Recent content by nkk2008

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    Finding the fermi energy in doped quantum well

    Homework Statement Regular Doping: Let's say that we want to introduce some electrons into a quantum well, by adding dopant atoms (donors) to the semiconductor. The "regular" way to do this would be to deposit our semiconductor films, first a "barrier" layer with large band gap, then the...
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    What is the best way to find a specific chemical for a lab class?

    Homework Statement I need to find a specific chemical for a lab class. The manual states the chemical must: Be used as a drug in the pharmaceutical industry Have one chiral center Be soluble (make 4 Molar solutions) in water So...any ideas? Or, better yet, is there a database where I...
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    Solving for Boyle Temperature in MATLAB

    Thanks. I actually already have a post with this exact problem in the Matlab forums. I realized that that may be the more helpful place to look after I posted this thread. -Nkk
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    Can the Percentage of Energy Lost to Friction Be Negative?

    It is always positive. A negative loss is an addition and if that were the case, we would all have infinite motion machines that produce energy via friction. A nice idea, but impossible. Nkk
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    Solving for Boyle Temperature in MATLAB

    Homework Statement So I honestly had to idea where to put this. I know how to solve the problem, but I cannot get Matlab to work. This questions is more of a MATLAB question. I figured since the underlying problem was physical in nature I would post here, so forgive me if I am wrong. The...
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    Vector Equations to sys of diff eq

    So for 1A I would just break it into three eqs like: \frac{q_{r}}{A}=-k \frac{d}{dr}T_{r} \frac{q_{\phi}}{A}=-k \frac{1}{r} \frac{d}{d \phi}T_{\phi} \frac{q_{\theta}}{A}=-k \frac{1}{r sin(\phi)} \frac{d}{d \theta}T_{\theta} Is that right? That was easy... Maybe I am both overthinking...
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    Vector Equations to sys of diff eq

    Homework Statement The problem has four very similar parts: A)Rewrite the following vector equations as systems of differential equations: \frac{q}{A}=-k \nabla T (q is a vector) (spherical coordinates; k and A are constants) B)Rewrite the following vector equations as systems of...
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    What is the Meaning of Re(function)?

    Thank you both. Now that you both said it, it seems really obvious. The equation I was looking at was: Taking the real part makes sense, and fits well. Thanks again, Nkk
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    What is the Meaning of Re(function)?

    I have seen the symbol Re(function) used. What does the Re stand for? I thought it was the Riemann zeta function, but I am pretty sure I am wrong (that is a lower case zeta...obviously). Is it the same as the script R? I know this is a basic question, but I could not find documents online...
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    Java How do I check if there is nothing filling in the index at i of the array?

    I have an array of doubles that is too large (i.e. it is of length 10, but only indices 0 to 6 are filled). I want to trim it, and am having problems with the line for loop{ if(array[i] == null{//THIS LINE action } } It says that "the argument type == is undefined for types double...
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    Java Reading .xls in java using Apache POI

    I have been given the task to write a program that does some basic math and numerical integration on numbers. Those numbers are stored in a .xls file. I have looked online and have seen the Apache POI and whatnot, but I have some serious problems stemming from my total lack of knowledge: How...
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    Java How Can I Set Character Encoding in Java When Writing to a CSV File?

    Thank you very much. That is exactly what I was looking for. Is there any way to buffer the output to this writer? I remember reading that as of some past version of java, buffered readers and writers were preferred. Is that not the case here? Thanks, Nkk
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    Java How Can I Set Character Encoding in Java When Writing to a CSV File?

    Ok, so I have been asking a lot of java related questions this past week or so. Now, I have yet another one. My program takes a bunch of input in the form of arrays of doubles, and prints it out to a comma separated csv file for use in a spreadsheet. However, when I try to open the file, I...
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    Java Extracting a number out of a string in Java

    Ok, (and this is where my total lack of any real knowledge comes in), how do I keep its decimal nature? In reality, these numbers are speeds that will be fed into a physics model for total energy used, so they need to be pretty exact. Also, can someone explain exactly what makes an int...
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    Java Extracting a number out of a string in Java

    So...um...how do I convert it to a signed int? What is a signed int? I looked online, and am sort of confused. Thanks, nkk
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