and for the two tested diameters, the results were not satisfactory. The better correlation coefficient and the ratio of sample standard deviation to standard error of prediction are respectively equal to 0.757 and 2.02. For this configuration, the measured signal is mainly composed by the specularly reflected light, which overlaps and therefore masks the information related to chemical absorbance of SSC. On the contrary, Partial Least Squares regression (PLSr) models showed good performance in the estimation of SSC with the multiple-fiber probes. For two different positions of the collecting fiber, results showed good correlation between SSC and reflectance spectra for intact sugar beets, with a correlation coefficient higher than 0.90 and a ratio of sample standard deviation to standard error of prediction higher than 3.30. These first results are very promising. However, further improvement are needed in order to achieve a satisfactory accuracy: •optimization of the distance between emitting and collecting fiber, •reducing the multiple scattering using several preatraitements, •increasing the number of samples in order to increase the robustness of the models.

International audience; Near-infrared spectroscopy (NIRS) is a powerful non-destructive analytical method used to analyze major compounds in bulk materials and products and requiring no sample preparation. It is widely used in routine analysis and also in line in industries, in vivo with biomedical applications, or in field for agricultural and environmental applications. However, highly scattering samples subvert Beer-Lambert law's linear relationship between spectral absorbance and the concentration. Instead of spectral pre-processing, which is commonly used by NIR spectroscopists to mitigate the scattering effect, we put forward an optical method, i.e., coupling polarized light with NIR spectrometry, to free spectra from scattering effect. This should allow us to retrieve linear and steady conditions for spectral analysis. When tested in visible-NIR (Vis-NIR) range (400-800 nm) on model media, mixtures of scattering and absorbing particles, the setup provided significant improvements in absorber concentration estimation precision as well as in the quality and robustness of the calibration model.

International audience; NIR Spectroscopy ability was investigated to assess the fruit structure effect (passion fruit, tomato and apricot) on prediction performance of soluble solids content (SSC) and titratable acidity (TA). Relationships between spectral wavelengths and SSC and TA were evaluated through the application of chemometric techniques based on partial least squares (PLS). Good prediction performance was obtained for apricot with correlation coefficients of 0.93 and 0.95 for SSC and TA and root mean square errors of prediction (RMSEP%) of 3.3% and 14.2%, respectively. For the passion fruit and tomato, the prediction models were not satisfactorily accurate due to the high RMSEP. Results showed that NIR technology can be used to evaluate apricot internal quality, however, it was not appropriate to evaluate internal quality in fruits with thick skin, (passion fruit), and/or heterogeneous internal structure (tomato).

16th International Conference on Near Infrared Spectroscopy, La Grande-Motte, FRA, 02-/06/2013 - 07/06/2013; International audience; The objective of this study was to evaluate the potential of proximal hyperspectral imaging to (i) calibrate a model to predict soil respiration under controlled conditions, and (ii) to determine both spatial and temporal variations in soil respiration at a hundreds of micrometer scale. Calibration models based on spectra and respiration measured on standards were built then applied on hyperspectral images acquired on soil mesocosms (400 cm²), in order to predict their respiration pixel by pixel (0.2 mm²). The quality of the models was acceptable but their application to produce prediction maps faced some technical problems due to hyperspectral technology.

