If the graphene sheet starts out with low electron concentration the pulse increases the material s electrical conductivity.
The researchers then illuminated graphene with a strong light pulse and measured the change of electrical conduction by assessing the transmission of a second low-frequency light pulse.
one to modify the material and one to measure the electrical conduction. Gedik says that the pulses used to measure the conduction are much lower frequency than the pulses used to modify the material behavior.
Our experiment reveals that the cause of photoconductivity in graphene is very different from that in a normal metal or semiconductors,
The research team also included Jing Kong the ITT Career development Associate professor of Electrical engineering at MIT who provided the graphene samples used for the experiments;
Its top layer is made from graphite that the researchers exfoliated by placing the material in a microwave.
First in 2007 the team wirelessly lit a 60-watt light bulb from eight feet away using two large copper coils with similarly tuned resonant frequencies that transferred energy from one to the other over the magnetic field.
which uses an electromagnetic field to transfer energy between two coils is used in transformers and wireless toothbrushes.
The transmitter emanated a magnetic field oscillating at megahertz frequencies which the receiver matched ensuring a strong coupling between the units
and Samuel Wang a software engineer at Foursquare who was a graduate student in the Department of Electrical engineering
these molecules, found in the bacteria Haloarcula marismortui and Haloarcula vallismortis, did not induce a strong enough photocurrent an electric current in response to light to be useful in controlling neuron activity.
For years, Li-Shiuan Peh, the Singapore Research Professor of Electrical engineering and Computer science at MIT, has argued that the massively multicore chips of the future will need to resemble little Internets,
says Bhavya Daya, an MIT graduate student in electrical engineering and computer science, and first author on the new paper. ou can also have multiple paths to your destination.
a professor of electrical engineering and computer science at the University of Michigan. heir contribution is an interesting one:
At the IEEE s Conference on Privacy Security and Trust in July Oshani Seneviratne an MIT graduate student in electrical engineering and computer science and Lalana Kagal a principal research scientist at CSAIL will present a paper
and air conditioning) equipment to detect leaks, breaks, and general inefficiencies, as well as energy saving opportunities. The software then translates the data into graphs, metrics,
and take efficiency measures such as using chilly outdoor air, instead of air conditioning, to cool rooms. he idea is to make buildings better, by helping people save time, energy,
But now, MIT spinout FINSIX has invented an adapter that roughly one-quarter the size and one-sixth the weight of a conventional brick,
and Justin Burkhart SM 0 FINSIX has developed the world smallest laptop adapter, called the Dart.
the adapter is only slightly larger than an ordinary plug. The Dart runs on novel very high-frequency frequency (VHF) power-conversion technology, co-invented by Sagneri,
that delivers energy more often and in smaller chunks than traditional adapters, ultimately wasting less energy.
It does so by making the adapter switching frequency which transfers energy from the adapter to the battery run 1,
000 times faster. f you can increase that switching frequency, you can reduce the amount of energy that you have to store temporarily in the inductors and capacitors
Sagneri says. ee not really an adapter company; wee creating the commercially enabled technology to allow VHF power converters to become a significant portion of the market,
Under the tutelage of David Perreault, an MIT professor of electrical engineering, Sagneri helped develop a novel circuit that executes power conversion at very high frequency 30 to 300 megahertz
the company started focusing on laptop adapters. In traditional adapters, an array of switches flip to one state and take in AC voltage from a wall outlet,
where it then stored in inductors and capacitors and converted to DC voltage. The switches then flip to another state to deliver small chunks of the DC voltage to the battery,
In that analogy, the bucket is the adapter that collects the water (electricity) from a full tank (outlet) and dumps it into an empty tank (laptop battery.
with conventional adapters youe dipping a one-gallon bucket into the full tank once a minute,
and Burkhart were electrical engineering and computer science students who were excited to start a company. Around 2010, their interests merged in MIT Sloan 15.390 (New Enterprises),
Spreading pixels Oliver Cossairt, an assistant professor of electrical engineering and computer science at Northwestern University, once worked for a company that was attempting to commercialize glasses-free 3-D projectors. hat
For their first power-producing prototype they bought a small reliable wind turbine rotor and cut off some metal in the back that was dead weight
(which Rein co-founded) in Somerville Mass. where its first rotor is displayed proudly near the entrance along with enlarged photos of the first trial run.
and Marc Baldo, professor of electrical engineering. In most photovoltaic (PV) materials, a photon (a packet of sunlight) delivers energy that excites a molecule,
Think about a range around you like five feet says Gregory Wornell the Sumitomo Electric Industries Professor in Engineering in MIT s Department of Electrical engineering
an MIT graduate student in electrical engineering and computer science and lead author on the new paper, the new work is in the field of emantic parsing,
an MIT Phd student in electrical engineering and computer science (EECS) who invented the technology. With the prize money, the team including students from MIT, the California Institute of technology,
Exoelectrogens, coated on anodes, consume the wastewater remaining organic pollutants and, in the process, generate electricity.
