NPL worked with BAE Systems Advanced Technology Centre, to measure the pattern and efficiency of radiation emitted from next generation wearable antennas embedded in T-shirts.
Wearable antennas could be the future of wireless technology and have important applications in communications, security and healthcare, but as they are worn on the body it is particularly important to understand their performance. The human body absorbs electromagnetic signals and so there are concerns that the emitted signal from the antenna could suffer from power losses if worn too close.
The research tested a number of novel measurement techniques that could help the development of this exciting new technology, including measuring the radiation absorbed by a 'human dummy', designed from material that mimics the characteristics of human tissue.
Dr James Matthews, Principal Engineer, BAE Systems Advanced Technology Centre, said:
"NPL provided an excellent quality set of measurements, despite the difficulties inherent in wearable antenna technology. NPL took time to understand the requirements and took a proactive approach to the challenge, providing wider ranging measurements than originally anticipated."
NPL facilities used during the research included the Reverberation Chamber, Fully Anechoic Small Antenna Radiated Testing (SMART) Range, the EMC Ferrite Lined Fully Anechoic Room (FAR) and specific absorption rate (SAR) facilities.
The collaborative research revealed that there is an optimum distance for the position of the antenna in relation to the body, which can improve the antenna's efficiency. This information, when integrated into antenna design, will help developers produce better products.
Provided by National Physical Laboratory
"Testing the T-shirt antenna." June 30th, 2011. http://www.physorg.com/news/2011-06-t-shirt-antenna.html
quinta-feira, 30 de junho de 2011
terça-feira, 28 de junho de 2011
NEC claims spintronics memory breakthrough
By Jack Clark, 13 June, 2011 13:13
NEC and Tohaku University claim to have developed the world's first content addressable memory system that uses spintronics to store data even when there is no standby power.Spintronics is a technology for controlling not only individual electronics, but their spin as well, increasing the amount of information that can be stored per electron. The technology promises to increase the efficiency with which devices consume power.
Because data is stored in the spin of an electron, rather than its presence, information is encoded without moving the electron at a transistor gate level, which allows less power to be used in the encoding process.
The system that NEC and Tohaku University have developed uses magnets to maintain "the same high operation speed and non-volatile operation as existing circuits when processing and storing data on a circuit while power is off", NEC wrote in a statement on Monday.
The electrons retain their spin orientation when no longer exposed to the magnetic field, so data can be stored with no power running through the system. The magnetic field runs through the domain wall elements of the logic, so that data is stored within the content addressable memory (CAM) circuit rather than a separate memory pool.
By using spintronics in the CAM system the researchers claim to have halved the circuit area in comparison with existing technologies and cut power consumption.
However, NEC and Tohaku University did not disclose the temperature at which the CAM system operated. Room temperature spintronics is seen as highly desirable, as it increases the potential range of consumer applications. Traditionally, most experiments are done at close to absolute zero so as to reduce the amount of factors that can disturb electron spins. For spintronics to be worked into consumer hardware it will need to be achievable at normal temperatures or the cost will balloon.
Copyright © 1998-2011 CBS Interactive Limited. All rights reserved
New material promises faster electronics
The novel material graphene makes faster electronics possible. Scientists at the Faculty of Electrical Engineering and Information Technology at the Vienna University of Technology (TU Vienna) developed light-detectors made of graphene and analyzed their astonishing properties.
High hopes are pinned on this new material: Graphene, a honeycomb-like carbon structure, made of only one layer of atoms, exhibits remarkable properties. In 2010, the Nobel Prize was awarded for the discovery of graphene and its behavior. At the Photonics Institute at the TU Vienna, the electronic and optical properties of graphene are the focus of interest. Viennese scientists could now demonstrate how remarkably fast graphene converts light pulses into electrical signals. This could considerably improve date exchange between computers.
