magnet

摘要： BACKGROUND Electromagnetic interference(EMI),means disturbance to the operation of implanted electrical devices caused by external sources.If cardiac pacemaker is implanted into the body,the risk of EMI should be considered when performing neuromuscular electrical stimulation(NMES).So far,no case has been reported that clinical magnets are used to safely manage the EMI risk of patients with cardiac pacemaker in NMES.CASE SUMMARY A 72-year-old male with swallowing disorder due to pure motor lacunar syndrome was transferred to rehabilitation department six days after the symptom onset.EMI risk needed be considered when implementing NMES on pharyngeal muscles,since cardiac pacemaker was implanted on his left chest due to the sick sinus syndrome.In the first NMES,the function of the pacemaker was directly monitored using telemetric instruments.From the second day,by a simple method of placing a magnet on the pacemaker,we chose to move the pacemaker into a mode that the device was not influenced by external stimulus.This magnet method has been used repeatedly for a year for the safe NMES treatment.We could remove Levin tube four months after the initial symptom and dysphagia related symptoms had not been noted during two-year follow-up period.CONCLUSION This report is the first case of dysphagia rehabilitation that EMI risk was handled using mode change of pacemaker with magnet.This method is unfamiliar to doctors,but safe and easy approach.This paper could be guidance for clinicians who need to treat patients with EMI risk.

摘要： 利用专用的电磁仿真软件MAGNET对轴向双分裂和大容量等复杂干式变压器进行了不同运行工况下的磁场分析和验证.基于场路耦合法根据需要模拟的工况建立合适的2D或3D等效模型,并利用正确的等效电路和边界条件对变压器的运行工况进行有限元分析模拟,最终通过能量法或电压法得到相应工况下变压器的阻抗.实际测试结果表明该方法的计算精度可满足产品实际要求,可使用MAGNET对干式变压器的阻抗进行仿真计算和设计改进.

摘要： 针对径向电磁悬浮控制提出了一种Magnet/Simulink联合仿真的方法。首先在Magnet软件中建立径向电磁悬浮系统的模型,在Simulink中搭建PID控制电磁悬浮系统的程序框图,然后将Magnet中的径向电磁悬浮系统模型导入Simulink控制程序中,建立径向电磁悬浮系统Magnet/Simulink联合仿真控制模型,最终实现了径向电磁悬浮系统PID控制仿真。结果表明:Magnet/Simulink联合仿真方法可实现对悬浮控制过程中的电磁力、转子速度、转子位移等参数变化情况的实时监测;Magnet/Simulink联合仿真方法不但提高了电磁悬浮控制仿真的效率,且为探究控制方法或控制器参数对电磁悬浮系统的影响提出了一种新的思路。

摘要： Objective: New method to use magnet for localization and extraction of shell during head and neck surgery. Method: Series of 3 cases study all are boy’s 17_15_5 years old respectively. All are with penetrating shell injuries to head and neck in Salahaden General Hospital-Tikrit city-Iraq from 25-Oct.-2016 to 30 March 2017. This hospital is a central general governmental hospital that receives referral cases from region distal to the center of Salahaden province at north of Baghdad city (capital of Iraq) and plays a major rule in management of injured patient during war. The cases are selected after explanation of this new method to the patients, it is expected result, risk, possible complication, and unexpected sequelae that may happen after surgery. Prior consent from patients and their families about this sort of surgery has been got. These patients are from families of low socio economic group except the last one he is medium class. All are undergoing surgical management with the aid of magnet. Result: we have 3 cases of shell injuries to head and neck magnet is used successfully for identification of shells and helps in their extraction. Our trial is limited for metallic objects and limited depth. Conclusion: These results suggest that magnet aid removal of shell during head and neck surgery, is less invasive technique, minimal trauma to the surrounding tissues and reducing time of surgery.

摘要： The RE-Fe-B permanent magnets have a complex microstructure and they are susceptible to corrosion process. In this paper, the commercial nickel coatings adhesion was investigated. The microstructure of the RE-Fe-B without coating was analyzed by scanning electronic microscopy and electrochemical techniques. The interface magnet/coating was studied by scanning electron microscopy and the nickel-plated Nd-Fe-B commercial magnets were tested in a salt spray chamber. The ferromagnetic and RE-rich phases were observed. After the anodic polarization curve, a strong intergranular corrosion was observed and the RE-rich phase was preferentially attacked. The interface magnet/Ni coating presented inter-granular corrosion that can affect the nickel coating adherence. This attack had probably occurred during the electrodeposition process. Not all the samples suffered localized corrosion during the salt spray tests and the Ni triple-layer coating presented a few corrosion points. RE-Fe-B alloy magnets need to be protected with appropriate coatings to each environment to which they will be exposed and the protective coating must not be damaged.

摘要： A power system structure composed of a brushless DC motor and a cycloidal reducer for electric balanced vehicle has been proposed, and the temperature of important components in this structure would be discussed. The loss generated by the cycloid reducer is negligible, it’s only need to analyze the thermal field of motor. Since the temperature change will affect the material properties of the target motor, the electromagnetic and temperature fields, involved in the motor, are selected for coupling calculation to determine whether the final temperature distribution can meet the requirements of vehicle for use.

摘要： With the improvement of vehicles electrical equipment, the existing silicon rectification generator and permanent magnet generator cannot meet the requirement of the electric power consumption of the modern vehicles electrical equipment. It is di cult to adjust the air gap magnetic field of the permanent magnet generator. Consequently, the output voltage is not stable. The silicon rectifying generator has the problems of low e ciency and high failure rate.In order to solve these problems, a new type of hybrid excitation generator is developed in this paper. The developed hybrid excitation generator has a double-radial permanent magnet, a salient-pole electromagnetic combined rotor,and a fractional slot winding stator, where each rotor pole corresponds to 4.5 stator teeth. The equivalent magnetic circuit diagram of permanent magnet rotor and magnetic rotor is established. Magnetic field finite element analysis(FEA) software is used to conduct the modeling and simulation analysis on double-radial permanent magnet magnetic field, salient-pole electro-magnetic magnetic field and hybrid magnetic field. The magnetic flux density mold value diagram and vector diagram are obtained. The diagrams are used to verify the feasibility of this design. The designed electromagnetic coupling regulator controller can ensure the stable voltage export by changing the magnitude and direction of the excitation current to adjust the size of the air gap magnetic field. Therefore, the problem of output voltage instability in the wide speed range and wide load range of the hybrid excitation generator is solved.

摘要： 一种基于MagNet有限元的磁阀式可控电抗器结构优化方法。其包括绘制磁阀式可控电抗器铁芯尺寸图；建立磁阀式可控电抗器中矩形磁阀结构模型；分析磁阀式可控电抗器各部位的损耗分布；绘制磁阀式可控电抗器内部磁力线分布图；优化磁阀设计；检验优化结果等步骤。本发明提供的基于MagNet有限元的磁阀式可控电抗器结构优化方法的效果：本发明主要研究铁耗的形成机理，绘制出各部位的损耗分布，根据研究结果，针对磁阀结构饱和时产生的边缘效应，对矩形磁阀结构进行了优化设计，结果表明优化后的结构在磁阀饱和时漏磁明显减少，从而使电抗器性能得到提高。