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In this paper, the ignition process of the plasma scalpel is characterized by means of numerical simulation, shadowgraphy, and voltage–current measurements. The ignition process involves two phases: the pre-breakdown phase and the breakdown phase. Our study shows that in the pre-breakdown phase, the vapor layer is first generated around the corners of the active electrode and then gradually extends to cover the entire active electrode. Once the active electrode is fully covered by the vapor layer, the electric field reaches a maximum of 7.3 × 106 V m−1, which can cause discharge in the vapor layer. At this moment, the thickness of the vapor layer is approximately 100 μm. In the breakdown phase, the maximum electron density reaches 1018–1019 m−3. The plasma dissipates about 60% of the total power which is up to 125 W, thus enabling efficient cutting. In addition, we simulate the discharge characteristics of cutting various biological tissues. The results show that under the same voltage level, the higher the conductivity of biological tissues, the greater the discharge current. The biological tissues act as ballast resistors in equivalent circuits. [ABSTRACT FROM AUTHOR]

The current cassava planting mainly rely on artificial planting with labor intensity. A small amount of cassava plantation for other fruit and vegetable transplanting converted, the model usually failed to achieve accurate sowing in the process of the operation, resulting in low qualification rate and high seed leakage rate, so the central composite test design theory was used to carry out the optimization test to analyze parameters, and the influence of operating parameters on the qualification rate and seed leakage rate. With the qualification rate and seed leakage rate as the test indexes, the forward speed, crank speed and machine height as the test factors, the three horizontal response surface tests were conducted through the response surface method, and the regression model of each factor, the qualification rate and seed leakage rate were established by Design Expert software to study the influence law of various factors and their interaction on the test index. The field test results showed that the combination of operation parameters was forward speed 0.89-0.94 mµs -1, crank speed 43 rµmin-1, and implement height 383 mm, the planting qualification rate was 95.47%, and the seed leakage rate was 2.05%. The relative error with the optimized value of the model was less than 5%, which indicated that the model was reliable. The research results had important guiding significance for improving cassava planting effect, and could also provide reference for the optimization of design and parameter optimization of cassava planting mechanism in the future. [ABSTRACT FROM AUTHOR]

Viruses, as the most abundant entities on earth, play an important role in shaping bacterial communities, mediating gene transfer between host cells, and promoting biogeochemical cycles. Yet, soil viruses remain understudied, as there is a lack of information about the mechanisms of community construction, interactions between viruses and host bacteria, and ecological functions. To expand our understanding of soil viruses, we investigated six viromes across three land use types in northeast and southwestern China, including agricultural and forest soils. We analyzed viral and bacterial community composition and explored their interactions. We utilized metagenomic sequencing technology and high-throughput 16S rRNA gene sequencing to study viral and bacterial communities. Twenty-four viral families were detected in six viromes including sixteen dsDNA virus families and eight ssDNA virus families. Viral and bacterial communities were significantly different between various land use types, with viruses having greater disparities. The composition of bacterial communities in soils across different land use types was inconsistent with their viral communities. We identified abundant auxiliary carbohydrate-active enzyme genes from viromes. The results revealed that soil viral communities differ by land use type and that viruses could regulate bacterial carbon cycling processes by encoding auxiliary metabolic genes. [ABSTRACT FROM AUTHOR]