"Some people are so arachnophobic that they will actually kill any spiders they see."
I'm not afraid of spiders in the least, but I kill them because I don't want bugs in my house. Yes, spiders aren't insects (I said "bugs":P), yes they eat other bugs, but I still don't want one crawling around in my bedsheets!
I wouldn't go around killing spiders outside though, that would be dumb...
I'm a grad student in Robert Wolkow's research group so maybe I can clarify a couple of things.
It's true that such a tip would get dull easily if it were used like a knife or a tack or to poke at things. However what I think will be the best uses for it are situations where the tip is not in actual physical contact with a surface. In a field emission gun electron microscope, electrons are emitted from the tip where the field is highest; the sharper the tip the higher the field. There is no touching of a surface, just electrons being emitted from a point source.
Mr. Rezeq has shown us field ion microscopy (FIM) movies of the tip where you can clearly see it etched away from hundreds of atoms down to one. Now there are lots of atoms below that, but FIM only shows atoms where the field is highest. So that picture is a picture of where electron emission would occur as well, i.e. a single atom.
In STM having a sharp tip is also desirable, and there the end of the tip hovers over a surface, just barely but not actually touching it. Even then the tip can be damaged over time, but with care it can stay atom-sharp very long.
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It's -10 C outside now - do I pick death by squishing, or death by freezing?
"Some people are so arachnophobic that they will actually kill any spiders they see."
I'm not afraid of spiders in the least, but I kill them because I don't want bugs in my house. Yes, spiders aren't insects (I said "bugs" :P), yes they eat other bugs, but I still don't want one crawling around in my bedsheets!
I wouldn't go around killing spiders outside though, that would be dumb...
Yes, and no one ever gets sick because of the Sun! Oh wait, 8000 people die every year in the US from skin cancer.
I'm a grad student in Robert Wolkow's research group so maybe I can clarify a couple of things.
It's true that such a tip would get dull easily if it were used like a knife or a tack or to poke at things. However what I think will be the best uses for it are situations where the tip is not in actual physical contact with a surface. In a field emission gun electron microscope, electrons are emitted from the tip where the field is highest; the sharper the tip the higher the field. There is no touching of a surface, just electrons being emitted from a point source.
Mr. Rezeq has shown us field ion microscopy (FIM) movies of the tip where you can clearly see it etched away from hundreds of atoms down to one. Now there are lots of atoms below that, but FIM only shows atoms where the field is highest. So that picture is a picture of where electron emission would occur as well, i.e. a single atom.
In STM having a sharp tip is also desirable, and there the end of the tip hovers over a surface, just barely but not actually touching it. Even then the tip can be damaged over time, but with care it can stay atom-sharp very long.