Analysis and Design Optimization of Axial–Radial Flux Hybrid Excitation Permanent Magnet Eddy Current Coupling

Zhang Hongming,Liu Chengcheng,Zhang Shiwei,Wang Youhua,Lei Gang,Zhu Jianguo 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6

This paper proposes an axial–radial flux hybrid excitation permanent magnet eddy current coupling (HE-PMEC), where the ferrite magnet is employed for producing the radial flux and the DC excitation current is adopted for producing the axial flux. Moreover, a shielding layer is developed to regulate the radial magnetic field. Its magnetic field distribution, electromagnetic performance, and temperature distribution are calculated based on the 3D finite element method (FEM). By adjusting the applied DC excitation current density and the insertion depth of the shielding layer, the variable current starting process, the variable current braking process, and the speed regulation characteristic of the proposed HE-PMEC are obtained. It can be seen that the starting process, braking process, and speed regulation ability of the HE-PMEC have been enhanced greatly. Furthermore, the copper ring shape of the HE-PMEC is optimized by using the proposed improved multilevel optimization method. It can be seen that the performance of the HE-PMEC can be improved by using the new optimized copper ring shape. Lastly, compared with the conventional PMECs, the proposed HE-PMEC has shown its superior electromagnetic performance.

Momordicine I alleviates isoproterenol-induced cardiomyocyte hypertrophy through suppression of PLA2G6 and DGK-ζ

Hongming Li,Yumei Qiu,Mengdie Xie,Changsheng Ouyang,Xiaoyun Ding,Hao Zhang,Wei Dong,Yinhua Xiong,Xilan Tang 대한약리학회 2023 The Korean Journal of Physiology & Pharmacology Vol.27 No.1

This study aimed to observe the protective effect of momordicine I, a triterpenoid compound extracted from momordica charantia L., on isoproterenol (ISO)-induced hypertrophy in rat H9c2 cardiomyocytes and investigate its potential mechanism. Treatment with 10 μM ISO induced cardiomyocyte hypertrophy as evidenced by increased cell surface area and protein content as well as pronounced upregulation of fetal genes including atrial natriuretic peptide, β-myosin heavy chain, and α-skeletal actin; however, those responses were markedly attenuated by treatment with 12.5 μg/ml momordicine I. Transcriptome experiment results showed that there were 381 and 447 differentially expressed genes expressed in comparisons of model/control and momordicine I intervention/model, respectively. GO enrichment analysis suggested that the anti-cardiomyocyte hypertrophic effect of momordicine I may be mainly associated with the regulation of metabolic processes. Based on our transcriptome experiment results as well as literature reports, we selected glycerophospholipid metabolizing enzymes group VI phospholipase A2 (PLA2G6) and diacylglycerol kinase ζ (DGK-ζ) as targets to further explore the potential mechanism through which momordicine I inhibited ISO-induced cardiomyocyte hypertrophy. Our results demonstrated that momordicine I inhibited ISO-induced upregulations of mRNA levels and protein expressions of PLA2G6 and DGK-ζ. Collectively, momordicine I alleviated ISO-induced cardiomyocyte hypertrophy, which may be related to its inhibition of the expression of glycerophospholipid metabolizing enzymes PLA2G6 and DGK-ζ.

An experimental study on positioning conformance control of starch gelant in the heterogeneous porous media by using CT technology

Lei Zhang,Hongming Xu,Chunsheng Pu,Guangyu Yuan,Guangyao Leng,Chunlei Zhang 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-

In order to increase the economic efficiency of conformance control in the time of low oil price, a gelant should be injected into the specified location (positioning conformance control) to improve the swept volume in the maximum extent in the heterogeneous oil reservoir. For this purpose, an in-situ crosslinking polymer gelant (it is consisting of modified starch, acrylamide, N, N'- methylene diacrylamide, and potassium persulfate) is taken as the object of study by CT scan. Based on the dynamic and visible images of fluids distribution in the porous media, the gelant can be used to achieve the positioning conformance control because it can almost maintain a whole slug during transportation in porous media. According to the relationship of transportation distance and injection volume of the gelant in porous media, the gelant can be displaced to the specified location in porous media. In addition, the characteristics of water flooding of heterogeneous porous media before and after positioning conformance control are studied by CT scan, which can investigate the function of positioning conformance control and the extent of improving the swept volume in the heterogeneous reservoirs. The experimental results in this paper can provide theoretical guidance for the practical application of positioning conformance control in the heterogeneous oil reservoirs.

Multiphysical Design and Optimization of High-Speed Permanent Magnet Synchronous Motor with Sinusoidal Segmented Permanent Magnet Structure

Liu Chengcheng,Zhang Hongming,Wang Shaoheng,Wang Youhua,Lei Gang,Zhu Jianguo 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

High speed permanent magnet synchronous motor (HSPMSM) is an important driving motor for electric vehicles. Compared with the electric motor operated under normal speed, it is critical to reduce the torque ripple, vibration, and noise of the HSPMSM. Furthermore, The air-gap fux density total harmonic distortion and electromotive force total harmonic distortion determine by torque performance and vibration noise. This article uses analytical methods to analyze the infuence of permanent magnet sinusoidal segmentation (PMS) on the electromagnetic performance of surface-mounted HSPMSM. The fnite element method is used to calculate the infuence of diferent permanent magnet segmentation numbers, diferent adjacent permanent magnet decreasing thickness, and diferent center PM width on the electromagnetic performance of permanent magnet sinusoidal segmented surface-mounted high-speed permanent magnet synchronous motor (M2). Comparing the efectiveness of PMS in surface-mounted HSPMSM and interior HSPMSM. Furthermore, the rotor dynamics analysis and vibration noise analysis on M2 are performed, and the infuence of PMS on the stress and vibration noise of both motors’ rotors is summarized. This article proposes a parameter preprocessing grouping multiphysical multi-objective high-dimensional multilevel optimization method. Taking M2 as an example, a global optimization design was carried out for the high-dimensional structural parameters brought by PMS, which improved the electromagnetic performance of M2 and reduced the vibration noise and rotor stress.