This electricity travels through a circuit and onto cathodes coated with separate microbes that consume that electricity
Long-term MRIMRI uses magnetic fields and radio waves that interact with protons in the body to produce detailed images of the body s interior.
or diagnostic sensors says Timothy Lu an assistant professor of electrical engineering and biological engineering. Lu is the senior author of a paper describing the living functional materials in the March 23 issue of Nature Materials.
According to Tim Lu, an assistant professor of electrical engineering and biological engineering at MIT, it boils down to the inefficient bacteria-detection assays used in the food industry.
Escape velocitythe robotic fish was built by Andrew Marchese a graduate student in MIT s Department of Electrical engineering
which in turn releases the energy to the electric motor during acceleration. Custom software reads the driver s braking habits
An XL Hybrids electric motor adds torque to an existing powertrain meaning a customer can reduce the size of the engine from say a 6-liter to a 4. 8-liter
When we invented this new class of synthetic biomarker we used a highly specialized instrument to do the analysis says Bhatia the John and Dorothy Wilson Professor of Health Sciences and Technology and Electrical engineering and Computer science.
low-power signal processing chip that could lead to a cochlear implant that requires no external hardware.
both in MIT Department of Electrical engineering and Computer science, will also exhibit a prototype charger that plugs into an ordinary cell phone
and can recharge the signal processing chip in roughly two minutes. he idea with this design is that you could use a phone, with an adaptor,
the Joseph F. and Nancy P. Keithley Professor of Electrical engineering and corresponding author on the new paper. r you could imagine a smart pillow,
Another imaging technique, known as magnetoencephalography (MEG), uses an array of hundreds of sensors encircling the head to measure magnetic fields produced by neuronal activity in the brain.
Torralba an associate professor of electrical engineering and computer science and graduate student Wilma Bainbridge. Conversely it could also be used to make faces appear less memorable
Count the photonsas Ahmed Kirmani a graduate student in MIT s Department of Electrical engineering and Computer science and lead author on the new paper explains the very idea of forming an image with only a single photon detected at each pixel location is counterintuitive.
they follow a pattern known in signal processing as Poisson noise. Simply filtering out noise according to the Poisson statistics would produce an image that would probably be intelligible to a human observer.
Researchers in the Optical and Quantum Communications Group which is led by Jeffrey Shapiro the Julius A. Stratton Professor of Electrical engineering
This can be done by applying a magnetic or electric field, or by flowing two streams of liquid along the outer edges of the channel, forcing the particles to stay in the center.
Stephen Shum a graduate student in MIT s Department of Electrical engineering and Computer science and lead author on the new paper found that a 100-variable i-vector a 100-dimension approximation of the 120000-dimension space was an adequate
says Frans Kaashoek, the Charles A. Piper Professor in the Department of Electrical engineering and Computer science (EECS).
Such a system could be used to monitor patients who are at high risk for blood clots says Sangeeta Bhatia senior author of the paper and the John and Dorothy Wilson Professor of Health Sciences and Technology and Electrical engineering and Computer science.
To improve robots ability to gauge object orientation Jared Glover a graduate student in MIT s Department of Electrical engineering
And ambiguity is really the central challenge to getting good alignments in highly cluttered scenes like inside a refrigerator or in a drawer.
a professor of electrical engineering and computer science and director of CSAIL. e just needed a creative insight
an associate professor of electrical engineering and computer science at the University of Illinois at Urbana-Champaign who was not part of the research team. he possibilities are endless:
and other devices such as the cellphone charger that GCS later developed. e called it our universal adapter,
and air conditioning (HVAC) systems, which eat up about 50 percent of energy used in homes and buildings.
When atoms travel across such an electric field, they are drawn to places of minimum potential in this case, the troughs.
an MIT graduate student in electrical engineering and computer science and first author on the new paper. e need to regulate the input to extract the maximum power,
the Joseph F. and Nancy P. Keithley Professor in Electrical engineering, use an inductor, which is a wire wound into a coil.
When a current passes through an inductor, it generates a magnetic field which in turn resists any change in the current.
An electric current delivered by the device removes the membrane, releasing a single dose. The device can be programmed wirelessly to release individual doses for up to 16 years to treat
but they suffer from relatively low electrical conductivity, Mirvakili says. In this new work, he and his colleagues have shown that desirable characteristics for such devices,
Power electronics is a ubiquitous technology used to convert electricity to higher or lower voltages and different currents such as in a laptop power adapter
and laptop power adapters one-third the size or even small enough to fit inside the computer itself. his is a once-in-a-lifetime opportunity to change electronics
an MIT associate professor of electrical engineering and computer science who co-invented the technology. Other cofounders and co-inventors are Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor in Electrical engineering, now chair of CEI technical advisory board;
alumnus Bin Lu SM 7, Phd 3, CEI vice president for device development; Ling Xia Phd2, CEI director of operations;
Major applications CEI is currently using its advanced transistors to develop laptop power adaptors that are approximately 1. 5 cubic inches in volume the smallest ever made.
and the inverters that convert the battery power to drive the electric motors. The silicon transistors used today have constrained a power capability that limits how much power the car can handle.
a workshop hosted by the Department of Electrical engineering and Computer science, where entrepreneurial engineering students are guided through the startup process with group discussions and talks from seasoned entrepreneurs.
