Numeral analysis model for shielding failure of transmission line under lightning stroke

He, Jinliang,Tu, Youping,Zeng, Rong,Lee, J.B.,Chang, S.H.,Guan, Zhicheng IEEE 2005 IEEE transactions on power delivery Vol.20 No.2

The shielding failure is the occurrence of a lightning stroke that bypasses the overhead ground wires and terminates on the phase conductors. The correct design to improve the shielding effect of transmission line to lightning is one of the key problems of transmission line design. A numerical analysis model for shielding failure of transmission line based on electromagnetic field theory is proposed in this paper. The electrical field of the system including lightning leader, transmission line and ground is solved, the range of lightning current striking the phase conductor is obtained, and the shielding failure probability of transmission line is calculated. The lightning leader model and the critical breakdown electrical field intensity of long gap are discussed. The analyzed results by numerical analysis model are compared with those by the electrogeometric model.

Efficiency of gerAa, tupA and ca transformation in Bacillus subtilis for self-healing of concrete cracks

Hanxing He,Gefei Li,Jiantao Zhang,Jinlong Zhang,Mingyue Luo,Wenkai Hu,Yamin Lin,Ziyu Deng,Zhicheng Liu,Weizhao Chen,Xu Deng 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.5

A genetic approach was proposed to modify the characteristics of Bacillus subtilis strain WB800 (B. subtilis WB800) for selfhealing of concrete cracks. Three genes, namely gerAa which encodes germination receptors activated by L-alanine, tupA which is responsible for the synthesis of teichuronopeptide, and ca which encodes carbonic anhydrase (CA) catalyzing the synthesis of carbonate ion, were separately transformed into WB800. To protect bacterial cells from being squeezed, microspheres were produced with microcrystal cellulose (MCC) before the introduction of bacteria into the specimens. The results showed that the modified B. subtilis expressing GerA achieved 39.9% of germination ratio compared to 17% by the original host cells. With the transformation of tupA, the modified strain demonstrated higher resistance to alkaline environments, tolerating pH as high as 11, while the original strain only tolerated pH 9. The modified strain expressing CA induced more calcium carbonate than the original cells. Energy dispersive spectroscopy (EDS) identified the produced precipitate to be calcite (CaCO3). Moreover, a mathematical model was developed to optimize the influential factors of calcium precipitation process. Finally, based on the above results, an effective self-healing of concrete crack was achieved. This study may provide a promising strategy to improve the efficiency of bacterial self-healing of concrete cracks.

Influence of overhead transmission line on grounding impedance measurement of substation

Zeng, Rong,He, Jinliang,Lee, Jaebok,Chang, S.,Tu, Youping,Gao, Yanqing,Zou, Jun,Guan, Zhicheng IEEE 2005 IEEE transactions on power delivery Vol.20 No.2

How to precisely measure the grounding impedance of large-scale substations is a fundamental guarantee for the safe operation of power systems. If the ground wires were connected to the grounding grid, these ground wires would shunt a part of the injected measuring current and allow the measured grounding impedance to be smaller than the actual impedance of the grounding system. Based on an actual 500-kV grounding system, this paper discusses how to analyze the influence of the overhead ground wire on the measured grounding impedance and how to obtain the real grounding impedance of the grounding system. A numerical analysis model considering the grounding system, the transmission lines, towers, and their grounding devices, based on the multilayer soil model analyzed from field test data of apparent soil resistivity, was constructed to analyze the influence of ground wires and tower grounding resistances on grounding impedance, and the general effects of different parameters, such as tower impedance, grounding impedance, and circuits of transmission lines, were analyzed. The real grounding impedance of the substation with connected overhead ground wires was validated, and some useful results have been obtained, based on the field-measured values and numerical analysis.

Lightweight high-precision pedestrian tracking algorithm in complex occlusion scenarios

Qiang Gao,Zhicheng He,Xu Jia,Yinghong Xie,Xiaowei Han 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.3

Aiming at the serious occlusion and slow tracking speed in pedestrian target tracking and recognition in complex scenes, a target tracking method based on improved YOLO v5 combined with Deep SORT is proposed. By merging the attention mechanism ECA-Net with the Neck part of the YOLO v5 network, using the CIoU loss function and the method of CIoU non-maximum value suppression, connecting the Deep SORT model using Shuffle Net V2 as the appearance feature extraction network to achieve lightweight and fast speed tracking and the purpose of improving tracking under occlusion. A large number of experiments show that the improved YOLO v5 increases the average precision by 1.3% compared with other algorithms. The improved tracking model, MOTA reaches 54.3% on the MOT17 pedestrian tracking data, and the tracking accuracy is 3.7% higher than the related algorithms and The model presented in this paper improves the FPS by nearly 5 on the fps indicator.

