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Issue no. 42, 2011
Published: Dec 09, 2011 |
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 Researchers build silicon chip alternative | | A novel way to concentrate sun's heat | | IBM scientists unveil Racetrack memory chip prototype | | 3-D model of rat brain circuit created | | Noise can help make signals clearer | | Biggest telescope starts observations | | Russian scientists to attempt clone of woolly mammoth |
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| Researchers build silicon chip alternative |
Swiss researchers have created the first computer chip made out of
molybdenite (MoS2), a naturally occurring mineral that has been touted
as a low-energy alternative to silicon. The integrated circuit was made
in the Laboratory of Nanoscale Electronics and Structures (LANES) at the
Ecole Polytechnique Federale de Lausanne (EPFL). The researchers said
their experiments prove that molybdenite chips can be made smaller than
silicon chips, use less electricity and be more flexible.
So far, it has not been possible to make layers of silicon less than two
nanometres thick, because of the risk of initiating a chemical reaction
that would oxidise the surface and compromise its electronic properties.
Molybdenite, on the other hand, can be worked in layers only three atoms
thick, making it possible to build chips that are at least three times
smaller. Even at this minute scale, the material remains stable and
conduction is easy to control, according to the researchers.
Molybdenite can also rival silicon in its ability to amplify electronic
signals, with an output signal that is four times stronger than the
incoming signal. This means that MoS2 transistors are very
energy-efficient, and according to the team there is considerable
potential for creating more complex chips. Finally, the flexibility of
molybdenite could make it suitable for use in flexible electronics, such
as in the design of flexible sheets of chips. These could one day be
used to manufacture computers that roll up or devices that could be
affixed to the skin, the researchers said. |
| InfoWorld.com
Dec 07, 2011 |
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| A novel way to concentrate sun's heat |
Most technologies for harnessing the sun's energy capture the light
itself, which is turned into electricity using photovoltaic materials.
Others use the sun's thermal energy, usually concentrating the sunlight
with mirrors to generate enough heat to boil water and turn a generating
turbine. A third approach is to use the sun's heat - also concentrated
by mirrors - to generate electricity directly, using solid-state devices
called thermophotovoltaics.
Now, researchers at MIT have found a way to use thermophotovoltaic
devices without mirrors to concentrate the sunlight, potentially making
the system much simpler and less expensive. The key is to prevent the
heat from escaping the thermoelectric material, something the team
achieved by using a photonic crystal: essentially, an array of precisely
spaced microscopic holes in a top layer of the material.
The approach mimics Earth's greenhouse effect: Infrared radiation from
the sun can enter the chip through the holes on the surface, but the
reflected rays are blocked when they try to escape. This blockage is
achieved by a precisely designed geometry that only allows rays that
fall within a very tiny range of angles to escape, while the rest stay
in the material and heat it up.
The next step in the research is to test different materials in this
configuration to find those that produce power most efficiently. |
| R&D Magazine / Nanoscale Research Letters
Dec 02, 2011 |
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| IBM scientists unveil Racetrack memory chip prototype |
Details of the first real-world test of a new memory chip technology
have been revealed by IBM scientists. The demonstration involved
Racetrack memory - a system which stores information as magnetic
patterns on tiny wires. IBM said the technology promises faster data
access speeds than were possible using hard drives or flash disks.
The team - based in New York, California and Taiwan - has been working
on the process since 2008. The prototype chip consists of 256 Racetrack
cells. Each cell consists of a single magnetic nanowire, 60-240
nanometres wide and 15-20 nanometres thick. Electric pulses are applied
to the wires creating 'domain walls' with 'regions' between them.
These regions pass over a magnetic read/write head which faces them in
one direction or another, representing the 0s and 1s of computer data.
The small magnetic regions can be 'raced' at speed along the wires -
giving the technique its name.
Advocates of Racetrack claim it could potentially read and write data
hundreds of thousands of times faster than is possible on commercial
hard disks. That would put access speeds at roughly the rate offered by
DRAM (Dynamic Random Access Memory) chips. These are already used in
current PCs to run programs, but 'forget' data as soon as the computers'
power supplies are switched off.
The scientists noted that the circuitry involved was created using IBM's
standard microchip-making technologies, highlighting its potential as a
realistic replacement to existing memory storage techniques. |
| BBC News
Dec 06, 2011 |
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| 3-D model of rat brain circuit created |
After six years and several million dollars, scientists have created a
3-D model of a rat brain circuit. The accomplishment is a first step
toward creating a complete computer model of the brain that will allow a
deeper understanding of how our noggins work - and what causes them to
malfunction, according to the scientists behind the feat.
For a starting point, researchers at the Max Planck Florida Institute
are focused on how the rat brain processes information gathered by a
single whisker. They did so because studies in their lab and elsewhere
have shown that a single whisker is able to detect, in complete
darkness, whether a gap is safe to jump over and, if so, trigger the
order to jump.
