Pub Date : 2024-09-26DOI: 10.1109/TMAG.2024.3468308
Dawei Liu;Gaolei Wang;Wenhao Li
In order to improve the compression resistance and torque density of rim-driven thruster (RDT) to cope with complex and harsh deep-sea conditi ons, a flux-modulated RDT (FM-RDT) is proposed. This RDT uses a flux-modulated machine (FMM) as the driving machine, which utilizes a modulation ring to realize pressure protection in the deep sea and realizes the high-torque drive through the magnetic field modulation effect. The subdomain model is established in the air-gap and permanent magnet regions, and the permeance network (PN) model is established in the ferromagnetic regions. The nonlinear hybrid analytical model (HAM) of global magnetic field of FM-RDT is developed by combining the two models with boundary magnetic flux. The calculation results of HAM are compared with the finite element method (FEM), and the torque and magnetic saturation performance of the structure are analyzed. In addition, the open water hydrodynamic performance of FM-RDT is simulated and analyzed by using the computational fluid dynamics (CFD) method. The results show that the FM-RDT has a wider operating range and speed regulation range, and it is more suitable as the thruster for low-speed and heavy-duty deep-sea underwater vehicles.
{"title":"Global Magnetic Field Distribution and Open Water Hydrodynamic Performance of a Flux-Modulated Rim-Driven Thruster","authors":"Dawei Liu;Gaolei Wang;Wenhao Li","doi":"10.1109/TMAG.2024.3468308","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3468308","url":null,"abstract":"In order to improve the compression resistance and torque density of rim-driven thruster (RDT) to cope with complex and harsh deep-sea conditi ons, a flux-modulated RDT (FM-RDT) is proposed. This RDT uses a flux-modulated machine (FMM) as the driving machine, which utilizes a modulation ring to realize pressure protection in the deep sea and realizes the high-torque drive through the magnetic field modulation effect. The subdomain model is established in the air-gap and permanent magnet regions, and the permeance network (PN) model is established in the ferromagnetic regions. The nonlinear hybrid analytical model (HAM) of global magnetic field of FM-RDT is developed by combining the two models with boundary magnetic flux. The calculation results of HAM are compared with the finite element method (FEM), and the torque and magnetic saturation performance of the structure are analyzed. In addition, the open water hydrodynamic performance of FM-RDT is simulated and analyzed by using the computational fluid dynamics (CFD) method. The results show that the FM-RDT has a wider operating range and speed regulation range, and it is more suitable as the thruster for low-speed and heavy-duty deep-sea underwater vehicles.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 11","pages":"1-14"},"PeriodicalIF":2.1,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142517995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The round bar steel made of C45 steel material is widely used as a general machine part material, such as springs for automobiles. This round steel bar requires high-speed surface defect inspection during the manufacturing process. In this research, an inspection method is proposed in which a round steel bar is moved at a high speed of 1 m/s in a ring-shaped permanent magnet with a single differential detection coil to detect surface defects in the round steel bar. In addition, the possibility of estimating the location of a circumferential defect on the round steel bar is demonstrated by using two double-sided quadrupole permanent magnets with only one differential detection coil.
{"title":"Detection and Location Estimate of External Surface Defects Using Velocity Effects From Double-Sided Quadrupole Permanent Magnets","authors":"Masafumi Kuromizu;Akihiko Motoyama;Kai Komatsubara;Takaaki Nara;Yuji Gotoh","doi":"10.1109/TMAG.2024.3469108","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3469108","url":null,"abstract":"The round bar steel made of C45 steel material is widely used as a general machine part material, such as springs for automobiles. This round steel bar requires high-speed surface defect inspection during the manufacturing process. In this research, an inspection method is proposed in which a round steel bar is moved at a high speed of 1 m/s in a ring-shaped permanent magnet with a single differential detection coil to detect surface defects in the round steel bar. In addition, the possibility of estimating the location of a circumferential defect on the round steel bar is demonstrated by using two double-sided quadrupole permanent magnets with only one differential detection coil.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 12","pages":"1-4"},"PeriodicalIF":2.1,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1109/TMAG.2024.3462648
{"title":"IEEE Magnetics Society Information","authors":"","doi":"10.1109/TMAG.2024.3462648","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3462648","url":null,"abstract":"","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 10","pages":"C2-C2"},"PeriodicalIF":2.1,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10695793","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A model for predicting the vector hysteresis properties of non-oriented steel sheets under multiaxial stress is proposed. Based on the magneto-elastic energy of a single crystal and coordinate transformation from crystal to sample, the effective field contains anisotropy, and magneto-mechanical characteristics are derived. By combining the effective field with the energy-based (EB) model, the sensibility of mechanical stress is accounted for in both the reversible and irreversible magnetization aspects. Comparisons between measured and calculated results are performed to validate the model. The results show that the model can accurately predict the rotational magnetic properties under multiaxial stress.
