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Archive for January 2010

One sloshing step closer

Hold still, now, this will take a while:

When J. K. Rowling described Harry Potter’s invisibility cloak as “fluid and silvery”, she probably wasn’t thinking specifically about silver-plated nanoparticles suspended in water. But a team of theorists believe that using such a set-up would make the first soft, tunable metamaterial — the “active ingredient” in an invisibility device.

The fluid proposed by Ji-Ping Huang of Fudan University in Shanghai, China, and colleagues, contains magnetite balls 10 nanometres in diameter, coated with a 5-nanometre-thick layer of silver, possibly with polymer chains attached to keep them from clumping.

The chains and columns would lie along the direction of [a] magnetic field. If they were oriented vertically in a pool of water, light striking the surface would refract negatively — bent in way that no natural material can manage.

The trick, so far, has been widening the spectrum within which the metamaterials can function: while they’ve successfully blocked infrared in similar experiments, they’re a long way from blocking the complete range of visible wavelengths.

(Source here. Via Fark.)

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Moscow takes a stand

The Russian agency in charge of advertising has ruled that invisible persons cannot appear, so to speak, in beer commercials.

This ruling plugs a loophole in existing law, which forbids the display of humans and animals, live or animated, in such advertising; even having the characters offstage is forbidden.

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