On account of the ubiquity of nitrogen heterocycles and their biological properties, the great attention is paid to developing methodologies of their synthesis and functionalization. For this purpose, the study of functionalization of enamides constitutes an important topic due to the utility of these motifs in the construction of complex heterocyclic derivatives. Palladium-catalyzed reactions of cross-coupling are rapid and efficient methods of choice for synthesis of enamides particularly starting from enol phosphates derived from lactams, imides or amides.The first chapter of the thesis evokes the original C-P coupling reaction of chiral and achiral secondary phosphine boranes with different enol phosphates in mild reaction conditions, leading to corresponding enamido-phosphine boranes. This methodology permits the construction of libraries of novels phosphines. Also, the reaction of nucleophilic addition of phosphide anions onto various enecarbamates acyclic was elaborated, giving an access to original beta-phosphino alpha-amino acids, bearing the quaternary carbon on alpha position to nitrogen.The second chapter is devoted to the preparation and characterization of organic chromophores based on the pyrazinic core, which are likely to exhibit the fluorescence properties. These compounds were designed to form new sensitizing systems for lanthanide cations and could be used as organic sensitizers for molecular imaging in near infrared.; En raison de l’omniprésence des hétérocycles azotés et de leurs propriétés biologiques, une attention particulière est accordée au développement de méthodologie pour leur synthèse et leur fonctionnalisation. L’étude de la fonctionnalisation d’énamides constitue une thématique importante car ces motifs s’avèrent être des outils synthétiques polyvalents permettant d’accéder à des dérivés hétérocycliques complexes. Les réactions de couplage Pd-catalysées constituent une méthode de choix rapide et efficace pour la synthèse d'énamides, notamment à partir de phosphates d'énols issus de lactames, d’imides ou d’amides. Le premier chapitre de ce travail porte sur le couplage organopalladié C-P de phosphines boranes secondaires chirales ou achirales avec des phosphates d’énols. Ce couplage C-P original, réalisé dans des conditions douces, conduit aux énamido-phosphines boranes correspondantes et offre de nombreuses possibilités pour la constitution d’une librairie de phosphines originales. Parallèlement à ce travail, l’addition nucléophile d’anions phosphures sur divers ène-carbamates acycliques conduit à des acides alpha-aminés béta-phosphorés originaux, porteurs d’un carbone quaternaire en alpha de l’azote. Le deuxième chapitre de la thèse porte sur la préparation et la caractérisation de chromophores organiques originaux basés sur un noyau pyrazinique et qui sont susceptibles de présenter des propriétés de fluorescence. Ces composés sont conçus pour former des nouveaux systèmes sensibilisateurs de cations de lanthanides, et être utilisés comme sensibilisateurs organiques pour l'imagerie moléculaire dans le proche infrarouge.

On account of the ubiquity of nitrogen heterocycles and their biological properties, the great attention is paid to developing methodologies of their synthesis and functionalization. For this purpose, the study of functionalization of enamides constitutes an important topic due to the utility of these motifs in the construction of complex heterocyclic derivatives. Palladium-catalyzed reactions of cross-coupling are rapid and efficient methods of choice for synthesis of enamides particularly starting from enol phosphates derived from lactams, imides or amides.The first chapter of the thesis evokes the original C-P coupling reaction of chiral and achiral secondary phosphine boranes with different enol phosphates in mild reaction conditions, leading to corresponding enamido-phosphine boranes. This methodology permits the construction of libraries of novels phosphines. Also, the reaction of nucleophilic addition of phosphide anions onto various enecarbamates acyclic was elaborated, giving an access to original beta-phosphino alpha-amino acids, bearing the quaternary carbon on alpha position to nitrogen.The second chapter is devoted to the preparation and characterization of organic chromophores based on the pyrazinic core, which are likely to exhibit the fluorescence properties. These compounds were designed to form new sensitizing systems for lanthanide cations and could be used as organic sensitizers for molecular imaging in near infrared.; En raison de l’omniprésence des hétérocycles azotés et de leurs propriétés biologiques, une attention particulière est accordée au développement de méthodologie pour leur synthèse et leur fonctionnalisation. L’étude de la fonctionnalisation d’énamides constitue une thématique importante car ces motifs s’avèrent être des outils synthétiques polyvalents permettant d’accéder à des dérivés hétérocycliques complexes. Les réactions de couplage Pd-catalysées constituent une méthode de choix rapide et efficace pour la synthèse d'énamides, notamment à partir de phosphates d'énols issus de lactames, d’imides ou d’amides. Le premier chapitre de ce travail porte sur le couplage organopalladié C-P de phosphines boranes secondaires chirales ou achirales avec des phosphates d’énols. Ce couplage C-P original, réalisé dans des conditions douces, conduit aux énamido-phosphines boranes correspondantes et offre de nombreuses possibilités pour la constitution d’une librairie de phosphines originales. Parallèlement à ce travail, l’addition nucléophile d’anions phosphures sur divers ène-carbamates acycliques conduit à des acides alpha-aminés béta-phosphorés originaux, porteurs d’un carbone quaternaire en alpha de l’azote. Le deuxième chapitre de la thèse porte sur la préparation et la caractérisation de chromophores organiques originaux basés sur un noyau pyrazinique et qui sont susceptibles de présenter des propriétés de fluorescence. Ces composés sont conçus pour former des nouveaux systèmes sensibilisateurs de cations de lanthanides, et être utilisés comme sensibilisateurs organiques pour l'imagerie moléculaire dans le proche infrarouge.

