Electric_Machinery_Fundamentals_4th_Edition_部分20
大学物理-电磁学(英文授课)
大学物理-电磁学（英文授课）IntroductionElectromagnetism is a field of physics that concerns itself with the study of electromagnetic forces and fields. It is a branch of physics that focuses on the interaction between electrically charged particles, including charged particles at rest and moving charges. This course is designed to help students understand the basic principles of electromagnetism, including electric and magnetic fields, electromagnetic radiation, and electromagnetic waves.Electric FieldsElectric fields are created by electric charges, which are either positive or negative. The electric field is said to be the space surrounding a charged particle. If another charged particle is placed in the electric field, it will experience a force. The direction of the force depends on the charge of the particle and the direction of the electric field.Magnetic FieldsMagnetic fields are created by moving charges. A magnetic field is said to be the space surrounding a magnetic object. If a charged particle is placed in a magnetic field, it will move in a circular path. The direction of the circular path depends on the charge of the particle and the direction of the magnetic field. Electromagnetic FieldsAn electromagnetic field is created by the interaction of an electric field and a magnetic field. Electromagnetic fields have both electric and magnetic components, and they travel through space at the speed of light. Electromagnetic waves are a form of electromagnetic radiation that carries energy. Electromagnetic radiation includes radio waves, microwaves, infrared light, visible light, ultraviolet light, X-rays, and gamma rays.Maxwell's EquationsMaxwell's equations describe the behavior of electric and magnetic fields. They are a set of partial differential equations that relate the electric and magnetic fields to the electric charges and currents that are present. The equations describe how an electric field can produce a magnetic field, and a magnetic field can produce an electric field. They also describe how the electromagnetic fields propagate through space.Electromagnetic WavesElectromagnetic waves are waves of energy that are propagated through space by the interaction of electric and magnetic fields. Electromagnetic waves do not require any medium to propagate through. They can travel through a vacuum, which is why they are also known as vacuum waves.Electromagnetic waves are classified based on their frequency and wavelength. Radio waves have the lowest frequency, and gamma rays have the highest frequency. Radio waves have the longest wavelength, and gamma rays have the shortest wavelength.Applications of ElectromagnetismElectromagnetism has many practical applications in our daily lives. Some of the most common applications include electric motors, generators, transformers, telecommunication devices, medical imaging devices, and microwave ovens. Electromagnetism has also played a significant role in the development of modern technology, including computers, television, radio, and mobile phones.ConclusionElectromagnetism is a fascinating field of physics that has wide-ranging applications in our daily lives. This course provides students with a comprehensive understanding of electric and magnetic fields, electromagnetic radiation, and electromagnetic waves. By studying electromagnetism, students can gain a deeper appreciation for the fundamental principles that govern the behavior of the universe around us.Electromagnetism is one of the four fundamental forces of nature, along with gravity, strong nuclear force, and weak nuclear force. It is a field of physics with numerous applications in our modern society. Without the understanding of electromagnetism, we would not have the modern comforts that we have today, including electricity, the internet, cell phones, and many other devices.One of the most significant contributions of electromagnetism to modern society is the use of electric motors. Electric motors are devices that convert electrical energy into mechanical energy.They are used in a wide range of applications, from household appliances to transportation systems. The underlying principle of electric motors is electromagnetic induction, which is the process of inducing an electric current in a conductor