Study on Enhancing Lightning Protection Scheme of Catenary in Subway Viaduct Section

Rui-Fang Li,Kui Chen,Li-Sheng Chen,Xiao-Bin Cao,Guang-Ning Wu,Xue-Qin Zhang 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

Viaduct increases the height of subway catenary, namely magnifies lightning attraction scope that lead to higher possibility of suffering lightning stroke. Therefore, it is necessary to analyze performance of lightning striking to catenary of subway in viaduct section and propose an improving lightning protection scheme. In this paper, using ATP-EMTP simulation software to establish an associated model to evaluate lightning withstand level of catenary with existing lightning protection schemes including arrester and grounding point, an improving lightning protection scheme is proposed — every pillar ground earth and arresters are installed with some installing spacing between 200m to 400m based on lightning damage degree and reliability requirements — according to analyzing results: while lightning withstand level is lowest for lightning striking to the neutral pillar, lightning withstand level is greatest for lightning striking to the both-ends pillar that arrester and grounding point are both installed; grounding point could obviously improve lightning withstand level for lightning striking to ground wire while arrester could obviously improve the lightning withstand level for lightning striking to catenary; every pillar ground earth could enhance the lowest lightning withstanding level up to 2.5 times than of that pillar ground earth across every 200m.

Practical coherency model suitable for near- and far-field earthquakes based on the effect of source-to-site distance on spatial variations in ground motions

Rui-fang Yu,Abduwahit Abduwaris,Yan-Xiang Yu 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.73 No.6

In this study, the spatial variation mechanisms of large far-field earthquakes at engineering scales are first investigated with data from the 2008 Ms 8.0 Wenchuan earthquake. And a novel ‘coherency cut-off frequency’ is proposed to distinguish the spatial variations in ground motions in the low-frequency and high-frequency ranges. Then, a practical piecewise coherency model is developed to estimate and characterize the spatial variation in earthquake ground motions, including the effects of source-to-site distances, site conditions and neighboring topography on these variations. Four particular earthquake records from dense seismograph arrays are used to investigate values of the coherency cut-off frequency for different source-to-site distances. On the basis of this analysis, the model is established to simulate the spatial variations, whose parameters are suitable for both near- and far-field earthquake conditions. Simulations are conducted to validate the proposed model and method. The results show that compared to the existing models, the proposed model provides an effective method for simulating the spatial correlations of ground motions at local sites with known source-to-site distances.

Autoxidation of Cycloalkenes by the System “Molecular Oxygen-bis(acetylacetonato) Cobalt (II) Complex-butyraldehyde”

Fang, Zhao,Tang, Rui-Ren,Zhang, Rui-Rong,Huang, Ke-long Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.10

Oxidation of cycloalkenes with $O_2$ promoted by heterogeneous bis(acetylacetonato) cobalt (II) complex catalyst which can be recycled has been performed under mild conditions. It was found that $\beta$-ionone, cyclohexene, 1-methylcyclohexene, and $\alpha$-ionone were efficiently oxidized with $O_2$ in the presence of Co (II) complex and butyraldehyde at $55\;{^{\circ}C}$. A simple treatment of the resulting products led to epoxides as predominant products and a small amounts of allylic oxides, the chemoselectivity for the former being 82.1 - 90.8% with a 70.6 - 98.6% substrate conversion. On the other hand, oxidation of 1-phenylcyclohexene, 1-cyclohex-1-enylethan-1-one, $\alpha$-pinene, and $\beta$-pinene gave allylic oxides as major products.

miR-638 is a new biomarker for outcome prediction of non-small cell lung cancer patients receiving chemotherapy

Fang Wang,Jian-fang Lou,Yan Cao,Xin-hui Shi,Peng Wang,Jian Xu,Er-fu Xie,Ting Xu,Rui-hong Sun,Jianyu Rao,Pu-wen Huang,Shi-yang Pan,Hong Wang 생화학분자생물학회 2015 Experimental and molecular medicine Vol.47 No.-