Evaluation of uncertainty affecting predictions is a major trend in analytical chemistry and chemometrics. Several approximate expressions and resampling methods have been proposed for the estimation of prediction uncertainty when using multivariate calibration. This article proposes a new expression for the variance of prediction, adapted to near infrared spectroscopy specificities and particularly to the spectral error structure, induced by the high colinearity of the variables. The proposed analytical expression enables a detailed evaluation of the different contributions and components of uncertainty affecting the model. An application to real data of feedstuff near infrared spectra related to protein content has shown its advantages.

Huit méthodes de transfert d'étalonnage basées sur l'élimination ses signaux orthogonaux ont été comparées dans l'objectif de transférer les modèles d'étalonnage de teneur en huile et en protéine de soja: Les méthodes sont: Dynamic orthogonal projection (DOP), transfer by orthogonal projection (TOP), error removal by orthogonal subtraction (EROS), orthogonal signal correction (OSC), orthogonal projection to latent structures (O-PLS) ainsi que des modifcations et extensions de ces méthodes . Toutes ont été comparées sur le transfert inter-marques ou intra-marques, à partir de spectres obtenus sur 2 Foss Infratecs et deux Bruins OmegAnalyzerGs. La méthode donnant les résultats les plus prometteurs est la méthode DOP modifiée par la matrice des différences, alors que les méthodes TOP et EROS modifiées n'ont pas apporté d'amélioration. / Eight calibration transfer methods based on the removal of orthogonal signal were compared for the standardization of whole soybean protein and oil models. Dynamic orthogonal projection (DOP), transfer by orthogonal projection (TOP), error removal by orthogonal subtraction (EROS), orthogonal signal correction (OSC), and orthogonal projections to latent structures (O-PLS) as well as the modification and extension of some of these methods were compared in the transfer of models in intra and inter-brand situations using two Foss Infratecs and two Bruins OmegAnalyzerGs. For each brand, a master was designated and its models transferred onto the second unit of its network and the two units of the second brand. Calibration models were transferable from brand to brand with similar or better precision than when each instrument was calibrated on its own calibration set (for Infratec 1229, the relative predictive determinant (RPD) increased in intra and inter-brand calibration transfer situations from 10.42 to 11.45 and 10.57, with DOP and EROS respectively). Performance of each method was different across parameters, instruments, and validation sets. DOP modifications on the determination of the difference matrix showed promising results while TOP and EROS extensions to include variability specifically present in certain crop years did not bring any beneficial effects.

* Methods based on near infrared spectroscopy used to assess wood properties are susceptible to variations in physical parameters (temperature, grain size, etc.). As wood is a hygroscopically sensitive material, we studied the effects of moisture on near infrared absorbance and calibration to accurately determine the application potential of this technique under routine. * A collection of Eucalyptus urophylla X E. grandis hybrid wood pieces were analysed to obtain reference calibration of polyphenol contents in wood extracts via NIR spectra acquired under constant moisture conditions. Other specimens from the same source were assessed to obtain spectra for eight moisture contents spanning a broad variation range. The effects of moisture on absorption and on estimates based on a reference model were analysed. * An increase in moisture content prompted a rise in near infrared absorption over the entire spectrum and for water O-H absorption bands. The polyphenol content estimates obtained by assessing specimens against the reference calibration at variable moisture contents revealed prediction bias. Five correction methods were then tested to enhance the robustness relative to moisture. * In-depth calibration and external parameter orthogonalization (EPO) were found to be the most efficient methods for offsetting this factor., * Les méthodes basées sur la spectroscopie proche infrarouge pour estimer les propriétés du bois sont sensibles aux variations des paramètres physiques (température, granulométrie...). Le bois étant un matériau hygroscopique sensible, l'influence de l'humidité sur l'absorbance et l'étalonnage proche infrarouge a été étudiée afin de mieux considérer les possibilités d'applications dans des conditions réelles. * Un étalonnage de référence de la quantité de polyphénols présents dans les extraits a été établi à partir de spectres d'une collection de bois d'hybrides d'Eucalyptus urophylla X E. grandis à humidité constante fixée. D'autres spectres ont été obtenus sur des échantillons de même provenance mais à 8 teneurs en eau couvrant une large plage de variation. L'influence de l'humidité sur l'absorbance proche infrarouge puis sur l'estimation par le modèle de référence a été analysée. * Une augmentation de l'humidité élève la ligne de base du spectre d'absorbance et également les régions d'absorbance caractéristiques de la liaison O-H de l'eau. Les estimations de la quantité de polyphénols à partir de l'étalonnage de référence sur les échantillons à humidité variable révèlent un biais sur les prédictions. * Parmi les cinq méthodes de correction testées pour rendre l'étalonnage robuste vis-à-vis de l'humidité, l'étalonnage exhaustif et l'EPO (External Parameter Orthogonalisation) s'avèrent être les plus efficaces et permettent de s'affranchir de ce facteur.