Converting Light into Electrical Signals
When data is transmitted by light pulses (for instance in fiber optic cables) the pulses have to be converted back into electrical signals, which can be processed by a computer. This conversion of light into electrical current is possible due to the photoelectric effect, which was originally explained by Albert Einstein. In certain materials, light can cause electrons to leave their positions and travel through the material freely, whereby electrical current occurs. “Light detectors which convert light into electronic signals have been around for a long time. But when they are made of graphene, they react faster than most other materials could”, Alexander Urich explains. He investigated the optical and electronic properties of graphene together with Thomas Müller and Professor Karl Unterrainer at TU Vienna.
Analysis using Ultra Short Laser Pulses
The scientists had already shown last year that graphene can convert light into electronic signals with remarkable speed. However, the reaction time of the material could not be determined – the photoelectric effect in graphene is so fast that it just cannot be measured by the usual measuring methods. But now, sophisticated technological tricks could shed some light on the properties of graphene. At TU Vienna, laser pulses were fired at the graphene photo-detector in quick succession, and the resulting photo-current was measured. If the time delay between the laser pulses is changed, the detector’s maximum frequency can be determined. “Using this method we could show that our detectors can be used up to a frequency of 262 GHz”, Thomas Müller (TU Vienna) says. This corresponds to a theoretical upper bound for data transfer using graphene photo-detectors of more than 30 gigabytes per second. It has yet to be determined to what extent this is technically feasible, but this result clearly shows the remarkable capability of graphene and its potential for optoelectronic applications.
Fast Signals for Fast Electronics
The main reason for the fact that graphene-photodetectors can operate at such high frequencies is the short life-span of the charge carriers in graphene. The electrons which are removed from their fixed position and contribute to the electrical current settle down at another fixed position after a few picoseconds (millionths of a billionth of a second, 10-12 seconds). As soon as this happens, the graphene photodetector is ready for another light signal which frees new electrons, creating the next electrical signal.
The fast reaction time of graphene is one more item on the list of remarkable properties of this material. In graphene, charge carriers can travel extremely far without being disturbed. It can absorb light in a huge spectral range, from infrared to visible light – unlike standard semiconductors, which can only absorb a small part of the spectrum. In addition to this, graphene can conduct heat extremely well and has an exceptionally high breaking strength.
Provided by Vienna University of Technology
"New material promises faster electronics." June 28th, 2011. http://www.physorg.com/news/2011-06-material-faster-electronics.html
High hopes are pinned on this new material: Graphene, a honeycomb-like carbon structure, made of only one layer of atoms, exhibits remarkable properties. In 2010, the Nobel Prize was awarded for the discovery of graphene and its behavior. At the Photonics Institute at the TU Vienna, the electronic and optical properties of graphene are the focus of interest. Viennese scientists could now demonstrate how remarkably fast graphene converts light pulses into electrical signals. This could considerably improve date exchange between computers.
Converting Light into Electrical Signals
When data is transmitted by light pulses (for instance in fiber optic cables) the pulses have to be converted back into electrical signals, which can be processed by a computer. This conversion of light into electrical current is possible due to the photoelectric effect, which was originally explained by Albert Einstein. In certain materials, light can cause electrons to leave their positions and travel through the material freely, whereby electrical current occurs. “Light detectors which convert light into electronic signals have been around for a long time. But when they are made of graphene, they react faster than most other materials could”, Alexander Urich explains. He investigated the optical and electronic properties of graphene together with Thomas Müller and Professor Karl Unterrainer at TU Vienna.
Analysis using Ultra Short Laser Pulses
The scientists had already shown last year that graphene can convert light into electronic signals with remarkable speed. However, the reaction time of the material could not be determined – the photoelectric effect in graphene is so fast that it just cannot be measured by the usual measuring methods. But now, sophisticated technological tricks could shed some light on the properties of graphene. At TU Vienna, laser pulses were fired at the graphene photo-detector in quick succession, and the resulting photo-current was measured. If the time delay between the laser pulses is changed, the detector’s maximum frequency can be determined. “Using this method we could show that our detectors can be used up to a frequency of 262 GHz”, Thomas Müller (TU Vienna) says. This corresponds to a theoretical upper bound for data transfer using graphene photo-detectors of more than 30 gigabytes per second. It has yet to be determined to what extent this is technically feasible, but this result clearly shows the remarkable capability of graphene and its potential for optoelectronic applications.