{"title":"Anisotropic Vector Hysteresis Modeling for Non-Oriented Electrical Steel Sheets Under Multiaxial Stress","authors":"Ruiying Chen;Floran Martin;Yongjian Li;Shuaichao Yue;Yating Li;Anouar Belahcen","doi":"10.1109/TMAG.2024.3467696","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3467696","url":null,"abstract":"A model for predicting the vector hysteresis properties of non-oriented steel sheets under multiaxial stress is proposed. Based on the magneto-elastic energy of a single crystal and coordinate transformation from crystal to sample, the effective field contains anisotropy, and magneto-mechanical characteristics are derived. By combining the effective field with the energy-based (EB) model, the sensibility of mechanical stress is accounted for in both the reversible and irreversible magnetization aspects. Comparisons between measured and calculated results are performed to validate the model. The results show that the model can accurately predict the rotational magnetic properties under multiaxial stress.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 12","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142736592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A semi-analytical method is presented in this article for evaluating the magnetic properties of soft magnetic composites (SMCs), and the quantitative structure-activity relationship between microstructural parameters and macroscopic magnetic properties of SMCs is investigated. First, a new homogenization model is developed with the objective of characterizing the microstructure of SMC. The concepts of insulating layer, pore, and surface roughness structure are introduced. Meanwhile, the thickness of the insulating layer is calculated using the least square, the mass density and volume fraction of the particles are determined using a discrete element method (DEM), and the surface roughness of the particles is characterized using a periodic square waveform. Then, by analyzing the relationship between the microstructural parameters and magnetic properties, analytical expressions are derived to realize the evaluation of the macroscopic permeability and eddy current loss of the SMC. Finally, the SMC-prepared samples are tested by the dc magnetization method and ring sample method, respectively, to verify the reliability of the proposed semi-analytical method by comparing the experimental and evaluation results.
{"title":"Semi-Analytical Method for Evaluating Magnetic Properties of SMC Based on Homogenization Model","authors":"Xuanzhe Zhao;Dianhai Zhang;Ziyan Ren;Kaimeng Shi;Yanli Zhang;Chang-Seop Koh","doi":"10.1109/TMAG.2024.3467670","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3467670","url":null,"abstract":"A semi-analytical method is presented in this article for evaluating the magnetic properties of soft magnetic composites (SMCs), and the quantitative structure-activity relationship between microstructural parameters and macroscopic magnetic properties of SMCs is investigated. First, a new homogenization model is developed with the objective of characterizing the microstructure of SMC. The concepts of insulating layer, pore, and surface roughness structure are introduced. Meanwhile, the thickness of the insulating layer is calculated using the least square, the mass density and volume fraction of the particles are determined using a discrete element method (DEM), and the surface roughness of the particles is characterized using a periodic square waveform. Then, by analyzing the relationship between the microstructural parameters and magnetic properties, analytical expressions are derived to realize the evaluation of the macroscopic permeability and eddy current loss of the SMC. Finally, the SMC-prepared samples are tested by the dc magnetization method and ring sample method, respectively, to verify the reliability of the proposed semi-analytical method by comparing the experimental and evaluation results.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 11","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142517996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1109/TMAG.2024.3466289
Karl Hollaus;Valentin Hanser;Markus Schöbinger
To facilitate simulations in the design of electrical machines with a laminated core, often only a slice model is considered instead of the entire machine. We propose a method where the expensive 3-D eddy current problem (ECP) of the slice model is replaced by a cheap static magnetic field problem (SMFP) with an effective material (EM) in a 2-D finite element (FE) model. The EM is obtained by solving suitable cell problems (CPs). Losses and reactive powers are assumed to be the same in the CPs. The method with the EM is very efficient and accurate compared with the ECP as shown by numerical simulations of an electrical machine. Voltage excitation of the machine is considered, i.e., the FE model is coupled with an external circuit.
