Issue no. 40, 2011 Published: Nov 18, 2011 |
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Scientists at MIT replicate brain activity with chip |
Metallic hydrogen makes its debut, maybe |
Liquid could power and cool mobile supercomputers |
New material promises faster internet |
Engineers boost battery strength with small holes |
Sensor-laden dragonfly may help future robots soar |
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| Scientists at MIT replicate brain activity with chip |
Scientists are getting closer to the dream of creating computer systems
that can replicate the brain. Researchers at MIT have designed a
computer chip that mimics how the brain's neurons adapt in response to
new information. Such chips could eventually enable communication
between artificially created body parts and the brain. It could also
pave the way for artificial intelligence devices.
There are about 100 billion neurons in the brain, each of which forms
synapses - the connections between neurons that allow information to
flow - with many other neurons. This process is known as plasticity and
is believed to underpin many brain functions, such as learning and
memory. The MIT team has been able to design a computer chip that can
simulate the activity of a single brain synapse. Activity in the
synapses relies on so-called ion channels which control the flow of
charged atoms such as sodium, potassium and calcium.
The 'brain chip' has about 400 transistors and is wired up to replicate
the circuitry of the brain. Current flows through the transistors in the
same way as ions flow through ion channels in a brain cell. The team
plans to use their chip to build systems to model specific neural
functions, such as visual processing. Such systems could be much faster
than computers which take hours or even days to simulate a brain
circuit. The chip could ultimately prove to be even faster than the
biological process. |
| BBC News
Nov 17, 2011 |
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| Metallic hydrogen makes its debut, maybe |
Hydrogen gas squeezed at tremendous pressures has transformed into a
metal, according to scientists at the Max Planck Institute for Chemistry
in Mainz, Germany, whose bold claim is being met with scepticism.
Many scientists have tried to make metallic hydrogen since its existence
was first predicted in 1935. The substance is thought to form at high
pressures, such as those in Jupiter's core. It may be a superconductor
at room temperature, useful for making wires that carry electricity with
little loss of current. And NASA hopes to one day put it to work as a
rocket fuel that would be more powerful than anything around today.
To see if hydrogen could be made to conduct electricity, the team
squeezed a room temperature sample of the gas between two diamonds. At a
pressures of more than 2.3 million times that of Earth's atmosphere, the
hydrogen became opaque and reflective. Its resistance to the flow of
current dropped to one ten-thousandth that of hydrogen at lower
pressures. That is evidence that the gas changed into something else,
say the researchers. To show that this new substance was a metal, they
cooled it from room temperature to 30 kelvins. The resistance rose
slightly, but the material remained conductive.
However, other physicists aren't convinced that the hydrogen changed
into the long-sought metal. 'People have thought they created metallic
hydrogen before, and they turned out to be wrong,' says William Nellis,
a physicist now at Harvard. In 1996 he and colleagues at Lawrence
Livermore National Laboratory in California used shock waves to make
hydrogen that conducted electricity but survived only for a fraction of
a second, not long enough to definitively prove that it was a metal. To
satisfy the critics, the team plans to refine their experiment. |
| Science News / Nature Materials
Nov 16, 2011 |
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| Liquid could power and cool mobile supercomputers |
Getting microchips wet is normally best avoided. But a new type of chip
that is both powered and cooled by fluid pumping through it could power
the computers, smartphones and tablets of the future. If the design is
successful, its inventors at IBM argue an entire supercomputer - like
Watson, the firm's natural-language-processing trivia savant - could one
day be squeezed onto mobile devices small enough to fit in your pocket.
The team's idea is to stack hundreds of silicon wafers on top of each
other to create three-dimensional processors. Between each layer is a
pair of fluidic networks. One of these carries in charged fluid to power
the chip, while the second carries away the same fluid after it has
picked up heat from the active transistors - effectively creating a
microscopic flow battery.
