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Australian Overturns 15 Years of Nano-Science Doctrine
Roland Piquepaille writes "Dr John Sader, from the University of Melbourne, discovered a design flaw in a key component of the Atomic Force Microscope (AFM). He 'used established mechanical principles to prove that the popular V-shaped cantilever inadvertently degrades the performance of the instrument, and delivers none of its intended benefits.' This finding may reshape the industry by proposing a single new standard and because the AFM 'has been the instrument of choice for three dimensional measurements at the atomic scale, since its invention in 1986.' Check this column for more details and an AFM diagram or read the original University of Melbourne's article. You also can visit the
'How AFM works' page."
In the mean time, can someone possibly provide examples of any popular theories or situations that this discovery may have thrown off? I just want something more substance than "it changed a lot".
But if an Australian overturns something does that not mean its actually the right way up ?
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
Ill be sending my refund form right now!
Since the Aussie police have raided all the Universities and removed MP3/DivX collections they've had to turn their attention to work.
Hope noone at my company realises this.
I don't do AFM, but my labmate has. He said that this flaw was well-known, and that most people dumped the v-shaped cantilevers in favor of nanotubes (I think) or straight cantilevers. Cool thing he said was that to get a tip, very popular was the gunk that piles up after you clean an electron microscope. One man's trash is another's treasure, I suppose.
If modern string theory is true then most nano science applications will fail to work.
Recall that standard supersymmetry work with strings in 11 space dimensions on Yang-Calbai manifolds. At sizes below 15 angstroem you'll effects from these 11 dimensions. Especially has the wave equation non-trivial, non-analytic solutions and Hygens' principle fails (due to the topology of the Yang-Calbai manifolds, recall that the 5th deRham cohomology group is non-trivial).
So you'll get the effect of string resonance - strings are coupled together the 3rd order Laplace equation which overrules strong and weak interaction. This means that control of dynamical systems below the 15 angstroem barrier is impossible - you'll always get 5th order resonance which collapses the control Lie-algebra.
So all these nifty little nano-machines won't work, they'll be just little protein blob wiggling around and doing nothing useful.
As an example see this example.
Owner of a Mensa membership card.
The all-important cantilevers are placed in light contact with a sample and moved across its surface, detecting any change in surface topography. Cantilever calibration is a fundamental issue in the use of the instrument.
is the actual quote. Dont know where you got internet from.
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
*passes hand over head*
"Sic Semper Tyrannosaurus Rex."
It's very intriguing that a mathematician has been able to mathematically prove that V-shaped cantilevers are worse for Atomic Force Microscopy.If the proof is so conclusive, however, it would have been nice for them to wait until they'd fabricated some straight-beam cantilever AFM tips, so that they could do a nice thorough study proving that they get better performance using them for actual data.
(It shouldn't be any more difficult, and it might be a little easier, even, to make straight beam cantilever tips than to make V-shaped ones. This is because the cantilever part of the tip is typically made by some sort of photochemical etching, and a straight beam is certainly a simpler shape to etch.)
Anyway, even with recent advancements in tip design technology atomic force microscopy is still rather inexact when it comes to getting good results consistently. As much as they try to design good tips, you'll never really know if you'll get good images from it until you mount it in the AFM and actually use it. I've certainly heard of grad students who will find a good tip (through trial and error) and become very protective of it (which is hard to do because they're extremely delicate), just because getting good results from Atomic Force Microscopy can often be tricky business, and a tip that you know is good is a great advantage.
-------------------- the list is long. dirac angestung gesept
The tips are very delicate, and so far, they only seem to be made by photochemical etching. This is in contrast to Scanning Tunneling Electron micrscopes, which you can (and people do) make out of reasonably cheap parts.
This is because an STM tip can just be a pointy piece of wire, snipped off with pliers, and still give decent results some of the time. Also, there are easy techniques for making sharper STM tips yourself, such as electrochemical etching, which in this case is a very simple, easy-to-do-at-home process.
-------------------- the list is long. dirac angestung gesept
Does somebody know why twist is a problem? I tried to look up the RevSciInstr article, but couldn't find it.
karma police: arrest this man, he talks in maths; he buzzes like a fridge, he's like a detuned radio. [radiohead]
V-shaped cantilevers work fine. People can obtain atomic resolution with them. What more could you want?
I have used both straight and V-shaped. If there is a difference in performance, the difference is mostly likely very small and over-shadowed by other factors.
I heard that they when they started making ATMs, the first tips were "made" by smashing a diamond between two plates of steel, then trying as many of the resultant crystal fragments as possible to see which one gave the best resolution. They "estimated" that the ones which gave the best resolution had a tip with the sharpness of a single atom.
AFMs are being used to do alot more than measure nowadays. This summer I worked on Dip-Pen Nanolithography which uses an AFM like a fountian pen of sorts. It's pretty cool stuff, and if that cantilever is off (the piece which holds the "nub" of the pen) then all of the work done could be rendered incorrect... DPN Information
I've been working on the software for these types of instruments since 1991. Making something that resolves atoms at room temperature is quite a daunting task. In electronics, just the basic Johnson Noise of resistors becomes significant when trying to resolve such tiny measurements. On top of that, the thermal drift of the metal in your instrument which moves your measuring device relative to what your measuring is enough to prevent you from seeing atoms. Then you also have to worry about digital noise generated by your processors radiating into the sensor electronics over ground and power leads.
To make a commerically viable AFM, you need a lot of smart people from several different fields. But even then, these people have to have a few years of building this sort of instrumentation under their belt. It is not easy at all. And the machining costs alone will always dictate a high price for these instruments.
-todd-
PS - Although atoms get a lot of press, I think the most interesting uses of AFM are in biology and hard drive research. These certainly produce the more spectacular looking images.