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365 results on '"Feng, Zihao"'

1. Microscopic characteristics of SF6 partial discharge induced by a floating linear metal particle

Author

Feng, Zihao, Jiang, Yuanyuan, Zhang, Liyang, Liu, Zhigang, Wang, Kai, Wang, Xinxin, Zou, Xiaobing, Luo, Haiyun, and Fu, Yangyang

Subjects
Physics - Plasma Physics, Physics - Applied Physics
Abstract

Direct current (DC) gas insulated transmission lines (GILs) have been widely used in power transmission, but might be threatened by partial discharge due to the presence of floating impurities (e.g., dust and metal particles) inside the sealed chamber. In this letter, by using a 2D fluid model we characterize the microscopic properties of the partial discharge induced by a floating linear metal particle in SF6 (both the discharge propagation and interaction between space charge and metal particle) under negative high voltage direct current (HVDC) conditions. Due to the strong electronegativity of SF6, the spatiotemporal distributions of the charged species (electrons, positive and negative ions), space charge, and reduced electric field are rather different from those in air. Notably, a negative ion region is observed around the top tip of the metal particle, and it plays an important role in the generation and propagation of primary and secondary streamers in SF6, which may lead to severe motion characteristics of the particle and aliasing of partial discharge signals. Additionally, we analyze the charging process and electric force reversal phenomenon, which may provide a more precise understanding of the underlying mechanisms of the firefly motion previously reported for DC GILs.

Published
2024

7. Structural damage characteristics and mechanism of granite residual soil

Author

Lu Yiwei, Shi Yujie, Chen Bin, Feng Zihao, and Hu Jieming

Subjects
granite residual soil, structural, microstructure, shear strength, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Deep and thick weathered granite crusts widely distributed in Xiangdong area, Hunan Province, due to their special structure, often induce geological disasters such as landslides under the conditions of excavation or atmospheric precipitation. In this article, using the direct shear test, X-ray diffraction test and scanning electron microscope test, the mechanical properties and the response mechanism of the microstructure of the granite residual soil in eastern Hunan area under different states were studied, and the structural damage mechanism of the granite residual soil was analysed. Based on the comprehensive structural potential, the theory characterizes its structure. The results show that the granite residual soil is mainly composed of minerals such as quartz, mica, kaolinite and feldspar, and it also contains a small amount of chlorite and calcite. The damage is mainly reflected in the attenuation of cohesion, while the change of the internal friction angle is small. The microscopic manifestation is the failure of the bridging structure between the aggregates, and the inter-granular pores are interconnected. The difference and shear strength response reflect the susceptibility to disturbance of granite residual soil and reflect that the structural strength has been damaged under the disturbance of human factors.

Published
2024
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