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Your search keyword '"Zhu, Chengqian"' showing total 10 results
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10 results on '"Zhu, Chengqian"'

8. Rail potential control with train diagram optimization in multitrain DC traction power system

Author

Zhu, Chengqian, Du, Guifu, Ding, Yawen, Huang, Weiguo, Wang, Jun, Fan, Mingdi, and Zhu, Zhongkui

Abstract

ABSTRACTCurrently, abnormally elevated rail potential exists in the DC traction power system, which greatly threatens the safe operation of the line. In order to realize the reflux safety, timetable optimization of multitrain based on improved Seeker Optimization Algorithm (SOA) is proposed to suppress the rail potential of the system. Firstly, the simulation model of the system is built and the calculation process of rail potential is proposed. Secondly, an optimization model based on maximum rail potential is formulated, where the dwell time is the decision variable and is adjusted to change the regenerative power distribution of the system. Finally, the improved SOA is used to handle the optimization model. Compared with the maximum rail potential before optimization, the simulation results demonstrate that the maximum rail potential is reduced by 55.5% with the proposed method, which greatly improves the reflux safety of the multi-train subway system.

Published
2022
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10. Vector promoters used in Klebsiella pneumoniae.

Author

Jiang, Xiao, Zhu, Chengqian, Lin, Jie, Li, Jingkang, Fu, Shuilin, and Gong, Heng

Subjects
*KLEBSIELLA pneumoniae, *METABOLIC regulation, *ESCHERICHIA coli, *GENE expression, *GLYCERIN
Abstract

Much effort has been devoted to the metabolic engineering of Klebsiella pneumoniae; however, our knowledge of the actual expression level of promoters used in K. pneumoniae is limited. In this study, the expression levels of three promoters were compared systematically by using the lacZ reporter gene with different carbon sources in K. pneumoniae. The results showed that, although promoters P T5 and P tac designed for Escherichia coli were functional, P T5 appeared more efficient and the induction/repression ratio of P tac was decreased extremely in K. pneumoniae. The basal level of P tac for lacZ expression reached 396.5 U/mg, which was 9.5-fold higher compared with P T5 in LB medium, indicating P tac can be used as an efficient 'constitutive' promoter as well as an efficient induced promoter in K. pneumoniae. In different carbon sources medium, a newly constructed endogenous constitutive P bud proved to be a stable and weak promoter. On the basis of our data, a set of P bud and P tac promoters could meet the broad range (about 1,000 orders of magnitude) of gene expression needed for engineered K. pneumoniae in glycerol-based medium. [ABSTRACT FROM AUTHOR]

Published
2016
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