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Hongchao Guo,Tianqi Lei,Jinguang Yu,Defa Wang,Xiaolei Li 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.2
In order to study the mechanical property degradation rule of Q690 high-strength steel in the ocean wave splash area, the rusted specimen is obtained by indoor damp heat surrounding soaking environment corrosion test. The scanning electron microscopy, uniaxial tensile and cyclic loading tests of corroded steel are performed. This paper analyzes the steel from elastic modulus, yield strength, ductility and law of hysteresis degradation under diff erent corrosion cycles and establishes the constitutive model of HSS. The results show that the appearance of HSS is obviously aff ected by the corrosion cycle. With the increase of the corrosion cycle, reddish-brown fl aky corrosion products are formed on the surface of the steel and there are obvious corrosion pits. After 100 days of corrosion, the corrosion rate of steel reached 7.21%; the elastic modulus and yield strength under uniaxial tension load decreased by 10.2% and 4.9%. Under the eff ect of cyclic reciprocating load, the hysteretic energy is reduced by 15.3%; at the same time, the test curve is fi tted by the secondary plastic fl ow model and the Ramberg–Osgood model and it is found that the shape parameter S 1 and the cyclic strengthening coeffi cient K’ are reduced by 20.1% and 10.2%, While the shape parameter S 2 and the cycle strengthening index n’ have no obvious changes.
A transcription factor TaTCP20 regulates the expression of Ppd-D1b in common wheat
Wei Fan,Song Tianqi,Zhou Jianfei,Cheng Jie,Li Ruibo,Yu Ming,Zhang Yunrui,Yu-Yang Song,Zhang Bo,Zhang Xiaoke 한국식물생명공학회 2021 Plant biotechnology reports Vol.15 No.3
Photoperiod (Ppd) genes play an important role in the adaptation of wheat to the ecological environment. However, the transcriptional regulation mechanism of photoperiodic genes has remained elusive. This study isolated a full-length promoter of Ppd-D1b (2518 bp) from the common wheat genome. Several essential core cis-acting elements and numerous light-responsive cis-acting regulatory elements were identifed in Ppd-D1b promoter by the in-silico analysis. Ten 5’-deleted length fragments of the Ppd-D1b promoter fused with GUS were constructed and named D0 ~D9, then transferred them into Arabidopsis thaliana. GUS gene driven by full-length (D0) in transgenic Arabidopsis thaliana showed the same rhythm with Ppd-D1b in wheat under short-day conditions (SDs, 8-h light/16-h dark). The expression of GUS gene in D0 reached its peak at 3 h after dawn, then decreased to the lowest and remained stable. Analysis of the series of 5’-deleted fragments showed that at 3 h after dawn, GUS gene expression activity decreased signifcantly in D7a due to removal of CHEBS (CCA1 HIKING EXPEDITION binding site). Moreover, yeast one-hybrid (Y1H) and dual-luciferase (dual-LUC) assays revealed that TaTCP20 could bind to the Ppd-D1b promoter to increase its transcriptional activity. This study revealed a transcription factor, TaTCP20, which activated Ppd-D1b by binding to CHEBS, provided a foundation for the theoretical research on wheat’s photoperiodic response mechanism.
Virtual resistance with compensation link control strategy for traction network‑EMUs systems
Xuesong Zhou,Yifan Hu,Yu Tian,Tianqi Wang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.4
A coupled system composed of a traction network and electric multiple units (EMUs) may oscillate or be prone to instabilitydue to the influence of the large number of nonlinear power electronic devices introduced by the EMUs. To solve thisproblem, this paper proposes a virtual resistance with a compensation link control strategy for the four-quadrant convertersof EMUs. First, based on the actual background, input and output impedance models of the coupled system are established,including the output impedance model of the traction network and the input impedance model of the EMUs. Based on theabove models, the factors affecting the stability of the coupled system are analyzed by utilizing the impedance matching analysis method and the generalized Nyquist stability criterion (GNC). In the proposed control strategy, virtual resistance is used to adjust the loop gain and to increase system damping, which can improve the stability margin of the system. Virtual resistance can also increase the initial power equivalent to improve system stability. The introduction of the compensation link is to suppress the increasing tendency of the intermediate DC voltage steady-state error caused by the virtual resistance. The parameters of the virtual impedance and the compensation link are designed by forbidden region criterion to meet engineering requirements. With the proposed control strategy, the maximum EMU number to ensure system stability has been significantly increased. Finally, simulations and experiments verify the correctness of the analysis and the effectiveness of the proposed control strategy.
Longitudinal Dynamic End Effect of Single-Sided Linear Induction Motor for Medium–Low Speed Maglev
Wang Ying,Liu Xuelong,Lu Weiguo,Wen Tianqi,Yu Fan,Wu Qian 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4
The Short Primary Single-sided Linear Induction Motor (SLIM) applied in medium–low maglev vehicle has end eff ect that will cause a signifi cant reduction of train thrust. This paper analyzes the relationship between the Longitudinal Dynamic End Eff ect (LDEE) and the speed of SLIM. It is concluded that LDEE increases with the motor speed. The LDEE at motor’s exit area is called tailing eff ect. We take advantage of the tailing eff ect between adjacent SLIMs to make the air-gap magnetic fi eld of these motors continuous by adjusting their intervals and excitation phase diff erence. The several SLIM on the same side of the vehicle is equivalent to a “whole motor” with overall one entry area and one exit area. This method can reduce the resistance of the whole vehicle running at high speed, which can provide a new solution for the design of high-speed SLIM applied in Maglev
Yishuo Ding,Jiangui Li,Longyang Wang,Chen Wang,Guofu Zhu,Yuying Cheng,Tianqi Yu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.12
Dynamic wireless power transfer (DWPT) has received extensive attention due to its advantages of high security, high convenience, and high efficiency. To solve the problems of the mutual inductance and output power drop of DWPT systems for inspection robots, a new DWPT system with a trapezoidal-rectangular coupler has been proposed. First, the DWPT system topology and the switching strategy of the transmitting coil are introduced. Second, the real-time mutual inductances of the coupler in linear and curved motion are derived. Third, a new trapezoidal transmitting coil is presented. Finally, the performance of the DWPT system with the trapezoidal-rectangular coupler (TRC) is tested and compared to the DWPT system with the rectangular-rectangular coupler (RRC). Experimental results show that the minimum mutual inductance of the TRC is increased by 58.71%, and that the minimum output power is more than doubled in curved motion. Moreover, the mutual inductance drop rates of the TRC in linear and curved motion are reduced by 21.23% and 18.42%, respectively. The output power drop rates of the TRC-DWPT system are reduced by 18.99% and 16.12%, respectively. In addition, the Litz wire consumption is reduced by 8.28% in linear motion.