为了便于模拟设计带有层叠铁芯的电机，通常只考虑一个切片模型，而不是整个电机。我们提出了一种方法，即在二维有限元（FE）模型中，用带有有效材料（EM）的廉价静态磁场问题（SMFP）取代切片模型中昂贵的三维涡流问题（ECP）。通过求解合适的单元问题（CPs）可获得电磁场。假设各单元问题中的损耗和无功功率相同。通过对一台电机进行数值模拟，可以看出与 ECP 相比，使用 EM 的方法非常高效和精确。考虑了机器的电压激励，即 FE 模型与外部电路耦合。
{"title":"Effective Material and Static Magnetic Field for the 2-D/1-D-Problem of Laminated Electrical Machines","authors":"Karl Hollaus;Valentin Hanser;Markus Schöbinger","doi":"10.1109/TMAG.2024.3466289","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3466289","url":null,"abstract":"To facilitate simulations in the design of electrical machines with a laminated core, often only a slice model is considered instead of the entire machine. We propose a method where the expensive 3-D eddy current problem (ECP) of the slice model is replaced by a cheap static magnetic field problem (SMFP) with an effective material (EM) in a 2-D finite element (FE) model. The EM is obtained by solving suitable cell problems (CPs). Losses and reactive powers are assumed to be the same in the CPs. The method with the EM is very efficient and accurate compared with the ECP as shown by numerical simulations of an electrical machine. Voltage excitation of the machine is considered, i.e., the FE model is coupled with an external circuit.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 12","pages":"1-4"},"PeriodicalIF":2.1,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10689458","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142736538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-23DOI: 10.1109/TMAG.2024.3466273
Xiangxian Zeng;Chin-Hsing Kuo;Emre Sariyildiz
This article presents a numerical approach for computing and synthesizing the force between two permanent magnets (PMs) under general conditions. Initially, a general formula for determining the interactive force between two arbitrary PMs is derived, resulting in a unified 6-D integral for any magnet pairs. Following this, a computational algorithm utilizing Monte Carlo (M-C) integration for solving the integral is developed. The significance of the presented method is twofold. First, the derived formula and algorithm are unified, enabling the computation of forces between two magnets under general conditions, allowing for arbitrary shapes, magnetizations, and relative locations of the magnets. Second, the approach is applicable to the design synthesis problems, where the geometries of the magnets are to be designed to achieve the prescribed interactive force. Numerical examples are provided to demonstrate the generality and feasibility of the method for magnet-force analysis and synthesis. In addition, the accuracy and efficiency of the proposed approach are discussed and compared with the finite-element-analysis (FEA) simulation in the case studies.
{"title":"A Computational Approach for the Analysis and Synthesis of the Interactive Force Between Two General Permanent Magnets by Using Monte Carlo Integration","authors":"Xiangxian Zeng;Chin-Hsing Kuo;Emre Sariyildiz","doi":"10.1109/TMAG.2024.3466273","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3466273","url":null,"abstract":"This article presents a numerical approach for computing and synthesizing the force between two permanent magnets (PMs) under general conditions. Initially, a general formula for determining the interactive force between two arbitrary PMs is derived, resulting in a unified 6-D integral for any magnet pairs. Following this, a computational algorithm utilizing Monte Carlo (M-C) integration for solving the integral is developed. The significance of the presented method is twofold. First, the derived formula and algorithm are unified, enabling the computation of forces between two magnets under general conditions, allowing for arbitrary shapes, magnetizations, and relative locations of the magnets. Second, the approach is applicable to the design synthesis problems, where the geometries of the magnets are to be designed to achieve the prescribed interactive force. Numerical examples are provided to demonstrate the generality and feasibility of the method for magnet-force analysis and synthesis. In addition, the accuracy and efficiency of the proposed approach are discussed and compared with the finite-element-analysis (FEA) simulation in the case studies.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 11","pages":"1-17"},"PeriodicalIF":2.1,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142518156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In a delta connection, most of the battery voltage is applied directly to the motor’s phase terminals, resulting in a voltage that is root three times higher than in a wye connection. This characteristic makes delta connections suitable for low-voltage, high-speed systems. However, the presence of 3 n-th harmonic components in the phase back electromotive force (BEMF) of delta-connected motors can induce circulating currents that flow exclusively within the circuit. These circulating currents lead to additional Joule losses and degrade motor performance. This article analyzes the effect of circulating currents on motor efficiency according to different speeds and torques. The presented study models maintain a similar magnitude of the fundamental component of BEMF but differ in the magnitude of the third harmonic component. A six-step circuit was established to compare the currents, losses, and efficiencies of the study models using finite element analysis (FEA). The copper losses were categorized into those caused by the fundamental component of phase current and those caused by the circulating currents. Subsequently, the efficiencies of the study models were compared across different speed and torque ranges, accounting for the separated copper loss components and iron losses. The results show that the improved model achieves an efficiency that is more than 18% higher than that of the basic model in the low-speed and low-torque areas. Finally, the study models were manufactured and evaluated through testing.
