查询词典 The Magnet

This invention discloses a preparation method for anti-corrosion rare earth magnet material characterizing that it takes the optimized grain-boundary phase design as the starting point on the basis of a dual alloy method to select Nd base alloy with high crystal forming ability as the assist alloy and reduces the temperature of the press mold blank in a quartz container to room temperature from over grain-boundary phase melting point with the water extraction way to get enough cooling rate and guarantee the non-grain-boundary phase, compared with the material of the same composition prepared by ordinary method, the weightlessness of this invented material reduces over 30% after testing the weightlessness of the material by laying it for 96 hours under 121deg.C, 2 atmosphere and 100% humid environment to show the advanced performance of anti-corrosion.

本发明公开了一种耐腐蚀稀土永磁材料的制备方法，其特征是它在双合金法制备工艺的基础上，以优化晶界相设计为出发点，选取具有较高非晶形成能力的Nd基合金为辅合金，并在烧结回火时将置于耐高温石英容器中的压型坯件，从晶界相熔点以上以水淬冷却的方式降温至室温，以达到足够的冷却速率，确保得到非晶晶界相，根据本发明制得的耐腐蚀稀土永磁材料，通过测量在121℃、2个大气压以及100％湿度环境下放置96小时后材料的失重情况，结果显示本发明得到的材料与常规方法制备的相同成分的稀土永磁材料相比失重减少了30％以上，充分证明其具备了更优越的耐腐蚀性能。可广泛应用于电子、汽车、计算机、电力、机械、能源、环保、国防、医疗器械等领域。

ABSTRACT The researches of this thesis are carried out around the development of high performance machine tool spindle permanent magnet synchronous motor and its drive system. Five parts are included: First of all, concerning the operating characteristics of the machine tool spindle drive system, the optimum current control strategies of spindle PMSM are determined; The design rules of spindle PMSM's key parameters are summarized, based on the study on the influences of the design parameters on the performances of the PMSM operating at different current control strategies; The practical methods to improve the flux-weakening ability of the PMSM are presented; Based on the analysis and comparison of the operating performances of PMSM with different rotor structures, a novel PMSM rotor structure, which is of excellent mechanical performance, suitable for fluxweakening operation and can improve the torque output capacity in the same time, is presented.

本文围绕高性能机床主轴永磁同步电动机及其传动系统的设计研究展开，所做工作主要包括五部分：首先，确定了主轴永磁同步电动机定子电流的最优控制策略；通过对不同控制策略下主要设计参数对主轴永磁同步电动机性能影响的计算研究，总结了参数设计规律；提出了永磁同步电动机弱磁扩速的实用措施；在分析比较不同转子磁路结构电机的性能，尤其是弱磁扩速能力的基础上，提出了一种机械性能优越，易于弱磁扩速，同时能保证电机恒转矩运行时的转矩输出能力的新型转子磁路结构。

Shutdown, removed the row fan, fan struck by hand, the sense of rotation of the fan is very flexible, so use flat screwdriver inserted under the roots of the gap fanleaf bend to the will of the fan and fan-Block separation and jumped over the fan, the fan to see in the center of a small arc with several magnet surrounded a round shield-shaped, it is clear that this is the fan motor rotor, while the stator is fixed together with the fan-Block a micro-winding, if the fan and fan blocks together, the micro-coil is inserted to the internal rotor.

关机，将该排风扇拆下，用手拨动扇叶时，感觉扇叶的转动很不灵活，故用平头起子插入扇叶根部底下的缝隙内向上翘，将整个扇叶与扇座分离，翻过扇叶时，看到在扇叶的中心部位有一个用数条小弧形磁铁围成的圆罩形，显然，这就是该风扇电机的转子，而定子是与扇座固定在一起的一个微型绕组，若将扇叶与扇座组合在一起，则该微型绕组正好能插在转子的内部。

Fix a super intense magnet at the north pole of the terrestrial globe, the top of the terrestrial globe is the magnetic field controller which senses the distance between the terrestrial globe and the controller through the sensor; when the distance becomes shorter, the controller will automatically reduce the magnetic field; on the other hand, when the distance becomes greater, the controller will automatically increase the magnetic field and, in this way, guarantee a certain distance between the terrestrial globe and the controller.

