Stanford Develops Carbon Nanotubes

Researchers at Stanford University have demonstrated the first functional computer constructed using only carbon nanotube transistors.

Scientists have been experimenting with transistors based on carbon nanotubes, or CNTs, as substitutes for silicon transistors, which may soon hit their physical limits.

The rudimentary CNT computer is said to run a simple operating system capable of multitasking, according to a synopsis of an article published in the journal Nature.

Made of 178 transistors, each containing between 10 and 200 carbon nanotubes, the computer can do four tasks summarized as instruction fetch, data fetch, arithmetic operation and write-back, and run two different programs concurrently.

The research team was led by Stanford professors Subhasish Mitra and H.S. Philip Wong.

“People have been talking about a new era of carbon nanotube electronics moving beyond silicon,” Mitra said in a statement. “But there have been few demonstrations of complete digital systems using [the] technology. Here is the proof.”

IBM last October said its scientists had placed more than 10,000 transistors made of nano-size tubes of carbon on a single chip. Previous efforts had yielded chips with just a few hundred carbon nanotubes.

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MIT Develops Inflatable Antenna

Satellites the size of shoe boxes, which are expected to one day allow researchers to explore space more efficiently, will soon have greater range.

MIT researchers have built and tested an inflatable antenna that can fold into such a satellite, then inflate in orbit to enable long range communications — from seven times the distance possible today.

The technology will let the small satellites, called CubeSats, move further into space and send valuable information to scientists back on earth.

“With this antenna, you could transmit from the moon, and even farther than that,” said Alessandra Babuscia, a researcher on the inflatable antenna team at MIT, in a statement. “This antenna is one of the cheapest and most economical solutions to the problem of communication. But all this research builds a set of options to allow the spacecraft … to fly in deep space.”

The MIT effort comes as engineers at the University of Michigan work on ways to propel such small spacecraft into interplanetary space. The team is building a plasma thruster that could fit in a 10-centimeter space and push a small satellite-bearing spacecraft into deep space.

The university researchers using superheated plasma that would push through a magnetic field to propel a CubeSat.

The MIT researchers are seeking to solve the communications problems and enable far-afield CubeSats to send data to and receive instructions from Earth.

The CubeSat devices cannot support radio dishes that are used today to let spacecraft communicate when far from Earth’s orbit.

The inflatable antennas significantly amplifies radio signals, allowing a CubeSat to transmit data back to Earth at a higher rate, according to the university.

MIT engineers have built two prototype antennae, each a meter wide, out of Mylar, which is a polyester film known for its strength and use as an electric insulator. One antenna was a cone shape, while the other looks more like a cylinder when inflated. Each fits into a 10-cubic-centimeter space within a CubeSat.

Each prototype contains a few grams of benzoic acid, which can be converted to a gas to inflate the antenna, MIT noted.

In testing, the cylindrical antenna performed “slightly better” than the cone shaped device, transmitting data 10 times faster, and seven times farther than existing CubeSat antennae.

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