Magnetic Field Analysis of Hollow Halbach Long Stator Permanent Magnet Synchronous Linear Motor for Suspension Permanent Magnet Maglev Train

Yongchao Wang,Kuangang Fan,Qishou Pang 한국전자파학회 2023 Journal of Electromagnetic Engineering and Science Vol.23 No.4

In suspended permanent magnet maglev trains, the magnetic field generated by hollow-type permanent magnet synchronous linear motors is one of the main sources of low-frequency electromagnetic fields. To investigate the magnetic field generated by the linear motor in the train, this paper first establishes the 2D and 3D models of the linear motor using ANSYS electromagnetic software. Then, the electromagnetic simulation of the magnetic field of the linear motor is performed under conditions of no load and full load. Next, the magnetic field of the motor is measured using a six-channel high-precision magnetic field test system, and the simulation and measurement results are compared. The result analysis indicates that the energy distribution of the electromagnetic field generated by the linear motor is uniform and that the magnetic induction intensity falls within the range of 0–1.1 T. Meanwhile, the linear motor can form a closed loop with a small electromagnetic field energy leakage. Combined with its installation structure, the radiation to the surrounding environment is weak, and the interference with the normal operation of the train control communication equipment is minimal. This study lays a foundation for analyzing electromagnetic distribution on the surface of the suspended permanent magnet maglev train. It also provides a basis for formulating various electromagnetic radiation protection measures and provides theoretical support for developing suspended permanent magnet maglev trains.

Spine Surgical Robotics: Current Status and Recent Clinical Applications

Jiangtao Wang,Junxian Miao,Yi Zhan,Yongchao Duan,Yuanshun Wang,Dingjun Hao,Biao Wang 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

With the development of artificial intelligence and the further deepening of medical-engineering integration, spine surgical robot-assisted (RA) technique has made significant progress and its applicability in clinical practice is constantly expanding in recent years. In this review, we have systematically summarized the majority of literature related to spine surgical robots in the past decade, and not only classified robots accordingly, but also summarized the latest research progress in RA technique for screw placement such as cervical, thoracic, and lumbar pedicle screws, cortical bone trajectory screws, cervical lateral mass screws, and S2 sacroiliac screws; guiding targeted puncture and placement of endoscope via the intervertebral foramen; complete resection of spinal tumor tissue; and decompressive laminectomy. In addition, this report also provides a detailed evaluation of RA technique’s advantages and disadvantages, and clarifies the accuracy, safety, and practicality of RA technique. We consider that this review can help clinical physicians further understand and familiarize the current clinical application status of spine surgical robots, thereby promoting the continuous improvement and popularization of RA technique, and ultimately benefiting numerous patients.

A COST-EFFECTIVE PROCESS FOR SYNTHESIZING MAGNESIUM BORATE NANORODS AND ITS MECHANICAL PROPERTY FOR REINFORCED NYLON-6 COMPOSITES

LICONG WANG,YUAN LIU,YUSHAN ZHANG,DAN CHEN,YUQI WANG,ZELIANG DONG,YONGCHAO LU,XIPING HUANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.7

Magnesium borate (Mg 2 B 2 O 5 Þ nanorods were synthesized by a two-step process, includingsolution-chemical technology and a ternary-°ux method, using concentrated seawater and H 3 BO 3as raw materials. X-ray di®raction (XRD) showed that the sample had triclinic structure. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM) indicated that it consisted of rod-like particles with an average diameter of 100 – 150 nmand length over 5 ? m. Di®erential thermal analysis (DTA) con¯rmed that the melting point ofthe ternary-°ux and the formation temperature of Mg 2 B 2 O 5 were lower than single-°ux process. The formation of Mg 2 B 2 O 5 nanorods was more e±cient by ternary-°ux than single-°ux. Me-chanical property of Mg 2 B 2 O 5 nanorods reinforced Nylon-6 composites showed that KH550 wasthe optimal coupling agent and made the strength of the composites to be improved to differentdegrees.

