以中国东北大兴安岭加格达奇林区为研究区,基于环境(HJ)卫星遥感数据提取森林植被指数,结合实测样点叶面积指数(leaf area index,LAI)数据构建研究区LAI遥感反演模型,获取研究区森林LAI。在此基础上,利用研究区LAI影像对LAI遥感产品GLOB...以中国东北大兴安岭加格达奇林区为研究区,基于环境(HJ)卫星遥感数据提取森林植被指数,结合实测样点叶面积指数(leaf area index,LAI)数据构建研究区LAI遥感反演模型,获取研究区森林LAI。在此基础上,利用研究区LAI影像对LAI遥感产品GLOBCARBON LAI和MODIS LAI数据进行精度验证。研究结果表明:研究区LAI遥感反演模型中,基于比值植被指数(SR)的线性回归模型精度最高,模型R2为0.606(RMSE=0.251 6),相对误差19.89%;在研究区,GLOBCARBON LAI数据均值高于反演值,而MODIS LAI均值则相对较低,两者相对误差分别为12.2%和11.8%;通过对不同LAI值域的对比分析发现,研究区两种遥感LAI产品的最大误差均在LAI的低值区。展开更多
A flower-like BiOBr photocatalyst(CS/BiOBr)was prepared by using the carbon material derived from corn straw(CS)as the carrier.The prepared composites were characterized by X-ray diffraction(XRD),Fourier transform inf...A flower-like BiOBr photocatalyst(CS/BiOBr)was prepared by using the carbon material derived from corn straw(CS)as the carrier.The prepared composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FIIR)spectra,scanning electron microscope(SEM),X-ray photoelectron spectra(XPS),and UV-Vis diffuse reflectance spectra(UV-Vis DRS).The SEM analyses indicate that the introduction of CS promotes the formation of a unique flower-like structure in BiOBr,which not only optimizes the efficiency of light capture but also increases the specific surface area of BiOBr.The bandgap of the composite was narrower compared with the pure BiOBr.The CS/BiOBr composites exhibited higher photocatalytic activity than pure CS and BiOBr under visible light irradiation,and a higher first-order reaction rate constant(k)of 0.0437 min-1 than BiOBr(0.0146 min^(-1)),and exhibited excellent stability and reusability during the cyclic run.The enhanced photocatalytic activity is attributed to the efficient separation of photoinduced electrons and holes.Superoxide radicals and holes were the major active species.展开更多
文摘A flower-like BiOBr photocatalyst(CS/BiOBr)was prepared by using the carbon material derived from corn straw(CS)as the carrier.The prepared composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FIIR)spectra,scanning electron microscope(SEM),X-ray photoelectron spectra(XPS),and UV-Vis diffuse reflectance spectra(UV-Vis DRS).The SEM analyses indicate that the introduction of CS promotes the formation of a unique flower-like structure in BiOBr,which not only optimizes the efficiency of light capture but also increases the specific surface area of BiOBr.The bandgap of the composite was narrower compared with the pure BiOBr.The CS/BiOBr composites exhibited higher photocatalytic activity than pure CS and BiOBr under visible light irradiation,and a higher first-order reaction rate constant(k)of 0.0437 min-1 than BiOBr(0.0146 min^(-1)),and exhibited excellent stability and reusability during the cyclic run.The enhanced photocatalytic activity is attributed to the efficient separation of photoinduced electrons and holes.Superoxide radicals and holes were the major active species.
