查询词典 magnetic field

Faraday's law is that when the flux in the conductor loop changes, it produces electromotive force in the conductor loop, and obeys to contour integral law , Maxwell Curl Theory is that when the magnetic intensity of a certain point in ether space changes, there produces electric field at that point in ether space, which is the field mutual production theory of "electric field produces magnetic field and magnetic field produces electric field" in the free space which everybody is familiar with, and it obeys differential law , Lorentz magnetic force is that when metal electrons cut magnetic lines, metal electrons forced by move along the conductor to form inductive current, in fact, it doesn't matter whether coil moves or magnet moves, only if there exists relative motion between magnetic field and conductor, metal electrons must cut magnetic lines, which is,"coil stills while magnet moves to the left" and "magnet stills while coil moves to the right" these two situations are the same, which both belong to metal electrons having cut magnetic lines.

法拉第定律指导体环路里的磁通量发生变化时，在导体环路上产生电动势，而且服从围线积分律；麦克斯韦旋度理论指以太空间某点的磁场强度发生变化时，在以太空间的该点产生电场，即大家熟知的自由空间里"电场生磁场与磁场生电场"之互生场理论，而且服从微分律；洛伦兹磁力指金属电子切割磁力线时，金属电子受力沿着导体漂移而形成感应电流，其实，无论线圈运动或是磁铁运动，只要磁场与导体存在相对运动，则金属电子必然切割磁力线，即，"线圈静止而磁铁向左运动"与"磁铁静止而线圈向右运动"这两种情况是一样的，都属于金属电子切割了磁力线。

A mathemetical model of magnetic field in electromagnetic separation of inclusions from molten aluminum under rectangle coil and 50Hz current is presented according to the magnetic vector potential integral equation and the basic theory of magnetohydrodynamics. The magnetic field distribution in the gap of coils is simulated by the model and the actual magnetic field distribution also is measured. The experimental results show that the magnetic field distribution in the gap of coils is uniform and is consistemt with the model simulation. The magnetic field designed accord the simulated result is proved suitable in the practice.

摘 要：根据电磁流体力学的基本理论，利用矢量磁位积分，建立了在采用矩形电磁线圈和工频电源的条件下电磁分离铝熔体中夹杂的电磁场数学模型，模拟计算了电磁感应线圈气隙中的磁场分布状态，同时对制做的感应线圈的实际磁场进行了测量模拟计算磁场的分布状态与实际磁场的测量结果基本一致，都表明在电磁感应线圈气隙中磁场分布均匀，可以进行分离铝熔体中的非金属夹杂。

objective to study the intensity of magnetic field on a special meridian magnetic applicaˉtion.methods a special meridian magnetic application is found the variations of the intensity of magnetic field when it is in vitro,nipped by fingers and stuck on skin of meridian and non-meridian.results the variation of the inˉtensity of magnetic field and the difference of the two poles have a statistical significance when the special meridian magnetic applicationon straight line and interval10mm compares to on other conditions above.conclusion owing to a definite directivity of the magnetic field gradient is produced when the magnetic application on the meridians,it is hopeful to carry out the effects of the tonic and vent by acupuncture.

目的 研究循经传感磁疗贴的磁场强度变化。方法一种特制的磁疗贴，在体外、指捏、敷贴于皮肤表面的经络走行和非经络走行区时所测得的磁场强度变化。结果当该磁疗贴直线排列，间隔10mm时，与单独磁疗贴的初始相比，磁场强度发生明显变化，且具有两极差异；敷贴于皮肤经络走行区，与体外及非经络走行区相比，磁场强度变化显著，尤其在手阴经的走行区域，具有显著的统计学意义。结论该磁疗贴在经络走行线上形成的磁场梯度，具有明确的方向性，有望实现针刺产生的补与泄的作用。

Electromagnetics course mainly including basic phenomena and laws of electro- magnetics, electrostatic field in vacuum, in conductor and in electric medium, electric energy, stabilized current, stabilized magnetic field and its basic laws, electric and magnetic fields caused by a moving chager in lower speed, the transform of electric and magnetic fields between different systems of coordinates, inductive laws, eddy field, self inductance, mutual inductance and transient, molecule current and magnetic substance, ferromagnet, boundary conditions, magnetic circuit theorem, energy of magnetic field and density of magnetic energy, displacement current, Maxwell's equation, electromagnetic wave, Poynting vector.

