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252 results on '"Zhu, Zhiying"'

55. Thermal Analysis of Axial Permanent Magnet Flywheel Machine Based on Equivalent Thermal Network Method

Author

Yibo Li, Guo Jie, Zhu Zhiying, and Wei Zhang

Subjects
Materials science, General Computer Science, Thermal resistance, finite element analysis, 02 engineering and technology, Bearingless flywheel machine, 01 natural sciences, Flywheel, equivalent thermal network method, 0103 physical sciences, Thermal, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Electrical and Electronic Engineering, Thermal analysis, 010302 applied physics, 020208 electrical & electronic engineering, General Engineering, Mechanics, Finite element method, Electromagnetic coil, Magnet, Heat transfer, temperature rise, lcsh:Electrical engineering. Electronics. Nuclear engineering, lcsh:TK1-9971, thermal analysis
Abstract

The axial permanent magnet magnetic bearingless flywheel machine (APM-BFM) mostly operates under the state of high-power fast charging and discharging. Due to the characteristics of high-power density per unit volume, the centralized windings have small heat dissipation area and high thermal loads, the temperature rise on APM-BFM is a very important issue. Thermal analysis is thus of particular importance particularly for modern machines since the temperature rise and distribution are significant during their running under higher electromagnetic loads commonly used nowadays. In this paper, the equivalent thermal network method is proposed to evaluate the temperature rise of the APM-BFM. The equivalent thermal network model is established based on the basic theorem of heat transfer. The thermal resistance and heat source in the machine are analyzed and calculated, and the thermal balance equation is established. The temperature rise of each node is solved, and finally the validity of the model is verified by finite element magnetic-thermal coupling simulation.

Published
2021

56. Analysis of pole-slot combination of novel flux-adjustable permanent magnet adjustable speed drive with fixed air-gap.

Author

Li Yibo, Huang Jiacai, and Zhu Zhiying

Subjects
PERMANENT magnets, ELECTROMAGNETISM, MANUFACTURED products, FINITE element method, SQUIRREL cage motors
Abstract

Copyright of Journal of Southeast University (English Edition) is the property of Journal of Southeast University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2023
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57. Capturing two new salts of the anticancer drug gefitinib.

Author

Zhai, Lihai, Zhu, Zhiying, Guo, Lihong, Yu, Junhou, Dong, Huaimin, and Zhang, Guimin

Subjects
*X-ray powder diffraction, *ANTINEOPLASTIC agents, *DIFFERENTIAL scanning calorimetry, *GEFITINIB, *SURFACE analysis
Abstract

In this text, the new crystal forms of geffitinib were explored through evaporation solution crystallization experiment. The formation of salts was confirmed by the single crystal X-ray diffraction, powder X-ray diffraction, thermo gravimetric analysis and differential scanning calorimetry, Raman spectroscopy, hot-stage microscopy and Hirshfeld surface analysis. Furthermore, Hirshfeld surface analysis confirmed that the driving force and supporting force for the formation of crystals were C-C, C-H, N-H, H-H, O-H and Cl-H interactions. The dissolution rate of the new salts of gefitinib in phosphate buffer of pH 6.8 was evaluated, and the results showed a significant increase in solubility. [ABSTRACT FROM AUTHOR]

Published
2023
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59. A dual‐phase‐conducted type bearingless switched reluctance flywheel motor with hybrid outer rotor

Author

Zhu Zhiying, Zhou Yunhong, Yukun Sun, and Jiahao Jiang

Subjects
Physics, Control theory, Rotor (electric), law, Phase (waves), Electrical engineering. Electronics. Nuclear engineering, Electrical and Electronic Engineering, Switched reluctance motor, Flywheel, TK1-9971, law.invention, Dual (category theory)
Abstract

A novel dual‐phase‐conducted type bearingless switched reluctance flywheel motor is proposed, which has a hybrid outer rotor comprising circular segment and scalloped lamination segment, and only one set of winding is placed on each stator pole. In order to drive the flywheel to accelerate or slow down, two phases of windings in this motor conduct simultaneously. One phase provides radial suspension force, and the other phase provides electromagnetic torque. There exits satisfying decoupling between torque and suspension force. With the circular segment of the rotor, the continuity and stability of radial force can be enhanced. Finite element analysis results confirm the feasibility of the theoretical scheme.

Published
2021

76. Image Sanitization in Online Social Networks: A General Framework for Breaking Robust Information Hiding

Author

Zhu, Zhiying, Wei, Ping, Qian, Zhenxing, Li, Sheng, and Zhang, Xinpeng

Abstract

With the development of robust information hiding (RIH) approaches, secret messages can be extracted successfully from stego-data after transmission through lossy channels of online social networks (OSNs). To interrupt illegal covert communications in OSNs, some methods sanitize the uploaded images by image processing operations to destroy the hidden data that may exist. However, none of the existing methods takes the RIH methods that can resist scaling into consideration, while scaling is a common operation in OSNs. In this paper, we first propose a general framework for image sanitization in OSN platforms, which serves as a countermeasure against the RIH. By using such a framework, the secret messages embedded in the upload images can be removed and the quality of the sanitized image can be well maintained. Our framework contains two deep neural networks: Scaling-Net and SC-Net. The Scaling-Net is dedicated to the sanitization of oversized images while the SC-Net is designed for other images. To achieve a good image quality, we also propose a discriminator for adversarial training of the Scaling-Net and SC-Net. Experimental results on different datasets demonstrate that our proposed method outperforms the state-of-the-art methods. The source code and pretrained models are available at our code repository (https://github.com/zyzhu19/Image_Sanitization).

