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The fractal characteristics of tidal creeks in the Gaizhou Beach are analyzed based on high-resolution images fusion of Landsat TM and ERS-2, and then the graphic models and characteristics of converse information tree of tidal creeks in the Gaizhou Beach are established. A calculation model is established based on the above results, and at the same time, quantitative calculation of the evolution characteristics and the diversity between the northern and the southern parts of the Gaizhou Beach is carried out. By the supervised classification of these images, distribution and areas of high tidal flats, middle tidal flats and low tidal flats in the Gaizhou Beach are studied quantitatively, and image charactistics of seashell habitats in the Gaizhou Beach and the correlation between mudflat distribution and seashell habitats are studied. At last, the engineering problems in the Gaizhou Beach are discussed. 相似文献
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In this work, four kinds of natural seashells (clam shell, oyster shell, scallop shell, and conch shell) are investigated as catalysts for the Knoevenagel reaction to produce arylmethylenemalonitriles, among which conch shells show the highest catalytic activity due to their mixed phases of calcite and aragonite, resulting in the relatively weak base strength and fewer number of basic sites. Solvent effect and catalyst usage are systematically investigated, and conch shells show high universality for nine aromatic aldehydes to produce the desired products with high yield in short time under optimized conditions. In addition, this catalyst possesses good recyclability and could be used four times without obvious deactivation. In all, conch shell is an efficient, low‐cost, green, and recyclable catalyst for the Knoevenagel reaction. 相似文献
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