MicroRNAs (miRNAs), a class of small non-coding RNAs, mediate gene expression by either cleaving target mRNAs or inhibiting their translation. They have key roles in the tumorigenesis of several cancers, including non-small cell lung cancer (NSCLC). The aim of this study was to investigate the clinical significance of miR-638 in the evaluation of NSCLC patient prognosis in response to chemotherapy. First, we detected miR-638 expression levels in vitro in the culture supernatants of the NSCLC cell line SPC-A1 treated with cisplatin, as well as the apoptosis rates of SPC-A1. Second, serum miR-638 expression levels were detected in vivo by using nude mice xenograft models bearing SPC-A1 with and without cisplatin treatment. In the clinic, the serum miR-638 levels of 200 cases of NSCLC patients before and after chemotherapy were determined by quantitative real-time PCR, and the associations of clinicopathological features with miR-638 expression patterns after chemotherapy were analyzed. Our data helped in demonstrating that cisplatin induced apoptosis of the SPC-A1 cells in a dose- and time-dependent manner accompanied by increased miR-638 expression levels in the culture supernatants. In vivo data further revealed that cisplatin induced miR-638 upregulation in the serum derived from mice xenograft models, and in NSCLC patient sera, miR-638 expression patterns after chemotherapy significantly correlated with lymph node metastasis. Moreover, survival analyses revealed that patients who had increased miR-638 levels after chemotherapy showed significantly longer survival time than those who had decreased miR-638 levels. Our findings suggest that serum miR-638 levels are associated with the survival of NSCLC patients and may be considered a potential independent predictor for NSCLC prognosis.

Influence of Amorphous and Silicon Steel on Performance of Permanent Magnet Synchronous Motors Used in Steering Pump of Electric Vehicles

Rui-fang Liu,Xin Ma,Jun-ci Cao,Shuang-xia Niu,Zhi-gang Wu 한국자기학회 2019 Journal of Magnetics Vol.24 No.2

Amorphous materials have the advantages of high permeability and low core losses. Their application in the motor can reduce the energy consumption and improve the efficiency. To investigate the advantage of amorphous materials on the performance of permanent magnet synchronous motors (PMSMs) at lower speed situation, three 1.5 kW motors used in steering pumps of electric vehicles are analyzed and compared. Two prototypes and the experimental platform are built. The experimental results indicate that the efficiency of the PMSM motor with amorphous materials increases by 1.4 % at 1200 rpm, which shows that amorphous materials can also improve the motor performance at lower speed. To further take advantage of amorphous materials, the particle swarm optimization algorithm is used to optimize the dimensions of amorphous motor and the efficiency is increased by 0.54 %.

Dynamic response analysis of generally damped linear system with repeated eigenvalues

Rui-fang Yu,Xi-yuan Zhou,Mei-qiao Yuan 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.4

For generally damped linear systems with repeated eigenvalues and defective eigenvectors, this study provides a decomposition method based on residue matrix, which is suitable for engineering applications. Based on this method, a hybrid approach is presented, incorporating the merits of the modal superposition method and the residue matrix decomposition method, which does not need to consider the defective characteristics of the eigenvectors corresponding to repeated eigenvalues. The method derived in this study has clear physical concepts and is easily to be understood and mastered by engineering designers. Furthermore, this study analyzes the applicability of step-by-step methods, including the Newmark beta and Runge-Kutta methods for dynamic response calculation of defective systems. Finally, the implementation procedure of the proposed hybrid approach is illustrated by analyzing numerical examples, and the correctness and the effectiveness of the formula are judged by comparing the results obtained from the different methods.

Autoxidation of Cycloalkenes by the System “Molecular Oxygen-bis(acetylacetonato) Cobalt (II) Complex-butyraldehyde”

Zhao Fang,Rui-ren Tang,Rui-rong Zhang,Ke-long Huang 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.10

Oxidation of cycloalkenes with O2 promoted by heterogeneous bis(acetylacetonato) cobalt (II) complex catalyst which can be recycled has been performed under mild conditions. It was found that β-ionone, cyclohexene,1-methylcyclohexene, and α-ionone were efficiently oxidized with O2 in the presence of Co (II) complex and butyraldehyde at 55 oC. A simple treatment of the resulting products led to epoxides as predominant products and a small amounts of allylic oxides, the chemoselectivity for the former being 82.1 - 90.8% with a 70.6 - 98.6% substrate conversion. On the other hand, oxidation of 1-phenylcyclohexene, 1-cyclohex-1-enylethan-1-one, α-pinene, and β-pinene gave allylic oxides as major products.