Published
2023
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79. Optimization Design of an Axial Split-Phase Bearingless Flywheel Machine with Magnetic Sleeve and Pole-Shoe Tooth by RSM and DE Algorithm

Author

Jin Zhu, Xi Zhu, Zhu Zhiying, Yajie Yu, and Zhu Hailang

Subjects
Control and Optimization, axial split-phase, Stator, Split-phase electric power, Energy Engineering and Power Technology, 02 engineering and technology, bearingless flywheel machine, 01 natural sciences, lcsh:Technology, Flywheel, law.invention, response surface methodology, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Torque, parameter optimization, Response surface methodology, Electrical and Electronic Engineering, Suspension (vehicle), Engineering (miscellaneous), Mathematics, 010302 applied physics, Renewable Energy, Sustainability and the Environment, lcsh:T, 020208 electrical & electronic engineering, Finite element method, Differential evolution, Algorithm, Energy (miscellaneous), differential evolution algorithm
Abstract

In order to improve the suspension and torque performance of a bearingless flywheel machine, a new type of axial split-phase bearingless flywheel machine with a magnetic sleeve and pole-shoe tooth is analyzed and optimized as described in this paper. Based on the basic structure and working characteristics of the machine, the response surface methodology (RSM) and differential evolution (DE) algorithm are adopted to further optimize the parameters of the stator teeth of the machine to improve the radial space utilization and motor output performance. Firstly, the Box&ndash, Behnken design (BBD) and finite element analysis (FEA) are combined to select the representative optimization parameter combinations to establish the sample data space, and the response surface models of machine torque and suspension force are established using the least square method. Besides this, the DE algorithm is employed to obtain the optimal tooth profile parameter configuration for the multi-objective optimization of machine performance. Finally, the output performances of the machine before and after optimization are compared under initial and optimized winding turns. The results show that, compared with the initial structure, the average torque and suspension force of the optimized machine increase by 36.46 % and 108.22% respectively, which demonstrates the effectiveness of the tooth profile optimization method. At the same time, an experimental prototype is also produced, laying the experimental foundation for further practical exploration.

Published
2020

80. Performance comparison of 12/12 pole with 8/10 and 12/14 pole bearingless switched reluctance machine

Author

Zhu Jin, Zhu Zhiying, Guo Xuan, and Jiang Yongjiang

Subjects
Physics, Rotor (electric), Stator, 020208 electrical & electronic engineering, 02 engineering and technology, Switched reluctance motor, law.invention, Magnetic circuit, Electromagnetic coil, law, Control theory, Magnet, 0202 electrical engineering, electronic engineering, information engineering, Torque, Electrical and Electronic Engineering, Machine control
Abstract

In this Letter, three types of bearingless switched reluctance machines (BSRMs) with different hybrid stator structures are designed and analysed. First of all, topologies of three BSRMs, the conventional 8/10 pole, 12/14 pole BSRMs and a novel 12/12 pole BSRM with axial split phase inner stator permanent magnet structure, are given. Then, the electromagnetic performances, including the distribution of magnetic fields, suspension force and electromagnetic torque are comprehensively compared by means of 2D and 3D finite-element method (FEM). The results based on theoretical analysis and FEM reveal that the proposed 12/12 pole BSRM would exhibit complete decoupling, shorter magnetic circuit, higher torque (power) density and suspension force than the conventional ones. Further, it is found that four degree-of-freedom suspension of the rotor can be realised by two-phase suspension windings in the proposed 12/12 pole BSRM. Finally, a prototype machine is designed and manufactured to verify the validity of the topology design and electromagnetic performance.

Published
2019

89. A Novel Bearingless Switched Reluctance Machine with Axial Split Phase Inner Stator Permanent Magnet Structure

Author

Jiang Yongjiang, Y. Sun, and Zhu Zhiying

Subjects
Electromagnetic field, Physics, Stator, 020209 energy, Split-phase electric power, 02 engineering and technology, Finite element method, Switched reluctance motor, law.invention, Control theory, law, Magnet, 0202 electrical engineering, electronic engineering, information engineering, Torque, Energy transformation
Abstract

Flywheel energy storage system (FESS) is a kind of physical energy storage device for electromechanical energy conversion. Bearingless switched reluctance machine (BSRM) fully preserves the excellent characteristics of switched reluctance motor, and improves the high speed performance and operation efficiency by active control of its own radial force. In this paper, a novel BSRM with axial split phase inner stator permanent magnet (PM) structure is proposed to cancel the electromagnetic coupling between torque winding and suspension winding. In order to verify the effectiveness of the proposed BSRM, its electromagnetic field is analyzed by the finite element method (FEM).

Published
2018

99. Smoking Among Chinese Livery Drivers

Author

Leng, Jennifer C., primary, Lei, Lei, additional, Lei, Shu Fang, additional, Zhu, Zhiying, additional, Mo, Nancy, additional, Sou, Brian, additional, Mujawar, Imran, additional, and Gany, Francesca, additional

Published
2018
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