An adaptive marine predator algorithm based optimization method for hood lightweight design

Zhang Chenglin,He Zhicheng,Li Qiqi,Chen Yong,Chen Shaowei,NIE XINYU 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.3

The lightweight design of the hood is crucial for the structural optimization of an entire vehicle. However, traditional high-fidelity-based lightweight methods are time-consuming due to the complex structures of the hood, and the lightweight results heavily rely on engineering experiences. To this end, an improved adaptive marine predator algorithm (AMPA) is proposed to solve this problem. Compared to the original marine predator algorithm (MPA), the proposed AMPA adapts to optimization problems through three enhancements, including chaotic theory-based initialization, a mixed search strategy, and dynamic partitioning of iteration phases. Experimental comparisons of AMPA, MPA, and eight state-of-the-art algorithms are conducted on IEEE CEC2017 benchmark functions. AMPA outperforms the others in both 30- and 50-dimensional experiments. Friedman and Wilcoxon’s sign-rank tests further confirm AMPA’s superiority and statistical significance. An implicit parametric model of the hood is generated, and the critical design variables are determined through global sensitivity analysis to realize hood lightweight. The stacking method is employed to construct a surrogate meta-model of the hood to accelerate the optimization efficiency of the vehicle hood. Utilizing the meta-model and the proposed AMPA, the hood mass is reduced by 7.43% while all six static and dynamic stiffness metrics are enhanced. The effectiveness of the proposed optimization method is validated through finite element analysis.

Geological characteristics and main controlling factors of Permian lacustrine tight oil in the eastern part of the Junggar Basin

Junwei Zhao,Huaimin Xu,Cui He,Lin Li,Zhen Yi,Huijing Fang,Zhicheng Lei 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.2

The Junggar basin is rich in oil and gas resources, and recently, unconventional oil and gas reservoirs have become important targets. Significant amounts of oil and gas are located in Permian formations in the Shazhang–Dajing area, however, fewer studies have focused on unconventional oil and gas reservoirs, particularly on the factors controlling the distribution of unconventional reservoirs. In this study, a sequence stratigraphic framework of the study area was developed based on cores, well logs and seismic data. Source rock samples were analyzed, including tests of kerogen, vitrinite reflectance, chloroform bitumen, organic carbon and group composition. The physical properties and pore characteristics of reservoir samples were also analyzed using scanning electron microscope and high resolution electron microscope. The Permian Pingdiquan Formation comprises three thirdorder sequences in which individual sequence can be divided into a low-stand system tract (LST), a transgression system tract (TST), an early high-stand system tract (E-HST), and a late high-stand system tract (L-HST). Several source rock lithologies have high total organic carbon (TOC), and are matured, having excellent hydrocarbon generation potential. Clastic and dolomitic rocks are the main reservoirs, and nanometer-scale pores are the main reservoir space in the tight reservoirs. The distribution of tight oil is controlled by the sequence stratigraphy, palaeogeomorphic units, and sedimentary facies. The fine sediments, which were generally deposited near the initial flooding surface (FFS) and the maximum flooding surface (MFS), are favorable zones for tight oil. The distributions of the hydrocarbon source rocks are controlled by the depositional environment, depending on the palaeogeomorphic units; the deep depression in the Huoshaoshan area and the moderately-deep depression in the Shishugou area are two distinct hydrocarbon generating centers. The distribution of tight oil is clearly controlled by the sedimentary facies; the tight oil is mainly located in the fan delta front and lacustrine depositional environments. The distribution of tight oil in this area is summarized, and favorable areas of tight oil are proposed.

Local Joule heating targets catalyst surface for hydrocarbon combustion

Qian Xiong,Xingbao Zhu,Ri He,Xueyi Mei,Yexin Zhang,Zhicheng Zhong,Wei Zhao,Weiming Nie,Jian Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

Most industrial catalytic reactions are achieved by external heating and catalysts are entirely heated tooffer enough thermal energy to surface active sites. However, there is an inherent drawback that mostinput energy is dissipated into the bulk while minor is donated to the surface, leading to high energywaste. Here, we proposed a so-called local Joule heating method via passing an electric current throughpacked catalyst nanoparticles with a large contact resistance, which can generate sufficient heat to targetat the surface region. We selected hydrocarbon combustion, a common way to eliminate unburned pollutants,as a probe reaction and used the conductive antimony-doped tin oxide (ATO) as a model catalyst. Compared with traditional external heating, this method consumed one order lower energy input,reduced the macroscopically average temperature for same conversion by 100 C, improved the durabilitywith smaller activity loss within 100 h operation, and suppressed water poisoning effect by 60 %. Also, the combustion was sparked in seconds by pulsing electric current into the catalyst bed, allowing anapplication in prompt treatment of leaked hydrocarbons. The local Joule heating between contactednanoparticles, which could focus thermal energy on catalyst surface, is prospective to improve catalysisefficiency.