Recent content by carbon9

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    Graduate How to calculate complex permittivity from complex conductivity

    Hi, I got the complex conductivity vs. frequency table of a metamaterial. Its first lines are like this: f conductivity 1GHz 0.004+0.00297i 1.1GHz 0.004+0.00295i 1.2GHz 0.003+0.00294i the table goes up to 10GHz. Now the problem is that I need to enter...
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    Graduate Series expansion of the signum function of sine

    Hi, I just read a physics paper and there it expands signum of a sine function as below: sgn(sin(wt))=(4/pi)*{sin(wt)+(1/3)*sin(3wt)+(1/5)*sin(5wt)+...} How can we expand sgn(sin(wt)) like this? Thanks.
    • carbon9
    • Thread
    • Expansion Function Series Series expansion Sine
    • Replies: 1
    • Forum: Calculus
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    Graduate Current density in graphene-giant?

    Hi, I just read a paper on graphene's basic properties and it says that since current density J is given as J=q*n*v where q is the elementary charge, n is the electron density and v is the Fermi velocity of electrons and for graphene n=6*10^12 cm^-2 and v=10^8 cm/s, the current density...
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    Writing a Letter to a Professor - Tips & Guidelines

    Thank you very much. Really helped lots.
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    Writing a Letter to a Professor - Tips & Guidelines

    Letter to a professor! Hello, I'm doing my PhD work and I'm planning to go to a university that has experimental opportunities on my thesis. I'm thinking to send a letter to the professors who are the heads of those experimental laboratories. I found some places and profs. But I have a...
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    Graduate What is the Density of States (DOS) for Metallic Carbon Nanotubes?

    Thank you Sokrates. I'll look deeper and post here if I can get it. Regards, carbon9
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    Graduate Band theory of Conduction, what constititue resistance?

    Hi, About the resistance of nanodevice, you can look at this site. I think you can find an explanation: http://nanohub.org/resources/2041/ Cheers
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    Graduate What is the Density of States (DOS) for Metallic Carbon Nanotubes?

    Hi all, Sorry for starting a new thread that is similar to another previous one but the question I'll ask is different in fact. Please consider the DOS of a metallic CNT given in this thread: https://www.physicsforums.com/showthread.php?t=351722 On the other hand, the DOS of 1-D...
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    Graduate What is the Explanation for the DOS of Metallic CNT?

    Hi again, In the same book of Hanson, the equation for the DOS of 1-D wires are given as http://img5.imageshack.us/img5/5562/adszvkj.jpg How can I determine the Enx,ny values for this equation for the given DOS plot at the first post? DOS function seems to start from 0 however it is...
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    Graduate What is the Explanation for the DOS of Metallic CNT?

    Thank you very much Sokrates.
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    Graduate What is the Explanation for the DOS of Metallic CNT?

    Thanks.
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    Graduate What is the Explanation for the DOS of Metallic CNT?

    Thank you again, Sokrates. Yes, according the plot given, there seems only 1 conduction channel. Hence, the conductance of the CNT will then be G= \\{2q^2}/{h} totally for spin up and spin down electronic current. However, in the literature (and in the book I mentioned) it is written that...
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    Graduate What is the Explanation for the DOS of Metallic CNT?

    Thank you sokrates. So, for example, if we inject electrons having 0.5eV, then does it mean that there will be only one conduction mode for these electrons?
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    Graduate What is the Explanation for the DOS of Metallic CNT?

    DOS of metallic CNT Hi all, I am in doubt on a subject. The density of states function of a metallic CNT, is given as http://img196.imageshack.us/img196/5629/adszuci.jpg in the book "Introduction to Nanoelectronics" of Hanson. On the other hand, in the same book, it is said that...
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    Graduate Wavefunction of a 2-particle system.

    Thanks adolescent00.