by varying the magnetic field around it.Another important application of electromagnetism is in generators. Generators are devices that convert mechanical energy into electrical energy. They are often used in power plants to generate electricity that is distributed to homes and businesses. The principle of electromagnetic induction is also used in generators. When a conductor moves through a magnetic field, an electric current is induced in the conductor.Electromagnetism also plays a central role in the functioning of transformers. A transformer is a device that changes the voltage of an alternating current (AC) power supply. Transformers are used to step up or step down the voltage of an AC power supply. They are used in power grids to maintain a constant voltage throughout the grid. The principle used in transformers is electromagnetic induction, with the primary and secondary coils of wire interacting with the magnetic field to produce the desired voltage change. Telecommunication devices, including radios, televisions, and cell phones, also rely on the principles of electromagnetism. The radio waves used for communication are a form of electromagnetic radiation. Radio waves are used to transmit and receive signals between devices. The workings of these devices depend on the principles of electromagnetic induction and electromagnetic radiation.In addition to powering devices, electromagnetism is used in medical imaging devices. Magnetic resonance imaging (MRI) machines use magnetic fields and radio waves to produce images of the body's internal structures. The patient is placed in a powerful magnetic field, which causes the protons in their body to align with the field. A radio wave is then sent through the body, causing the protons to produce a signal. The signal is detected, and an image is produced based on the strength and location of the signal.Microwave ovens are another example of electromagnetism in action. These appliances use microwaves to cook food. Microwaves are a type of electromagnetic radiation with a frequency of around 2.4 GHz. The microwaves cause the water molecules in the food to vibrate rapidly, producing heat. This heats the food quickly and evenly, making it a popular method for cooking.The study of electromagnetism has also led to the development of modern technology. Computers, televisions, radios, and cell phones all rely on the principles of electromagnetism. The development of these technologies has revolutionized the way we live and communicate. The internet, for example, would not exist without the principles of electromagnetism.In conclusion, electromagnetism is a fascinating field of physics with numerous practical applications in our daily lives. It is the foundation of modern technology, and our society would not be the same without it. By studying electromagnetism, we can gain a deeper understanding of the world around us and appreciate thefundamental principles that govern our universe. As technology advances, we can expect even more exciting and innovative applications of electromagnetism in the years to come.。
制药工程专业英语unit 1、2、3、4、5、16、17、18、19、20中文翻译(庄永思,吴达俊版)
1、生产的药品其生产或出身不同药剂可以分为三类：Ⅰ.完全（合成纤维）合成材料，Ⅱ.天然产物，和Ⅲ.产品从（半合成产品）的部分合成。
本书的重点是团体的最重要的化合物Ⅰ和Ⅲ一所以药物合成。
这并不意味着，但是，天然产品或其他代理人并不太重要。
它们可以作为有价值的领导结构，他们常常为原料，或作为重要的合成中间体产品的需要。
表1给出了获取药剂的不同方法的概述。
（表1对药物的可能性准备）方法举例1、全合成，超过75％的药剂（合成纤维）2、分离（天然产物）天然来源：2.1植物-生物碱;酶;心甙，多糖，维生素E;类固醇的前体（薯蓣皂素，sitosterin），柠檬醛（中间产品维生素A，E和K）2.2动物器官一酶;肽激素;胆酸从胆;胰岛素）从胰脏;血清和疫苗2.3从角蛋白和明胶L -氨基酸;三一胆固醇从羊毛油脂的其他来源水解3.一抗生素发酵; L -氨基酸，葡聚糖，对类固醇有针对性的修改,例如11 -羟基化;也胰岛素，干扰素，抗体，肽激素，酶，疫苗4。
部分合成修改（半合成剂）天然产品: 一生物碱化合物;半合成/ 3-内酰胺类抗生素;类固醇;人胰岛素其中几个重要的治疗作用最初是从天然产品天然来源获得更有效的今天，我。
大肠杆菌更经济的准备..由全合成。
这样的例子包括L-氨基酸，氯霉素，咖啡因，多巴胺，肾上腺素，左旋多巴，肽类激素，前列腺素，D -青霉胺，长春胺，以及几乎所有的维生素。
在过去的几年里发酵-岛大肠杆菌微生物过程变得极其重要。
通过现代技术和基因选择的结果导致了突变体的微生物创造高性能，发酵，已成为首选方法各种各样的物质。
这两个Eukaryonts（酵母菌和霉菌）和Prokaryonts（单细胞细菌，放线菌和）用于微生物。
下列产品类型可以得到：1.细胞的物质（单细胞蛋白），2.酶，3.主要降解产物（主要代谢物），4.二级降解产物（次生代谢物）。
不顾来自某些微生物，大肠杆菌粘膜生产的葡聚糖克明串珠mesenteroides，2和3级是毒品有关的准备工作。
chapter1-fundermental of electric circuit
7
Fundamentals of Electric Circuits
–A great many systems behave in a reasonably linear fashion over a limited range----allowing us to model them as linear systems if we keep the range limitations in mind. –Linear problems are inherently more easily solved than their nonlinear counterparts.