This Ph.D. work deals with the development of lanthanide-based bioprobes for biomedical analyses and imaging. For this purpose, two different approaches have been followed, one focusing on visible-emitting complexes, while the second addresses the sensitization of NIR-emitting LnIII ions. The homoditopic ligands H2LC2 and H2LC3 have been tailored to self-assemble with lanthanide ions (LnIII) into neutral triple-stranded bimetallic helicates of overall composition [Ln2(L)3] and also to provide a versatile platform for further derivatization. The grafting of polyoxyethylene groups onto the pyridine (H2LC2) or the benzimidazole (H2LC3) units ensures water solubility, while maintaining large thermodynamic stability and adequate antenna effect for the excitation of LnIII ions. The conditional stability constants are large at physiological pH, with logβ23 reaching values in the range 22-25 for helicates with H2LC2 and H2LC3. The ligands triplet states feature adequate energy to efficiently sensitize the EuIII luminescence (QEu L = 21 and 11 % for L = H2LC2 and H2LC3, respectively) in aerated water at pH 7.4. Conversely, energy back transfer occurring in [Tb2(LC3)3] precludes a good sensitization of the TbIII luminescence, and only the TbIII helicate with H2LC2 displays sizeable quantum yield (QTbL = 11 %). Furthermore, it has been demonstrated that ligand H2LC2 sensitizes the emission of other visible- and NIR-emitting LnIII ions, such as SmIII or YbIII, for which in cellulo luminescence is evidenced, a rare observation. The EuIII emission spectra of both helicates arise from a main species with pseudo-D3 symmetry and without coordinated water. Cytotoxicity experiments reveal no significant effect of the helicates on the viability of several cancerous cell lines and cell imaging properties of the EuIII helicates are demonstrated for the HeLa cell line by luminescence microscopy. Bright EuIII emission is seen after relatively short time (15-30 min) and low helicate incubation concentrations (10 µM). Similar images were obtained for [Sm2(LC2)3] and [Tb2(LC2)3] using slightly higher loading concentration. The helicates stain the cytoplasm and the permeation mechanism is likely to be endocytosis. The described luminescent helical stains are robust chemical species which remain mostly undissociated in the cell medium and which resist to the presence of other complexing agents, as demonstrated in the case of H2LC2. All these properties make these helicates potential bioprobes for interacting with biological material and for cell imaging applications. As near-infrared (NIR) light, in addition to be less energetic than visible light, displays better penetrability into the human body, the development of bioprobes emitting in the near-infrared range is of prime importance for deeper tissue imaging, especially for early diagnosis of tumors. We therefore investigate the ability of new polydentate podands to sensitize the NIR luminescence of NdIII and YbIII ions. These ligands have been designed in a way to take advantage of the chelating effect of bidentate (Tsox, TsoxMe) or tridentate 8-hydroxyquinolinate (8-HQ) subunits (T2soxMe). The interaction between the ligands and LnIII ions in aqueous solution leads to the formation of stable 1:1 chelates (pLn in the range of 12-16), all the chromophoric 8-HQ units being coordinated to the metal center, exploiting the entropic effect generated by the anchor. At physiological pH, one major species is present for all the ligands regardless of the LnIII ion used. The low energy triplet states of the ligands are particularly well-suited for an efficient sensitization of the NdIII- or YbIII-centered luminescence (QNdL = 0.02-0.04 % and QYbL = 0.13-0.37 %) in buffered aqueous solution. ErIII NIR luminescence is also detected in water for the chelates with Tsox and TsoxMe. Lifetime determinations point in all cases to the absence of coordinated water molecules in the inner coordination sphere of the LnIII ion. It has also been demonstrated that methylation of the amide functions of Tsox removes the quenching mechanism induced by the proximate N-H groups and increases both the lifetimes and quantum yields of the TsoxMe chelates, with the YbIII complex being one of the most NIR luminescent lanthanide-based edifices described so far. Ligand TsoxMe thus appears to be the best candidate of the series regarding to the development of NIR probes for bioanalyses. Furthermore, other applications, for instance in telecommunications, are still conceivable since the incorporation of the Yb-TsoxMe chelate into sol-gel silica films has proven to be successful, the chelate withstanding the sol-gel process, while providing a slight enhancement of photophysical properties compared to the same chelate in aqueous solution.

