电流

The factors that affected the degradation rate of methyl red are discussed, including the concentration of methyl red, the kind of electrolyte, the concentration of sodium bromide, the anodic current density, the material of electrode, the cathodic current density and the flow rate of oxygen at the catholyte.

探讨甲基红浓度、电解质种类、电解质浓度、阳极电流密度、电极材料、阴极电流密度与阴极室氧气流量等因表对甲基红电分解的影响。

The results show that the technical parameters and the concentration of sodium molybdate have obvious effect on the composition of the alloy. The crystal grain size is from 6.2 to 12.7 nm and changes with current density, temperature and the pH value of the electrolyte.The crystalline growth of the alloy accords with the model of three-dimensional growth. The surface morphology is mainly determined by the rate competitions between the growing direction of vertical surface and the expanding direction along the surface towards circumambient. The results of the X-ray data show the presence of the multiphase containing solid solution and intermetallic compound in the deposits. The deposit phases alter from the FeNi and FeMo solid solution to the FeNi and MoNi4structure at 3 A/dm2. The deposits internal stress increases linearly with the decrease of the grain size. The lattice parameter of the deposits are slightly distorted

结果表明：工艺条件和钼酸钠浓度对合金组成的影响较大；所得合金晶粒尺寸为6.2~12.7 nm，并随电流密度、温度和电镀液的pH值的改变而变化；合金的晶体生长符合晶核三维生长模型，镀层表面形貌由平行和垂直于基体的生长速度的相对大小决定；镀层物相为固溶体和金属间化合物的多相结构，当电流密度为3 A/dm2时，镀层物相由FeNi和FeMo固溶相转化为FeNi和

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。

Motor speed is controlled by varying the current in the field windings.for example,when the amount of current flowing through the field windings is increased, the field strength increases, causing the armature wingdings to produce a larger counter EMF which slows the motor.conversely,when the field current is decreased, the field strength decreases, and the motor speeds up because the conter EMF is reduced.

调速控制的不同目前在外地windings.for例如，当电流流动量的通过外地绕组是增加，电场强度的增加，导致电枢wingdings产生较大的反电势而减慢motor.conversely当外地电流降低，电场强度降低，电机的速度，因为conter电磁场降低。

It introduces a kind of novel loading test system, based on the operation principle of damper. this loading system is operated by the driving motor. it realizes the loading, in that the damper has a negative drive force that puts on the motor. Based on the ordinary electromagnetic damper, the thesis presents a novel hybrid excitation electromagnetic damper which has adjustable work characteristic, analyses the working principle and structural feature of the electromagnetic damper, deduces the formulas to calculate the eddy current density through the Electromagnetic theory, analyses the distribution of the eddy current in the cotyloid rotor, and also studies the method of calculating the damp torque, establishes the mathematical model of the electromagnetic damper, analyses the relationship between the electromagnetic damper structural parameter and damp torque, researches the engineering design and analysis method of the electromagnetic damper, provides theory foundation for the design and analysis of the electromagnetic damper, contrives a hybrid excitation electromagnetic damper that satisfies the target request, designs a set of compound excitation electromagnetic damping loading control system whose control core is AT89C51 monolithic integrated circuit, analyses the electric circuit part, and carries on the experimental test to this set of electric circuits. Finally it debugs this electromagnetic damping loading system, this system satisfies the target request proposed.

论文提出了一个全新的加载测试系统种类，该加载系统是在阻尼器工作原理基础上，利用电动机拖动阻尼器运转，从而阻尼器产生一个与运动方向相反的阻尼力矩，该力矩作用在电动机上实现对电动机加载测试；同时，论文在一般电磁阻尼器基础上提出了一种新型的可调式复合励磁电磁阻尼器结构，该种阻尼器的工作特性在一定范围内可进行调节；论文分析了电磁阻尼器的工作原理和结构特点，运用电磁场理论分析推导了电磁阻尼器的涡电流密度公式，分析了涡电流在转子杯内的分布图，并对阻尼力矩计算方法进行了研究，建立了电磁阻尼器的数学模型，分析了电磁阻尼器结构参数和阻尼力矩之间的关系，对电磁阻尼器的设计和分析方法进行了研究，为电磁阻尼器的工程设计建立了理论基础；设计了满足技术指标要求的复合励磁电磁阻尼器和一套以AT89C51单片机为控制核心的复合励磁电磁阻尼加载控制系统，对该控制系统硬件电路各部分进行了分析和设计，对软件进行了设计，并对控制电路进行了试验调试，该系统满足所提出的加载指标要求。

The paper aim at the three-phase voltage source SPMW-inverter, which is applied in variable-speed wind turbines system, adopts the theory of nonlinear counterchange and nonlinear feedback, creates the three-phase voltage source PWM-inverter's nonlinear model, and deduces it's feedback linearization equation, consequently, the three-phase voltage source PWM-inverter active and reactive current decoupling control is proposed.

该文针对变速风力发电机组系统所用的三相电压型SPWM 逆变器，采用非线性变换和非线性反馈理论，建立了三相电压型 PWM 逆变器非线性数学模型，推导出其反馈线性化方程，从而得出三相电压型 PWM 逆变器有功电流和无功电流的解耦控制策略。

To measure the offset current, close a specific crosspoint and use an electrometer or SMU to measure the current with everything in place except the device under test.

为了测量偏移电流，请闭合特定的交叉点，并利用一个静电计或SMU来测量电流。在测量时，除被测装置外，所有的其它设备要连接完整。

A hypothetical drained cell model retrofitted from a 160kA Hall-Heroult cell was set up to calculate the current distribution in the cathode when the anode bottom and cathode top surfaces were declivous. Two half anode-cathode slice thermo-electrical models with the collector bars installed slopingly or horizontally were adopted to calculate the potential drop and electricity distribution of the cathode.

摘 要：将某厂现有的160kA Hall-Heroult铝电解槽改造成导流槽后，在阴极上表面和阳极底面呈斜坡状的条件下，计算了采用不同阴极导杆安装方式时阴极的电位和电流分布，即通过建立导流槽内部从阳极到阴极的一个半切片电热场模型，用有限元法分别对水平和平行于阴极斜坡两种不同导流槽阴极导杆的安装方式下阴极电位和表面电流密度分布进行了计算。

The article analyses the method of long distance transmutation, dentally discusses work principle of current transmitter, designs interface circuit of current transmitter.

论文分析了数据远距离传输方法，详细论述了电流环的工作原理，根据需要设计了电流环接口电路。

And discuss some key point of integrated management system design, include hazard identification and risk assessment and risk control in the occupational health and safety management, the measure of satisfaction target of customer, the flawlessness of law system, the integration of the integrated management system and enterprise standardization system, unify lead institution and work orgnization, integreted internal audit and integrated management review.

同时，论述了一体化管理体系构建中的几个主要问题，包括职业健康安全管理中的危险源辨识、风险评价和风险控制、顾客满意度的科学监测、法律、法规体系的完善、一体化管理体系与企业标准化体系的有机结合、统一的领导机构和工作机构、一体化的内部审核和管理评审。

Deepwater Taranaki is investigated for its petroleum potential, using all available seismic data tied to shallow-water wells.

运用与浅水井相关的现有全部震波探测数据考察了深海区塔拉纳基盆地的油藏前景。