•Linear circuit analysis can be separated into four broad categories:
–Dc analysis –Transient analysis –Ac analysis –Frequency response analysis
•The simple fact of the matter is that no physical system is ever perfectly linear. Then why study linear analysis?
15
Battery
Fundamentals of Electric Circuits
Notice:
An ideal circuit component is a mathematical model of an actual electrical component, like a battery or a light bulb. It is important for the ideal circuit component used in a circuit model to represent the behavior of the actual electrical component to an acceptable degree of accuracy. Circuit analysis is based on mathematical techniques and is used to predict the behavior of the circuit model and its ideal circuit components. .
Fundamentals of Machine Tools
Fundamentals of Machine ToolsIn many cases products from the primary forming processes must undergo further refinements in size and surface finish to meet their design specifications.To meet such precise tolerance the removal of small amounts of material is ually machine tools are used for such operation.In the United States material removal is a big business—in excess of ＄36×109 per year,including material,labor,overhead,and machine-tools shipments,is spent.Since 60 percent of the machanical and industrial engineering and technology graduate have something connection with the machining industry either through sale,design,or operation of machine shops,or working in related industry,it is wise for an engineering student to devote some time in his curriculum to studying material removal and machine tools.A machine tool provide the means for cutting tools to shape a workpiece to required dimensions;the machine supports the tool and the workpiece in a controlled relationship through the functioning of its basic members,which are as follows:(a)Bed,Structure or Frame.This is the main member which provides a basis for,and a connection between,the spindles and slides;the distorion and vibration under load must be kept to a minimum.(b)Slides and Slideways.The translation of a machine element(e.g. the slide) is normally achieved by straight-line motion under the constraint of accurate guiding surface(the slideways).(c)Spindles and Bearings.Angular displacement take place about an axis of rotation;the position of this axis must be constant within extremely fine limits in machine tools,and is ensured by the provision of precision spindles and bearings.(d)Power Unit.The electric motor is the universally adopted power unit for machine tools.By suitably positioning individual motors,belt and gear transmissions and reduced to a minimum.(e)Transmission Linkage.Linkage is the general term used to denote the mechanical,hydraulic,pneumatic or electric mechanisms which connect angular andlinear displacements in defined relationship.There are two broad divisions of machining operations:(a)Roughing,for which the metal removal rate,and consequently the cutting force,is high,but the required dimensional accuracy relatively low.(b)Finishing,for which the metal removal rate,and consequently the cutting force,is low,but the required dimensional accuracy and surface finish relatively high.It follows that static loads and dynamic loads,such as result from an unbalanced grindingwheel,are rmore significant in finishing operations than in roughing operations.The degree of precision achieved in any machining process will usually be influenced by the magnitude of the deflections,which occur as a result of the force acting.Machine tool frames are generally made in cast iron,although some may be steel casting or mild-steel fabrications.Cast iron is chosen because of its cheapness,rigidity,compressive strength and capacity for damping the vibrations set-up in machine operations.To avoid massive sections in castings,carefully designed systems of ribbing are used to offer the maximum resistance to bending and torsional stresses.Two basic types of ribbing are box and diagonal.The box formation is convenient to produce,apertures in walls permitting the positioning and extraction of cores.Diagonal ribbing provides greater torsional stiffness and yet permits swarf to fall between the sections;it is frequently used for lathe beds.The slides and slideways of a machine tool locate and guide members which move relative to each other,usually changing