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Objective: This study aimed to improve the application range and bioavailability of ursolic acid. Methods: The W/O/W pickering emulsion was prepared by a two-step process with ursolic acid as emulsifier and pectin as external aqueous phase. The preparation conditions of W/O emulsion were optimized by a single factor experiment, and the effects of pectin mass concentration on physicochemical properties, microstructure, rheological properties and long-term stability of W/O/W pickering emulsion were studied. Results: The optimal preparation technology of W/O emulsion was ursolic acid mass concentration of 4 g/100 mL, water-oil mass ratio of 2∶3, homogenization speed of 9 000 r/min, homogenization time of 5 min. The particle size of the double emulsion prepared with pectin as the external aqueous phase was between 30～40 μm. The absolute value of zeta potential, rheological property and storage stability of the emulsion at 4 ℃ were significantly improved with the increase of pectin mass concentration. Conclusion: The stable pickering double emulsion could be prepared when the mass concentration of pectin was 0.3, 0.4, 0.5 g/100 mL.

Objective: To screen lactic acid bacteria strains with strong ability to produce extracellular polysaccharide. Methods: Forty strains of lactic acid bacteria isolated and preserved in the laboratory were selected, and the commercial strain L. rhamnosus GG （LGG） was used as the positive control strain. The strains with high extracellular polysaccharide yield were screened by colony drawing method and phenol-sulfuric acid method, and their stress resistance, safety and antibiotic sensitivity were tested in vitro. The phenotypic characteristics and species identification of the finally obtained strains were analyzed. Results: After primary screening and secondary screening of 40 strains of lactic acid bacteria, 10 strains of lactic acid bacteria with high extracellular polysaccharide production were obtained. After comprehensive evaluation of polysaccharide production, stress resistance and preliminary safety of the 10 strains of lactic acid bacteria, 4 strains of lactic acid bacteria with high EPS production were finally isolated and identified, namely, 2 strains of lactobacillus paracasei （LZ9089, LZ9Y10）, 1 strains of Lactobacillus casei （LZ9183） and 1 strains of Lactobacillus brevis （LZ9285）. Conclusion: Four strains with high exopolysaccharide yield have good basic probiotic characteristics and have potential development and utilization value.

In this paper, the urban signal propagation characteristics based on the location of blind sources are investigated. To address the issue of blind electromagnetic radiation sources in complex urban environments, intelligent methods for propagation channel path classification, and model determination are brought forth based on field test data. The intelligent classification method distinguishes between the Line-of-Sight (LoS) path channel and a direct path, the LoS multipath channel with a direct path and other multiple paths, and the Non-Line-of-Sight (NLoS) multipath channel without a direct path from the source to the test point. The modeling aspect determines the model type to which the received signal belongs based on the statistical model derived from the tested data of a specific source. A validation measurement system was constructed for the FM broadcasting band, and validation campaigns were conducted in the city of Wuhan. The process and analysis of the data using this method demonstrate the accurate distinction of the different propagation path channels and models and involve the construction of a statistical model for the FM band in Wuhan's urban area. [ABSTRACT FROM AUTHOR]

Parabolic equations (PE) are commonly employed for calculating the spatial propagation loss of wireless signals. The initial field is a crucial factor. To investigate the impact of construction accuracy on the calculation of radio wave propagation loss, we selected the half-wave dipole antenna and its Gaussian approximation to examine the influence of wide-angle PE modeling. We analyzed the disparities between the actual antenna pattern and the Gaussian beam approximation, as well as the discrepancies in the corresponding initial field and the calculation of radio wave propagation loss in PE modeling. The simulation results indicate that the error of the Gaussian approximation increases as the angle of departure from the antenna main beam increases, with a relative error of approximately 30% in the initial field. A comparison between the experimental test of the broadcast signal and the simulation calculation reveals that the model based on the actual antenna aligns more closely with the measured value on a flat underlying surface. However, in mountainous areas with significant fluctuations, the simulation results are consistent with each other and higher than the measured value. The inversion results obtained through the particle swarm optimization algorithm demonstrate that the model based on the actual antenna exhibits superior inversion accuracy for the tropospheric atmospheric duct structure. [ABSTRACT FROM AUTHOR]