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[资源] 惊暴！经典的纳米图片和动画！

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This animation loop shows the results of a molecular dynamics simulation done with NanoEngineer-1. It is the first time the Drexler-Merkle differential gear has ever been simulated. While the individual frames of the animation loop were rendered using POV-Ray, NanoEngineer-1 generated the POV-Ray files automatically. The gearbox casing was hidden to expose the internal gearing mechanism. Notice that the front and back shafts rotate in opposite directions. If you'd like to see how this was done, click "How I Simulated the Drexler-Merkle Differential Gear".
Dr. Drexler provides the following brief description of the differential gear:
In this view the two cylindrical shafts and their facing bevel (conical) gears are shown, along with two of the four casing-mounted pinion gears that mesh with both shaft-gears. Acceptably smooth motion (despite the atomic granularity of the building blocks) is made possible by geometry and symmetries. For example, the shaft-gears have 14-fold symmetry, while the casing has 4-fold symmetry; if one pinion gear is exactly opposite a shaft-gear tooth, its 90-degree partners will be opposite shaft-gear grooves. Thus, energy fluctuations at the tooth-meshing frequency will cancel, leaving only higher-frequency, lower-amplitude fluctuations as barriers to rotation. The shafts rotate in the casing on standard sliding-interface bearings, using the same principle to achieve smooth motion. The lowest quality bearings are those between the pinion gears and the casing, which lack the regularity required for high smoothness.
The structure is designed to be built chiefly of hydrogen (white), carbon (gray), silicon (black), nitrogen (blue), phosphorus (purple), oxygen (red), and sulphur (yellow). The larger size of second-row atoms helps in constructing tapered gears and reduces the number of atoms needed to construct the outer cylinder of the casing. Such structures are far beyond the state of the art of chemical synthesis today, but their design and modeling is becoming straightforward.
- K. Eric Drexler
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