在地球仪的北极固定一个超强磁铁，地球仪上面是磁场控制器，通过传感器感知地球仪与控制器的距离。

After take analyzed deeply for the opened magnet circuit with FEMM (Finite Element Method Magnetics) we find out the field distributing that is separated into three sections . One is the main area what we called as positive field section. Beside the main field there are tow areas that are called the inverted field sections. Loudspeaker arise a very serious distortion when the voice coil moving into inverted field areas. The direction of induced current in the coil part of entered inverted field area is same with the current driving into loudspeaker so that total currents increas largely and heat increase rapidly. With more coils moving into inverted area the voice coil will take on negative inductance properties. It is the main reason that voice coil is burned by heating with increasing current due to arise negative inductance. So opened magnetic circuit is not suitable for the woofers in which the voice coil have wider displacement range. When using this kind magnetic circuit design, the voice coil moving range should be less than the range of positive field to avoid loudspeaker arise serious distortion and heating. Even though voice coil moving range is in the positive area, loudspeaker will still arise more distortion because the field distribution is very cliffy at tow sides of the positive area and full range of magnetic field distribution is not parallel that will arise distortion. Base on above reasons, opened magnetic circuit is not an ideal magnetic circuit for low-frequency loudspeakers. But it can be used in mid-range or high-frequency productions.

开式磁路是由2片钕铁硼磁铁和主导磁板和导磁垫片组成，我们在实践过程中发现这种磁路结构不适合于低频扬声器的使用，我们通过使用FEMM（Finite Element Method Magnetics）软件包对该磁路进行了分析，该磁路的磁场范围被分成3个区域，其中在主导磁板附近形成一个正向磁场，在正向磁场的两边存在反向的磁场，音圈在工作时有很大一部分进入了反向磁场中，在反向磁场内线圈的感应电流方向与驱动电流方向相同，使得音圈呈现出负感抗特性，由于音圈的负感抗特性引起电流的增加导致音圈发热甚至烧毁，因此在扬声器中使用开式磁路时，音圈的运动范围应控制在正向磁场范围之内，否则音圈运动到反向磁场区域时将会产生很大的失真和发热，即使在设计时已经将音圈的运动范围控制在正向磁场范围之内，由于正向磁场的2个边缘磁场强度衰减太快，同时开式磁路中磁场的分布不是平行的，而是自由发散的分布，这样肯定会导致扬声器的非线性失真，因此我们得到的结论是：开式磁路并不是一个理想的磁路，它不适合于低频扬声器的使用，但它还可以应用于中高频扬声器。

The opened magnetic circuit is composed as tow NdFeB permanent magnets and a top plate without U-yoke. After take analyzed deeply for the opened magnet circuit with FEMM (Finite Element Method Magnetics) we find out the field distributing that is separated into three sections . One is the main area what we called as positive field section. Beside the main field there are tow areas that are called the inverted field sections. Loudspeaker arise a very serious distortion when the voice coil moving into inverted field areas. The direction of induced current in the coil part of entered inverted field area is same with the current driving into loudspeaker so that total currents increas largely and heat increase rapidly. With more coils moving into inverted area the voice coil will take on negative inductance properties. It is the main reason that voice coil is burned by heating with increasing current due to arise negative inductance. So opened magnetic circuit is not suitable for the woofers in which the voice coil have wider displacement range. When using this kind magnetic circuit design, the voice coil moving range should be less than the range of positive field to avoid loudspeaker arise serious distortion and heating. Even though voice coil moving range is in the positive area, loudspeaker will still arise more distortion because the field distribution is very cliffy at tow sides of the positive area and full range of magnetic field distribution is not parallel that will arise distortion. Base on above reasons, opened magnetic circuit is not an ideal magnetic circuit for low-frequency loudspeakers. But it can be used in mid-range or high-frequency productions.

