Re: [Sci.nanotech] Carbon Games


On a dark an' dismal Sat, 05 Apr 2008 01:27:33 -0500, in flickering lampl=
ight, "Perry E. Metzger"
<perry@xxxxxxxxxxxx> scribed with phoenix qill :

mike <mikespam@xxxxxxxxxxxxxxxxxxxxxxxxx> writes:
Well.
I know i said fire away, but i wasn't expecting
a flame. The moderators are usually careful
about that....

I believe I stuck pretty strictly to the facts. You may not like the
facts, but that does not make the posting a "flame".

[I like facts, one is that i know only a little amount of them,
So please just stick to fact, correct my naive notions.
But please, leave out the rude comments.
Not everyone was taught as you were, and what you'd assume as
self evident can easily trip up people like me. -mike]

<<#>>
Right, first, i don't really know where the carbon dioxide slipped into
the text. Sorry for that, was intended to be all carbon.
The other things like 'normal temp' you refer to?
It's hot, that's what the laser's for, to 'keep it active' a gas.

Carbon doesn't generally become a gas until well past
4000K. Regardless of how you heat it, you will end up with something
that will more or less destroy anything it comes into contact
with.

Would it be ionised?
If so could it be possible to capture it in a magnetic field?
Then we might have some measure of positional control by manipulating
the field.

Furthermore, even once turned into a gas, a monatomic form is
not energetically favored until very high temperatures, where
entropy effects overcome the exceptionally strong carbon-carbon bond
energy, thus making your proposal even more unlikely.

I've just had a look at a copy of the Periodic table, and realised that i
actually mis-remembered where carbon is. Oops. :-)
Isn't there some way to build an environment that would favour the
formation of desired length nanotubes?

<<#>>
A carbon atom is order of magnitude the same size as a silicon
atom. To make a "perforation" this size in a silicon surface would
imply somehow removing individual silicon atoms with a laser.

Which i have read has been done. [might not be silicon, though]

I assure you that no one has yet found a way to remove single atoms in
precisely defined (that is, defined down to an atomic radius) positions
with a laser.

Sorry, i must have mis-recalled it. I thought it was work done by or for
the microelectronic's miniturisation agenda.
Perhaps i just wanted to believe it was already done, but it was just a
proposal?

<<#>>
You are referring to interference effects. Such effects do not involve
the creation of fields with a characteristic length tens of thousands
of times below the wavelength of the light in use. Again, what you
propose is quite clearly impossible without the use of frequencies far
beyond the ability of current technology to control.

So it might 'eventually become possible?
There's no physical barrier to it working?

<<#>>
Besides, it isn't clear you could even get the Si atoms to
reliably absorb the x-rays -- they'd likely pass through the surface
instead.)

Okay, what would you suggest?

I have no suggestions -- you are attempting to perform impossible
tasks. Even if I wished to, I could not provide you with ways to
perform them.

You could suggest i stay away from lasers :-)

Si atoms would just migrate and close your hole up.
They would move that fast? I thought we would have them vibrate
and eventually seal the holes, but i was assuming months.

Depassivated Si surfaces are notoriously reactive because they are
very energetically disfavored. The surface will spontaneously
re-arrange to minimize its energy.

That's annoying, and to me unexpected. How the devil does doping a
chip work if that's the situation, wouldn't the foreign atoms be instantly
expelled? Does that happen?

<<#>>
If you could magically keep it from vaporizing what it came into
contact with, it would react instantly with depassivated silicon -- it
would not "move through" holes.

Okay! alright already. Silicon is out, then.

[Don't call them magic holes again, please.]

Why not? You need magic to make them, and apparently they have
the magic property of extruding nanotubes out the other side.

Since you have decided to respond, please accept first my thanks,
and second my request that you treat all this as lighthearted,
and friendly. [At the moment you are coming over as a bit, well, aggressive.]

<<#>>
Any laser capable of breaking a carbon-silicon bond would melt or
vaporize the entire silicon structure. In any case, no carbon atom
will ever travel through an impossible-to-produce single atom wide
hole in a layer of silicon because, were it not so energetic as to
damage the hole itself, it would *always* bond to the Si long before
it could get through the hole, so it essentially wouldn't matter how
often you try.

I think i was after a more softer approach, the laser was only ever
intended to be the 'stirring rod' never letting the carbon settle.
the only way out was to be a hole in the chamber...

Why not a hexagon? It had to be something, and that just dropped in place.
Do you have a specific reason it cannot be one?

Why not make it into a pentagon, or a tic tac toe grid, or any other
pattern? Even if you could get single C atoms to emerge in a
hexagonal pattern, what is special about a hexagon? Again, perhaps you
are under the misapprehension that a single wall carbon nanotube is
hexagonal in cross section, but it is not, so what is the purpose of a
hexagonal pattern?

I wasn't aware of anything specifically, and hexagon as i said,
'just dropped in place'.

Regardless, the idea is implausible. This isn't chocolate frosting
being forced through a pastry tube -- the carbon atoms, even if you
could get them to emerge from your hexagon, will not nicely queue up
and bond to each other, in a hexagonal pattern or in any other pattern.

So, if placed next to each other with a Scanning atomic microscope
they would also fail to bond? I was under the impression they would.

All that's important is providing the carbon with plenty of
opportunity to bind in some stable ring formation, and still be open
to linking to more from the feed side.

Why would the carbon atoms bond in any particular shape whatsoever?
If they could make it through the holes at all, they'd be arriving in
a temporally randomized pattern, with wildly different energies
(following the Boltzmann distribution for a substance at that
temperature) and would almost certainly leave the holes with quite
uncorrelated trajectories. They would not be within a typical
carbon-carbon bond length of each other, and if they became close
enough to each other there would be no particular reason for them to
form any particular pattern of bonding.

I think this is because you saw the fact that they'd have to be highly
energetic fast moving atoms, while i envisioned a slow, impossible situation
of them caught temporarily and only able to escape by bonding to an
atom caught in the holes, and being drawn through.

This idea is more or less as plausible as the notion that you could
make humans by forcing bits of homogenized cow through a short slot in
a piece of *** steel.

This doesn't relate, in any way. I am talking about atoms, and that
'notion' above, as you call it is not.

It does relate, in that it is more or less an equally plausible idea.

It doesn't relate and is simply rude. Please, drop it.

<<#>> <<#>>
It won't work because none of it makes any sense at all.

Yet you still responded to it?

Correct. I've got the bad habit of explaining why incorrect ideas are
incorrect when I encounter them.

I do have a similar habit, and the point of this was to find out
what was wrong with it.
I'm under no illusion that, had been possible, it would've been done
long ago, i just couldn't see why it shouldn't be possible.
And since things had gotten so quiet here, i saw no harm in posting it.

<<#>>

I'm afraid that the archives, which are astonishingly complete, show
no previous postings from your account. Perhaps you've posted in the
past from other accounts, but I see no reason to assume the moderators
would be able to know that.

One of them does, however i have had a lot of spam and am
attempting to reduce it, you might want to try again removing 'spam'
from the email addy. But it's probably not worth it.

I suggest that you re-read the beginning of my original post and
then decide if that was justified.
Still, not too bad considering you didn't understand it.

I understood what you were, more or less, proposing. Unfortunately,
the proposal has no germ of a plausible idea within.

A shame, i am hoping to see the space elevator in my lifetime, it
will need various lengths of nanotubes won't it?
(At the least, they'd be handy.)
Still, even just an open ended system for making them would be nice.
I'm just frustrated that things have gone so quiet, and i hope that it's
because everyone's hard at work and a nice surprise is coming. :-)

mike :-)

.

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