Редактирование: Molecular Machinery (раздел)

=== Fullerene Gears ===

{{Molmac
| Name = NASA Carbon Nanotube Gears, Original
| Image = NASA CNT Gears rapid.gif
| Author = [http://www.ipt.arc.nasa.gov/han.html Jie Han], [http://alglobus.net/NASAwork/ Al Globus], and [http://www.ipt.arc.nasa.gov/jaffe.html Richard Jaffe]
| Date = 1997 
| ComponentNumber = 2
| AtomNumber = 992 
| Height = 2.5 nm 
| Width = 4.5 nm 
| Depth = 2.9 nm
| FileName = CNTGears
| Extension = mmp
}}

The design and operation of carbon nanotube based gears was originally studied using computational methods at NASA in the late 1990s. Benzyne molecules (as teeth) are attached to carbon nanotubes (shafts) to form gears that can operate at GHz frequencies. The animations above (and below) show how the gears would function.

The NASA research team states:

"''Our theoretical investigations of the structure and operating conditions of such machines show that the gear is very robust and can operate under adverse conditions such as slipping, conditions in which an ordinary macro-scale gear would fall apart. Computer simulations also show that nanogears, or other machines, in the future could be powered through lasers or externally controlled electric fields.''"

"''Though when we first designed this and showed its operation through computer simulations, we were not sure if anyone can actually attach molecules to the side of a nanotube or how difficult a job it would be. But recently, research groups have succeeded in attaching atoms and molecules to nanotubes. This is promising. We believe then a gear of this type can actually be made in the lab.''"

[[Software#NanoEngineer|NanoEngineer-1]] makes it easy to recreate molecular models of the NASA gears and simulate them using [[Software#NanoDynamics|NanoDynamics-1]]. ND1 produces a special "movie file" containing the atom positions at each iteration of the simulation run. Selected frames from the movie are then rendered with [[Software#QuteMol|QuteMolX]] and finally combined into an animation file.

{{Molmac
| Name = NASA Carbon Nanotube Gears, Double
| Image = NASA CNT Gears Double.gif
| Author = [http://www.ipt.arc.nasa.gov/han.html Jie Han], [http://alglobus.net/NASAwork/ Al Globus], and [http://www.ipt.arc.nasa.gov/jaffe.html Richard Jaffe]
| Date= 1997
| ComponentNumber = 2
| AtomNumber = 1,008
| Width = 4.2 nm
| Height = 2.5 nm
| Depth = 2.9 nm
| FileName = NASA CNT Gears Double
| Extension = mmp
}}

These gears are called the NASA Globus Gear since a nice rendering of this gear was found on [http://alglobus.net/NASAwork/ Al Globus' web page].

A [http://www.ipt.arc.nasa.gov/gallery.html gallery of the original NASA carbon nanotube gears is located here].

For further reading:

J. Han, A. Globus, R. Jaffe and Glenn Deardorff, "[http://www.iop.org/EJ/abstract/0957-4484/8/3/001 Molecular Dynamics Simulation of Carbon Nanotube Based Gears]", Nanotechnology, Vol. 8, pp. 95-102 (1997).

D. Srivastava,"[http://www.iop.org/EJ/abstract/0957-4484/8/4/005 A Phenomenological Model of the Rotation Dynamics of Carbon Nanotube Gears with Laser Electric Fields]", Nanotechnology, Vol. 8, pp. 186-192 (1997).

{{Molmac
| Name = Small Bearing
| Image = SmallBearing.gif
| Author = [[Eric Drexler]]
| Date = 1994
| ComponentNumber = 2
| AtomNumber = 206
| Width = 0.9 nm
| Height = 1.8 nm
| Depth = 1.8 nm
| FileName = SmallBearing
| Extension = mmp
}}

This small bearing was designed by [[Eric Drexler]]. It was originally written about in his book [[Molecular Manufacturing#Nanosystems: Molecular Machinery, Manufacturing and Computation|Nanosystems: Molecular Machinery, Manufacturing and Computation]] (page 296).

The animation above was created from an [[Software#NanoDynamics|NanoDynamics-1]] molecular dynamics simulation of the small bearing. The small bearing is an excellent model for the beginner to [http://nanoengineer-1.net/mediawiki/index.php?title=Tutorial_lesson:_Modeling_a_small_molecular_bearing construct] and simulate. It includes two components (ring and shaft) and only 206 atoms, which means that a simulation with complete rather quickly. It is a great way to get some experience using [http://nanoengineer-1.net/mediawiki/index.php?title=Feature:Rotary_Motor rotary motors] in NanoEngineer-1 that create torque to drive components of molecular models.

The MD simulation you see above took only 2 minutes to complete on my laptop with the following parameters:

* frames: 500
* steps per frame: 10.0 femtoseconds
* temperature: 300K

The animation loop was rendered using [http://qutemol.sourceforge.net/ QuteMol]. Creating an animation like this one is relatively easy since QuteMol can be launched from within NanoEngineer-1. Each frame of an animation can then be saved from [http://qutemol.sourceforge.net/ QuteMol].

To learn how to model the small bearing, [http://nanoengineer-1.net/mediawiki/index.php?title=Tutorial_lesson:_Modeling_a_small_molecular_bearing check out this video tutorial].

The small bearing is also featured in a [http://nanoengineer-1.net/mediawiki/index.php?title=Unmasking_the_Stroboscopic_Illusion new video] produced by Will Ware and Dr. Eric Drexler. To learn more about the video, read the article [http://nanoengineer-1.net/mediawiki/index.php?title=Unmasking_the_Stroboscopic_Illusion "Unmasking the Stroboscopic Illusion - Why the thermal motion shown in standard MD videos is misleading"].