开式磁路是由2片钕铁硼磁铁和主导磁板和导磁垫片组成，我们在实践过程中发现这种磁路结构不适合于低频扬声器的使用，我们通过使用FEMM（Finite Element Method Magnetics）软件包对该磁路进行了分析，该磁路的磁场范围被分成3个区域，其中在主导磁板附近形成一个正向磁场，在正向磁场的两边存在反向的磁场，音圈在工作时有很大一部分进入了反向磁场中，在反向磁场内线圈的感应电流方向与驱动电流方向相同，使得音圈呈现出负感抗特性，由于音圈的负感抗特性引起电流的增加导致音圈发热甚至烧毁，因此在扬声器中使用开式磁路时，音圈的运动范围应控制在正向磁场范围之内，否则音圈运动到反向磁场区域时将会产生很大的失真和发热，即使在设计时已经将音圈的运动范围控制在正向磁场范围之内，由于正向磁场的2个边缘磁场强度衰减太快，同时开式磁路中磁场的分布不是平行的，而是自由发散的分布，这样肯定会导致扬声器的非线性失真，因此我们得到的结论是：开式磁路并不是一个理想的磁路，它不适合于低频扬声器的使用，但它还可以应用于中高频扬声器。

The thesis illustrates the principle of the and its application in the system, establishes the simulation model of the vector control system of PMSM based on the EKF and successfully realizes the application of the speedless sensor in motor control. Firstly, based on the mathematic model of permanent-magnet synchronous motor, the PMSM vector control system is built. Secondly, the Extended Kalman Filter is designed for the on-line estimation of the speed and rotor position by only using measurements of the motor voltages and currents.

首先，基于PMSM的数学模型，建立了电机的矢量控制仿真模型；其次，设计了扩展卡尔曼滤波器，通过检测电机端电压、相电流对电机转速和转子位置进行在线实时估计，实现了PMSM的无传感器矢量控制；最后，在Matlab7.0环境下进行的系统仿真试验表明，该方法具有优良的转角跟踪特性和较好的转速跟踪特性，同时系统具有较强的抗负载扰动性能和较佳的控制性能。

Based on the developed iron loss of surface-mounted permanent magnet machine of Slemon and Xian Liu, the expressions of the peak and the time rate change of flux density in the teeth and the yoke are derived, considering the beveling edges of the PM. According to the basic concept of the eddy current loss, the analytic calculations of the average eddy current loss density in the teeth and the yoke are presented respectively. Hence, a calculation method for the iron losses of PM with beveling edges is presented.

在Slemon和Xian Liu表面置磁型永磁电机改进铁耗算法的基础上，分别推导了考虑磁体边缘斜角时定子齿与轭的磁通密度的幅值及其时间变化率的表达式，结合涡流损耗的基本概念，分别提出了永磁电机定子齿与轭的平均涡流损耗密度的解析计算方法，由此建立了永磁电机铁耗的解析模型。

If the fluidity of the injection was bad, the appearance of the product would berough, brittle, and very difficult to satisfy the actual application. In order to improve thefluidity of the melting-body in full filling condition, different types of lubricant function were used in the paper. Though the metallic soap might enhance the fluidity of themelting-body, the dosage was huge, which might cause drops on the mechanics intensityof the product, and cause magnet to be crisp and easy to crack.

为改善在高填充时熔体的流动性，研究了不同润滑剂的作用，金属皂类可以提高熔体的流动性，但用量较大，会导致产品的力学强度的下降，磁体脆而容易开裂，乙撑双硬脂酰胺可以提高熔体的流动性，复合材料的力学强度也较高。

For improving the static and dynamic seal properties of the magnetic fluid seal, the correlation between the seal capacity and the residual induction intensity and coercive force of permanent magnet has been studied. An ANSYS model for analyzing parametrically magnetic path was developed and optimize design of the magnetic path parameters has also been carried out based on the model and simulation analysis.

为了提高磁流体动、静密封的能力，文中探讨了磁性材料中剩余磁感应强度和矫顽力与磁流体密封能力之间的相互关系；建立了基于磁路参数化的ANSYS模型，通过磁路的仿真，数值计算实现了磁流密封结构的优化设计。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。