Fast Signals for Fast Electronics
The main reason for the fact that graphene-photodetectors can operate at such high frequencies is the short life-span of the charge carriers in graphene. The electrons which are removed from their fixed position and contribute to the electrical current settle down at another fixed position after a few picoseconds (millionths of a billionth of a second, 10-12 seconds). As soon as this happens, the graphene photodetector is ready for another light signal which frees new electrons, creating the next electrical signal.
The fast reaction time of graphene is one more item on the list of remarkable properties of this material. In graphene, charge carriers can travel extremely far without being disturbed. It can absorb light in a huge spectral range, from infrared to visible light – unlike standard semiconductors, which can only absorb a small part of the spectrum. In addition to this, graphene can conduct heat extremely well and has an exceptionally high breaking strength.
Provided by Vienna University of Technology
"New material promises faster electronics." June 28th, 2011. http://www.physorg.com/news/2011-06-material-faster-electronics.html
segunda-feira, 27 de junho de 2011
Subatomic quantum memory in diamond demonstrated
Physicists working at the University of California, Santa Barbara and the University of Konstanz in Germany have developed a breakthrough in the use of diamond in quantum physics, marking an important step toward quantum computing. The results are reported in this week's online edition of Nature Physics.
The physicists were able to coax the fragile quantum information contained within a single electron in diamond to move into an adjacent single nitrogen nucleus, and then back again using on-chip wiring.
"This ability is potentially useful to create an atomic-scale memory element in a quantum computer based on diamond, since the subatomic nuclear states are more isolated from destructive interactions with the outside world," said David Awschalom, senior author. Awschalom is director of UCSB's Center for Spintronics & Quantum Computation, professor of physics, electrical and computer engineering, and the Peter J. Clarke director of the California NanoSystems Institute.
Awschalom said the discovery shows the high-fidelity operation of a quantum mechanical gate at the atomic level, enabling the transfer of full quantum information to and from one electron spin and a single nuclear spin at room temperature. The process is scalable, and opens the door to new solid-state quantum device development.
Scientists have recently shown that it is possible to synthesize thousands of these single electron states with beams of nitrogen atoms, intentionally creating defects to trap the single electrons. "What makes this demonstration particularly exciting is that a nitrogen atom is a part of the defect itself, meaning that these sub-atomic memory elements automatically scale with the number of logical bits in the quantum computer," said lead author Greg Fuchs, a postdoctoral fellow at UCSB.
Rather than using logical elements like transistors to manipulate digital states like "0" or "1," a quantum computer needs logical elements capable of manipulating quantum states that may be "0" and "1" at the same time. Even at ambient temperature, these defects in diamond can do exactly that, and have recently become a leading candidate to form a quantum version of a transistor.
However, there are still major challenges to building a diamond-based quantum computer. One of these is finding a method to store quantum information in a scalable way. Unlike a conventional computer, where the memory and the processor are in two different physical locations, in this case they are integrated together, bit-for-bit.
"We knew that the nitrogen nuclear spin would be a good choice for a scalable quantum memory –– it was already there," said Fuchs. "The hard part was to transfer the state quickly, before it is lost to decoherence."
Awschalom explained: "A key breakthrough was to use a unique property of quantum physics –– that two quantum objects can, under special conditions, become mixed to form a new composite object." By mixing the quantum spin state of the electrons in the defect with the spin state of the nitrogen nucleus for a brief time –– less than 100 billionths of a second –– information that was originally encoded in the electrons is passed to the nucleus.
"The result is an extremely fast transfer of the quantum information to the long-lived nuclear spin, which could further enhance our capabilities to correct for errors during a quantum computation," said co-author Guido Burkard, a theoretical physicist at the University of Konstanz, who developed a model to understand the storage process.