Functional analysis of ascP in Aeromonas veronii TH0426 reveals a key role in the regulation of virulence

Guan Yongchao,Zhang Meng,Wang Yingda,Liu Zhongzhuo,Zhao Zelin,Wang Hong,An Dingjie,Qian Aidong,Kang Yuanhuan,Sun Wuwen,Shan Xiaofeng 한국미생물학회 2022 The journal of microbiology Vol.60 No.12

Aeromonas veronii is a pathogen which can induce diseases in humans, animals and aquatic organisms, but its pathogenic mechanism and virulence factors are still elusive. In this study, we successfully constructed a mutant strain (ΔascP) by homologous recombination. The results showed that the deletion of the ascP gene significantly down-regulated the expression of associated effector proteins in A. veronii compared to its wild type. The adhesive and invasive abilities of ΔascP to EPC cells were 0.82-fold lower in contrast to the wild strain. The toxicity of ΔascP to cells was decreased by about 2.91-fold (1 h) and 1.74-fold (2 h). Furthermore, the LD50 of the mutant strain of crucian carp was reduced by 19.94-fold, and the virulence was considerably attenuated. In contrast to the wild strain, the ΔascP content in the liver and spleen was considerably lower. The titers of serum cytokines (IL-8, TNF-α, and IL-1β) in crucian carp after the infection of the ΔascP strain were considerably lower in contrast to the wild strain. Hence, the ascP gene is essential for the etiopathogenesis of A. veronii TH0426.

Developing homogeneous ion exchange membranes derived from sulfonated polyethersulfone/N-phthaloyl-chitosan for improved hydrophilic and controllable porosity

Zhixue Li,Zhun Ma,Yuting Xu,Xiaomeng Wang,Yongchao Sun,Rong Wang,Jian Wang,Xueli Gao,Jun Gao 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.8

Ion exchange membranes (IEMs) composed of sulfonated poly (ether sulfone) (SPES) and N-phthaloyl chitosan (NPHCs) were synthesized. NPHCs was employed in membrane fabrication to improve the porosity and hydrophilicity of membranes. The effect of blend ratio of sulfonation (DS) and NPHCs content on physico-chemical characteristics of home-made membranes was investigated. The morphology of prepared membranes was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD) and scanning electron microscopy (SEM). SEM images revealed the formation of a more porous membrane structure and smoother surface. The electrochemical and physical properties of CEMs were characterized comprising water content, contact angle, ion exchange capacity (IEC) and thermal stability. Membrane water content, surface hydrophilicity and IEC were enhanced with increase of DS and NPHCs blend ratios in casting solution. Furthermore, the diffusion coefficient was also improved slightly with increase of DS and NPHCs blend ratios in prepared membranes. Membrane potential, permselectivity, transport number and areal membrane resistance all showed decreasing trends by the increase in NPHCs blend ratio in casting solution. These results indicated that the prepared membrane has good prospective and great potential for desalination in electrodialysis applications.

A Bound Estimation Method for Robust Adaptive Fuzzy Asymptotic Tracking of Switched Nonlinear Systems with Its Application

Yongchao Liu,Qidan Zhu,Lipeng Wang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.2

This article focuses on designing a robust adaptive fuzzy asymptotic control method for uncertain switched nonlinear systems in presence of arbitrary switching signals. The unknown dynamics of switched systems are addressed by making use of fuzzy logic systems. Different from the existing approximation-based schemes, the asymptotic tracking performance is achieved by employing a bound estimation method, some smooth functions and the backstepping technique. Through constructing Lyapunov function, the devised scheme can guarantee the stability and asymptotic convergence character of the controlled systems. Finally, the availability of the presented approach is verified via simulation examples.

Extended Equal Service and Differentiated Service Models for Peer-to-Peer File Sharing

Jianwei Zhang,Yongchao Wang,Wei Xing,Dongming Lu 한국통신학회 2013 Journal of communications and networks Vol.15 No.2

Peer-to-peer (P2P) systems have proved the most effective and popular file sharing applications in recent years. Previous studies mainly focused on equal service and differentiated service strategies when peers have no initial data before their downloads. For an upload-constrained P2P file sharing system, wemodel both the equal service process and the differentiated service process when the initial data distribution of peers satisfies some special conditions. Moreover, we show how to minimize the time required to distribute the file to any number of peers. The proposed fluid-based models can reveal the intrinsic relations among the initial data amount, the peer set size, and the minimum last finish time. The closed-form expressions derived from the extended models can closely approximate chunk-based models and systems, especially for relatively large files. As an application of the extended models, we show how to provide differentiated service efficiently to multiple peer sets. Since no limits are imposed on the upload bandwidth of peers or the size of each peer set, we believe that our analytic process and the results achieved can provide not only fundamental insights into bandwidth allocation and data scheduling but also a helpful reference for both improving systemperformance and building an effective incentive mechanism for P2P file sharing systems.

