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LED（Light Emitting Diode，发光二极管）是一种能够将电能转化为可见光的液态半导体器件。
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更多 “LED（Light Emitting Diode，发光二极管）是一种能够将电能转化为可见光的液态半导体器件。” 相关考题
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光纤分为单模光纤与多模光纤，这两种光纤的区别是 （12） 。A.单模光纤的纤芯大，多模光纤的纤芯小B.单模光纤比多模光纤采用的波长长C.单模光纤的传输频带窄，而多模光纤的传输频带宽D.单模光纤的光源采用发光二极管（Light Emitting Diode），而多模光纤的光源采用激光二极管（Laser Diode）
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Computer MouseThe basic computer mouse is an amazingly clever invention with a relatively simple design that allows us to point at things on the computer and it is very productive.Think of all the things you can do with a mouse like selecting text for copying and pasting,drawing,and even scrolling on the page with the newer mice with the wheel. Most of us use the computer mouse daily without stopping to think how it works until it gets dirty and we have to learn how to clean it. We learn to point at thing before we learn to speak,so the mouse is a very natural pointing device.Other computer pointing devices include light pens,graphics tablets and touch screen,but the mouse is still our workhorse.The computer mouse was invented in 1964 by Douglas Englehart of Stanford University.As computer screens became popular and arrow keys were used to more around a body of text,it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful.The introduction of the mouse,with the Apple Lisa computer in 1983,really started the computer public on the road to relying on the mouse for routine computer tasks.How does the mouse work?We have to start at the bottom,so think upside down for now. It all starts with mouse ball. As the mouse ball in the bottom of the mouse rolls over the mouse pad,it presses against and turns two shafts.The shafts are connected to wheels with several small holes in them. The wheels have a pair of small electronic light-emitting devices called light emitting diodes (LED)mounted on either side.One LED sends a light beam to the LED on the other side.As the wheels spin and a hole rotates by,the light beam gets through to the LED on the other side.But a moment later the light beam is blocked until the next hole is in place.The LED detects a changing pattern of light,converts the pattern into an electronic signal,and sends the signal to the computer through wires in a cable that goes out the mouse body.This cable is the tail that helps give the mouse its name.The computer interprets the signal to tell it where to position the cursor on the computer screen.So far we have only discussed the basic computer mouse that most of you probably have or have used.One problem with this design is that the mouse gets dirty as the ball rolls over the surface and picks up the dirt. Eventually you have to clean your mouse. The newer optical mice avoid this problem by having no moving parts.When an ordinary computer mouse gets dirty,it has to be replaced with a new one.A:Right B:Wrong C:Not mentioned
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Computer Mouse The basic computer mouse is______(51)amazingly clever invention with a relatively simple design that allows us to point at things on the computer and it is very productive.Think of all the things you can do with a mouse like selecting text for copying and pasting , drawing , and even scrolling（滚动）on the page with the newer mice with the wheel.Most of us use the computer mouse daily without stopping to think how it______(52)until it gets dirty and we have to learn how to______(53)it.We learn to point at things______(54)we learn to speak,so the mouse is a very natural pointing device.Other computer pointing devices include light pens,graphics tablets and touch screens,but the mouse is still our workhorse. The computer mouse was_____(55)in 1964 by Douglas Englehart of Stanford University.As computer screens became more popalar and arrow keys were used to move around a body of text,it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful.The introduction of the mouse,with the Apple lisa computer in 1983,really started the computer public on the road to relying on the mouse_____(56)routine computer tasks. How does the mouse work?We have to start at the bottom,so think upside down for now.It all starts with the mouse ball.As the mouse ball in the bottom of the mouse rolls over the mouse pad,it presses against and turns two shafts（轴）.The shafts are connected to wheels with several small holes in them.The wheels have a pair of small electronic light-emitting devices______(57) light-emitting diodes(LED)mounted on either side.One LED sends a light beam to the LED on______(58)side.As the wheels spin and a hole rotates by,the light beam gets through to the LED on the other side.But a moment______(59)the light beam is blocked until the next hole is in place.The LED______(60)a changing pattern of light, converts the pattern______(61)an electronic signal,and sends the signal to the computer through wires in a cable that goes out of the mouse body.This cable is the tail that helps give the mouse its name.The computer interprets the signal to tell it where to position the cursor on the computer______(62). So far we have only discussed the basic computer mouse that______(63)of you probably have or have used.One problem with this design is that the mouse gets dirty as the ball rolls over the surface and picks up dirt.______(64)you have to clean your mouse.The newer optical mice______(65)this problem by having no moving parts.61._________A:in B:fromC:for D:into
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瑞典皇家科学院10月7日宣布，将2014年诺贝尔物理学奖授予日本科学家赤崎勇、天野浩和美籍日裔科学家中村修二，以表彰他们在（）的发现。A、红色发光二极管（LED.方面B、蓝色发光二极管（LED.方面C、黄色发光二极管（LED.方面D、绿色发光二极管（LED.方面
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Which of the following items can be used as a discharge lamp？（）A、Halogen lampB、Light Emitting Diodes （LED）C、Fuser lampD、Cleaning roller
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Which of the following type of lamp is used for heating a fuser？（）A、XenonB、HalogenC、IncandescentD、Light Emitting Diode
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单选题Which of the following type of lamp is used for heating a fuser？（）A
XenonB
HalogenC
IncandescentD
Light Emitting Diode
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单选题Which of the following items can be used as a discharge lamp？（）A
Halogen lampB
Light Emitting Diodes （LED）C
Fuser lampD
Cleaning roller
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单选题瑞典皇家科学院10月7日宣布，将2014年诺贝尔物理学奖授予日本科学家赤崎勇、天野浩和美籍日裔科学家中村修二，以表彰他们在（）的发现。A
红色发光二极管（LED.方面B
蓝色发光二极管（LED.方面C
黄色发光二极管（LED.方面D
绿色发光二极管（LED.方面
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