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The interaction between invasive plants and soil microbial communities is critical for plant establishment. However, little is known about the assembly and co-occurrence patterns of fungal communities in the rhizosphere soil of Amaranthus palmeri. The soil fungal communities and co-occurrence networks were investigated in 22 invaded patches and 22 native patches using high-throughput Illumina sequencing. Despite having little effect on alpha diversity, plant invasion significantly altered the composition of the soil fungal community (ANOSIM, p < 0.05). Fungal taxa associated with plant invasion were identified using linear discriminant analysis effect size (LEfSe). In the rhizosphere soil of A. palmeri, Basidiomycota was significantly enriched, while Ascomycota and Glomeromycota were significantly reduced when compared to native plants. At the genus level, the invasion of A. palmeri dramatically increased the abundance of beneficial fungi and potential antagonists such as Dioszegia, Tilletiopsis, Colacogloea, and Chaetomium, while it significantly decreased the abundance of pathogenic fungi such as Alternaria and Phaeosphaeria. Plant invasion reduced the average degree and average path length, and increased the modularity value, resulting in a less complex but more effective and stable network. Our findings improved the knowledge of the soil fungal communities, network co-occurrence patterns, and keystone taxa in A. palmeri-invaded ecosystems.

In the present study, vacuum evaporation method is used to deposit Bi2Se3 film onto Si nanowires (NWs) to form bulk heterojunction for the first time. Its photodetector is self-powered, its detection wavelength ranges from 390 nm to 1700 nm and its responsivity reaches its highest value of 84.3 mA/W at 390 nm. In comparison to other Bi2Se3/Si photodetectors previously reported, its infrared detection length is the second longest and its response speed is the third fastest. Before the fabrication of the photodetector, we optimized the growth parameter of the Bi2Se3 film and the best Bi2Se3 film with atomic steps could finally be achieved. The electrical property measurement conducted by the physical property measurement system (PPMS) showed that the grown Bi2Se3 film was n-type conductive and had unique topological insulator properties, such as a metallic state, weak anti-localization (WAL) and linear magnetic resistance (LMR). Subsequently, we fabricated Si NWs by the metal-assisted chemical etching (MACE) method. The interspace between Si NWs and the height of Si NWs could be tuned by Ag deposition and chemical etching times, respectively. Finally, Si NWs fabricated with the Ag deposition time of 60 s and the etching time of 10 min was covered by the best Bi2Se3 film to be processed for the photodetector. The primary n-Bi2Se3/p-Si NWs photodetector that we fabricated can work in a self-powered mode and it has a broadband detection range and fast response speed, which indicates that it can serve as a promising silicon-based near- and mid-infrared photodetector.

Urban air pollution has received increasing attention in recent years. To investigate the interaction between several heavy metal elements and the degree of atmospheric pollution, the leaves of three evergreen tree species—Chinese juniper (Juniperus chinensis L.), dragon juniper (Juniperus chinensis L. ‘Kaizuca’), and cedar (Cedrus deodara (Roxb. ex D.Don) G.Don)—were collected from main road intersections in the urban area of Tianjin, China. Two different treatments—water washing (WW) and ethanol washing (EW)—were used, and the contents of Cu, Mn, Cd, and Zn were measured in both washed and unwashed (UW) leaves. It was found that the heavy metal contents within Chinese juniper and dragon juniper were ranked as Mn > Zn > Cu > Cd, and the metal accumulation index (MAI) value was higher for dragon juniper. For the three plants, water washed off 5.36% to 58.58% of the total heavy metals in the needles, while ethanol washed off 16.08% to 71.60% of the total. Both washes were more effective for Cu, Zn, and Cd, and especially for the element Cd. Ethanol could clean off 38.64% to 71.60% of the total Cd from the leaves. Ethanol had a better elution effect compared to water, and the trend of the Cd content in the leaves of the three plants showed a change after the use of different washing methods, which suggests that the water washing may have masked the real difference.

As a novel non-destructive testing technique, capacitive imaging (CI) has been used to detect defects within the insulation layer and metal surface of an insulated metallic structure, that is, pipe or vessel. Due to the non-linearity of the probing field, the defects at different depths in the insulation layer are difficult to compare accurately using the conventional CI sensor with a single pair of electrodes. In addition, the conventional CI sensor cannot provide adequate information to discriminate the defects in the insulation layer and metal surface. In order to solve the above-mentioned problems, the multi-electrode sensor is introduced. The multi-electrode sensor uses multiple quasi-static fringing electric fields generated by an array of coplanar electrodes to obtain extra information about the defects in the specimen. In this work, the feasibility of multiple quasi-static electric fields detecting the defects was demonstrated and the Measurement Sensitivity Distributions (MSDs) of the multi-electrode sensor detecting the defects were acquired using the FEM models. The simulation and experimental results show that the Dynamic Change Rates (DCRs) of the measured values obtained at the center of the defects in the insulator layer and metal surface present different variation patterns, which can be used to discriminate these two different kinds of defects. The reasons for the different variation patterns of DCRs were explained by the changing trends of MSDs with increased electrode separation. In addition, it was demonstrated that the different depths of the defects in the insulator layer can be compared accurately by comprehensive analysis of the detection results from all the electrode pairs.