In this paper, the inhibitory effect of preinjected rejuvenation liquid on trees in cross-linked polyethylene (XLPE) cables was investigated. Experimental samples were prepared by inserting needles into XLPE samples, and many equally-spaced holes existed in the outer semiconductive layer. All cable samples were divided into two groups. One sample group was treated with rejuvenation liquid, while the other group was the control group. A tree accelerated aging system was used to obtain trees in the XLPE cable samples. During the aging experiment, an impulse voltage was applied to the samples repeatedly. The micromorphologies of the two groups were observed. Based on the micromorphologies, two parameters were determined: the initiation rate of electrical trees and the average length of trees. Furthermore, the electric field distribution was simulated to analyze the initiation of electrical trees. The results indicate that an electrical tree is much harder to initiate in the pretreated XLPE cables than in the untreated cables. This phenomenon is likely attributed to the dielectrophoretic forces in the pretreated cables. Moreover, rejuvenation liquid deposited in XLPE causes a substantial reduction in the Maxwell stress of molecular chains. Rejuvenation liquid inhibits electrical tree initiation and water tree growth to a great extent.

Abstract. In this paper, we demonstrate how probabilistic model checking can be applied to a study of dependability analysis for a Software-Defined Network with the PRISM tool for probabilistic model checking. Based on probabilistic model checking, the Software-Defined Network is modelled using large and complex Markov chains. In order to improve the reliability of the system, we propose a multi-controller architecture. The results of the designed system model are verified and visualized using PRISM.

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Soil acidification has occurred and accelerated in Jiaodong Peninsula, China, causing serious problems, such as manganese (Mn) toxicity and soil organic carbon (SOC) losses. However, the relationships between SOC and soil Mn are still unclear. This study aimed to explore the changes of Mn fractions and SOC under soaking conditions and the acidification‐induced positive coupled relationship between them. A sequential extraction for Mn species after acid soaking of a Cambisol was conducted, and the soil (pre‐ and post‐soaking) was characterised by X‐ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that acidification of a Cambisol (from pH 6.48 to pH 2.79) induced SOC losses (15.8% of initial SOC). Meanwhile, lower mobile or immobile Mn (especially oxide‐Mn) significantly decreased, accompanied by an increase in readily soluble Mn. It was further shown that the amount of decrease in free Mn reached 268.7 mg kg−1, accounting for 93.8% of the total loss of soil Mn, indicating that the reductive dissolution of amorphous Mn (III/IV) oxides is the dominant reaction in acidified Cambisols. This result was also supported by XRD and SEM. Correlation analysis showed that under soil acidification, the reductive dissolution of amorphous Mn (III/IV) oxides drove losses of both SOC and soil Mn. Therefore, a possible reaction mechanism was proposed: at neutral and alkaline pH, immobile complexes of Mn (III/IV) and particulate organic carbon (POC) formed; and, at acidic pH, readily mobile complexes of Mn (II) and dissolved organic carbon (DOC) formed. Our research suggested that Mn‐organic carbon complexes regulated the transport, transformation, and leaching of soil Mn and SOC, and future research should focus on the soil acidification‐driven Mn reduction‐carbon oxidation processes. Highlights Acidification accelerated soil organic carbon losses. Acidification induced reductive dissolution of amorphous Mn (III/IV) oxides. A positive couple relationship between SOC and soil Mn existed in acidified soils.

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