996 resultados para Rui Santps


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The grey system theory studies the uncertainty of small sample size problems. This paper using grey system theory in the deformation monitoring field, based on analysis of present grey forecast models, developed the spatial multi-point model. By using residual modification, the spatial multi-point residual model eras developed in further study. Then, combined with the sedimentation data of Xiaolangdi Multipurpose Dam, the results are compared and analyzed, the conclusion has been made and the advantages of the residual spatial multi-point model has been proved.

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The remote sensing based Production Efficiency Models (PEMs), springs from the concept of "Light Use Efficiency" and has been applied more and more in estimating terrestrial Net Primary Productivity (NPP) regionally and globally. However, global NPP estimates vary greatly among different models in different data sources and handling methods. Because direct observation or measurement of NPP is unavailable at global scale, the precision and reliability of the models cannot be guaranteed. Though, there are ways to improve the accuracy of the models from input parameters. In this study, five remote sensing based PEMs have been compared: CASA, GLO-PEM, TURC, SDBM and VPM. We divided input parameters into three categories, and analyzed the uncertainty of (1) vegetation distribution, (2) fraction of photosynthetically active radiation absorbed by the canopy (fPAR) and (3) light use efficiency (e). Ground measurements of Hulunbeier typical grassland and meteorology measurements were introduced for accuracy evaluation. Results show that a real-time, more accurate vegetation distribution could significantly affect the accuracy of the models, since it's applied directly or indirectly in all models and affects other parameters simultaneously. Higher spatial and spectral resolution remote sensing data may reduce uncertainty of fPAR up to 51.3%, which is essential to improve model accuracy.

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Hydroquinone was chosen as an electroactive probe to study the beta-cyclodextrin (beta-CD) modified poly(N-acetylaniline) (PNAANI) electrode. The beta-CD modified PNAANI electrode was prepared by electrooxidation of the PNAANI electrode in a beta-CD/DMSO solution. The electrochemical properties of the beta-CD inclusion complex of hydroquinone on the PNAANI electrode and hydroquinone on the beta-CD modified PNAANI electrode were studied. In the cyclic voltammogram of hydroquinone at the beta-CD/PNAANI electrode, DeltaE(p) of the peaks is sharpening and the area of the peaks is increasing, which can be due to the inclusion of hydroquinone into the cavity of beta-CD immobilized at the electrode surface. The beta-CD/PNAANI film was characterized by X-ray photoelectron spectroscopy and H-1 NMR. The mechanism for beta-CD incorporation into the polymer film was also proposed.