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We studied microbial communities in two paddy soils, which did not receive nitrogen fertilization and were distinguished by the soil properties. The two microbial communities differed in the relative abundance of gram-negative bacteria and total microbial biomass. Variability in microbial communities between the two fields was related to the levels of phosphorus and soil moisture. Redundancy analysis for individual soils showed that the bacterial community dynamics in the high-yield soil were significantly correlated with total carbon, moisture, available potassium, and pH, and those in the low-yield cores were shaped by pH, and nitrogen factors. Biolog Eco-plate data showed a more active microbial community in the high yield soil. The variations of enzymatic activities in the two soils were significantly explained by total nitrogen, total potassium, and moisture. The enzymatic variability in the low-yield soil was significantly explained by potassium, available nitrogen, pH, and total carbon, and that in the high-yield soil was partially explained by potassium and moisture. We found the relative abundances of Gram-negative bacteria and Actinomycetes partially explained the spatial and temporal variations of soil enzymatic activities, respectively. The high-yield soil microbes are probably more active to modulate soil fertility for rice production.

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A novel three-dimensional graphene-like networks material (3D-GLN) exhibiting the hierarchical porous structure was fabricated with a large-scale preparation method by employing an ion exchange resin as a carbon precursor. 3D-GLN was first studied as the effective microwave absorbing material. As indicated from the results of the electromagnetic parameter tests, and the minimum reflection loss (RL) of the 3D-GLN reached −34.75 dB at the frequency of 11.7 GHz. To enhance the absorption performance of the nonmagnetic 3D-GLN, the magnetic Fe3O4 nanoparticles were loaded on the surface of the 3D-GLN by using the hydrothermal method to develop the 3D-GLN/Fe3O4 hybrid. The hybrid exhibited the prominent absorbing properties. Under the matching thickness of 3.0 mm, the minimum RL value of hybrid reached −46.8 dB at 11.8 GHz. In addition, under the thickness range of 2.0–5.5 mm, the effective absorption bandwidth (RL < 10 dB) was 13.0 GHz, which covered part of the C-band and the entire X-band, as well as the entire Ku-band. The significant microwave absorption could be attributed to the special 3D network structure exhibited by the hybrid and the synergistic effect exerted by the graphene and the Fe3O4 nanoparticles. As revealed from the results, the 3D-GLN/Fe3O4 hybrid could be a novel microwave absorber with promising applications.

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As one of the most commonly used solvents, ethanol exhibits weak fluorescence when excited by ultraviolet (UV) light. Until now, the fluorescence of ethanol-doped nanoparticles has not been studied. In this paper, eleven different concentrations of SiO2 nanoparticles (diameter 100 nm) were doped in ethanol, and corresponding colloids were formed. The excitation and emission spectra of the colloids were measured. The experimental results indicated that the SiO2 nanoparticles obviously enhanced the fluorescence of ethanol. Under excitation at 306 nm, the enhancement effect is the best when the concentration of SiO2 nanoparticles is 4.452 x 10(12) ml(-1), and the enhancement factor is nearly 50 times at the peak position of 360 nm. At the excitation wavelength of 360 nm, the enhancement effect is the best when the concentration of SiO2 nanoparticles is 1.113 x 10(13) ml(-1), and the enhancement factor is nearly 40 times at the peak position of 397 nm. The result of this article will reduce the test limit of ethanol by two magnitudes.