The assessment of greenhouse gas emissions from soils requires an accurate knowledge on the fate of carbon (C) and nitrogen (N) in soils. This knowledge shouldn't be limited to C and N stocks in soils but should incorporate the quantification of functional soil organic matter (SOM) fractions with different turnover rates. Conventional analysis can't be used to assess such functional properties of SOM over large geographical areas. Near-infrared reflectance spectroscopy (NIRS) is a rapid and cheap method that could achieve this goal. This technology has proven its efficiency to discriminate among functional SOM fractions and to predict C, N on large sets of soil samples at a large regional scale. NIRS can be used for the detailed analysis of decomposition and aggregation of SOM, two key ecosystem processes that control C and N budget in soils. This review points up the improvement of NIR prediction models by the technique of local calibration and the potential of NIR analysis to assess the ontogeny and heterogeneity of detritus in soils. Mapping soil C, N and SOM fractions at the European level is a challenge that NIRS can help to take up.

International audience; A spatialized surface energy balance model was validated over the database acquired in the framework of the ReSeDA program. The benefit of the SEBAL model we considered was to compute wind speed and air temperature using the information contained in the spatial variability of convective fluxes. The multitemporal database allowed performing a validation over cycles of several crops. Problems induced by mixed pixels were reduced using high spatial resolution remote sensing data. We verified the validity of the model basic assumption, i.e. the simultaneous presence of partial areas with very high and very low evaporation rates, and the resulting relation between surface temperature and albedo. Besides, the model provided estimates of wind speed and air temperature close to the field references. The validation of soil heat flux showed the inadequacy of the empirical relationship used through a significant underestimation of the references. The validation of sensible heat flux provided similar results as compared to previous studies that dealt with model validations over databases including numerous situations.; Nous avons validé un modèle de bilan d'énergie de surface en utilisant la base de données ReSeDA. L'intérêt du modèle SEBAL était d'estimer la vitesse du vent et la température de l'air à partir de l'information contenue dans la variabilité spatiale des flux convectifs. La base de données multitemporelle permettait d'effectuer une validation en considérant les cycles de plusieurs cultures. Les problèmes dûs aux pixels mixtes étaient réduits par l'utilisation de données télédétectées à haute résolution spatiale. Nous avons pu vérifier la validité de l'hypothèse de base du modèle, i.e. la présence simultanée de zones très évaporantes ou peu évaporantes, ainsi que la relation entre albedo et température qui en résulte. De plus, le modèle a fourni des estimations de la vitesse du vent et de la température de l'air proche des mesures de référence. La validation du flux de chaleur dans le sol a montré que la relation empirique générait une sous-estimation importante. La validation du flux de chaleur sensible a fourni des résultats comparables à ceux rencontrés dans la littérature et concernant la validation de modèles sur des bases de données incluant de nombreuses situations.