What's more, there is a specific region of the brain that is dedicated
to processing information from a dedicated whisker, according to the
researchers. That region is called the cortical column, a vertically-
organised series of connected neurons that form a brain circuit and an
elementary building block of the cortex.
To build the model, the researchers studied the cortical column in awake
and anesthetised rats as well as brain slices and then used computer
software and other tools to reconstruct it. It is composed of 16,000
neurons, each of which can be divided into one of nine different cell
types that has characteristic functional, structural and connectivity
properties. The model can now be used to run computer simulations that
show, in realistic detail, how signals flow within the brain. So, they
can begin to understand, for example, what neurons fire as the rat
detects the gap and decides whether or not to jump. |
| MSNBC
Dec 07, 2011 |
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| Noise can help make signals clearer |
Scientists have shown the energy conditions, under which a weak signal
supplied to a physical system emerges as a stronger signal at the output
thanks to the presence of random noise - a process known as stochastic
resonance. Stochastic resonance goes against the intuitive idea that
where noise is present, the signal tends to fade. It occurs in systems
where the response is not proportional to the applied input signal,
known as nonlinear systems.
Scientists from the Institute of Physics, in Bhubaneswar, India, used a
model consisting of a symmetric double-well energy potential in which a
particle moves randomly. They studied the effect of the steepness of the
walls of the confining energy potential by observing the movement of the
particle, which they subjected to an external sinusoidal signal that
alternately lowers either of the wells.
The team selected a quantifier - the average work done on the system by
the signal - to determine the conditions under which the particle moving
from one well to the opposite side well and back at every cycle of the
signal reaches stochastic resonance. They found that it only occurs when
the potential is 'hard', meaning that it has sufficiently steep walls,
but breaks down otherwise.
Previous work used different quantifiers and found similar results,
confirming their findings using numerical simulations. This study
contributes to improving scientists' understanding of stochastic
resonance. It could, ultimately, contribute to gaining deeper insights
into physics-related phenomena such as the processing of unclear images
to increase their resolution and the functioning of sensory neurons in
humans. |
| R&D Magazine / European Physical Journal B
Dec 06, 2011 |
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| Biggest telescope starts observations |
RadioAstron, effectively the largest radio telescope ever built, is up
and running. The telescope's main component, a 10-metre radio dish
aboard the spacecraft Spectr-R, launched in July to an oblong orbit that
extends between 10,000 and more than 300,000 kilometres from Earth.
By coordinating observations with radio telescopes on Earth in a
technique called interferometry, the telescope can make observations as
sharp as a single dish spanning the entire distance between the two
farthest dishes. When Spectr-R is at its farthest from Earth, the system
acts like one enormous telescope about 30 times as wide as our planet,
boasting 10,000 times the resolution of the Hubble Space Telescope.
In its first observation on 15 November, Spektr-R was about 100,000
kilometres above Earth. The space telescope linked up with three
32-metre antennas in Russia's QUASAR Network, a 70-metre antenna in
Evpatoria, Ukraine, and the 100-metre Effelsberg telescope in Germany to
target a bright, distant galaxy called 0212+735.
Over its five-year mission, RadioAstron will take detailed looks at
objects such as the black hole at the centre of nearby galaxy M87,
nascent planetary systems and neutron stars. It will detect radio waves
emitted by water masers, clouds of water molecules in the discs of
galaxies, which could help measure how far those galaxies are from
Earth. That in turn could help study the expansion of the universe and
dark energy. |
| New Scientist
Dec 08, 2011 |
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| Russian scientists to attempt clone of woolly mammoth |
Scientists from Russia and Japan are undertaking a Jurassic Park-style
experiment in an effort to bring the woolly mammoth out of extinction.
The scientists claim that a thigh bone found in August contains
remarkably well-preserved marrow cells, which could form the starting
point of the experiment. The team claim that the cloning could be
complete within the next five years.
The team, from the Siberian mammoth museum and Japan's Kinki University,
said that they planned to extract a nucleus from the animal's bone
marrow and insert it into the egg of an African elephant. Similar
procedures have been done before with mixed results. In 2009 it was
reported that the recently extinct Pyrenean ibex was brought back to
life briefly using 10-year-old DNA from the animal's skin. The cloned
ibex died within minutes of being born, due to breathing difficulties.
The Roslin Institute, famous for cloning Dolly the sheep, no longer
conducts cloning work but has published some thoughts on the
possibilities of bringing extinct species back to life. It said it was
extremely unlikely such an experiment would be successful, especially
using an elephant surrogate. The success rate for such an experiment
would be in the range of 1-5%, it said. |
| BBC News
Dec 07, 2011 |
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