A Novel Distributed Equivalent Circuit Model for Single-Core Cables

Li Rui-Fang,Hu Hao,Cao Xiao-Bin,Li Zhong-Mei,Li Jun-Hao,Zhu Chuan-Lin,Liu Le-Jia 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

The number of cables used for urban power supply increases rapidly. The sheath current in these cables, which is generated via induction, produces a current loss. When the situation is serious, the ground lead and the middle connector of the cable will be burned. In this paper, the existing single-core cable equivalent circuit model is used to calculate the sheath current of a 3-phase cable under the condition of non-transposition and cross connection. By comparing the calculated results with the simulation and the experimental results, it is found that the current distribution law for the sheath, which was obtained using the existing model, difers substantially from both the simulation and actual measurements. The error reason of the existing model is revealed, and it is found that the magnitude and phase of the current in the metal sheath of the cable varies with the position under the combined efect of distributed capacitances in the cable and the core-current fux, especially for a 3-phase cross connection, each section of the cable does not meet Kirchhof’s laws, but the sheath electric current in the existing models are considered equal everywhere. Therefore, a novel cable equivalent model is proposed in this paper, which is based on a distributed circuit, and an equation to calculate the sheath current is derived. The model presented in this paper corrects the problems of the existing model, which can be applied to power system, subway, high-speed rail, and any application of single-core cables.

Study on Enhancing Lightning Protection Scheme of Catenary in Subway Viaduct Section

Li, Rui-Fang,Chen, Kui,Chen, Li-Sheng,Cao, Xiao-Bin,Wu, Guang-Ning,Zhang, Xue-Qin The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.2

Viaduct increases the height of subway catenary, namely magnifies lightning attraction scope that lead to higher possibility of suffering lightning stroke. Therefore, it is necessary to analyze performance of lightning striking to catenary of subway in viaduct section and propose an improving lightning protection scheme. In this paper, using ATP-EMTP simulation software to establish an associated model to evaluate lightning withstand level of catenary with existing lightning protection schemes including arrester and grounding point, an improving lightning protection scheme is proposed - every pillar ground earth and arresters are installed with some installing spacing between 200m to 400m based on lightning damage degree and reliability requirements - according to analyzing results: while lightning withstand level is lowest for lightning striking to the neutral pillar, lightning withstand level is greatest for lightning striking to the both-ends pillar that arrester and grounding point are both installed; grounding point could obviously improve lightning withstand level for lightning striking to ground wire while arrester could obviously improve the lightning withstand level for lightning striking to catenary; every pillar ground earth could enhance the lowest lightning withstanding level up to 2.5 times than of that pillar ground earth across every 200m.

Dynamic response analysis of generally damped linear system with repeated eigenvalues

Yu, Rui-Fang,Zhou, Xi-Yuan,Yuan, Mei-Qiao Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.4

For generally damped linear systems with repeated eigenvalues and defective eigenvectors, this study provides a decomposition method based on residue matrix, which is suitable for engineering applications. Based on this method, a hybrid approach is presented, incorporating the merits of the modal superposition method and the residue matrix decomposition method, which does not need to consider the defective characteristics of the eigenvectors corresponding to repeated eigenvalues. The method derived in this study has clear physical concepts and is easily to be understood and mastered by engineering designers. Furthermore, this study analyzes the applicability of step-by-step methods, including the Newmark beta and Runge-Kutta methods for dynamic response calculation of defective systems. Finally, the implementation procedure of the proposed hybrid approach is illustrated by analyzing numerical examples, and the correctness and the effectiveness of the formula are judged by comparing the results obtained from the different methods.