E-BLUE MAKES RECYCLING EASY
Recycling paper could be made simpler by an ink that disappears when heated. Developed by the Japanese consumer electronics giant Toshiba, the erasable ink can be used in ordinary laser printers and in pens. To help distinguish it from ordinary ink it has been tinted blue, and named 鈥渆-blue鈥�.
Toshiba has also developed a desktop erasing machine that can wipe pages clean at the rate of about 100 per hour. The company began selling e-blue printer toner, pens and erasing machines in Japan last week. The machine, which comes with a supply of erasable printer toner, sells for around 拢1600.
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SILICON ON THE WAY OUT?
The first measurements of the mobility of electrons in carbon nanotubes show they are the fastest semiconductors at room temperature. Electron mobility is important because the speed of a microchip depends on how fast electrons can respond to the electric fields applied within it. Silicon, the workhorse of modern microelectronics, is already being replaced by faster semiconductors such as gallium arsenide for the most demanding applications. Chip makers expect to have to replace it entirely with a faster material by 2010.
Electrons in nanotubes can travel 50 times as fast as in silicon, Michael Fuhrer of the University of Maryland, College Park, reported in the online journal Nano Letters (DOI: 10.1021/nl034841q. But raw speed isn鈥檛 the whole story. While engineers know how to mass-produce compact silicon devices cheaply, nanotube electronics is in its infancy. 鈥淢any challenges remain before nanotubes can be used instead of silicon in computer chips,鈥� Fuhrer says.
WI-FI FRIENDLY OVENS
A simple array of magnets could stop radio noise from microwave ovens interfering with Wi-Fi computer networks and cordless phones. The interference comes from the magnetron that ovens use to generate microwaves by accelerating and decelerating electrons within it. But the electrons normally travel at different speeds, producing microwaves at a range of frequencies in the region of the spectrum around 2.4 gigahertz, which is shared by Bluetooth and Wi-Fi devices, and cordless phones. This wide range of frequencies is impossible to filter out and can interfere with wireless telephone and internet connections.
Now nuclear physicists at the University of Michigan in Ann Arbor have shown that creating a magnetic field around the magnetron with a simple array of magnets dramatically reduces the range of velocities the electrons can have. This ensures that the microwave oven produces a single, precise frequency which is easier to filter out.
