Search results for "Spectral data"
showing 10 items of 56 documents
13C NMR spectra of eudesmane derivatives
1992
The 13C NMR spectral data of 18 eudesmane derivatives, mainly acids and esters of natural and synthetic origin, are reported, and the γ-effect of the epoxide ring in two diastereoisomeric epoxy esters is discussed.
Dual Substituent Parameter Modeling of Theoretical, NMR and IR Spectral Data of 5-Substituted Indole-2,3-diones
2002
Correlations of AM1 and PM3 theoretical data, 13C-NMR substituent chemical shifts (13C-SCS) and IR carbonyl group wave numbers [ν(C3â•ÂO)] were studied using dual substituent parameter (DSP) models for 5-substituted indole-2,3-diones. For the C7 atom a reverse substituent effect attributed to extended À-polarization was observed. On the other hand, the DSP approaches for the C3 atom showed normal substituent effects with some contribution of reverse effect supported strongly by 13C-SCS correlations. In the ν(C3â•ÂO) and p(C3â•ÂO) DSP correlations the field effect contribution predominates over the resonance effect, which justifies the using of earlier suggested vibrational cou…
ChemInform Abstract: Synthesis of (+)-Pechueloic Acid and (+)-Aciphyllene. Revision of the Structure of (+)-Aciphyllene.
2008
Abstract 1α H ,7α H ,10α H -Guaia-4,11-dien-3-one and its 1β H ,10β H diastereomer, easily obtained from (+)-dihydrocarvone, are good starting materials for the synthesis of natural guaiane derivatives. Allylic oxidation of the 1α H ,10α H isomer gave as main product its 13-hydroxy derivative and a small amount of (+)-7β-hydroxy-1α H ,10α H -guaia-4,11-dien-3-one, whereas the 1β H ,10β H diastereomer afforded selectively the (−)-7α-hydroxy-1β H ,10β H enantiomer in excellent yield. From the 13-hydroxy derivative (+)-pechueloic acid and (+)-methyl pechueloate were synthesized. Deoxygenation at C 3 of the 1β H ,10β H guaiadienone afforded a guaiadiene with the reported structure for aciphylle…
Synthesis, infrared and121Sb M�ssbauer spectra of some Antimony(III) Thiocyanate Complexes
1989
The first isolation of an antimony(III) thiocyanate complex salt, [(CH3)4N][Sb(CNS)4] (I), and of two adducts of the Sb(CNS)3 formal unit with potentially tridentate nitrogen donors, Sb(CNS)3tpta (II) and [Sb(CNS)3]3(dqp)2 (III), is described. In these derivatives, infrared and Mossbauer spectral data are essentially indicating the predominant presence of N-bonded thiocyanate. For complex I, the occurrence also of groups bridging through the nitrogen atom is advanced. Synthese, IR- und 121Sb-Mosbauer-Spektren von Antimon (III)-thiocyanat-Komplexen Die erstmalige Darstellung eines Antimon(III)-thiocyanat-Komplexes, [(CH3)4N][Sb(CNS)4] (I) und von zwei Addukten der formalen Sb(CNS)3-Einheit m…
Feature Selection Approach based on Mutual Information and Partial Least Squares
2014
Feature selection technology can improve the modeling accuracy and reduce model’s complexity, especially for the high dimensional spectral data. Aim at this problem, feature selection approach based on mutual information (MI) and partial least square (PLS) is proposed in this paper. MI values between features and responsible variable are calculated, and the threshold value using to select final features is optimal selected based on PLS algorithm. The numbers of the latent values of the PLS and the threshold value of MI are selected according the modeling performance simultaneously. The experimental results based on the near-infrared spectrum show that the proposed approach has better perfor…
Linking the Molecular Signature of Heteroatomic Dissolved Organic Matter to Watershed Characteristics in World Rivers
2015
Large world rivers are significant sources of dissolved organic matter (DOM) to the oceans. Watershed geomorphology and land use can drive the quality and reactivity of DOM. Determining the molecular composition of riverine DOM is essential for understanding its source, mobility and fate across landscapes. In this study, DOM from the main stem of 10 global rivers covering a wide climatic range and land use features was molecularly characterized via ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). FT-ICR mass spectral data revealed an overall similarity in molecular components among the rivers. However, when focusing specifically on the contributi…
Integration of 3D and multispectral data for cultural heritage applications: Survey and perspectives
2013
International audience; Cultural heritage is increasingly put through imaging systems such as multispectral cameras and 3D scanners. Though these acquisition systems are often used independently, they collect complementary information (spectral vs. spatial) used for the study, archiving and visualization of cultural heritage. Recording 3D and multispectral data in a single coordinate system enhances the potential insights in data analysis. Wepresent the state of the art of such acquisition systems and their applications for the study of cultural her- itage. Wealso describe existing registration techniques that can be used to obtain 3D models with multispec- tral texture and explore the idea…
Registration of 3D and Multispectral Data for the Study of Cultural Heritage Surfaces
2013
International audience; We present a technique for the multi-sensor registration of featureless datasets based on the photogrammetric tracking of the acquisition systems in use. This method is developed for the in situ study of cultural heritage objects and is tested by digitizing a small canvas successively with a 3D digitization system and a multispectral camera while simultaneously tracking the acquisition systems with four cameras and using a cubic target frame with a side length of 500 mm. The achieved tracking accuracy is better than 0.03 mm spatially and 0.150 mrad angularly. This allows us to seamlessly register the 3D acquisitions and to project the multispectral acquisitions on th…
Pulvérisation ciblée sur les tâches d’adventices détectées par drône en colza
2019
L’idée de cartographier les zones infestées par les adventices pour restreindre la surface traitée, et donc les quantités d’herbicides utilisées, méritait d’être testée. Depuis l’acquisition des données par drone, en passant par le traitement des images, jusqu’à l’exploitation de la carte par le pulvérisateur au champ. C’est pourquoi, Terres Inovia a décidé de collaborer avec AIRINOV pour conduire un essai sur colza en vue de la pulvérisation ciblée sur les tâches d’adventices détectées préalablement par drone. Cette étude exploratoire avait pour objectif de vérifier l’intérêt, la faisabilité, la pertinence et l’efficacité d’une telle technique. Elle s’inscrit dans le projet européen H2020 …
Remote and proximal sensing for precision agriculture and viticulture". Special issue
2021
International audience; Special Issue InformationDear Colleagues,Remote and proximal sensing are the two most common techniques concerning the acquisition of information about an object or any phenomenon without physical contact with the object. Remote sensing is widely tied to the use of satellite, airborne or UAV platforms using multi- or hyperspectral imagery. In terms of proximal sensing, the sensor is close to the object and is installed on platforms ranging from handheld, fixed installations, or robotics and tractor-embedded sensors. The types of sensors range from simple RGB or grey-level-cameras to multispectral and hyperspectral high resoluted imaging systems or even thermographic …