- Carbon-Nanotube Memory that Really Competes
- Holographic discs set to smash storage records
- Bug enzyme generates fuel from water
- Scientists read minds with infrared scan
Carbon-Nanotube Memory that Really CompetesJanuary 26th, 2009
(PhysOrg.com) -- Researchers in Finland have created a form of carbon-nanotube based information storage that is comparable in speed to a type of memory commonly used in memory cards and USB "jump" drives.
The group's memory scheme has a write-erase time of 100 nanoseconds, which is about 100,000 times faster than previously reported carbon-nanotube memory, and retains this ability over more than 10,000 write-erase cycles.
The memory scheme stores information using single-walled carbon-nanotube transistors, specifically field-effect transistors, which are among the fastest carbon-nanotube electrical components. Each transistor consists of four key parts, the gate, source, drain, and substrate.
As a substrate, Törmä and her colleagues chose a silicon wafer. The 20nm hafnium oxide separates the substrate, which was also used as the gate in this case, from the rest of the structure. Choosing hafnium dioxide as the gate "dielectric" material appears to be the key to the device's fast operation, as it can trap and release charge very quickly and efficiently.
On top of the hafnium-oxide layer, the group deposited a few drops of a carbon-nanotube solution. Using an atomic force microscope, they identified nanotubes with the proper alignment; only those nanotubes became transistors. They then created source and drain electrodes for each nanotube using the metal palladium, with the nanotube forming the transistor's conductive channel.
Finally, the researchers deposited another 20-nanometer layer of hafnium oxide on top of the nanotube transistor, to "passivate" the surface, preventing unwanted reactions.
"The fast memory operation we have demonstrated could potentially also be realized using other carbon materials, such as carbon-nanotube bundles or graphene," said Törmä.
Each transistor can store information for about 150,000 seconds, or about 42 hours. This is quite short, although Törmä and her group think they can improve it by adding an oxide layer between the gate and the nanotube.
Citation: Nano Lett., Article ASAP DOI: 10.1021/nl8029916 source
My comment: I'm not too keen on the technical stuff neither, but this sounds very promising indeed. And it reminds me so much of the idea of Alchemy.
Holographic discs set to smash storage records
- 17:06 22 January 2009 by Colin Barras
A dual-layer Blu-ray disc can store an impressive 50 gigabytes, but discs which can hold 20 times as much data have just taken a step closer, thanks to new materials that make reading and writing 3D holograms more reliable.
CDs and DVDs store data as pits on their surface that are read by a laser. A Blu-ray disc can hold over five times more data than a standard DVD because the pits are much smaller.
A pair of laser beams is used to write data into discs of light-sensitive plastic. At the points where the lasers meet, the intense light causes molecules in the disc's material to merge into chains, creating a physical pattern that locks the 0s and 1s into the disc. This pattern can be read back at a later date using another laser because the changed patches interact differently with light.
However, in the plastic normally used for holographic data storage, the structural changes caused by the laser also cause the material to shrink . The volume change isaround 0.23% , but the distortion is enough to mean that the 1s and 0s can't be burned at the highest densities.
Craig Hawker's team at the University of California in Santa Barbara has now solved that problem by replacing the polymer's small molecules with larger, branched ones. These need to make fewer bonds to create a patch of the alternate form of the material, cutting distortion to just 0.04%.
Pioneering companies developing holographic data-storage devices could benefit from the new technique by squeezing at least 1000 gigabytes of data onto a standard disc. source
Bug enzyme generates fuel from water
- 17:01 13 January 2009 by Colin Barras
Light-powered, bacterial enzyme-containing nanoparticles that release hydrogen from water could lead the way to new strategies for generating the energy-rich gas.
A class of enzymes called hydrogenases are used by organisms to convert hydrogen ions to hydrogen gas during anaerobic - without oxygen - respiration. These enzymes have long interested chemists searching for alternatives to existing, expensive, platinum-catalysed hydrogen generation.
The metal-containing enzymes are all crippled in varying degrees by the presence of oxygen and are also damaged by the very hydrogen they produce. That makes them difficult and expensive to use on industrial scales.
Now Reisner and colleague Fraser Armstrong have discovered that one bacterial hydrogenase is much more resistant to both gases.
The nickel, iron and selenium-rich enzyme, first isolated by Juan Fontecilla-Camps at the University of Joseph Fourier in Grenoble, France, is produced by a sulphate-reducing bacterium.
Its efficiency is relatively unaffected by the presence of hydrogen gas, and it continues to work even if the surrounding air contains 1% oxygen by volume - ordinarily even a few parts per million of oxygen would block hydrogenase activity.
The new enzyme also binds strongly to titanium dioxide nanoparticles, making it easy to produce a kind of light-powered, hydrogen-generating dust.
The dust particles are each attached both to the enzyme and to light-absorbing dye molecules that are used in some solar cells.
In the presence of an electron-donating buffer solution, the dye absorbs light and releases excited electrons, which then pass to the enzyme. Suitably energised, the hydrogenase then converts hydrogen ions from water molecules into hydrogen gas - just as they would during the bacteria's respiration.
Developing that complete system of water splitting is Reisner and Armstrong's next goal, they say.
The turnover rates for hydrogen gas cycling are comparable with platinum catalysts under certain conditions, so studying the new hydrogenase might inform the "design" of simpler catalysts that are as effective as platinum, but considerably cheaper. source
My comment: Again-nice! This could give a wonderful perspective to solar cells. And that would mean cheap renewables. Enough said, let's see how far they can go.
Scientists read minds with infrared scanFebruary 10th, 2009
Researchers at Canada's largest children's rehabilitation hospital have developed a technique that uses infrared light brain imaging to decode preference - with the goal of ultimately opening the world of choice to children who can't speak or move.
In a study published this month in The Journal of Neural Engineering, Bloorview scientists demonstrate the ability to decode a person's preference for one of two drinks with 80 per cent accuracy by measuring the intensity of near-infrared light absorbed in brain tissue.
"This is the first system that decodes preference naturally from spontaneous thoughts," says Sheena Luu, the University of Toronto PhD student in biomedical engineering who led the study under the supervision of Tom Chau, Canada Research Chair in pediatric rehab engineering.
Most brain-computer interfaces designed to read thoughts require training. The nine adults in Luu's study received no training. Prior to the study they rated eight drinks on a scale of one to five.
Wearing a headband fitted with fibre-optics that emit light into the pre-frontal cortex of the brain, they were shown two drinks on a computer monitor, one after the other, and asked to make a mental decision about which they liked more. "When your brain is active, the oxygen in your blood increases and depending on the concentration, it absorbs more or less light," Luu says. "In some people, their brains are more active when they don't like something, and in some people they're more active when they do like something."
After teaching the computer to recognize the unique pattern of brain activity associated with preference for each subject, the researchers accurately predicted which drink the participants liked best 80 per cent of the time.
In future, Luu envisions creating a portable, near-infrared sensor that rests on the forehead and relies on wireless technology, opening up the world of choice to children who can't speak or move.
Luu notes that the brain is too complex to ever allow decoding of a person's random thoughts. "However, if we limit the context - limit the question and available answers, as we have with predicting preference - then mind-reading becomes possible."
More information: http://www.iop.org/EJ/abstract/1741-2552/6/1/016003source
My comment: That is awesome! True, it won't decode all of your thoughts, but it could be the base for interaction between you and a computer. Think of it like this, there are sensors to follow your eyes and with this preference-detector you could "tell" the pc to open a folder or send something or simply answer of questions with "ok" and "cancel'. It's not straight-forward but it's again a preference. That's sooooo exciting!