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1,375 results on '"Zhang, Wenqian"'

53. Insulation condition evaluation of oil-immersed transformer based on entropy weight hierarchy method

Author

LI Bo, ZHANG Wenqian, LIU Wei, CUI Dezhi, JIANG Jun, and ZHANG Chaohai

Subjects
insulation condition, analytic hierarchy process, entropy weight method, weight combination, differentiation evaluation, oil-immersed transformer, Applications of electric power, TK4001-4102
Abstract

In order to evaluate the insulation condition of oil-immersed transformers effectively, a weight allocation method considering expert experience and degradation state is proposed in this paper. Firstly, a hierarchical structure for insulation condition evaluation is built based on dissolved gas in oil, ambient temperature and defect information, and subjective weights is assigned to each index based on expert experience. Then, the method of combined weight is adopted to introduce entropy weight into the weight allocation of index layer, thus weights of the index layer are dynamically adjusted to reflect the differences in the individual operation process while retaining expert experience for the criterion layer. Furthermore, the transformer insulation state is subdivided into five states from common four to realize more accurate perception of insulation state. Finally, case study of four 500 kV transformers shows that the method proposed can effectively identify normal transformers and discriminate abnormal transformers compared with the method based only on objective or subjective weight, which verifies the rationality of the method.

Published
2023
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55. A best bound for $\lambda_2(G)$ to guarantee $\kappa(G) \geq 2$

Author

Zhang, Wenqian and Wang, Jianfeng

Subjects
Mathematics - Combinatorics, 05C50
Abstract

Let $G$ be a connected $d$-regular graph with a given order and the second largest eigenvalue $\lambda_2(G)$. Mohar and O (private communication) asked a challenging problem: what is the best upper bound for $\lambda_2(G)$ which guarantees that $\kappa(G) \geq t+1$, where $1 \leq t \leq d-1$ and $\kappa(G)$ is the vertex-connectivity of $G$, which was also mentioned by Cioab\u{a}. As a starting point, we solve this problem in the case $t =1$, and characterize all families of extremal graphs., Comment: 10 pages

Published
2021

77. Harmonic current variation characteristics of shunt capacitors based on full-phase FFT algorithm

Author

Liu Ke, Song Rui, Liu Yutong, Han Jun, and Zhang Wenqian

Subjects
full phase, fast fourier transform algorithm, shunt capacitor, harmonic current variation, phase difference algorithm, 42a38, Mathematics, QA1-939
Abstract

Shunt capacitors can effectively improve the system voltage level and increase the economy of grid operation. However, under the effect of harmonics, the capacitor bank is prone to harmonic resonance, which causes overcurrent and overvoltage and threatens the safe operation of the capacitor itself and the system. To avoid damage to capacitors due to harmonics, the harmonic current variation characteristics of shunt capacitors are investigated. Based on the established mathematical model of shunt capacitors, the characteristics of harmonic current amplification under different harmonic states are analyzed. Based on the amplification characteristics and sampling law, the harmonic current signal is acquired using the full-phase fast Fourier transform algorithm. The full-phase fast Fourier transform algorithm is improved by the phase difference algorithm to complete harmonic current detection. The experiments show that the dynamic response time is 1.6 cycles with minimum steady-state error before and after the load current jump. When the capacitor changes from unit power factor to 0.89 inductance, the harmonic current at point A changes from 17.59A to 21.34A and 11.65 to 22.38A, respectively. The deviation values are 3.75A and 10.73A, respectively. It shows that the algorithm has good tracking ability for load currents and can effectively detect the harmonic currents of shunt capacitors and obtain accurate variation characteristics. It can ensure that the harmonic content of the shunt capacitor in the distribution system is relatively reasonable, and realize the safe, stable and economic operation of the equipment.

Published
2023
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83. Towards a sociological construction of the translator's brand : the case of Howard Goldblatt

Author

Zhang, Wenqian and Weightman, Frances

Subjects
418
Abstract

The present study aims to construct the concept of ‘the translator’s brand’ based on a case study of the American literary translator Howard Goldblatt. As a dynamic, accumulative and diachronic construction, the translator’s brand is different from existing notions in the scholarship of translation studies that are adopted to approach the translator’s presence, such as visibility, symbolic capital, translator-function and celebrity translators. The concept of ‘brand’ was originally examined from a marketing perspective to see how companies or products were able to stand out from their competitors. Later, it has been applied to people and places. However, as a human agent, the translator’s brand-building is not as strictly planned a process as that of the product, and cannot be approached from a marketing perspective alone. By combining the transferrable points from the ‘brand’ scholarship with the Bourdieusian sociology of cultural production and exchange, I argue that Goldblatt’s brand-building can be traced from three levels: intra-field (brand input), inter-field (brand investment) and inter-cultural (brand reception) levels. Based on a socio-archival investigation of materials mainly collected from the Chinese Literature Translation Archive, this thesis shows that at the intra-field level, the translator attained various forms of capital from his multiple identities and translation-related activities as brand input. This input was invested in the inter-field circuit and the translator got benefit from participation. At the inter-cultural level, Goldblatt’s brand has been differently received in the source and target cultures. What the ‘brand’ status means to Goldblatt is not immediate success or short-term profit in market logic, but rather a positive, distinctive and trustworthy image that has been perceived by other agents. This kind of brand image grants him a powerful status in the translation and publishing processes, which forms a stark contrast to the translator’s traditional invisible and inferior presence.

Published
2020

93. Spatial and Temporal Distribution of Arsenic Concentration in Rural Drinking Water and Health Risk Assessment in Northern China over the past 10 years: A Case Study of Inner Mongolia Autonomous Region

Author

Zhang, Wenyu, primary, Zhang, Xiangnan, additional, Zhang, Chenguang, additional, Jia, Xinrui, additional, Li, Huan, additional, Yue, Xuanzhi, additional, Wu, Duoduo, additional, Zhu, Jiake, additional, Zhang, Wenqian, additional, Qin, Yuhan, additional, and Fan, Yaochun, additional

Published
2024
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