Cerium ammonium nitrate (CAN)-catalyzed four-component one-pot synthesis of multi-substituted pyrano[2,3-\varvec{c}]pyrazoles under ultrasound irradiation

A convenient and efficient synthesis of multi-substituted dihydropyrano[2,3-c]pyrazole derivatives is reported. The four-component reaction of 4-hydrazinobenzoic acid, $\beta $ -keto esters, aromatic aldehydes, and malononitrile using 10 mol% CAN catalyst in water under ultrasound irradiation produced the target compounds in good-to-excellent yields. This method has advantages over conventional methods in being economic, non-toxic, and environmentally compatible due to its use of efficient and eco-friendly CAN catalyst and water solvent.     

基于实测高光谱和电磁感应数据的区域土壤盐渍化遥感监测研究

以新疆渭干河—库车河三角洲绿洲为例,利用实测得到的不同盐渍化程度的盐渍土高光谱数据和电磁感应数据(EM38)协同构建土壤高光谱盐分指数遥感监测模型,将该模型通过尺度效应转换用于校正传统的Landsat-TM多光谱遥感影像的土壤盐分光谱指数,用校正过的TM影像进行区域土壤盐分的反演,并利用实测土壤盐分数据对反演结果进行分析与验证。结果表明：将高光谱和电磁感应数据与多光谱遥感技术相结合进行区域土壤盐渍化信息的提取,其精度和反演效果(R2=0.799 3,p<0.01)明显优于传统多光谱遥感方法中单纯利用土壤盐分指数所建立的监测模型(R2=0.587 4,p<0.01),为今后更好地实现土壤盐渍化的高精度遥感动态监测研究提供了科学依据。