Provided by University of California - Santa Barbara
"Subatomic quantum memory in diamond demonstrated." June 27th, 2011. http://www.physorg.com/news/2011-06-subatomic-quantum-memory-diamond.html
The physicists were able to coax the fragile quantum information contained within a single electron in diamond to move into an adjacent single nitrogen nucleus, and then back again using on-chip wiring.
"This ability is potentially useful to create an atomic-scale memory element in a quantum computer based on diamond, since the subatomic nuclear states are more isolated from destructive interactions with the outside world," said David Awschalom, senior author. Awschalom is director of UCSB's Center for Spintronics & Quantum Computation, professor of physics, electrical and computer engineering, and the Peter J. Clarke director of the California NanoSystems Institute.
Awschalom said the discovery shows the high-fidelity operation of a quantum mechanical gate at the atomic level, enabling the transfer of full quantum information to and from one electron spin and a single nuclear spin at room temperature. The process is scalable, and opens the door to new solid-state quantum device development.
Scientists have recently shown that it is possible to synthesize thousands of these single electron states with beams of nitrogen atoms, intentionally creating defects to trap the single electrons. "What makes this demonstration particularly exciting is that a nitrogen atom is a part of the defect itself, meaning that these sub-atomic memory elements automatically scale with the number of logical bits in the quantum computer," said lead author Greg Fuchs, a postdoctoral fellow at UCSB.
Rather than using logical elements like transistors to manipulate digital states like "0" or "1," a quantum computer needs logical elements capable of manipulating quantum states that may be "0" and "1" at the same time. Even at ambient temperature, these defects in diamond can do exactly that, and have recently become a leading candidate to form a quantum version of a transistor.
However, there are still major challenges to building a diamond-based quantum computer. One of these is finding a method to store quantum information in a scalable way. Unlike a conventional computer, where the memory and the processor are in two different physical locations, in this case they are integrated together, bit-for-bit.
"We knew that the nitrogen nuclear spin would be a good choice for a scalable quantum memory –– it was already there," said Fuchs. "The hard part was to transfer the state quickly, before it is lost to decoherence."
Awschalom explained: "A key breakthrough was to use a unique property of quantum physics –– that two quantum objects can, under special conditions, become mixed to form a new composite object." By mixing the quantum spin state of the electrons in the defect with the spin state of the nitrogen nucleus for a brief time –– less than 100 billionths of a second –– information that was originally encoded in the electrons is passed to the nucleus.
"The result is an extremely fast transfer of the quantum information to the long-lived nuclear spin, which could further enhance our capabilities to correct for errors during a quantum computation," said co-author Guido Burkard, a theoretical physicist at the University of Konstanz, who developed a model to understand the storage process.
Provided by University of California - Santa Barbara
"Subatomic quantum memory in diamond demonstrated." June 27th, 2011. http://www.physorg.com/news/2011-06-subatomic-quantum-memory-diamond.html
Topic of the moment: Particle detection
With CERN’s Large Hadron Collider having reached a data milestone and amid reports of the possible discovery of previously unknown particles by the Tevatron, we take a look at the physics of particle detection.
In June, the total data accumulated by the Large Hadron Collider at CERN reached one “inverse femtobarn” of data, equivalent to 70 trillion particle collisions. Meanwhile, the head of the Tevatron particle accelerator in the US appointed a committee to evaluate the evidence for whether a completely new particle has been discovered.
But how does particle detection work?
All particle detectors, even the early bubble chambers which used ionisation and vapour trails to detect charged particles, work by capturing data from particle collisions. But the volume of data being produced by modern high-energy experiments means that detection methods much more sophisticated than the photography used with the bubble chambers are needed.
In the LHC
The Large Hadron Collider has four main particle detectors: ALICE, ATLAS, CMS and LHCb. These detectors are showered with the particles produced when the two beams of protons circulating around the LHC collide.
Each layer of a detector has a specific function, but the main components are semiconductor detectors which measure charged particles and calorimeters which measure particle energy.
