Study on Synthesis and Properties of Ba3Y4O9 Phosphors Doped with Up-Converted Rare Earth Ions (RE = Yb3+, Er3+)

Ba3Y(4−4x−4y)Er4xYb4yO9 precursor was synthesized by ammonium bicarbonate co-precipitation method, and its chemical formula is: (NH4)xBa3RE4(OH)y(CO3)z ·nH2O (RE3+ =Y3+, Er3+ and Yb3+). The target product was obtained by calcining at 1400 °C in muffle furnace after 5 h. By means of Thermogravimetric Analysis (TG), X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Fourier transform infrared (FT-IR), photoluminescence/photoluminescence excitation (PLE/PL), fluorescence attenuation and color coordinate, the composition, structural characteristics, particle morphology and fluorescence performance of the precursor and target product were studied. The particle size of the precursor was between 50 nm–100 nm, and the particle size of the calcined product was between 1 μm−2 μm. The absorption capacity of the fluorescent material to light is enhanced with the increase of doped ions. The optimal dosage of Yb3+/Er3+ co-doped Ba3Y(4−4x−4y)Er4xYb4yO9 was x = 0.05 and y = 0.20. The color coordinate of Ba3Y3Er0.2Yb0.8O9 phosphor is (0.73, 0.27) and the color temperature is 7383.6 K, showing excellent red light emission.

Deep machine learning of the spectral power distribution of the LED system with multiple degradation mechanisms

The performance and reliability of the light-emitting diode (LED) system significantly depend on the thermal–mechanical loading-enhanced multiple degradation mechanisms and their interactions. The complexity of the LED system restricts the theoretical understanding of the root causes of the luminous fluctuation or the establishment of the direct correlation between the thermal aging loading and the luminous outputs. This paper applies the deep machine learning techniques and develops a gated network with the two-step learning algorithm to build the empirical relationship between the design parameters and the thermal aging loading and the luminous output of LED products. The flexibility of the proposed method will be demonstrated by integrating it with different neural network architectures. The proposed gated network concept has been validated in both multiple LED chip packaging and LED luminaire under thermal aging loading. The validation of the luminous data of multiple LED chip packaging shows that the maximum differences of the correlated color temperature (CCT) and color coordinate are 2.6% and 1.0%, respectively. Moreover, the machine learning results of the LED luminaire exhibit that the differences of lumen depreciation, CCT and color coordinate are 1.6%, 1.9% and 1.1%, after 2160 h of thermal aging.

Anatomical and Image Analysis of Grain Coloration in Rye

In rye, there is a considerable variety of grain color which is determined by the diversity of compounds localized in different parts of the grain (caryopsis) - pericarp, testa, and aleurone. The localization of anthocyanins and proanthocyanidins was analyzed in 26 rye samples with identified anthocyanin genes, along with the analysis of CIE color coordinates. The Grain Scan program [1] was used to analyze images of individual grains. The localization of anthocyanins and proanthocyanidins was studied on longitudinal and cross sections of grains using light microscopy and MALDI-imaging. The violet-grained samples contain anthocyanins in the pericarp, and the green-grained samples contain anthocyanins in the aleurone layer. The green, violet and yellow-grained rye, with the exception of two anthocyaninless mutants vi3 and vi6, shows the presence of proanthocyanidins in the brown-colored testa. Four main color groups of the rye grains (yellow, green, brown, violet) could be differentiated using the color coordinate h° (hue angle). Interspecies and intraspecies variability for the localization of colored flavonoids in cereal grains is discussed.