the position of the tool relative to the workpiece.The movement genenally takes the forms of translation in a straight line,but is sometimes angulai rotation,e.g. tilting the wheel-head of a universal thread-grinding machine to an angle corresponding with the helix angle of the workpiece thread.The basic geometric elements of slides are flat,vee,dovetail and cylinder.These elements may be used separately or combined in various ways according to the applications.Features of slideways are as follows:(a)Accuracy of Movement.Where a slide is to be displaced in a straight line,this line must lie in two mutually perpendicular planes and there must be no sliderotation.The general tolerance for straightness of machine tool slideways is 0—0.02mm per 1000mm;on horizontal surfaces this tolerance may be disposed so that a convex surface results,thus countering the effect of “sag”of the slideway.(b)Means of Adjustment.To facilitate assembly,maintain accuracy and eliminate “play” between slideing members after wear has taken place,a strip is something inserted in the slides.This is called a ually,the grib is retained by socket-head screw passing through elongated slots;and is adjusted by grub-screws secured by lock nuts.(c)Lubrication.Slideways may be lubricated by either of the following systems:1)Intermittently through grease or oil nipples,a method suitable where movements are infrequent and speed low.2)Continuously,e.g. by pumping through a metering value and pipe-work to the point of application;the film of oil introduced between surfaces by these means must be extremely thin to avoid the slide “floating”.If sliding surfaces were optically flat oil would be squeezed out,resulting in the surfaces sticking.Hence in practice slide surfaces are either ground using the edge of a cup wheel,or scraped.Both processes produce minute surface depresssions,which retain “pocket” of oil,and complete separation of the parts may not occur at all points;positive location of the slides is thus retained.(d)Protection.To maintain slideways in good order,the following conditions must be met:1)Ingress of foreign matter,e.g. swarf,must be prevented.Where this is no possible,it is desirable to have a form of slideway,which does not retain swarf,e.g. the inverted vee.2)Lubricating oil must be retained.The adhensive property of oil for use on vertical or inclined slide surface is important;oils are available which have been specially developed for this purpose.The adhesiveness of oil also prevents it being washed away by cutting fluids.3)Accidental damage must be prevented by protective guards.A machine tool performs three major functions:1)it rigidly supports the workpiece or its holder and the cutting tool; 2)it provides relative motion between the workpieceand the cutting tool; 3)it provides a range of feeds and speeds.Machines used to remove metal in the form of chips are classified in four general groups:those using single-point tools,those using multipoint tools,those using random-point tools(abrasive),and those that considered special.Machines using basically the single-point cutting tools include:1)engine lathes,2)turret lathes , 3)tracing and duplicating lathes, 4)single-spindle automatic lathes,5)multi-single automatic lathes , 6)shapers and planers, 7)boring machines.Machines using multipoint cutting tools include:1)drilling machines, 2)milling machines, 3)broaching machines, 4)sawing machines, 5)gear-cutting machines.Machines using random-point cutting tools include:1)cylindrical grinder,2)centreless grinders, 3)surface grinders.Special metal removal methods include:1)chemical milling, 2)electrical discharge machining, 3)ultrasonic machining. The lathe removes material by rotating the workpiece against a cutter to produce external or internal cylindrical or conical surfaces.It is also commonly used for the production of flat surfaces by faing,in which the workpiece is rotated while the cutting tool is moved perpendicularly to the axis of rotation.The engine lathe is the basic turning machine from which other turning machines have been developed.The drive motor is located in the base and drives the spindle through a combination of belts and gears,which provides the spindle speeds from 25 to 1500 rpm.The spindle is a sturdy hollow shaft,mounted between heavy-duty bearings,with the forward end