The semiconductor detectors use materials such as silicon to create diodes – components that conduct electrical current in only one direction. Charged particles passing though the large number of strips of silicon placed around the proton beam collision point create a current that can be tracked and measured.
The position where particles originate is also important – if one appears deep within the detector it is likely to have been produced by the decay of another particle produced earlier, possibly within the collision itself.
Calorimeters are calibrated to be either electromagnetic or hadronic. The former will detect particles such as electrons and photons, while the latter will pick up protons and neutrons. Particles entering a calorimeter are absorbed and a particle shower is created by cascades of interactions.
It is the energy deposited into the calorimeter from these interactions that is measured. Stacking calorimeters allows physicists to build a complete picture of the direction in which the particles travelled as well as the energy deposited, or determine the shape of the particle shower produced.
ATLAS is also designed to detect muons, particles much like electrons but 200 times more massive, which pass right through the other detection equipment. A muon spectrometer surrounds the calorimeter, and functions in a similar way to the inner silicon detector.
Analysing the data
With so many particle collisions, accelerators such as the LHC generate a huge amount of data, which take a great deal of computing power to capture and analyse. To achieve this, CERN developed the LHC Computing Grid.
The Grid is a tiered network in which data are first processed by the computers at CERN, then sent on to regional sites for further processing, and finally sent to institutions all around the world to be analysed.
The results of experiments can be compared with those predicted by current theories of particle physics to look for any differences. At the LHC, particle physicists are hoping that the collisions will produce a Higgs boson, the as-yet-theoretical particle thought to be responsible for the existence of mass.
At the Tevatron, where they collide protons and antiprotons, the data that one team believed showed an entirely new type of particle appeared as a bump in a graph of experimental data that was not present in the theoretical predictions.
However this was only seen in data from one of the accelerator’s detectors and wasn’t present in the other against which it was compared. It is now believed to have been a phantom signal.
Physicists will have to keep waiting for the first sight of the Higgs – or other new particles.
text: Chris White
In June, the total data accumulated by the Large Hadron Collider at CERN reached one “inverse femtobarn” of data, equivalent to 70 trillion particle collisions. Meanwhile, the head of the Tevatron particle accelerator in the US appointed a committee to evaluate the evidence for whether a completely new particle has been discovered.
But how does particle detection work?
All particle detectors, even the early bubble chambers which used ionisation and vapour trails to detect charged particles, work by capturing data from particle collisions. But the volume of data being produced by modern high-energy experiments means that detection methods much more sophisticated than the photography used with the bubble chambers are needed.
In the LHC
The Large Hadron Collider has four main particle detectors: ALICE, ATLAS, CMS and LHCb. These detectors are showered with the particles produced when the two beams of protons circulating around the LHC collide.
Each layer of a detector has a specific function, but the main components are semiconductor detectors which measure charged particles and calorimeters which measure particle energy.
The semiconductor detectors use materials such as silicon to create diodes – components that conduct electrical current in only one direction. Charged particles passing though the large number of strips of silicon placed around the proton beam collision point create a current that can be tracked and measured.
The position where particles originate is also important – if one appears deep within the detector it is likely to have been produced by the decay of another particle produced earlier, possibly within the collision itself.
Calorimeters are calibrated to be either electromagnetic or hadronic. The former will detect particles such as electrons and photons, while the latter will pick up protons and neutrons. Particles entering a calorimeter are absorbed and a particle shower is created by cascades of interactions.
It is the energy deposited into the calorimeter from these interactions that is measured. Stacking calorimeters allows physicists to build a complete picture of the direction in which the particles travelled as well as the energy deposited, or determine the shape of the particle shower produced.
ATLAS is also designed to detect muons, particles much like electrons but 200 times more massive, which pass right through the other detection equipment. A muon spectrometer surrounds the calorimeter, and functions in a similar way to the inner silicon detector.
