Comparative Analysis of Magnetic Slot Wedges Design for Increasing Performance of Railway Traction Motor

Liu, Huai-Cong,Cho, Sooyoung,Hong, Hyun-Seok,Joo, Kyoung-Jin,Ham, Sang-Hwan,Lee, Ju The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.6

This study focuses on the effects of using open stator slots in an interior permanent magnet traction motor with a magnetic slot wedge design in order to increase the power density at its base speed. In addition, such a configuration reduces the torque ripple under field-weakening conditions. Five different wedge models were selected, each of which was evaluated using a finite element analysis (FEA). Based on the initial model, we designed magnetic slot wedges for maximum back-EMF and minimum cogging torque. In addition, the d-q axis inductance was slightly altered due to the magnetic slot wedges. Finally, we analyzed the performance of a traction machine under field weakening control. Moreover, we have outlined the requirements for an ideal magnetic slot wedge design.

Schisantherin A Improves Learning and Memory of Mice with D-Galactose-Induced Learning and Memory Impairment Through Its Antioxidation and Regulation of p19/p53/p21/ Cyclin D1/CDK4/RB Gene Expressions

Cong Liu,Weijing Sun,Ning Li,Jiaqi Gao,Chunyan Yu,Chunmei Wang,Jinghui Sun,Shu Jing,JianGuang Chen,He Li 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.7

Schisantherin A (SCA) was evaluated for possible function in restoring the learning and memory impairment induced by D-galactose in mice. ICR mice were treated with D-galactose subcutaneously (220 mg·kg−1), and followed by SCA in different doses (1.25, 2.50 and 5.00 mg·kg−1, administered orally) for 42 days. Effects of SCA on learning and memory were examined by step-through tests and Morris water maze tests. The activity of superoxide dismutase (SOD), the content of malondialdehyde (MDA) in the peripheral blood and hippocampus of mice were assayed by water-soluble tetrazolium-1 (WST-1) and thiobarbituric acid (TBA) methods. The contents of 8 hydroxy deoxy guanosine (8-OHdG) in the hippocampus of mice were detected by immunosorbent assay methods, respectively. Quantitative real-time PCR and Western Blot were respectively used to detect the expression of p19, p53, p21, cyclin D1, CDK4 and RB genes, and the phosphorylation of RB in the hippocampus of mice. We found that SCA significantly improved the learning and memory impairment induced by D-galactose in mice. After SCA treatment, SOD activity was increased and the content of MDA was decreased in both peripheral blood and hippocampus of mice. 8-OHDG content was also decreased in the hippocampus of mice. Furthermore, the expression of p19, p53 and p21 genes was reduced and the expression of cyclin D1 and CDK4 and the phosphorylation of RB protein were elevated in the hippocampus. SCA may improve the learning and memory impairment induced by D-galactose by enhancing the antioxidant capacity, and regulating the expression of p19/p53/p21/cyclinD1/CDK4 genes, and the phosphorylation of RB protein in the hippocampus of mice.

NEW INTEGRATED MULTI-ALGORITHM FUSION LOCALIZATION AND TRAJECTORY TRACKING FRAMEWORK OF AUTONOMOUS VEHICLES UNDER EXTREME CONDITIONS WITH NON-GAUSSIAN NOISES

Cong Liu,Hui Liu,Lijin Han,Changle Xiang 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.1

This paper proposes a novel integrated multi-algorithm fusion localization and trajectory tracking framework for autonomous vehicles under extreme conditions with non-Gaussian noises. Firstly, in order to solve the problem that GPS signals are interfered with non-Gaussian noises or lost, a localization method based on Particle Filter (PF) is designed, which takes full advantage of the reference objects position information and vehicle driving state information, thus realizing the self-localization for high-speed autonomous vehicles. Besides, considering the accumulated errors of the model-driven Inertial Measurement Unit (IMU) in the long-horizon positioning prediction, an online future driving state prediction algorithm based on multi-order variable-step Markov model (MM) is proposed to calculate the future vehicle position in scenarios without reference. The fusion of these two methods can give full play to their respective advantages, thus improving the accuracy and robustness of the whole localization algorithm in scenes with non-Gaussian noises. Then, the location information and the future driving state are applied to the trajectory tracking controller based on adaptive model predictive control (AMPC). Finally, the CarSim-Matlab/Simulink cGAOo-simulations results show the effectiveness of the proposed framework when GPS signal is interfered with non-Gaussian noises, which further improve the positioning accuracy and autonomous tracking stability.

