RESUMEN
In this paper, we fabricated a 3×3 violet series-biased micro-LED array with high-output optical power and applied it in high-speed and long-distance visible light communication. By employing the orthogonal frequency division multiplexing modulation scheme, distance adaptive pre-equalization, and a bit-loading algorithm, record data rates of 10.23 Gbps, 10.10 Gbps, and 9.51 Gbps were achieved at 0.2 m, 1 m, and 10 m, respectively, below the forward error correction limit of 3.8×10-3. To the best of our knowledge, these are the highest data rates achieved by violet micro-LEDs in free space and the first communication demonstration beyond 9.5 Gbps at 10 m using micro-LEDs.
RESUMEN
InGaN-based micro-LEDs can detect and emit optical signals simultaneously, owing to their overlapping emission and absorption spectra, enabling color detection. In this paper, we fabricated a green InGaN-based micro-LED array with integrated emission and detection functions. On the back side of the integrated device, when the 80 µm micro-LED emitted light, the 200 µm LED could receive reflected light to accomplish color detection. The spacing between the 80 µm and the 200 µm micro-LEDs was optimized to be 1 mm to reduce the effect of the direct light transmitted through the n-GaN layer without reflection. The integrated device shows good detection performance for different colors and skin colors, even in a dark environment. In addition, light can be emitted from the top side of the device. Utilization of light from both sides of the integrated device provides the possibility of its application in display, communication, and detection on the different sides.
RESUMEN
The anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor (AnMBR) was investigated at two different operational modes, including no sludge discharge and daily sludge discharge of 20 L. The AnMBR provided excellent and reliable permeate quality with high COD removal efficiencies over 99%. The obvious accumulations of long chain fatty acids (LCFAs) and Ca(2+) were found in the anaerobic digester by precipitation and agglomeration. Though the physicochemical process contributed to attenuating the free LCFAs toxicity on anaerobic digestion, the digestion efficiency was partly influenced for the low bioavailability of those precipitates. Moreover, higher organic loading rate (OLR) of 5.8 kg COD/(m(3) d) and digestion efficiency of 78% were achieved as the AnMBR was stably operated with sludge discharge, where the membrane fouling propensity was also alleviated, indicating the crucial significance of SRT control on the treatment of high-strength kitchen waste slurry via AnMBRs.