Recent content by lifeson22

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    How hazardous is semiconductor etching?

    Thanks Mapes, for the insightful answer. I'm very excited about semiconductor processing, but have my reservation because of the many hazards involved. Your answer puts me a bit more at ease with the acid hazards.
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    Physics Physics a worthless degree?

    I'll point out one more thing. Physics is employable, but not as desirable in industry. You will get a job, but it *will* take a while (to be kind) and you will have to get creative. First, you might recognize that well-established industries like Aerospace don't exactly have an appreciation...
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    Physics Physics a worthless degree?

    Some would argue the first thing a degree should do for you is allow you to pay it back. You know, a job. Forget about a high-paying one, or a cool one. Just a job. Period. To pay back your fvcking debt. High salaries and coolness of work can come later. But you ought to be able to pay your...
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    How hazardous is semiconductor etching?

    Many of you may be annoyed by my question. I'm sorry in advance. I've just finished my M.S. in Materials Science & Engineering, and have gotten an offer as a Semiconductor Process Engineer. The specialty is lithography and wet chemistry - including wet etching. As an MSE student I learned...
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    Physics Physics a worthless degree?

    As usual, the going attitude is that you should be happy to sacrifice yourself for the privilege of doing physics. - Pretend you have no other life priorities, like a family, or the desire to travel. A real life interferes with physics. - Money isn't everything. Especially when there is...
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    MATLAB Code help Heat transfer

    And what are your units? On an aside, it's so warm in my room - it's like 28. And it's been warm for a while too - for almost 4 now. I tried to cool things down a bit by opening a gap in my window - a gap of 2. Now - good luck deciphering that. And then they wonder why nobody wants to...
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    Calculate amount of ferrite in a sample.

    You can estimate the concentration of ferrite in your sample by doing an areal analysis of your sample. You can do this by capturing a magnified image of your sample surface (taken from a microscope), and then using any of the many areal analysis software tools out there. An example of such...
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    Lever rule, help needed asap

    Consider the homogeneous liquid at the eutectic composition (50% To an 50% Lb). When you cool it to room temperature, you get two distinct phases, alpha and beta. By the lever rule, the relative concentration f alpha and beta phases is calculated as follows: 1. beta phase...
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    Glasses which enable you to see in black & white

    Yes - any glass made before 1951 in the televsion market. By going even farther in time you can also make it mute.
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    What really is Chemical engineering? and what can you DO with it?

    The theoretical frame of a chemist is not so different from that of a chemical engineer. The primary difference is in the type of application each focuses on: chemical engineers work with practical applications, and all their work has the ultimate goal of developing a working device; on the...
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    Relative Entropy?

    Entropy is a measure of the probability of finding a system in a given configuration - period. You might have seen it in your statistical physics or thermodynamics textbooks as: S\proptolog(g), where the g is the multiplicity of the system's configuration, given by the binomial distribution...
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    Entropy Transfer?

    A reversible process is one in which system+surroundings (the universe) gains no net entropy. But one can see an entropy increase at the expense of the other while observing this relationship: only if the entropy increase in one is equal to the entropy loss in the other. A reversible process...
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    Entropy Transfer?

    That's right. Following Kittel, the multiplicity for a system of N particles, each of which with only two states available ("up" or "down" spin) is simply g=\frac{N!}{N_{up}!N_{down}!} If I add one particle (say spin up), we have: g=\frac{(N+1)!}{(N+1)_{up}!N_{down}!} Since...
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    Entropy Transfer?

    I've noticed a terrific number of authors talk about "entropy transfer" across a system boundary. But entropy is defined as log(multiplicity), and is a measure of available states to a system in a given configuration. We can transfer mass, charge, energy, from one system to another, and thus...
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    Is 'real space' merely a convenient mental representation?

    In quantum mechanics, a free particle is described by a continuous superposition of wavefunctions, which can be done equivalently in real or momentum space. We can look at a particle's probability distribution in real space, take its Fourier transform, and obtain the particle's distribution in...