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Mastering the changes in the planting area of crops are critical for formulating sustainable agricultural development strategies. The Landsat 9 satellite provides continuous observational data for crop mapping. It is necessary to evaluate the potential of Landsat 9 images for canola mapping. According to literatures, some canola indices have been proposed in relation to the spectral features of the yellow canola flower, such as the canola ratio index (CRI), normalised difference yellowness index (NDYI), canola index (CI), canola flower index (CFI), normalised difference rapeseed flower index (NRFI) and winter rapeseed index (WRI). However, it is unclear which index has more potential to extract canola based on the Landsat 9 images. Therefore, the potentials of these indices for canola mapping were quantitatively compared by using different classification methods including supervised and unsupervised classification methods. For supervised classification methods and the CFI, the overall accuracy of canola mapping was above 90% and the kappa coefficient was above 0.8. For unsupervised classification methods, CFI also performs best. It was demonstrated that the CFI outperformed the other five indices for canola mapping. It was also confirmed that Landsat 9 images and the CFI exhibit promising potential for canola mapping via quantitative comparison. [ABSTRACT FROM AUTHOR]

Landsat-9 is the latest satellite of the Landsat program and provides useful agricultural remote sensing data. The earlier the crop distribution data is obtained, the greater the value of the data. However, whether Landsat-9 image is suitable for the early-season mapping of winter garlic and winter wheat is a problem worthy of attention. Therefore, this study evaluates the potential to use two Landsat-9 images, acquired on 13 December 2021 and 30 January 2022, for the early-season identification of winter garlic and winter wheat in China. According to J-M (Jeffries-Matusita) distances, we evaluated the separability of winter garlic, winter wheat, and other ground objects based on the two Landsat-9 images. Then, winter garlic and winter wheat were extracted by using unsupervised classification method, i.e. the IsoData and K-means clustering algorithms, and supervised classification method, i.e. the Random Forest (RF), and Support Vector Machine (SVM) algorithms. The separability between garlic and wheat in January is stronger than that in December. The classification overall accuracy based on the Landsat-9 image on 30 January 2022 is 92.03% with a kappa coefficient of 0.87 using the SVM algorithm. This period is about 4 months earlier than the crop harvest period. Landsat-9 images have good potentiality for early-season mapping of winter garlic and winter wheat. [ABSTRACT FROM AUTHOR]

H-ZSM-5 zeolites are successfully synthesized within 1 h with an organic template free system by the seed-assisted method. The synthetic method not only reduces the production cost of H-ZSM-5 zeolite, but also decreases the environmental pollution produced compared with that of the conventional synthesis process. Characterization by SEM, XRD, [N.sub.2] adsorption-desorption, N[H.sub.3]-TPD, and Py-IR confirms that the H-ZSM-5 product has a high crystallinity and reveals that the rapid synthesis process is in accordance with the seed surface crystallization mechanism. To improve the aromatic selectivity on the H-ZSM-5 zeolite, different concentrations of Mo and Zn catalysts were prepared by incipient wetness impregnation and the ion-exchange method. Mo-Zn/H-ZSM-5-SAS-1 h have similar catalytic lifetimes and higher selectivity of paraxylene in aromatic products compared with Mo-Zn/H-ZSM-5-seed in the reaction of methanol to aromatic. However, the catalytic lifetime of 6%Mo/H-ZSM-5-SAS-1 h is shorter than that of the 6%Mo/H-ZSM-5-seed catalyst in methane to benzene reaction under the same reaction conditions. Key words: rapid synthesis, H-ZSM-5, organic template free, seed-assisted, aromatization. Nous avons reussi a synthetiser des zeolithes H-ZSM-5 en 1 h dans un systeme sans agent structurant organique par la methode assistee par ensemencement. La methode de synthese que nous avons employee permet non seulement de reduire le cout de production de la zeolithe HZSM5, mais egalement de prevenir la pollution environnementale comparativement au procede de synthese classique. La caracterisation par microscopie electronique a balayage (MEB), diffraction des rayons X (DRX), adsorption-desorption de [N.sub.2], desorption thermoprogrammee d'ammoniac (N[H.sub.3]DTP) et pyrolyse couplee a la spectroscopie infrarouge (PylR) revele que le processus de synthese rapide est en accord avec le mecanisme de cristallisation par ensemencement de la surface. Afin d'ameliorer la selectivite aromatique de la zeolithe HZSM5, nous avons prepare des catalyseurs a differentes concentrations de Mo et de Zn par impregnation a humidite naissante et echange d'ions. Le catalyseur Mo-Zn/HZSM5SAS1 h a une duree de vie catalytique similaire et une selectivite parmi les produits aromatiques plus elevee pour le paraxylene que le catalyseur MoZn/HZSM5seed dans la reaction d'aromatisation du methanol. Cependant, la duree de vie catalytique du catalyseur 6%Mo/HZSM5SAS1 h est plus courte que celle du catalyseur 6%Mo/HZSM5seed dans la reaction d'aromatisation du methane en benzene dans les memes conditions de reaction. [Traduit par la Redaction] Mots-cles: synthese rapide, H-ZSM-5, sans agent structurant organique, assistee par ensemencement, aromatization., 1. Introduction Aromatic hydrocarbons are important chemical intermediates in the fine chemical industry and have huge industrial demand. (1) In recent decades, the methanol to aromatics (MTA) and methane to [...]