Analysing the data
With so many particle collisions, accelerators such as the LHC generate a huge amount of data, which take a great deal of computing power to capture and analyse. To achieve this, CERN developed the LHC Computing Grid.
The Grid is a tiered network in which data are first processed by the computers at CERN, then sent on to regional sites for further processing, and finally sent to institutions all around the world to be analysed.
The results of experiments can be compared with those predicted by current theories of particle physics to look for any differences. At the LHC, particle physicists are hoping that the collisions will produce a Higgs boson, the as-yet-theoretical particle thought to be responsible for the existence of mass.
At the Tevatron, where they collide protons and antiprotons, the data that one team believed showed an entirely new type of particle appeared as a bump in a graph of experimental data that was not present in the theoretical predictions.
However this was only seen in data from one of the accelerator’s detectors and wasn’t present in the other against which it was compared. It is now believed to have been a phantom signal.
Physicists will have to keep waiting for the first sight of the Higgs – or other new particles.
text: Chris White
quarta-feira, 22 de junho de 2011
Batteries that Recharge in Seconds
A new process could let your laptop and cell phone recharge a hundred times faster than they do now.
A new way of making battery electrodes based on nanostructured metal foams has been used to make a lithium-ion battery that can be 90 percent charged in two minutes. If the method can be commercialized, it could lead to laptops that charge in a few minutes or cell phones that charge in 30 seconds.
The methods used to make the ultrafast-charging electrodes are compatible with a range of battery chemistries; the researchers have also used them to make nickel-metal-hydride batteries, the kind commonly used in hybrid and electric vehicles.
How fast a battery can charge up and then release that power is primarily limited by the movement of electrons and ions into and out of the cathode, the electrode that is negative during recharging. Researchers have been trying to use nanostructured materials to improve the process, but there's usually a trade-off between total energy storage capacity (which determines how long a battery can run before needing a recharge) and charge rates. "People solved half the problem," says Paul Braun, professor of materials science and engineering at the University of Illinois at Urbana-Champaign.
Braun's group has made highly porous metal foams coated with a large amount of active battery materials. The metal provides high electrical conductivity, and even though it's porous, the structure holds enough active material to store a sufficient amount of energy. The pores allow for ions to move about unimpeded.
The first step in making the cathodes is to create a slurry of polymer spheres on the surface of a conductive substrate. Because of their shape and surface charge, the spheres self-assemble into a regular pattern. The Illinois researchers then use a common technique called electroplating to fill the space between the spheres with nickel. Next, they dissolve the polymer spheres, and most of the metal, to leave a nickel sponge that's about 90 percent open space. Finally, they grow the active material on top of the sponge.
"It's some distance to a product, but we have pretty good lab demos" with nickel-metal-hydride and lithium-ion batteries, says Braun. The Illinois group has made lithium-ion batteries that charge almost entirely in about two minutes. The method should be applicable to the cell sizes needed for laptops and electric cars, though the researchers have not made them yet.
"The performance they got is unprecedented," says Andreas Stein, a professor of chemistry at the University of Minnesota. Stein pioneered the polymer-particle templating method that Braun's group used. Braun's work is described in the journal Nature Nanotechnology.
Jeff Dahn, professor of physics at Dalhousie University, is skeptical that these electrodes will ever end up in products. "When you look at the flow chart for making this structure, it's pretty complicated, and that is going to be expensive," he says.
Braun acknowledges: "There are lots of people coming up with elegant [electrode] structures, but manufacturing them is tricky." He says, however, that his fabrication process combines existing methods that are currently widely used to make other products, if not to make batteries, and that it shouldn't be too difficult to adapt them. The process would add extra steps to making a battery, but these steps aren't particularly expensive or complex, Braun says.
Braun's group will next test the electrode structure with a wider range of battery chemistries and work on improving batteries' other half, the anode—a trickier project.
Copyright Technology Review 2011.
The methods used to make the ultrafast-charging electrodes are compatible with a range of battery chemistries; the researchers have also used them to make nickel-metal-hydride batteries, the kind commonly used in hybrid and electric vehicles.
