Crop growth and yield depend on canopy light interception （LI）. To identify a low-cost and relatively efficient index for measuring LI, several color attributes of red-green-blue （RGB）, hue-saturation-intensity （...Crop growth and yield depend on canopy light interception （LI）. To identify a low-cost and relatively efficient index for measuring LI, several color attributes of red-green-blue （RGB）, hue-saturation-intensity （HSI）, hue-saturation-value （HSV） color models and the component values of color attributes in the RGB color model were investigated using digital images at six cotton plant population densities in 2012-2014. The results showed that the LI values followed downward quadratic curves after planting. The red （R）, green （G） and blue （B） values varied greatly over the years, in accordance with Cai＇s research demonstrating that the RGB model is affected by outside light. Quadratic curves were fit to these color attributes at six plant population densities. Additionally, linear regressions of LI on every color attribute revealed that the hue （H） values in HSI and HSV were significantly linearly correlated with LI with a determination coefficient （R2）〉0.89 and a root mean square error （RMSE）=0.05. Thus, the H values in the HSI and HSV models could be used to measure LI, and this hypothesis was validated. The H values are new indexes for quantitatively estimating the LI of heterogeneous crop cano- pies, which will provide a theoretical basis for optimizing the crop canopy structure. However, further research should be conducted in other crops and under other growing and environmental conditions to verify this finding.展开更多
In this study, Zn4B6O13, Eu-and Tb-doped Zn4B6O13 phosphors were prepared by conventional solid state reaction method and the samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）...In this study, Zn4B6O13, Eu-and Tb-doped Zn4B6O13 phosphors were prepared by conventional solid state reaction method and the samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and photoluminescence spectroscopy（PL）. The doped rare-earth ions had little influence on the crystal structure of Zn4B6O13, but obviously affected the morphology of Zn4B6O13 particles. The PL results indicated that the 5% Eu-doped sample and 1% Tb-doped sample had the highest intensity in their respective different concentrations doped samples. The CIE chromaticity coordinates indicated that Zn4B6O13, Zn4B6O13：Eu and Zn4B6O13：Tb showed the three basic colors of blue, red and green, respectively. Evidently, the white light could appear only at appropriate intensity of blue, red and green components.展开更多
基金supported by the National Natural Science Foundation (31371561)
文摘Crop growth and yield depend on canopy light interception （LI）. To identify a low-cost and relatively efficient index for measuring LI, several color attributes of red-green-blue （RGB）, hue-saturation-intensity （HSI）, hue-saturation-value （HSV） color models and the component values of color attributes in the RGB color model were investigated using digital images at six cotton plant population densities in 2012-2014. The results showed that the LI values followed downward quadratic curves after planting. The red （R）, green （G） and blue （B） values varied greatly over the years, in accordance with Cai＇s research demonstrating that the RGB model is affected by outside light. Quadratic curves were fit to these color attributes at six plant population densities. Additionally, linear regressions of LI on every color attribute revealed that the hue （H） values in HSI and HSV were significantly linearly correlated with LI with a determination coefficient （R2）〉0.89 and a root mean square error （RMSE）=0.05. Thus, the H values in the HSI and HSV models could be used to measure LI, and this hypothesis was validated. The H values are new indexes for quantitatively estimating the LI of heterogeneous crop cano- pies, which will provide a theoretical basis for optimizing the crop canopy structure. However, further research should be conducted in other crops and under other growing and environmental conditions to verify this finding.
基金Project supported by the National Natural Science Foundation of China(21573142)
文摘In this study, Zn4B6O13, Eu-and Tb-doped Zn4B6O13 phosphors were prepared by conventional solid state reaction method and the samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and photoluminescence spectroscopy（PL）. The doped rare-earth ions had little influence on the crystal structure of Zn4B6O13, but obviously affected the morphology of Zn4B6O13 particles. The PL results indicated that the 5% Eu-doped sample and 1% Tb-doped sample had the highest intensity in their respective different concentrations doped samples. The CIE chromaticity coordinates indicated that Zn4B6O13, Zn4B6O13：Eu and Zn4B6O13：Tb showed the three basic colors of blue, red and green, respectively. Evidently, the white light could appear only at appropriate intensity of blue, red and green components.