Imaging of Anal Fistulas: Comparison of Computed Tomographic Fistulography and Magnetic Resonance Imaging

Changhu Liang,Yongchao Lu,Bin Zhao,Yinglin Du,Cuiyan Wang,Wanli Jiang 대한영상의학회 2014 Korean Journal of Radiology Vol.15 No.6

The primary importance of magnetic resonance (MR) imaging in evaluating anal fistulas lies in its ability to demonstrate hidden areas of sepsis and secondary extensions in patients with fistula in ano. MR imaging is relatively expensive, so there are many healthcare systems worldwide where access to MR imaging remains restricted. Until recently, computed tomography (CT) has played a limited role in imaging fistula in ano, largely owing to its poor resolution of soft tissue. In this article, the different imaging features of the CT and MRI are compared to demonstrate the relative accuracy of CT fistulography for the preoperative assessment of fistula in ano. CT fistulography and MR imaging have their own advantages for preoperative evaluation of perianal fistula, and can be applied to complement one another when necessary.

Extended Equal Service and Differentiated Service Models for Peer-to-Peer File Sharing

Zhang, Jianwei,Wang, Yongchao,Xing, Wei,Lu, Dongming The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.2

Peer-to-peer (P2P) systems have proved the most effective and popular file sharing applications in recent years. Previous studies mainly focused on equal service and differentiated service strategies when peers have no initial data before their downloads. For an upload-constrained P2P file sharing system, we model both the equal service process and the differentiated service process when the initial data distribution of peers satisfies some special conditions. Moreover, we show how to minimize the time required to distribute the file to any number of peers. The proposed fluid-based models can reveal the intrinsic relations among the initial data amount, the peer set size, and the minimum last finish time. The closed-form expressions derived from the extended models can closely approximate chunk-based models and systems, especially for relatively large files. As an application of the extended models, we show how to provide differentiated service efficiently to multiple peer sets. Since no limits are imposed on the upload bandwidth of peers or the size of each peer set, we believe that our analytic process and the results achieved can provide not only fundamental insights into bandwidth allocation and data scheduling but also a helpful reference for both improving system performance and building an effective incentive mechanism for P2P file sharing systems.

Exercise-mediated macrophage polarization modulates the targeted therapeutic effect of NAFLD: a review

Li Zhenyu,Wang Ying,Tian Zhuang,Xie Yongchao,김재철 한국운동영양학회 2023 Physical Activity and Nutrition (Phys Act Nutr) Vol.27 No.3

[Purpose] This review aims to explore the exercise-mediated hepatic macrophage polarization mechanism and its effect on improving and regulating non-alcoholic fatty liver disease (NAFLD) by analyzing the pathogenesis of NAFLD and the cause of the influence of hepatic macrophage polarization. In addition to exploring the varied effects of different exercise types on macrophage polarization regulation in NAFLD, to provide a direction and basis for the treatment of NA- FLD. [Methods] The research methodology involved a comprehensive search of the PubMed database using specific keywords such as “NAFLD”, “macrophage polarization”, and “exercise”, to retrieve relevant literature published. [Results] (1) The main factors inducing NAFLD were high-fat diet, obesity, insulin resistance (IR), changes in gut microbiota, and genetic variation in susceptibility. (2) Drug treatment, nutrient induction, microfactor induction, physiological environment induction, and other factors can induce the polarization of hepatic macrophages and affect NAFLD. (3) Different intensities, types, and frequencies of exercise have different effects on polarization macrophages, and may also differently effects improving liver inflammation, fibrosis, and NAFLD. Curently, regular moderate-intensity aerobic exercise is the most effective therapy for treating NAFLD. [Conclusion] Approaches to ameliorate NAFLD with exercise involve strategies to alter macrophage polarization by inhibiting M1 or driving M2 activation. However, research on the different types of exercise-mediated macrophage polarization mechanisms and differences in therapeutic effects is not yet sufficient. Future research is necessary to explore the exact mechanisms and differences in the effects of different exercises on the treatment of NAFLD.