This work identifies the cyanobacterial and algal extracellular products (ECPs) and their derived byproducts during preozonation. Laboratory experiments were performed on two cyanobacterial species (Oscillatoria tenuisa and Microcystis aeruginosa) and one algal species (Chlorella sp.) dominating eutrophic reservoirs. Gas chromatography, coupled with high-resolution electron-impact mass spectrometry (GC/EI-MS), and high-performance anion-exchange chromatography (HPAEC) was adopted. Over 20 compounds were detected in the mass spectra analyses of the cyanobacterial and algal extracts (including cells and filtrates). The main identified ECPs were classified as monosaccharides, fatty acids, hydrocarbons, and aldehydes. Odor-causing substances were also present in the cyanobacteria, such as trans-1,10-dimethyl-trans-9-decalol (geosmin) and 2-methylisoborneol (2-MIB). The results from ozonated cyanobacteria and algae indicated that the dissolved organic carbon (DOC) content of culture suspensions increased during ozonation. Most of the additional DOC is produced by the increased liberation of ECPs to the bulk phase. Several byproducts were present in the ozonated cyanobacterial and algal cultures: a total of 22 different organic compounds were detected-mostly aldehydes and phthalates.
In this paper, we present a 4×4 MIMO-OFDM system for wideband video transmision. This video transmission system is modified from the DVB-T system by including the MIMO technique and a proposed LLR-based adaptive hierarchical modulation involving channel SNR and H.264/AVC packet priority. In the proposed system, Reed-Solomen encoder packet format, inner interleaver structure and pilot pattern are designed for the adaptive hierarchical modulation and the MIMO-OFDM transmission. The proposed system can transmit at least four H.264/AVC streams at the same time and possesses high noise tolerability. Finally, we also design and develope an FPGA plateform to emulate its feasibility and the hardware capability. The FPGA system runs at 48MHz and achieves 20Mbps∼40Mbps throughput in 2×2 MIMO-OFDM transmission scheme at 6MHz bandwidth.
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