Graphene

Discussion in 'General Science' started by Wendy, May 15, 2009.

  1. Wendy

    Thread Starter Moderator

    Mar 24, 2008
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    I'm going to start putting various article links about graphine in this thread. It appears to be one of those up and coming materials that are stranger than fiction.

    http://www.physorg.com/news161529738.html
     
  2. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    Hi Bill:

    This is EXACTLY the sort of stuff we need to be alert to...I think there are going to be entire universes of possibilities of applications (and cash!) that we haven't even touched on. I've always been a big fan of materials engineering....I think it will be the "next semiconductor" industry.

    Eric
     
  3. mik3

    Senior Member

    Feb 4, 2008
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    I think we know nothing about universe yet. ;)
     
  4. Wendy

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  5. Wendy

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  6. Wendy

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  7. bituufg

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    Jul 8, 2009
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    The answer to #1 is .074 because gravity is a constant.

    The answer to #2 is "angular momentum = the sq root of velocity"

    answer to #3, I have worked out but get 2 different answers, so you can email me on wednesday, and by then I'll have the definitive answer.
     
  8. Wendy

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    Methinks you missed.
     
  9. Dave

    Retired Moderator

    Nov 17, 2003
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    Do you think?! :D

    Dave
     
  10. beenthere

    Retired Moderator

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    All answers are 43.
     
  11. b.shahvir

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    The other day I read in the papers a few grams of graphene can cover an entire football field.
     
  12. steveb

    Senior Member

    Jul 3, 2008
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    Well, that would definitely change the playing conditions.
     
  13. Wendy

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    Grahene makes a pretty decent lubercant, but I doubt they would notice. Still, brings some funny pictures to mind.
     
  14. MrShhh

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    Jul 7, 2009
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    A friend of mine is doing the final year of his phd on graphene...It's fascinating stuff! He was talking about charge within graphene moving at relativistic speeds the last time we spoke. And something about electron holes. Cool.
     
  15. Wendy

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    There is a very good chance CPUs will be made out of graphene soon, if some other material doesn't push it out of the running. It is the best semiconductor form of carbon. Diamond is a close runner up, and bucky tubes are a wild card (with the very real potential for superconductivity). Carbon is like a universal building block, you can make almost anything from it.
     
  16. b.shahvir

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    But what makes the processor speed up data transfer? low resistance or low parasitic reactances? thanx
     
  17. Wendy

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    Actually, nowdays it is the size of the transistor, as well as switching speed. The faster a transistor can go from on/off and off/on, the less heat it makes. The size enters into it because that limits how many transistors can fit on a die. Nowdays we are into the billions of transistors per die, so the little (and it is extremely small) amount of heat each transistor makes during switching adds up fast.
     
  18. b.shahvir

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    Me thinks the on/off speed of solid state device depends on value parasitic capacitance across the depletion layers of the semicontuctor. The larger the value of parasitic capacitance, lower the switching speed and vice-versa.

    Semiconductor resistance might not have anything to do with switching speed apart from heat dissipaton or power loss.

    Best regards,
    Shahvir
     
  19. Wendy

    Thread Starter Moderator

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    Tell that to a transistor that lets only 1 or 2 electrons through. We are in the realm of quantum (which is one reason graphene shines), the rules aren't quite the same.


    But even old tech, if a transistor switch has high impedance, and the output is low (but some finite), the semiconductor impedance also doesn't enter into it (I am assuming a really high input impedance). The only time there is conductance (ie, heat) is during the switching process when both transistors are on, which in turn only happens when they change states. A CPU that is not toggling draws pico amps or less.

    Yes, there is parasitic capacitance on the input of a FET, but remember we are talking extremely small sizes, so the capacitance is also extremely small. The smaller the transistor, the less parasitic capacitance.
     
  20. Wendy

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