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Category: computing – Page 788

At the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and Tufts University a team has developed a microfluidic chip that mimics human tissue for use in drug testing applications. The chip is based on a silk gel that overcomes the limitations of polydimethylsiloxane (PDMS), a silicon material widely used to host living cells within microfluidic devices. As an example, PDMS has problems handling lipids, absorbing them instead of letting them move freely along with other nearby compounds and so not applicable with lipid-based compounds. Additionally, PDMS is not biodegradable and so a small device based on it can’t easily be used as an implantable. Silk, on the other hand, just needed a bit of engineering to make a candidate that overcomes many of PDMS’s limitations.

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Yale researchers have devised a method that brings marketable Li-O2 batteries closer to reality, improving both the batteries’ performance and the ability to study them.

In recent years, lithium-oxygen batteries have intrigued researchers with their potential. They can store at least two to three times the energy as lithium-ion batteries can, which are the current standard for consumer electronics, so laptops could theoretically run longer on a single charge and electric cars would drive farther.

But they’re not quite there yet. For now, Li-O2 batteries operate sluggishly and have short lives. Compounding matters, it’s hard to get a sense of how to fix that because figuring out the exact nature of their chemistry has proved tricky.

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Micron sized onchip making printing and communication faster.

Researchers designed subwavelength micro-disk lasers (MDLs) as small as 1μm in diameter on exact (001) silicon, using colloidal lithography (dispersing silica colloidal beads as hard masks before etching the prepared QD material layers). Micron sized lasers are 1,000 times shorter in length, and 1 million times smaller than current onchip lasers.

A group of scientists from Hong Kong University of Science and Technology; the University of California, Santa Barbara; Sandia National Laboratories and Harvard University were able to fabricate tiny lasers directly on silicon — a huge breakthrough for the semiconductor industry and well beyond.

For more than 30 years, the crystal lattice of silicon and of typical laser materials could not match up, making it impossible to integrate the two materials — until now.

Continue reading “Micron sized onchip quantum dot lasers will enable faster communication and computing” | >

Graphene, a two-dimensional wonder-material composed of a single layer of carbon atoms linked in a hexagonal chicken-wire pattern, has attracted intense interest for its phenomenal ability to conduct electricity. Now University of Illinois at Chicago researchers have used rod-shaped bacteria — precisely aligned in an electric field, then vacuum-shrunk under a graphene sheet — to introduce nanoscale ripples in the material, causing it to conduct electrons differently in perpendicular directions.

The resulting material, sort of a graphene nano-corduroy, can be applied to a silicon chip and may add to graphene’s almost limitless potential in electronics and nanotechnology. The finding is reported in the journal ACS Nano.

“The current across the graphene wrinkles is less than the current along them,” says Vikas Berry, associate professor and interim head of chemical engineering at UIC, who led the research.

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Stable nanomagnets that ultimately improves data storage on the smallest of devices.

Abstract: So-called “zero-point energy” is a term familiar to some cinema lovers or series fans; in the fictional world of animated films such as “The Incredibles” or the TV series “Stargate Atlantis”, it denotes a powerful and virtually inexhaustible energy source. Whether it could ever be used as such is arguable. Scientists at Jülich have now found out that it plays an important role in the stability of nanomagnets. These are of great technical interest for the magnetic storage of data, but so far have never been sufficiently stable. Researchers are now pointing the way to making it possible to produce nanomagnets with low zero-point energy and thus a higher degree of stability (Nano Letters, DOI: 10.1021/acs.nanolett.6b01344).

Since the 1970s, the number of components in computer chips has doubled every one to two years, their size diminishing. This development has made the production of small, powerful computers such as smart phones possible for the first time. In the meantime, many components are only about as big as a virus and the miniaturization process has slowed down. This is because below approximately a nanometre, a billionth of a meter in size, quantum effects come into play. They make it harder, for example, to stabilise magnetic moments. Researchers worldwide are looking for suitable materials for magnetically stable nanomagnets so that data can be stored safely in the smallest of spaces.

In this context, stable means that the magnetic moments point consistently in one of two preassigned directions. The direction then codes the bit. However, the magnetic moments of atoms are always in motion. The trigger here is the so-called zero-point energy, the energy that a quantum mechanical system possesses in its ground state at absolute zero temperature. “It makes the magnetic moments of atoms fluctuate even at the lowest of temperatures and thus works against the stability of the magnetic moments”, explains Dr. Julen Ibañez-Azpiroz, from the Helmholtz Young Investigators Group “Functional Nanoscale Structure Probe and Simulation Laboratory” at the Peter Grünberg Institute and at the Institute for Advanced Simulation. When too much energy exists within the system, the magnetic moments turn over and the saved information is lost.

Continue reading “Atomic bits despite zero-point energy? Jülich scientists explore novel ways of developing stable nanomagnets” | >

Hmmm; okay.

As it turns out, the answer is not 42, it’s 42.3 — thousand. That’s how many discrete transistors spread across the 30 m2 room housing this massive computation machine. [James Newman’s] Megaprocessor, a seriously enlarged version of a microprocessor, is a project we’ve been following with awe as it took shape over the last couple of years.

[James] documented his work in great detail, and by doing so, took us on a journey through the inner workings of microprocessors. His monumental machine is now finished, and it’s the ultimate answer to how a processor – and pretty much everything that contains a processor – works.

Everyone of the ~42,300 transistors were hand-soldered to one of the massive PCBs, which look more like interactive circuit diagrams than actual circuit boards. This incredible amount of discrete transistors makes up the thousands of logic gates that eventually form the Megaprocessor’s registers, its arithmetic logic unit, its sequence control and also: its 256 bytes of RAM. Each logic gate displays the current IO state through LEDs, which also turns the RAM into a gigantic LED wall on which you can play Tetris. Despite its complexity, the Megaprocessor is pretty much self-documenting. [James] mounted all PCBs on large frames, which add up to a 10m long and 2m tall “computation display”. Detailed diagrams show the information flow between the functional blocks – and through the room.

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