used for mounting a drive plate to impart positive motion to the workpiece.The drive plate may be fastened to the spindle by threads,by a cam lock mechanism,or by a thread collar and key.The lathe bed is cast iron and provides accurately ground sliding surfaces(way)on which the carriage rides.The lathe carriage is a H-shaped casting on which the cutting tool is mounted in a tool holder.The apron hangs from the front of the carriage and contains the driving gears that move the tool and carriage along or across the way to provide the desired tool motion.A compound rest,located above the carriage provides for rotation of the tool holder through any desired angle.A hand wheel and feed screw are provided with a hand wheeland feed screw for moving the compound rest perpendicular to the lathe way.A gear train in the apron provides power feed for the carriage both along and across the way.The feed box contains gears to impart motion to the carriage and control the rate at which the tool moves relative to the workpiece.On a typical lathe feeds range from 0.002 to 0.160 in. per revolution of the spindle,in about 50 steps.Since the transmission in the feed box is driven from the spindle gears,the feeds are directly related to the spindle speed.The feed box gearing is also used in thread cutting and provides from 4 to 224 threads per in.The connecting shaft between the feed box and the lathe apron are the feed rod and the lead screw.Many lathe manufacturers combine these two rods in one,a practice that reduces the cost of the machine at the expense of accuracy.The feed rod is used to provide tool motion essential for accurate workpiece and good surface finishes.The lead screw is used to provide the accurate lead necessary for the thread cutting.The feed rod is driven through a friction clutch that allows slippage in case the tool is overloaded.This safety device is not provided in the lead screw,since thread cutting cannot tolerate slippage.Since the full depth of the thread is seldom cut in one pass,a chasing dial is provided to realign the tool for subsequent passes.The lathe tailtock is fitted with an accurate spindle that has a tapered hole for mounting drills,drill chucks,reamers,and lathe centers.The tailstock can be moved along the lathe ways to accommodate various lengths of workpieces as well as to advance a tool into contact with the worpiece.The tailstock can be offset relative to the lathe ways to cut tapers or conical surfaces.The turret lathe is basically an engine lathe with certain additional features to provide for semiautomatic operation and to reduce the opportunity for human error.The carriage of the turret lathe is provided with T-slots for mounting a tool-holding device on both sides of the lathe ways with tools properly set for cutting when rotated into position.The carriage is also equipped with automatic stops that control the tool travel and provide good reproduction of cuts.The tailstock of the turret lathe is of hexagonal design,in which six tools can be mounted.Althogh a large amount of time is consumed in setting up the tools and stops for operation,the turret lathe,once set,can continue toduplicate operations with a minimum of operator skill until the tools become dulled and need replacing.Thus,the turret lathe is economically feasible only for production work,where the amount of time necessary to prepare the machine for operation is justifiable in terms of the number of part to be made.Tracing and duplicating lathes are equipped with a duplicating device to automatically control the longitudinal and cross feed motions of the single-point cutting tool and provide a finished part of required shape and size in one or two passes of the tools.The single-spindle automatic lathe uses a vertical turret as well as two cross slids.The work is fed through the machine spindle into the chuck,and the tools are operated automatically by cams.The multispindle automatic lathe is provided with four,five,six,or eight spindles,with one workpiece mounted in each spindle.The spindles index around a central shaft,with the main tools slide accessible to all spindles.Each spindle position is provided with a side tool-slide operated independently.Since all of the slides are operated by cams,the preparation of this machine may take several days,and a production run of at least 