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Old 08-30-2007, 04:04 PM   #16
binky
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Great timing

Thank you for the snowflake- it is about 105 degrees here in the California desert, so even the thought of snow is comforting
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Old 08-30-2007, 04:08 PM   #17
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How do all six arms of the snowflake know to grow into the same shape? That's what I want to know.
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Old 08-30-2007, 04:10 PM   #18
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How do all six arms of the snowflake know to grow into the same shape? That's what I want to know.
I'm pretty sure it's in the genes.
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Old 08-30-2007, 04:26 PM   #19
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The shape of the center determines the shape of the arms.
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Old 08-30-2007, 05:47 PM   #20
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Starfish syndrome.
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Old 08-30-2007, 09:59 PM   #21
Beest
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I usually try and do this at least once each winter, personally I'm going for catching a falling flake, and imaging it without any prep. All that freezing with liquid nitrogen and bombarding with ions might change the structure.
Then again I haven't been successful yet.


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I had been wondering how they did it, beacause electron microscopes can only image objects whose surface is electrically conductive. -
Modern (for at least the last ten years) electron microscopes can image non conducting objects by using a low gas pressure in the chamber, incoming beam ionizes the gas around the beam providing a conducting path to dispel charge.

Low beam currents, and accelerating voltages, also help reduce sample charging in the Field emission type SEMs.

I bet you're sorry you asked now
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Old 08-30-2007, 10:36 PM   #22
monster
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Quote:
Originally Posted by Beest View Post
I usually try and do this at least once each winter, personally I'm going for catching a falling flake, and imaging it without any prep. All that freezing with liquid nitrogen and bombarding with ions might change the structure.
Then again I haven't been successful yet.

But you have done some nice pics of a chrysalis. And stuff.
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Old 08-31-2007, 03:29 AM   #23
Scriveyn
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Quote:
Originally Posted by Beest View Post
... Modern (for at least the last ten years) electron microscopes can image non conducting objects by using a low gas pressure in the chamber, incoming beam ionizes the gas around the beam providing a conducting path to dispel charge.

Low beam currents, and accelerating voltages, also help reduce sample charging in the Field emission type SEMs.

I bet you're sorry you asked now
Not at all - thanks B.
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Old 09-08-2007, 10:15 PM   #24
paxton
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Crystallization

Quote:
Originally Posted by middy View Post
How do all six arms of the snowflake know to grow into the same shape? That's what I want to know.
http://en.wikipedia.org/wiki/Crystallization
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