ALBERT

Description: The complete scattering matrix for cement dust was measured as a function of scattering angle from 5° to 160° at a wavelength of 532 nm, as a representative of mineral dust of anthropogenic origin in urban areas. Other related characteristics of cement dust, such as particle size distribution, chemical composition, refractive index and micro morphology were also analyzed. For this objective, a newly improved apparatus was built and calibrated using water droplets. Measurements of water droplets were in good agreement with Lorenz-Mie calculations. To facilitate the direct applicability of measurements for cement dust in radiative transfer calculation, the synthetic scattering matrix was computed and defined over the full scattering angle range from 0° to 180°. The scattering matrices for cement dust and typical natural mineral dusts were found to be similar in trends and angular behaviors. Angular distributions of all matrix elements were confined to rather limited domains. To promote the application of light scattering matrix in atmospheric observation and remote sensing, discrimination methods for various atmospheric particulates (cement dust, soot, smolder smoke, and water droplets) based on the angular distributions of their scattering matrix elements are discussed. The ratio -F 12 /F 11 proved to be the most effective discrimination method when a single matrix element is employed, aerosol identification can be achieved based on -F 12 /F 11 values at 90° and 160°. Meanwhile, the combinations of -F 12 /F 11 with F 22 /F 11 (or (F 11 -F 22 )/(F 11 +F 22 )) or -F 12 /F 11 with F 44 /F 11 at 160° can be used when multiple matrix elements at the same scattering angle are selected.

Description: We fabricated a series of stable Er-doped CaO-Al 2 O 3 (Ga 2 O 3 ) glasses by aerodynamic levitation (ADL) method. Using thermal analysis, we studied the influence of composition on the thermal stability of the glasses. The results unraveled the significance of composition on the stability of glasses. Magic angle spinning nuclear magnetic resonance (MAS-NMR) and Raman spectra were used to analyze the glass microstructure. The optical and spectroscopic properties were examined by UV-Vis absorption, steady-state fluorescence spectroscopy, transient state fluorescence spectroscopy, and luminescence quantum yield measurements. The results unraveled a clear concentration-dependent up-conversion and NIR emissions of Er 3+ , with obvious spectral broadening and redshift. The related mechanisms of decrease in fluorescent lifetime (from about 9 ms to 2 ms) and quantum yield (from about 75% to 5%) are discussed.