Optimal Slot Design of IPMSM in Railway With Independently Rotating Wheelsets

Liu, Huai-Cong,Lee, Ho-Joon,Seol, Hyun-Soo,Cho, Sooyoung,Lee, Ju,Oh, Ye Jun IEEE 2019 IEEE transactions on magnetics Vol.55 No.2

<P>This paper proposes a quasi-semi-closed (QSC) slot design method for an open-slot-type interior permanent magnet synchronous motor (IPMSM) for independently rotating wheelsets necessary to reduce the total harmonic distortion of no-load back-electromotive force and the torque ripple in the IPMSM. Four different slot-opening models were selected—the basic model, hairpin coil model, magnetic-wedge model, and QSC-slot model—and 2-D finite-element analysis was performed under open-circuit and load operations for each of the four models. Next, the relationships among the cogging torque, the torque ripple, and the saturation phenomenon in the core were analyzed. In addition, the manufacturing process, manufacturing cost, fill factor, end-winding resistance, copper loss, and efficiency were investigated. The experimental results verify the accuracy of the proposed method.</P>

Comparison of immunoadjuvant activities of four bursal peptides combined with H9N2 avian influenza virus vaccine

Cong Zhang,Jiangfei Zhou,Zhixin Liu,Yongqing Liu,Kairui Cai,Tengfei Shen,Cheng-Shui Liao,Chen Wang 대한수의학회 2018 Journal of Veterinary Science Vol.19 No.6

The bursa of Fabricius (BF) is a central humoral immune organ unique to birds. Four bursal peptides (BP-I, BP-II, BP-III, and BP-IV) have been isolated and identified from the BF. In this study, the immunoadjuvant activities of BPs I to IV were examined in mice immunized with H9N2 avian influenza virus (AIV) vaccine. The results suggested that BP-I effectively enhanced cell-mediated immune responses, increased the secretion of Th1 (interferon gamma)- and Th2 (interleukin-4)-type cytokines, and induced an improved cytotoxic T-lymphocyte (CTL) response to the H9N2 virus. BP-II mainly elevated specific antibody production, especially neutralizing antibodies, and increased Th1- and Th2-type cytokine secretion. BP-III had no significant effect on antibody production or cell-mediated immune responses compared to those in the control group. A strong immune response at both the humoral and cellular levels was induced by BP-IV. Furthermore, a virus challenge experiment followed by H&E staining revealed that BP-I and BP-II promoted removal of the virus and conferred protection in mouse lungs. BP-IV significantly reduced viral titers and histopathological changes and contributed to protection against H9N2 AIV challenge in mouse lungs. This study further elucidated the immunoadjuvant activities of BPs I to IV, providing a novel insight into immunoadjuvants for use in vaccine design.

DNA Polymorphism of Insulin-like Growth Factor-binding Protein-3 Gene and Its Association with Cashmere Traits in Cashmere Goats

Liu, Haiying,Liu, Chao,Yang, Guiqin,Li, Hui,Dai, Jin,Cong, Yuyan,Li, Xuejian Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.11

Insulin-like growth factor binding protein-3 (IGFBP-3) gene is important for regulation of growth and development in mammals. The present investigation was carried out to study DNA polymorphism by PCR-RFLP of IGFBP-3 gene and its effect on fibre traits of Chinese Inner Mongolian cashmere goats. The fibre traits data investigated were cashmere fibre diameter, combed cashmere weight, cashmere fibre length and guard hair length. Four hundred and forty-four animals were used to detect polymorphisms in the hircine IGFBP-3 gene. A 316-bp fragment of the IGFBP-3 gene in exon 2 was amplified and digested with HaeIII restriction enzyme. Three patterns of restriction fragments were observed in the populations. The frequency of AA, AB and BB genotypes was 0.58, 0.33 and 0.09 respectively. The allelic frequency of the A and B allele was 0.75 and 0.25 respectively. Nucleotide sequencing revealed a C>G transition in the exon 2 region of the IGFBP-3 gene resulting in R158G change which caused the polymorphism. Least squares analysis revealed a significant effect of genotypes on cashmere weight (p<0.0001), cashmere fibre length (p<0.001) and hair length (p<0.05) of the animals. The effect of genotypes on cashmere fibre diameter was not statistically significant (p>0.05). The animals of AB and BB genotypes showed higher cashmere weight, cashmere fibre length and hair length than the animals possessing AA genotype. These results suggested that polymorphisms in the hircine IGFBP-3 gene might be a potential molecular marker for cashmere weight in cashmere goats.

