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- 저자 : Jichang Guo (검색결과 2 건)
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Guo Zhen,Li Juan,Ge Lei,Yang Chenxi,Han Jichang 한국미생물학회 2020 The journal of microbiology Vol.58 No.9
The soil organic carbon (SOC) mineralization rate in sandy soil plays an important role in improving soil quality, and a research is needed to determine management practices that optimize the mineralization rate. When sandy soil is improved by adding soft rock, the specific promotion process of bacterium to SOC mineralization remain unclear. To investigate these mechanisms, we selected four treatments with soft rock to sand volume ratios of 0:1 (CK), 1:5 (C1), 1:2 (C2) and 1:1 (C3) to study. The mineralization rate of organic carbon was measured using the lye absorption method. Highthroughput sequencing and scanning electron microscopy were used to determine the bacterial community structure and soil microstructure, respectively. The results showed that the organic carbon content of the sandy soil increased significantly (182.22–276.43%) after using the soft rock treatments. The SOC mineralization rate could be divided into two stages: a rapid decline during days 1–8 and a slow decline during days 8–60. With increased incubation time, the intensity of the cumulative release of organic carbon gradually weakened. Compared with the CK treatment, the SOC mineralization accumulation (Ct) and the potential mineralizable organic carbon content (C0) in the C1, C2, and C3 treatments increased significantly, by 106.98–225.94% and 112.22– 254.08%, respectively. The cumulative mineralization rate (Cr) was 18.11% and 21.38% smaller with treatments C2 and C3, respectively. The SOC mineralization rate constant (k) decreased significantly after the addition of soft rock, while the half-turnover period (Th) changed inversely with k. Compared with the CK treatment, the number of gene copies of the soil bacteria increased by 15.38–272.53% after adding soft rock, with the most significant increase in treatment C3. The bacterial diversity index also increased significantly under treatment C3. The three dominant bacteria were Proteobacteria, Actinobacteria, and Chloroflexi. The correlation between Cr and one of the non-dominant bacteria, Firmicutes, was large, and the bacteria had a significant positive correlation with k. At the same time, the abundance of Firmicutes under treatments C2 and C3 was small. As the proportion of soft rock increased, the soil particles changed from point contact to surface contact, and the adhesion on the surface of the particles gradually increased. Results from this study show that the retention time of SOC can be increased and the carbon sequestration effect is better when the ratio of soft rock to sand is set to 1:2.
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Zhen Wang,Jichang Guo,Zhiqiong Chen,Zhiqiong Chen,Lisu Yu,Yuhao Wang,Hong Rao 한국통신학회 2022 Journal of communications and networks Vol.24 No.2
This paper considers a novel scenario, where a physicallayer security issue is studied in unmanned aerial vehicles(UAVs)-assisted cognitive relay system. A secondary unmannedaerial vehicle (SUAV) relay delivers information from multiplesecondary Internet of things (IoT) devices to a secondary user(SU) under the spectrum sharing with primary users (PUs). Inthe processing of the information transmission of the SUAV relay,a secondary eavesdropper (SE) wiretaps the information transmittedby the UAV relay with imperfect location information. Inorder to confuse the SE, a friendly SUAV jammer is employedto transmit jamming signals to the SE. To prevent the SEwiretapping information as much as possible, we aim to maximizeaverage worst-case secrecy rate of the secondary relay networkby jointly optimizing robust trajectories and power of the SUAVrelay and jammer under the power, trajectories, informationcausality and multiple interference temperature (IT) thresholdconstraints. Thus, we formulate the original problem whichis a challenging non-convex problem. We propose an effectivealgorithm to solve the original problem and attain locally optimalsolution based on the successive convex approximation (SCA)technology and the alternate optimization method. Simulationsare offered to demonstrate that our proposed resource allocationscheme can effectively improve the security performance ofthe SUAV relay network in comparison with other benchmarkschemes.
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