Issue no. 8, 2009
Published: Feb 27, 2009 |
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 Most powerful ever quantum chip undergoing tests |
| Stem cell 'fabrics' promise universal tissue |
| Do you have an eye for entanglement? |
| An impossible alloy now possible |
| Research advances nanowire technology for large-scale applications |
| Scientists invent world's smallest periscopes |
| Florida tests using magnets to repel crocodiles |
| Green wheel turns pedal bike into electric hog |
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| Most powerful ever quantum chip undergoing tests |
Quantum computing for the masses could come a step closer if tests prove
successful on a prototype chip designed to process more quantum data
than any previous device.
The prototype chip built by D-Wave Systems in British Columbia, Canada,
is designed to handle 128 qubits of information. The data is stored in
128 superconducting niobium loops as either a clockwise or an
anticlockwise current, representing a 0 or a 1, or as a qubit with both
currents at the same time in a quantum superposition. When the
information needs to be processed, the individual qubits are manipulated
by a magnetic field. To make the entire chip superconduct so that the
currents can flow indefinitely without dissipating heat, it is cooled to
0.01 °C above absolute zero.
Because superconducting circuits are relatively large, they are easier
to manufacture than other types of quantum devices, which manipulate
single electrons or photons and so need to be much smaller. It can be
built using standard semiconductor approaches. In addition, the method
of computation, called adiabatic computing, does not use logic gates,
further simplifying the design. The team has already tested a 28-qubit
version of the system as a proof of concept. |
| New Scientist
Feb 24, 2009 |
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| Stem cell 'fabrics' promise universal tissue |
Embryonic stem cells can survive being spun into polymer threads - a
technique that could be used to weave flexible synthetic tissues able to
adapt to any transplant environment, say UK biophysicists. The approach
could be a step towards the production of artificial organs.
There are a number of competing techniques for shaping living cells into
custom-made tissue, including one that uses air pressure to pull a cell
solution into long threads. University College London researchers have
shown that a similar technique can be employed to create threads of
embryonic stem cells. The group say this is the first time such cells
have been printed using any technique.
The team use a technique called electrospraying, where two stainless
steel needles, one inside the other, combine a stream of a viscous
biodegradable polymer with a suspension of embryonic stem cells.
Applying a voltage to the needles charges the polymer and cells and they
accelerate towards an 'earthed' copper ring a short distance beneath,
emerging as a single thin thread. Sheets can be woven by simply crossing
the thread repeatedly over a flat surface, while scanning the thread
over a mould can produce 3D forms. The polymer's viscosity alone holds
the fabric together. |
| New Scientist / Integrative Biology
Feb 26, 2009 |
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| Do you have an eye for entanglement? |
Physicists in Switzerland and the UK have proposed a way of using human
vision to observe the purely quantum effect of 'entanglement'.
The new experiment would first involve creating a pair of entangled
photons. One of the photons is then 'cloned' to create thousands of
identical photons. This is done by stimulated emission whereby the
original photon is sent through a pumped optical medium. Because the
clones are created in a coherent quantum process, it produces a pulse of
light that is intense enough to be seen with the naked eye - yet is
entangled with the second original photon. Measuring the polarisation of
the pulse will therefore reveal the polarization of the second photon.
The team proposes to measure the polarisation of the pulse by passing it
through a polarising filter, which allows light with parallel
polarisation to pass through while deflecting light with perpendicular
polarisation by 90 degrees. Two human observers - one looking along the
parallel path and the other the perpendicular path - could then
determine the polarisation of each pulse. Meanwhile, the polarisation of
the second photon of the pair would be determined by passing it through
a similar filter that is monitored by two sensitive photon detectors.
The humans should be able to predict the outcome of the measurement on
the second photon based on the observed polarisation of the pulse. In
other words, if the pulse is vertically polarised, then the second
photon will be horizontally polarised. |
| Physicsworld.com
Feb 26, 2009 |
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| An impossible alloy now possible |
What has been impossible has now been shown to be possible - an alloy
between two incompatible elements. A research team from Carnegie
Institution of Washington and Uppsala University has used high pressure
experiments and theoretical calculations to study the behaviour of Ce3Al
under high pressure.
They found that Cerium and Aluminium formed a so called substitutional
alloy under high pressure. Forming these alloys has been limited to
elements close in atomic radii and electronegativity up until now. The
difference in radii and electronegativity of Cerium and Aluminium was
diminished by applying pressure. Both synchrotron X-ray diffraction and
ab initio calculations showed the same cause for bringing the two
elements closer in radii and electronegativity, resulting in the new
alloy phase. After the release of pressure the substitutional alloy
still remained.