Improvement of low-temperature NH3-SCR catalytic activity over Mn-Ce oxide catalysts supported on sewage sludge char activated with KOH and H3PO4

Junchao Xu,Xiangyang Zhang,Yunlan Sun,Hongming Long,Zhimin Zheng 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.12

Pyrolysis is a very potential sludge treatment technology that is low-cost and environmentally friendly; particularly, the pyrolysis sewage sludge char (SC) can be used as a catalyst support. To improve the NO conversion efficiency of sludge char based catalysts, they were activated by potassium hydroxide and phosphoric acid, respectively. The catalysts of activated sludge char with or without Mn-Ce impregnation in the application of NO removal by lowtemperature SCR were investigated. The higher NO conversion efficiency of sludge char based Mn-Ce catalysts at low temperature were obtained. Compared with the 59% NO conversion efficiency of Mn-Ce/SC catalyst, the conversion efficiency of catalyst supported on KOH activated char (SCK) achieved 89% at 220 oC and of catalyst supported on H3PO4 activated char (SCP) reached 87% at 240 oC. The catalysts were analytically characterized using N2 adsorptiondesorption, XRD, FTIR, NH3-TPD and XPS measurements. The higher specific area, excellent dispersion of Mn-CeOx and more Brønsted acid sites are responsible for the higher NO conversion efficiency of Mn-Ce/SCK, while the higher NO conversion efficiency of Mn-Ce/SCP is enhanced by more Brønsted acid sites, oxygen-containing and some unique phosphorus-containing oxygen functional groups. It indicates that sludge char activated by KOH and H3PO4 is a potential low-temperature catalyst support.

Dislocation Density-Based Constitutive Model and Processing Map for T2 Copper During Isothermal and Time-Variant Deformation

Gang Chen,Yu Jin,Jing Wang,Cheng Zhang,Qiang Chen,Hongming Zhang,Xingjian Zhao,Zhiyong Li,Changhai Xie,Zhiming Du 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

Isothermal compression tests were carried out to study the hot deformation behavior of T2 copper under various conditions. The deformation parameters, such as temperature and strain rate, have strong influence on flow stress and microstructureevolution of the alloy. A unified dislocation density-based model considering dynamic recovery and recrystallization wasestablished. And material parameters of the developed model were optimized by genetic algorithm. Comparisons betweenthe experimental and model data demonstrates that the developed model can precisely describe the flow behavior at quitewide range of deformation conditions. Meanwhile, the designed iterative procedure allows the model to be applied in timevariantdeformation conditions. Processing map and microstructure examination were constructed to optimize the processingwindow of the studied alloy. According to the processing maps, flow instability mainly appeared at low temperatures of500–650 °C and strain rates higher than 0.1 s−1. The optimum deformation parameters of T2 copper was concluded as thetemperature range of 700–800 °C and the strain rate of 0.1–1 s−1.

Surfactant PVA-Stabilized Co–Mo Nanocatalyst Supported by Graphene Oxide Sheets Toward the Hydrolytic Dehydrogenation of Ammonia Borane

Xin Zhao,Dandan Ke,Shumin Han,Yuan Li,Hongming Zhang,Ying Cai 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11

By adding surfactant polyvinyl alcohol (PVA) and controlling the preparation process, we successfully synthesized Co–Mo catalysts. For further improving the dispersion, reduced graphene oxide sheets as catalyst carrier were introduced to synthesize Co–Mo@rGO composite catalyst as highly efficient catalysts for hydrolytic dehydrogenation of ammonia borane. The introduction of Mo for preparing Co–Mo@rGO catalyst helped to form alloy catalyst with better structure, better dispersity and smaller particle size. When the molar ratio of Co and Mo was 0.75 : 0.25, the bimetallic composite catalyst exhibited superior activity with TOF value of 16.29 mol H2 · min -1 · mol Co-Mo -1. The activation energy of the reaction was calculated to be 43.72 kJ · mol -1. Furthermore, the reusability tests reveal that waxberry-like Co–Mo still show good catalytic activity with 80.3 % of their initial activity in five successive runs. The enhanced catalytic activities were due to the synergistic interaction between graphene sheets and waxberry-like Co–Mo NPs, which was beneficial to improve the dispersion and stability of bimetallic NPs. Also, ligand effects on the formation of waxberry-like structure and amorphous state further promoted the catalytic activity.

Enhanced electrochemical performances of LiNi0.5Co0.2Mn0.3O2 cathode material co-coated by graphene/TiO2

Dang Mengyue,Li Ying,Xu Chaoxiang,He Yulin,Yu Chunpeng,Liu Wenbo,Jin Hongming,Zhu Mingyuan,Zhang Jiujun,Li Wenxian 한국물리학회 2021 Current Applied Physics Vol.32 No.-

The electrochemical performances of LiNi0.5Co0.2Mn0.3O2 (NCM523) layered cathode material, such as poor rate capacity and cycling stability caused by undesirable intrinsic conductivity and low rate of lithium ion transportation, are not fairly good especially at elevated rate and cut-off voltage. To improve these properties, in this study, the co-coating layer of graphene and TiO2 was constructed on NCM523 surface. The graphene/TiO2 coating layer could effectively prevent hydrofluoric acid (HF) attacks, suppress the side reaction, accelerate the lithium ion diffusion and facilitate the electron migration. The enhancement of cycle performance and rate capacity was contributed to the uniform co-modified surface, interacting each other and thus exhibiting synergistic effects.