生物医学工程专业英语之电子学基础

1,Electronic engineering,2,1. electronic 电的（与电有关的）2. engineering 工程，工程学3. circuit 电路4. common-base 共基极,part 1: Basic Circuits,3,5. common-emitter 共发射极6. common-collector 共集电极7. transistor 晶体管，三极管,4,8. impedance 阻抗9. ohm 欧姆10. megohm 兆欧11. voltage 电压,5,There are three basic ways of connecting transistors in a circuit: common-base, common-emitter, and common-collector.,6,In the common-bas connection, the signal is introduced in to the emitter-base circuit and extracted from the collector-base circuit. Because the input or emitter-base circuit has a low impedance in the order of 0.5 to 50 ohms, and the output or collector-base circuit has a high impedance in the order of 1000 ohms to one megohm, the voltage or power gain in this type of configuration may be in the order of 1500.,在共基极电路中，信号被引入到发射极基极电路和集电极基极电路提取。由于输入或发射极基极电路具有低阻抗在0.5到50欧姆，和输出或集电极基极电路具有高阻抗为1000欧姆到1兆欧，在这种类型的结构的电压或功率增益可以达到1500。,7,12. rectifier整流器13. diode 二极管14. current 电流,Part 2 : Basic rectifier circuits,8,Since current can flow through a diode in one direction, a diode can be used as a rectifier to change alternating current into direct current.,9,15. cycle 周期During one half of the a.c.cycle the rectifier conducts and current flows through the rectifier to the load.,10,16. pulsate 博动，波动17. amplitude 幅度The current always flows in the same direction but the flow of current is not continuous and is pulsating in amplitude.,11,18. frequency 频率The frequency of the output pulses is twice that of the half-wave rectifier.,12,19. in series 串联20. in parallel 并联Another rectifier circuit is known as the full-wave bridge rectifier circuit. In this arrangement, two rectifiers operate in series on each half of the cycle.,13,21. pulse 波，脉冲22. positive正的23. negative 负的24. baseline 基线,Part 3: The pulse,14,The pulse is made up of a positive step and a negative step. (if the step is above the baseline, it is called a positive step, if it is below the baseline it is called negative.),15,25. waveform波形26. rectangular矩形的，直角的27. sawtooth 锯齿Pulses waveforms used in electronic devices are: rectangular waveform, sawtooth waveform and so on.,16,28. capacitance 电容值，容抗29. electric 电的（靠电工作的）30. condenser 电容器，电容31. capacitor 电容器,Part 4: Capacitance,17,Electrical energy can be stored in an electric field. The device capable of doing this is called a capacitor or a condenser.,18,32. metallic 金属的33. dielectric 电介质A simple condenser consists of two metallic plates separated by a dielectric.,19,34. terminal 电极，终端，套管35. accumulate 蓄电，储电，积累36. electron 电子,20,A condenser is connected to a battery, the electrons will flow out of the negative terminal of the battery and accumulate on the condenser plate connected to that side.,21,37. potential 电势At the same time, the electrons will leave the plate connected to the positive terminal and flow into the battery to make the potential difference just the same as that of the battery.,22,38. charge 充电，电荷39. discharge 放电Thus the condenser is said to be charged. To discharge the condenser, the external circuit of these two plates is completed by joining terminals together with a wire.,23,40. farad 法拉41. volt 伏特42. ampere安培43. microfarad 微法,24,It is measured in farads. When a changes of one volt per second across it caused the current of one ampere to flow, the condenser is said to have the capacitance of one farad.,25,44. gravitation 重力，引力，万有引力45. mass 质量46. matter 物质,Part 5:Newtons law of universal gravitation,26,Newtons Law of Universal Gravitation states that: Every portion of matter attracts or tends to approach every other portion of matter in the universe with a force proportional to the masses and inversely proportional to the square of the distance.,27,47. resistance 电阻An ideal diode would have a forward resistance of zero and an infinite back resistance.,Part 6: Forward resistance and Back resistance of the Diod,28,48. cathode 负极49. anode 正极50. short circuit 短路,29,51. open circuit 断路52. germanium 锗fall somewhat或多或少eg：the price would be likely to fall somewhat，because producers labor costs will be lower。,30,desirable characteristic 可取的特点eg：In genuine love， where the lover does not regard the beloved as his or her competitor，intelligence is ofen a desirable characteristic in the beloved。