{"title":"Efficiency Analysis of BLDC Motor With Delta Connection According to Magnitude of Circulating Current","authors":"Ho-Young Lee;Kyoung-Soo Cha;Soon-O Kwon;Seung-Young Yoon;Chang-Hoon Seok;Myung-Seop Lim","doi":"10.1109/TMAG.2024.3465879","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3465879","url":null,"abstract":"In a delta connection, most of the battery voltage is applied directly to the motor’s phase terminals, resulting in a voltage that is root three times higher than in a wye connection. This characteristic makes delta connections suitable for low-voltage, high-speed systems. However, the presence of 3 n-th harmonic components in the phase back electromotive force (BEMF) of delta-connected motors can induce circulating currents that flow exclusively within the circuit. These circulating currents lead to additional Joule losses and degrade motor performance. This article analyzes the effect of circulating currents on motor efficiency according to different speeds and torques. The presented study models maintain a similar magnitude of the fundamental component of BEMF but differ in the magnitude of the third harmonic component. A six-step circuit was established to compare the currents, losses, and efficiencies of the study models using finite element analysis (FEA). The copper losses were categorized into those caused by the fundamental component of phase current and those caused by the circulating currents. Subsequently, the efficiencies of the study models were compared across different speed and torque ranges, accounting for the separated copper loss components and iron losses. The results show that the improved model achieves an efficiency that is more than 18% higher than that of the basic model in the low-speed and low-torque areas. Finally, the study models were manufactured and evaluated through testing.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 12","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142736591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Cauer ladder network (CLN) method can accelerate eddy current field analysis of electromagnetic devices in the time domain by reducing the order of the finite-element (FE) model. To control its accuracy, the reduction error should be estimated without conducting the FE analysis. In this study, we extend the estimation method in the frequency domain developed in a previous study to time-domain analysis. The proposed method is also extended to a multiport system. Numerical examples illustrate that the proposed error estimation method is effective.
{"title":"Error Estimation of the Cauer Ladder Network Method for the Time-Domain Analysis and Its Application to a Multiport System","authors":"Miwa Tobita;Stéphane Clénet;Shingo Hiruma;Wei Chen;Tetsuji Matsuo","doi":"10.1109/TMAG.2024.3466808","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3466808","url":null,"abstract":"The Cauer ladder network (CLN) method can accelerate eddy current field analysis of electromagnetic devices in the time domain by reducing the order of the finite-element (FE) model. To control its accuracy, the reduction error should be estimated without conducting the FE analysis. In this study, we extend the estimation method in the frequency domain developed in a previous study to time-domain analysis. The proposed method is also extended to a multiport system. Numerical examples illustrate that the proposed error estimation method is effective.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 12","pages":"1-4"},"PeriodicalIF":2.1,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article proposes a time-domain homogenization technique for windings using the B-input Cauer ladder network (CLN) method. First, the novel CLN procedure is presented to derive the equivalent circuit of a unit cell that acts as a homogenized model of the winding. The validity of the proposed method is then verified by comparing it with the results of homogenization of a winding using a semi-analytical approach. Finally, the derived equivalent circuit is applied to finite-element analysis (FEA) of a flat-wire inductor to demonstrate the effectiveness of the proposed method.
{"title":"Time-Domain Homogenization of Windings Using B-Input Cauer Ladder Network Method","authors":"Yasuhito Takahashi;Shingo Hiruma;Koji Fujiwara;Satoshi Imamori","doi":"10.1109/TMAG.2024.3464583","DOIUrl":"https://doi.org/10.1109/TMAG.2024.3464583","url":null,"abstract":"This article proposes a time-domain homogenization technique for windings using the B-input Cauer ladder network (CLN) method. First, the novel CLN procedure is presented to derive the equivalent circuit of a unit cell that acts as a homogenized model of the winding. The validity of the proposed method is then verified by comparing it with the results of homogenization of a winding using a semi-analytical approach. Finally, the derived equivalent circuit is applied to finite-element analysis (FEA) of a flat-wire inductor to demonstrate the effectiveness of the proposed method.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"60 12","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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