5000 parts is needed to justify its use.The principal advantage of this machine is that all tools work simultaneously,and one operator can handle several machines.For relatively simple parts,multispindle automatic lathes can turn out finished products at the rate of 1 every 5 sec.A shapers utilizes a single-point tool in a tool holder mounted on the end of the ram.Cutting is generally done on the forward stroke.The tool is lifted slightly by the clapper box to prevent excessive drag across the work,which is fed under the tool during the return stroke in preparation for the next cut.The column house the operating mechanisms of the shaper and also serves as a mounting unit for the work-supporting table.The table can be moved in two directions mutually perpendicular to the ram.The tool slide is used to control the depth of the cut and is manually fed.It can be rotated through 90 deg. On either side of its normal vertical position,which allows feeding the tool at an angle to the surface of the table.Two types of the driving mechanisms for shapers are a modified Whitworth quick-return mechanism and a hydraulic drive.For the Whitworth mechanism,the motor drives the bull gear,which drives a crank arm with an adjustable crank pin to control the length of the stroke.As the bull gear rotates,the rocker arm is forced to reciprocate,imparting this motion to the shaper ram.The motor on a hydraulic shaper is used only to drive the hydraulic pump.The remainder of the shaper motions are controlled by the direction of the flow of the hydraulic oil.The cutting stroke of the mechanically driven shaper uses 220 deg. of rotation of the bull gear,while the return stroke uses 140 deg..This gives a cutting stroke to return stroke ratio of 1.6 to 1.The velocity diagram shows that the velocity of the tool during the cutting stroke is never constant,while the velocity diagram for a hydraulic shaper shows that for most of the cutting stroke the cutting speed is constant.The hydraulic shaper has an added advantage of infinitely variable cutting speeds.The principal disadvantage of this type of machine is the lack of a definite limit at the end of the ram stroke,which may allow a few thousandths of an inch variation in stroke length.A duplicating device that makes possible the reproduction of contours from a sheet-metal template is available.The sheet metal template is used in conjunction with hydraulic control.Upright drilling machines or drill presses are available in a variety of sizes and types,and are equipped with a sufficient range of spindle speeds and automatic feeds to fit the needs of most industries.Speed ranges on a typical machine are from 76 to 2025 rpm.,with drill feed from 0.002 to 0.20 in. per revolution of the spindle.Radial drilling machines are used to drill workpieces that are too large or cumbersome to conveniently move.The spindle with the speed and feed changing mechanism is mounted on the radial arm;by combing the movement of the radial arm around column and the movement of the spindle assembly along the arm,it is possible to align the spindle and the drill to any position within reach of the machine.For work that is too large to conveniently support on the base,the spindle assembly can be swung out over the floor and the workpiece set on the floor beside the machine.Plain radial drilling machine provide only for vertical movement of thespindle;universal machines allow the spindle to swive about an axis normal to the radial arm and the radial arm to rotate about a horizontal axis,thus permitting drilling at any angle.A mutispindle drilling machine has one or more heads that drive the spindles through universal joints and telescoping splined shafts.All spindles are usually driven by the same motor and fed simultaneously to drill the desired number of holes.In most machines each spindle is held in an adjustable plate so that it can be moved relative to the others.The area covered by adjacent spindles overlap so that the machine can be set to drill holes at any location within its range.The milling operation involves metal removal with a rotating cutter.It includes removal of metal from the surface of a workspiece,enlarging holes,and form cutting,such as threads and gear teeth.Within an knee and column type of milling machine the column is the main supporting member for