（充满智慧在彼此相爱的人眼中是一个富有魅力的特点）53. crystal 晶体Crystal diodes often have lower back resistance than the tube diodes.,31,What are amps,watts and ohms?,Electricity 电力、电流neat简洁的Analogy 类比Plumping垂直Tank水槽Pressurized加压的 密封的Hose软管,32,diameter直径semidiameter radiuswaterwheel水车，水轮grinding磨的，刺耳的watermill水力磨粉机light bulb 电灯泡substitute替代rearrange重整，重排,33,conductive传导的dramatically戏剧性的，引人注目的motor发电机generator发电机 发生器handle n把手、把柄vt触摸、运用、处理,34,Computer Virus,35,Part1: whats a virus,fragment 碎片 片段viral 滤过性病菌的particle 粒子burst 爆发infect 感染,36,Computer viruses are called viruses because they share some of the traits of biological viruses. A computer cirus passes from computer to computer like a biological virus passes from person to person.,37,the analogy between computer and biological viruses stretches things a bit ,but there are enough similarities that the name stick计算机病毒和生物病毒之间的类比延伸一点，但有足够的相似性，这种相似性叫坚持。,38,Part2: early cases:executable viruses,word processor 文字处理器/程序bulletin公告embed 使嵌入 使插入unsuspect 不怀疑launch 发射floppy disk软盘upload上传,39,violently 暴力的 猛烈的trigger 触发activate 刺激 激活eras 擦除,40,Early viruses were pieces of code attached to a common program like a popular word processor.,41,Part3: boot sector viruses,boot sector viruses 引导扇区病毒trick 花招 诡计boot sector 启动区tiny 微小的compact disc（CD缩写）压缩盘，光碟shrinking habitat 收缩的栖息地niche 壁龛eliminate 消除 排除,42,As virus creators got more sophisticated,they learned new tricks.One important trick was the ability to load viruses into memory so they could keep running in the background as long as the computer remained on. This gace viruses a much more effective way to replicate themselves.Another trick was ,43,Part4: e-mail viruses,spectacular 惊人的via 经由harmless 无害的 无恶意的corrupting 使恶化 使腐烂Trojan horse 特洛伊木马Visual Basic for Applications (VBA)应用程序语言programmed adj 程序化的，按规划的 v 规划、制作Macro virus protection 宏病毒保护default 系统默认值fuel 刺激 加燃料,44,The latest thing in the world of computer viruses is the e-mail virus in March 1999 was spectacular.Melissa spread in Microsoft Word documents sent via e-mail, and it worked like this:,45,Part5: types of infection,spreadsheet program 电子表格程序wreak 发泄havoc 破坏worm 蠕虫piggyback 背负 在。背上specific 特定的 明确的,46,Part6:origins,origin 起源psychology 心理学 心理状态vandal 蓄意破坏者arsonist 纵火犯bust 使爆发spray-paint 喷漆,47,blow up 爆发 扩大 充气fascination 魅力explosion 爆炸 爆发wreck 破坏 失事gunpowder 火药involve 包含,48,brag 吹牛everest 珠穆朗玛峰compell强迫 迫使exploit 开发 开采 开拓harsh 严厉的 苛刻的,49,Part7 history,rare 稀有的Lock away 锁起来Macintosh 苹果公司生产的一种型号的计算机Dial up 拨号precursor 先驱wipe out 清除Load off 卸载 卸货check out检验,How do viruses spread?,What is a computer virus?,A computer virus is a program designed to spread itself by first infecting executable files or the system areas of hard and floppy disks and then making copies of itself.,How do viruses spread?,When you execute program code thats infected by a virus,the virus code will also run and try to infect other programs,either on the same computer or on other computer connected to it over a network.When you share a copy of an infected file with other computer users,running the file may also infect their computers.,What do viruses do to computers?,Viruses are software programs,the actual effect of any particular virus depends on how it was programmed by the person who wrote the virus.（creator）Some viruses are deliberately designed to damage files or otherwise interfere with your computers operation,while others dont do anything but try to spread themselves around.,Some general tips on avoiding virus infection,Install anti-virus software from a well-known,reputable company,update it regularly,and use it regularly.In addition to scanning for viruses on a regular basis ， configure scanner to start automatically each time you boot your system.,Viruses scan any new programs or other files that may contain executable code before you run or open them.Be extremely careful about accepting programs or other files during on-line chat sessions.Do regular backups备份.,Exercises:,If you want to avoid virus infections,you should install anti-virus software from a well-known,reputable company,update and use it regularly. When you execute program code thats infected by a virus,the virus code will on the same computer or on other computers connected to it over a network.,run and try to infect other programs,57,The discovery of electron,amidst 在。当中bold 大胆的corpuscle 微粒 血球specul