Using this biologically inspired approach to combine the electrical and
cooling systems into one should make it possible to reduce the power
consumption considerably. The team say they have demonstrated that it is
possible to use a liquid to transfer power via a network of fluidic
channels, and they plan build a working prototype chip by 2014. |
| New Scientist
Nov 16, 2011 |
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| New material promises faster internet |
Arizona State University researchers have created a new material that
they say can be used to develop next-generation computers, improve the
internet, increase the efficiency of silicon-based photovoltaic cells
and improve solid-state lighting and sensor technology. They have
synthesised a single-crystal nanowire from a compound of erbium - used
in doping optical fibres to amplify the signal.
While erbium's importance is well-recognized, producing erbium materials
of high quality has been challenging. The standard approach is to
introduce erbium as a dopant into various host materials, such as
silicon oxide, silicon, and many other crystals and glasses. What is
unique about the new material is that erbium is no longer randomly
introduced as a dopant. Instead, erbium is part of a uniform compound,
meaning the number of erbium atoms is a thousand times more than the
maximum amount that can be introduced in other erbium-doped materials.
Increasing the number of erbium atoms provides more optical activity to
produce stronger lighting. It also enhances the conversion of different
colours of light into white light to produce higher-quality solid-state
lighting and enables solar cells to more efficiently convert sunlight in
electrical energy. In addition, since erbium atoms are organised in a
periodic array, they do not cluster in this new compound. The fact that
the material has been produced in a high-quality single-crystal form
makes the optical quality superior to the other doped materials,
according to the researchers.
The team are now testing the new erbium compound for various
applications, such as increasing silicon solar cell efficiency and
making miniaturized optical amplifiers for chip-scale photonic systems
for computers and high-speed internet. |
| TG Daily
Nov 17, 2011 |
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| Engineers boost battery strength with small holes |
Batteries for phones and laptops could soon recharge ten times faster
and hold a charge ten times larger than current technology allows.
Scientists at Northwestern University in the US have changed the
materials in lithium-ion batteries to boost their abilities.
A mobile phone battery built using the new techniques would charge from
flat in 15 minutes and last a week before needing a recharge. The
density and movement of lithium ions are key to the process.
The team have found a way to cram more of the ions in and to speed up
their movement by altering the materials used to manufacture a battery.
They replaced sheets of silicon with tiny clusters of the substance to
increase the amount of lithium ions a battery can hold on to.
The recharging speed has been accelerated using a chemical oxidation
process which drills small holes - just 20-40 nanometres wide - in the
atom-thick sheets of graphene that batteries are made of. This helps
lithium ions move and find a place to be stored much faster.
The downside is that the recharging and power gains fall off sharply
after a battery has been charged about 150 times. However, even after
150 charges, which would be one year or more of operation, the battery
is still five times more effective than lithium-ion batteries on the
market today, according to the researchers. |
| BBC News / Advanced Energy Materials
Nov 15, 2011 |
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| Sensor-laden dragonfly may help future robots soar |
It's not a bird! It's not a plane! It's a dragonfly, and researchers
from Duke University and Howard Hughes Medical Institute are using a
microchip attached to its belly to understand the complex mechanics of
its flight. Dragonflies capture their prey mid-flight, requiring precise
control of horizontal and vertical movement to line up their meal with
their mouths.
The microchip weighs just one-tenth what a dragonfly does, and doesn't
interfere with its ability to fly and hunt. It's so light because it's
powered wirelessly and can transmit data at the rate of five megabits
per second - about the speed of a typical home internet connection. The
team want to determine how dragonflies manoeuvre through the air, which
may lead to advances in robotic flying vehicles of the future.
Electrodes connected to 16 neurons in the dragonfly's nerve cord will
transmit information that travels from the dragonfly's eyes as they spy
their prey to their motor control system. High-speed video will be
correlated with neural signals as the microchipped dragonflies capture
fruit flies, giving researchers insight into flight-control laws that
govern these winged wonders. |
| New Scientist
Nov 15, 2011 |
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