How fast a battery can charge up and then release that power is primarily limited by the movement of electrons and ions into and out of the cathode, the electrode that is negative during recharging. Researchers have been trying to use nanostructured materials to improve the process, but there's usually a trade-off between total energy storage capacity (which determines how long a battery can run before needing a recharge) and charge rates. "People solved half the problem," says Paul Braun, professor of materials science and engineering at the University of Illinois at Urbana-Champaign.
Braun's group has made highly porous metal foams coated with a large amount of active battery materials. The metal provides high electrical conductivity, and even though it's porous, the structure holds enough active material to store a sufficient amount of energy. The pores allow for ions to move about unimpeded.
The first step in making the cathodes is to create a slurry of polymer spheres on the surface of a conductive substrate. Because of their shape and surface charge, the spheres self-assemble into a regular pattern. The Illinois researchers then use a common technique called electroplating to fill the space between the spheres with nickel. Next, they dissolve the polymer spheres, and most of the metal, to leave a nickel sponge that's about 90 percent open space. Finally, they grow the active material on top of the sponge.
"It's some distance to a product, but we have pretty good lab demos" with nickel-metal-hydride and lithium-ion batteries, says Braun. The Illinois group has made lithium-ion batteries that charge almost entirely in about two minutes. The method should be applicable to the cell sizes needed for laptops and electric cars, though the researchers have not made them yet.
"The performance they got is unprecedented," says Andreas Stein, a professor of chemistry at the University of Minnesota. Stein pioneered the polymer-particle templating method that Braun's group used. Braun's work is described in the journal Nature Nanotechnology.
Jeff Dahn, professor of physics at Dalhousie University, is skeptical that these electrodes will ever end up in products. "When you look at the flow chart for making this structure, it's pretty complicated, and that is going to be expensive," he says.
Braun acknowledges: "There are lots of people coming up with elegant [electrode] structures, but manufacturing them is tricky." He says, however, that his fabrication process combines existing methods that are currently widely used to make other products, if not to make batteries, and that it shouldn't be too difficult to adapt them. The process would add extra steps to making a battery, but these steps aren't particularly expensive or complex, Braun says.
Braun's group will next test the electrode structure with a wider range of battery chemistries and work on improving batteries' other half, the anode—a trickier project.
Patent for arrays of nanoscale electrical probes awarded to NJIT today
Reginald C. Farrow and Zafer Iqbal, research professors at NJIT, were awarded a patent today for an improved method of fabricating arrays of nanoscale electrical probes. Their discovery may lead to improved diagnostic tools for measuring the spatial variation of electrical activity inside biological cells.
US Patent 7,964,143 discloses a nanoprobe array technique that allows for an array of individual, vertically-oriented nanotubes to be assembled at precise locations on electrical contacts using electrophoresis. The location of each nanotube in the array is controlled by a nanoscale electrostatic lens fabricated by a process commonly used in the manufacture of integrated circuits.
The research appeared in 2008 in the the Journal of Vacuum Science and Technology, entitled "Directed self-assembly of individual vertically aligned carbon nanotubes." Support for the research was provided by the Department of Defense.
The number of nanotubes deposited at each location is controlled by the geometry of the lens, which makes it possible to deposit a single nanotube in a window much larger than its diameter. After deposition, each individual nanotube can be modified to insulate the shaft and to sensitize it to a specific ion in the cell. The task is accomplished by attaching an appropriate functional molecule or enzyme to the tip of the nanotube.
The completed nanoprobe array may be configured for multiple diverse electrochemical events to be mapped on timescales limited only by the nature of the nanotube's contact with the cell membrane and the speed of integrated circuits.
For three different types of cells (human embryonic kidney cells, mouse neurons, and yeast), the NJIT researchers have measured the electrical response to a signal. This signal is generated by a pair of carbon nanotube probes spaced only six micrometers apart. Yeast cells are too small to measure with the tools most commonly used in the industry for determining electrical response.