电磁学课程的主要内容包括：静电的基本现象和基本定律，真空中的静电场，导体和电介质中的静电场，电场的能量与电场能量密度，稳恒电流，稳恒电流磁场的基本定律，运动电荷的电磁场，不同参照系之间电磁场的变换，电磁感应定律，涡旋电场，互感，自感，暂态过程，分子电流与磁介质，铁磁体，边界条件，磁路定理，磁场的能量和磁能密度，位移电流， Maxwell 方程组，电磁波和玻印廷矢量等。

Some people introduce subphotosphere magnetic charges or dipole, which can fit magnetic field on the photosphere, then the separatrix and separator above and on the photosphere can be located, the comparison between their location and location of flare ribbon support the idea of magnetic reconnection. It is called Source Method. Some people extrapolate magnetic fields of photosphere to corona by some method, then use QSLs method to investigate the relations between flare ribbons and magnetic field topology. Some people study relations between flare ribbons and singular point on the plane above photosphere. Some people investigate magnetic topology by analyzing magnetic field of photosphere directly.

或者以观测的光球磁场为基础，来构造光球下的磁荷或磁偶极等光球下磁源，进而研究光球上的磁拓扑结构与耀斑的关系；或者利用各种外推方法将光球磁场进行外推，然后用准分隔层的方法来研究磁拓扑结构与耀斑的关系；或者利用势场模型外推光球磁场，然后研究光球之上平行于光球的某一平面的两维奇点与耀斑的关系；或者直接利用观测的光球矢量场来研究磁场拓扑。

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。

Based on the analysis of displacement of the electron in transverse magnetic field ,computation of magnetic field of Helmholtz coil and the analysis of uniform scope of magnetic field,the expression of the electron displacement with magnetic field intensity in intensitive uniform magnetic field is modified by the authors.

为了衡量电子在横向磁场下的偏移量的实验中所测数据的优劣性，分析了电子在横向磁场下的偏移原理，，通过亥姆霍兹线圈全空间磁场的计算和磁场均匀性范围的分析；修正了电子在匀强磁场中偏移距离与磁感应强度的关系式，得到了电子在磁场中的偏移距离与产生匀强磁场的电流以及磁场大小的偏差率之间的关系以及成立的条件。

Experiment results indicate that the magnetic fluid flux has a direct relation with the magnetic field under the effect of traveling wave magnetic field. The bigger the magnetic field is, the more the flux is, when the structure of the magnetic fluid travellig pump and the saturation magnetization of magnetic fluid are constant. The volumes of the magnetic fluid from the travelling wave pump increase from 1.9 ml to 3.1 ml, when the magnetic field intensity increases from 25 900 A/m to 40 000 A/m. In addition, the change rate of the magnetic fluid decreases with the increase of the magnetic field due to the effect of magnetic field on magnetic fluid viscosity. The bigger the saturation magnetization of the magnetic fluid is, the more the flux is.

结果表明，行波磁场作用下的磁性流体流量与磁场的强度有直接关系：在磁性流体行波泵结构和磁性流体饱和磁化强度相同的条件下，磁场强度越强，其流量越大；当磁场强度从25900A/m增加到40000A/m时，单位时间内从行波泵内流出的磁性流体的体积由1.9 ml增加到3.1 ml；随着磁场强度的不断增加，磁性流体流量的变化率由于磁场对其粘度的影响而减小；而磁性流体的饱和磁化强度越大，其流量也越大。

Firstly, the relationship between the magnetic pole state of active magnetic pole and the running state of passive magnetic pole was analyzed. The electromagnet's four magnetic pole state and switch sequence, which can drive permanent magnet rotate, were ascertained. Secondly, taking one of magnetic pole state NS (N denotes electromagnet's left magnetic pole and S right magnetic pole) as an example, the distribution of space magnetic field was studied. In addition, the mathematical model of space magnetic field was set up based on the magnetic circuit fundamental and using the method of magnetic analysis and modeling. Lastly, the four states' mathematical model of space magnetic field was solved by using the MATLAB.

首先，分析系统主动磁极磁极状态和从动磁极转动状态之间的关系，确定驱动永磁体转动的电磁体4个磁极状态及切换顺序；其次，基于磁路基本原理，通过磁场分析和建模，以电磁体4个磁极状态之一的NS（N表示其左极、S为右极）为例，对电磁体的空间磁场分布进行研究并建立空间磁场数学模型；最后，以MATLAB为平台对4个磁极状态的空间磁场数学模型进行求解，将求解结果与实验数据进行对比。

It goes back to what I told you...

现在回到我告诉过你的。。。

With a supporter in Mr Charest and an admirer in Mr Dumont, Mr Harper may be encouraged to call an election himself.

由于在沙雷那边有个支持者，杜蒙那边有个崇拜者，鼓励哈珀为自己举行一次选举。