The morphological symptom of phosphorus deficiency at early stage is similar to the appearance of leaf aging process in preliminary phase, so that visual diagnostics of phosphorus deficiency in mini-cucumber plants at early stage is practically impossible. Near infrared reflectance spectra contain information about differences in compositions of leaf tissues between phosphorus-deficient plants and healthy plants. In the present paper, near infrared reflectance spectroscopy was used to provide diagnostic information on phosphorus deficiency of mini-cucumber plants grown under non-soil conditions. Near infrared spectra was collected from 90 leaves of mini-cucumber plants. Raw cucumber spectra was preprocessed by SNV and divided into 27 intervals. The top 10 principal components (PCs) were extracted as the input of BP-ANN classifiers by principal component analysis (PCA) while the values of nutrient deficient were used as the output variables of BP-ANN and three layers BP-ANN discrimination model was built. The best experiment results were based on the top 3 principal components of No. 7 interval when the spectra was divided into 27 intervals and identification rates of the ANN model are 100% in both training set and the prediction set The overall results show that NIR spectroscopy combined with BP-ANN can be efficiently utilized for rapid and early diagnostics of phosphorus deficiency in mini-cucumber plants.%采用水热方法合成Ce1-x(Fe0.5 La0.5)xO2-δ固溶体.利用X射线衍射技术(X-ray diffraction technique,XRD)表征样品的相结构,并对固溶体的晶胞参数进行拟合,通过紫外可见漫反射光谱(UV-Vis diffraction spectrum)及拉曼光谱(Raman spectrum)表征其电子跃迁性能及由于双离子掺杂所引起的一系列掺杂效应.XRD结果表明,Ce1-x(Fe0.5La0.5)xO2-δ固溶体为CeO2立方萤石结构,当掺杂量增加到x=0.30时出现了微弱的Fe2O3杂相衍射峰；讨论了两种离子在品格中不同的取代位置.晶胞参数随着掺杂量的增大而逐渐增大,当掺杂量达到x＝0.18后保持基本不变.紫外漫反射光谱表明,随着掺杂量的增大,固溶体的带隙吸收边红移,即能隙逐渐减小,Fe离子在CeO2晶格中表现为+3价.Raman光谱F2g振动峰位逐渐向低波数方向移动,同时振动峰逐渐宽化,进一步证明了掺杂离子的影响效应.
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