The researchers have also demonstrated depositing single wall carbon nanotubes on metal contacts in arrays of vias (windows in an insulator exposing the metal) spaced only 200 nanometers apart. They've also shown the ability to attach electrochemically different functional enzymes to vertically oriented single wall carbon nanotubes at different closely-spaced sites on the same chip.
Both today's patent and a companion patent awarded last year (7,736,979 ) teach a method for depositing a single nanotube vertically in an electronic circuit using techniques currently used in the fabrication of computer chips. This enables the bridging of electronic technology with biological sensing all the way down to the nanoscale.
Using the process called electrophoresis, the nanotubes in a liquid suspension are drawn to metal contacts at the base of precisely-located vias. Each via gets charged and acts like an electrostatic lens. Once the first nanotube is deposited the electric field is modified and can redirect other nanotubes from depositing on the metal, even though the via may have a diameter several times larger than the diameter of the nanotube element.
This discovery has led to the following patented and patent-pending technologies: a vertical transistor using a single one-nanometer carbon nanotube, a planar biofuel cell, and the nanoprobe array announced today.
Provided by New Jersey Institute of Technology
"Patent for arrays of nanoscale electrical probes awarded to NJIT today." June 21st, 2011. http://www.physorg.com/news/2011-06-patent-arrays-nanoscale-electrical-probes.html
US Patent 7,964,143 discloses a nanoprobe array technique that allows for an array of individual, vertically-oriented nanotubes to be assembled at precise locations on electrical contacts using electrophoresis. The location of each nanotube in the array is controlled by a nanoscale electrostatic lens fabricated by a process commonly used in the manufacture of integrated circuits.
The research appeared in 2008 in the the Journal of Vacuum Science and Technology, entitled "Directed self-assembly of individual vertically aligned carbon nanotubes." Support for the research was provided by the Department of Defense.
The number of nanotubes deposited at each location is controlled by the geometry of the lens, which makes it possible to deposit a single nanotube in a window much larger than its diameter. After deposition, each individual nanotube can be modified to insulate the shaft and to sensitize it to a specific ion in the cell. The task is accomplished by attaching an appropriate functional molecule or enzyme to the tip of the nanotube.
The completed nanoprobe array may be configured for multiple diverse electrochemical events to be mapped on timescales limited only by the nature of the nanotube's contact with the cell membrane and the speed of integrated circuits.
For three different types of cells (human embryonic kidney cells, mouse neurons, and yeast), the NJIT researchers have measured the electrical response to a signal. This signal is generated by a pair of carbon nanotube probes spaced only six micrometers apart. Yeast cells are too small to measure with the tools most commonly used in the industry for determining electrical response.
The researchers have also demonstrated depositing single wall carbon nanotubes on metal contacts in arrays of vias (windows in an insulator exposing the metal) spaced only 200 nanometers apart. They've also shown the ability to attach electrochemically different functional enzymes to vertically oriented single wall carbon nanotubes at different closely-spaced sites on the same chip.
Both today's patent and a companion patent awarded last year (7,736,979 ) teach a method for depositing a single nanotube vertically in an electronic circuit using techniques currently used in the fabrication of computer chips. This enables the bridging of electronic technology with biological sensing all the way down to the nanoscale.
Using the process called electrophoresis, the nanotubes in a liquid suspension are drawn to metal contacts at the base of precisely-located vias. Each via gets charged and acts like an electrostatic lens. Once the first nanotube is deposited the electric field is modified and can redirect other nanotubes from depositing on the metal, even though the via may have a diameter several times larger than the diameter of the nanotube element.
This discovery has led to the following patented and patent-pending technologies: a vertical transistor using a single one-nanometer carbon nanotube, a planar biofuel cell, and the nanoprobe array announced today.
Provided by New Jersey Institute of Technology
"Patent for arrays of nanoscale electrical probes awarded to NJIT today." June 21st, 2011. http://www.physorg.com/news/2011-06-patent-arrays-nanoscale-electrical-probes.html
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