the other components,and includes the base cotaining the drive motor,the spindle,and the cutter.The cutter is mounted on an arbor held in the spindle,and supported on its outer extremity by a bearing in the overarm.The knee is held on the column in dovetail slots,the saddle is fastened to the knee in dovetail slots,and the table is attached to the saddle.Thus,the build-up of the knee and column machine provide three motions relative to the cutter.A four motion may be provided by swiveling the table around a vertical axis provided on the saddle.Fixed-bed milling machines are designed to provide more rigidity than the knee and column type.The table is mounted directly on the machine base,which provides the rigidity necessary for absorbing heavy cutting load,and allows only longitudinal motion to the table.Vertical motion is obtained by moving the entire cutting head.Tracer milling is characterized by coordinated or synchronized movements of either the paths of the cutter and tracing elements,or the paths of the workpiece and model.In a typical tracer mill the tracing finger follow the shape of the master pattern,and the cutter heads duplicate the tracer motion.。
Ch电解质溶液
15
§8.1 电化学的基本概念和电解定律
－－法拉第定律(Faraday’s Law) 如果在电解池中发生如下反应：
Ch8. 电解质溶液
M z z e M ( s )
电子得失的计量系数为 z+，欲从阴极上沉积出1
mol M(s)，即反应进度为1 mol 时，需通入的电量为 Q
Q(1) z+eLz+F
－－基本概念
3、电化学装置
Ch8. 电解质溶液
➢ 电解池（electrolytic cell） ：
若在外电路中并联一个有一定电压的外加电源，则将有电流 从外加电源流入电池，迫使电池中发生化学反应，此时电能 转变为化学能，则该电池为电解池。
➢ 原电池（parimary cell）：
若电池能自发地在电极上发生化学反应，并产生电流，此时 化学能转变为电能，则该电池为原电池。
A
B
离子迁 移情况
最后结果
阳 极
++ －－－－←
+++ → _____ +_ _+ _+
+++++ → ← _____ +_+_ +_ +_ _+
+++++ ← ____ +_+_ +_
→ _ + ++ +
阴 极
A
B
迁移速率相等
24
§8.2 离子的电迁移和迁移数
－－－离子的电迁移现象
阳极
A
B
阴极
Ch8. 电解质溶液
Michael Faraday（1791－1867）
专业英语翻译第一章.doc
专业英语翻译第⼀章.doc注：电⽓⼯程及其⾃动化专业英语翻译 1~7⾯班级：1002班学号：20姓名：王定瑞PART 1 FUNDAMENTALS OF ELECTRIC ENGINEERINGChapter 1 Circuit Fundamentals第1部分的电⽓⼯程基础第1章电路原理1.1 Electrostatic Charges1.1 静电荷Protons and electrons are parts of atoms that make up all things in our world. The positive charge of a proton is similar to the negative charge of an electron. However, a positive charge is the opposite of a negative charge. These charges are called electrostatic charges. Each charged particle is surrounded by an electrostatic field.质⼦和电⼦部件的原⼦构成⼀切事物在我们的世界。
正电荷的质⼦是类似于负电荷的电⼦。
然⽽,⼀个正电荷的反⾯是⼀个负电荷。
这些指控被称为静电荷。
每个带电粒⼦周围是⼀个静电场。
The effect that electrostatic charges have on each other is very important. They either repel (move away) or attract (come together) each other. It is said that like charges repel and unlike charges attract.这个效应,静电指控对⽅是⾮常重要的。
Chap4-Introduction to Rotating Machines2010-2
The electrical frequency fe of the voltage generated in a synchronous machine: Hz
Jinlin GONG- School of Electrical Engineering
山东大学校长办公会议
Synchronous Machines
Rotor Stator
Hale Waihona Puke In dc machines
In order to minimize the effects of eddy currents, the armature structure is typically built from thin laminations of electrical steel which are insulated from each other.
In a generator, this torque opposes rotation, and mechanical torque must applied from the prime mover to sustain rotation. In a synchronous motor:
Alternating current
S
F
Stator
Rotor
Rotating magnetic field
dc excitation current
fixed magnetic field
A steady electromechanical torque is produced when the rotor rotates in synchronism with the magnetic filed of stator.
Newman的能源机-翻译版-前9章
第1章历史的回顾非重点第2章回转仪（陀螺仪）的运动Chapter 2 GYROSCOPIC ACTIONS注：mechanical开始解释成“机械的”，后来改为“力学的”，在有“机械”或“力学”的翻译处可能不通，不影响理解。
"The way in which Faraday made use of his lines of force in coordinating the phenomena of electric induction shows him to have been a mathematician of high order, and one from whom the mathematicians of the future may derive valuable and fertile methods."-James Clerk Maxwell法拉第用力线表示电感应现象展示了他已经是一个有很高水平的数学家，未来的数学家可能从他的方法中得到宝贵和丰富的方法。
-麦克斯韦I will begin with the scientific facts concerning my initial reading in March, 1965 on the nature of Michael Faraday's Generator.我将从我在1965年3月开始读的迈克尔-法拉第的发电机中的科学事实开始。
Anyone who cannot recognize the veracity of certain conclusions that I understood when I initially studied Faraday's facts has been unjustly influenced by the teaching process which rewards one for memorization and discourages questioning of the subject matter taught.所有人都没有认识到某些结论的真像，当我开始学习法拉第的研究时我已经明白了，这些事实被不鼓励质疑鼓励死记硬背的教学过程不公正的影响了。