感应电流的

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。

In order to reduce the inductive current and the power loss caused by the current when the power system runs naturally, this article brings forward a way to reduce the power loss through a multiple impedance to insulate the lightning shield line and ground, so that the system can run economically.

为减小系统正常运行时避雷线中出现的感应电流及其电能损耗，提出了利用复合阻抗隔离避雷线与杆塔的方法，EMTP程序对该方法数字仿真的结果证明了它的可行性和有效性，但系统序阻抗也会随之改变，故有必要调整系统保护的整定，以满足系统对保护的要求。

It is recommended that the probabilistic distribution of the Spatial field intensity, the ground field intensity and the induced current in human body should be used as a measure of the level of the electrostatic induction.

根据国内多个500千伏变电站的试验数据，本文着重叙述为什么宜采用空间场强、地面场强以及人体感应电流这三者的统计分布来表征高压变电站的静电感应水平；对于新设计的变电站，提出了比较合理的允许场强值；这时对暂态电击问题仍要重视，文中也提出了一些减少暂态电击的措施。

High strength: Aluminum-magnesium-silicon alloy wire possesses high strength, its min value of tensile strength is 170% of the value of general hard and round aluminum wire(H8), is a fine armored material;②Low loss:as a non-magnetism material, no eddy current loss will happened on aluminum-magnesium-silicon alloy wire; when under 20℃, itsunit resistance corresponding to 52.3~53.0%IACS (international annealed copper wire standard), so that, the heat loss caused by induced current is very low;③Light weight: the density of aluminum-magnesium-silicon is only 2.7g/cm3 it largely reduced the total weight of armored cable.

该电缆突出的优点是：①高强度：铝-镁-硅合金丝具有较高的强度，其抗拉强度的最小值都是普通硬圆铝线（H8）抗拉强度的170%，是一种较好的铠装材料；②损耗小：铝-镁-硅合金丝为非磁性材料，不存在涡流损耗；其在20℃时的电阻率相52.5~53.0%IACS，因此由感应电流产生的热损耗很小；③重量轻：铝-镁-硅合金丝的密度仅为2.7g/cm3，明显降低了铠装电缆的整体重量。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。