The discovery opens up the possibility for finding new alloys with other
ratios between Cerium and Aluminium, as well as alloys with Cerium and
other incompatible elements. These new alloys may possess interesting
and useful mechanical, electronic, and magnetic properties, according to
the researchers. |
| PhysOrg.com / Proceedings of the National Academy of Science
Feb 26, 2009 |
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| Research advances nanowire technology for large-scale applications |
Researchers at Northeastern University, US, created a network of
nanowires that can be scaled up more efficiently and cost-effectively to
create displays such as the NASDAQ sign in New York City's Times Square.
Using Gallium nitride (GaN), a highly effective semiconductor material,
the team created, for the first time, a horizontally aligned network of
GaN nanowires, which are integral components in the development of
electrical circuits in the nanoscale. GaN is currently used to create
light-emitting diodes (LED) and blue and ultra-violet emitting lasers.
Electrodes allow for the flow of electricity between GaN nanowires and
electrical wires, and the horizontal structure of the GaN nanowire
networks are more easily attached to electrodes than vertical networks.
In addition, the GaN nanowires have a cubic structure, with optical and
transport properties that are more advanced than other nanowire
structures, resulting in a more effective electrical circuit.
In terms of manufacturing, these horizontal network patterns can also be
scaled up to large wafer sizes that are more compatible with the
technology used to integrate them into new nanoelectronic devices. These
devices connect nanotechnology and electronic devices to develop smaller
and less costly manufacturing processes and products. |
| PhysOrg.com / Journal of Materials Chemistry
Feb 26, 2009 |
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| Scientists invent world's smallest periscopes |
Scientists at Vanderbilt University in the US have invented the world's
smallest version of the periscope and are using it to look at cells and
other micro-organisms from several sides at once.
The researchers have dubbed their devices 'mirrored pyramidal wells'.
They consist of pyramidal-shaped cavities moulded into silicon whose
interior surfaces are coated with a reflective layer of gold or
platinum. They are microscopic in dimension - about the width of a human
hair - and can be made in a range of sizes to view different-sized
objects. When a cell is placed in such a well and viewed with a regular
optical microscope, the researcher can see several sides simultaneously.
The Vanderbilt group is not the first to make microscopic pyramidal
wells, but it is the first to apply them to make 3D images of micro
organisms. In 2006, a group of scientists in England created pyramidal
micromirrors and applied them to trapping atoms. And last spring
researchers at the National Institute of Standards and Technology used
similar structures to track nanoparticles. |
| Eureka Alert / Journal of Microscopy
Feb 25, 2009 |
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| Florida tests using magnets to repel crocodiles |
Florida wildlife managers have launched an experiment to see if they can
keep crocodiles from returning to residential neighbourhoods by
temporarily taping magnets to their heads to disrupt their 'homing'
ability. Researchers at Mexico's Crocodile Museum in Chiapas reported in
a biology newsletter they had some success with the method, using it to
permanently relocate 20 of the reptiles since 2004.
Crocodiles are notoriously territorial and when biologists move them
from urban areas to new homes in the wild, they often go right back to
the place where they were captured, travelling up to 16 kilometres a
week to get there. Scientists believe they rely in part on the Earth's
magnetic fields to navigate, and that taping magnets to both sides of
their heads disorients them.
Once an endangered species, American crocodiles' numbers have rebounded
to nearly 2,000 in coastal south Florida, their only habitat in the
continental US. That puts them in increasing contact with humans,
especially in areas where backyards border on canals around Miami and
the Florida Keys. Crocodiles are still classified as a threatened
species, so game managers are reluctant to move them to new areas where
they might be killed battling other resident crocodiles for turf rights. |
| Reuters
Feb 25, 2009 |
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| Green wheel turns pedal bike into electric hog |
Scientists at MIT are testing a new power generation, storage and
propulsion system known as the GreenWheel that will turn any pedal
bicycle into an electric hog.
From the outside, the GreenWheel has the radius of a small dinner plate
and is about 5cm thick. Inside the aluminium frame sits the three major
GreenWheel components: an electric generator, batteries and an electric
motor. The GreenWheel can be installed on any bike frame or wheel size,
but the original spokes have to be replaced with shorter spokes.
Under its current configuration, a bike powered solely by a single
GreenWheel has an estimated range of 40 kilometres. Pedalling the bike
doubles the range under electric power, provided the rider isn't
travelling at the nearly top speed of 48 kilometres an hour. The bike
can be charged by pedalling or by plugging it into the electric grid. |
| MSNBC
Feb 18, 2009 |
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