Design,Preparation And Application Of Simulation Material With Green Vegetation Characteristic Spectrum In NIR Interval

Aim to withstand the hyperspectral remote sensing probing technology and improve the fighting capability and concealment of weapons,the reflectance spectra of simulation materials that is similar to green vegetation was designed in the Vis-NIR interval.However,at present,for the simulation materials there are some shortcomings in the NIR region.Therefore,the diffuse reflectance spectra of green healthy plants in the Vis-NIR region have been analyzed in detail here,and the mechanism of characteristic spectrum in related waveband was verified.Based on these principles,spectral simulation materials of corresponding band were designed.Furthermore,with combining spectral simulation materials of each band,the composite simulation material with the same both “color” and “spectrum” to green vegetation in Vis-NIR was obtained.Finally,the polyurethane coating was prepared with composite simulation material as filler,and its spectral property was analyzed.The results are as follows:1.Chlorophyll,the structure of leaves and water are found to be the key factors to green vegetation's reflective spectra in the Vis-NIR interval.Based on this concept,the combination of Cr2O3,porphyrins,and layered double hydroxides(LDHs)were applied to simulate the overall green vegetation's spectra in Vis-NIR wavelength interval.2.It was proposed that the red edge is the common spectral characteristic of chlorophyll,porphyrins and metalloporphyrins.The red edge is caused by Q band which is attributed to a2u(?)-eg(?*)transition of porphyrins.Furthermore,the factors that influence red position are also briefly concluded.3.The influences of experimental parameters on NIR reflectance spectra of Mg-Al-LDHs were analyzed by controlling variable method,and the optimal experimental parameters were chosen.Characterized by XRD,IR,TG and Raman,Mg-Al-Cl-LDHs was found to be of very similar reflectance spectra to green vegetation in NIR region,excellent thermostability,and high transparency in UV-Vis region.Besides,it was investigated that the characteristics of NIR spectrum of a serials of LDHs with different divalent,tervalent metal ions and interlayer anion.The LDHs of transition metal ions exist specific absorption peaks caused by d-d transition of transition metal ions in brucite layer.4.Reflectance spectral similarity of composite spectral simulation material,which contains Cr2O3,leaf power and LDHs,compared with green vegetation was done to ensure optimal proportion of composite.Polyurethane coating of high reflectance spectral similarity with green vegetation was prepared by the composite as filler and proper reflectivity conditioning agent,and the similarity between which and green vegetation was also calculated and discussed.