Design of Permanent Magnet-Assisted Synchronous Reluctance Motor for Maximized Back-EMF and Torque Ripple Reduction

Liu, Huai-Cong,Kim, In-Gun,Oh, Ye Jun,Lee, Ju,Go, Sung-Chul IEEE 2017 IEEE transactions on magnetics Vol.53 No.6

<P>This paper proposes the optimization of the shape and size of a ferrite magnet and the arrangements necessary to reduce torque ripple and maximize back electromotive force (B-EMF) in a permanent-magnet-assisted synchronous reluctance motor. First, four different models of general magnet arrangements were selected, and analysis using the finite-element method was performed under open circuit and load operations for each of the four models. Next, the relationship between the cogging torque and the torque ripple was analyzed, considering the segment saturation phenomenon. Then, based on the initial model, the design was optimized for maximum B-EMF and minimum torque ripple, and the total harmonic distortion was measured. Finally, the validity and superiority of the optimized design were confirmed by manufacturing a prototype motor and performing the experiment.</P>

Application of a C-Type Filter Based LCFL Output Filter to Shunt Active Power Filters

Liu, Cong,Dai, Ke,Duan, Kewei,Kang, Yong The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

This paper proposes and designs a new output filter called an LCFL filter for application to three phase three wire shunt active power filters (SAPF). This LCFL filter is derived from a traditional LCL filter by replacing its capacitor with a C-type filter, and then constructing an L-C-type Filter-L (LCFL) topology. The LCFL filter can provide better switching ripple attenuation capability than traditional passive damped LCL filters. The LC branch series resonant frequency of the LCFL filter is set at the switching frequency, which can bypass most of the switching harmonic current generated by a SAPF converter. As a result, the power losses in the damping resistor of the LCFL filter can be reduced when compared to traditional passive damped LCL filters. The principle and parameter design of the LCFL filter are presented in this paper, as well as a comparison to traditional passive damped LCL filters. Simulation and experimental results are presented to validate the theoretical analyses and effectiveness of the LCFL filter.

20世纪中国文学中人性与道德之关系研究

??(Liu Cong) 한국중어중문학회 2011 중어중문학 Vol.48 No.-

The problem of “Morality” was one of the most heavy topics in China in the beginning of 20th century because human nature had been imprisoned by the moral idea of old feudalism for too long time. In the whole 20th century, people constantly adjusted the relation between the morality and the human nature and try to make human nature reside poetically under the sky of morality. The conflict between human nature and social moral norms is an eternal topic accompanying the growing up of mankind, which exists for ever, and will become sharper and more evident in the tremendous changes of history. The cultural history of mankind shows us that the footsteps of human nature and morality should take each other as tropics: The establishment of moral norms should take human nature as a purpose, and the healthy development of human nature should also follow the necessary moral standards.

Simulation Analysis of Cylinder Impact Performance Influenced by Shaft Sleeve Structure

Liu, Cong,Xiao, Pei,Li, Xingli,Li, Gangyan Korean Society for Fluid machinery 2018 International journal of fluid machinery and syste Vol.11 No.1

To study the cylinder motion characteristics, cylinder and shaft sleeve stress characteristics of cylinder stroke and return process influenced by different shaft sleeve structure, the cylinders with non-chamfering shaft sleeve, C0.3 chamfering shaft sleeve and R0.3 round corner shaft sleeve were used for simulation of cylinder stroke and return process. The results show that the piston velocity curves of three kinds of shaft sleeve are identical. Maximum stress of different shaft sleeves fluctuates and maximum stress elements of C0.3 and R0.3 shaft sleeve are similar. When cylinder strokes, maximum stress of cylinder occurs at the end of piston rod connected to the load; the stress of C0.3 shaft sleeve is the lowest. When cylinder returns, maximum stress of cylinder occurs at the shaft sleeve; the stress of C0.3 and R0.3 shaft sleeve differ little and are both lower than that of non-chamfering shaft sleeve. It provides a reference for structure optimization and service life improvement of the cylinder shaft sleeve.