Moreover their method enables this value to be tuned through the application of an electric field meaning graphene circuit elements made in this way could one day be rewired dynamically without physically altering the device.
Applying an electric field pulse can change the sign of the surface charges. That's an unstable situation Rappe said in that the positively charged surface will want to accumulate negative charges and vice versa.
You could come along with a tip that produces a certain electric field and just by putting it near the oxide you could change its polarity Martin said.
They have accomplished this by bringing a graphene sheet very close to a magnetic insulator-an electrical insulator with magnetic properties.
Magnetic substances like iron tend to interfere with graphene's electrical conduction. The researchers avoided those substances
In their experiments Shi and his team exposed the graphene to an external magnetic field. They found that graphene's Hall voltage-a voltage in the perpendicular direction to the current flow-depended linearly on the magnetization of yttrium iron garnet (a phenomenon known as the anomalous Hall effect seen in magnetic materials like iron and cobalt.
Broadly speaking organic solar cells convert light into electric current in four steps. First the cell absorbs sunlight which excites electrons in the active layer of the cell.
new tool for medical imaging,"says Prasad, also a SUNY Distinguished Professor of chemistry, physics, medicine and electrical engineering at UB."
E-jet printing refers to a technique called electrohydrodynamic jet described as a micro/nanomanufacturing process that uses an electric field to induce fluid jet printing through micro/nanoscale nozzles.
An electric field at the nozzle opening causes ions to form on the meniscus of the ink droplet.
The electric field pulls the ions forward deforming the droplet into a conical shape. Then a tiny droplet shears off and lands on the printing surface.
They wrote that these arrays as well as those constructed with multiple different QD materials directly patterned/stacked by e-jet printing can be utilized as photoluminescent and electroluminescent layers.
The difficulty with the e-jet printing method is that the electric field at one nozzle affects the fields of neighboring nozzles.
The pieces of plastic were subjected then to an increasing electric field until they crackled. Fullerenes turned out to be the type of additive that most effectively protects the insulation plastic.
The researchers will also test the method in high-voltage cables for direct current, since direct current is more efficient than alternating current for power transmission over very long distances c
#Arming nanoparticles for cancer diagnosis and treatment UCD researchers have manipulated successfully nanoparticles to target two human breast cancer cell lines as a tool in cancer diagnosis and treatment.
when exposed to alternating magnetic fields causing cell death (magnetic hyperthermia). The UCD team led by Conway Fellows Professor Gil Lee in the School of Chemistry
and Barry Rand an assistant professor of electrical engineering and the Andlinger Center for Energy and the Environment.
Batteries have called two electrodes an anode and a cathode. The anodes in most of today's lithium-ion batteries are made of graphite.
The theoretical maximum storage capacity of graphite is limited very at 372 milliamp hours per gram hindering significant advances in battery technology said Vilas Pol an associate professor of chemical engineering at Purdue University.
The researchers have performed experiments with a porous interconnected tin-oxide based anode which has nearly twice the theoretical charging capacity of graphite.
The researchers demonstrated that the experimental anode can be charged in 30 minutes and still have a capacity of 430 milliamp hours per gram (mah g 1)
The anode consists of an ordered network of interconnected tin oxide nanoparticles that would be practical for commercial manufacture
catalyzed by the gold releases electrons generates an easily measurable electric current. The gold nanotubes conduct electricity especially well due to their one-dimensional structure.
transistors for flexible electronics high-efficiency light-emitting diodes resonator-based mass sensors and integrated near-field optoelectronic tips for advanced scanning tip microscopy.
Because of that it has an electrical conductivity at least 10 times higher than the activated carbon now used to make commercial supercapacitors.
but their electrical conductivity is very low Ji said. We want fast energy storage and release that will deliver more power
Yael Hanein of Tel aviv University's School of Electrical engineering and head of TAU's Center for Nanoscience and Nanotechnology and including researchers from TAU the Hebrew University of Jerusalem and Newcastle University.
creating the possibility of electric generators powered by air. One-atom thick material graphene first isolated and explored in 2004 by a team at The University of Manchester is renowned for its barrier properties
They hypothesise that such harvesting can be combined together with fuel cells to create a mobile electric generator that is fuelled simply by hydrogen present in air.
You put a hydrogen-containing gas on one side apply small electric current and collect pure hydrogen on the other side.
Coe-Sullivan, then a Phd student in electrical engineering and computer science, was working with Bulovic and students of Moungi Bawendi, the Lester Wolfe Professor in Chemistry,
When associate professor Qi Hua Fan of the electrical engineering and computer science department set out to make a less expensive supercapacitor for storing renewable energy he developed a new plasma technology that will streamline the production of display screens.
#Graphene/nanotube hybrid benefits flexible solar cells Rice university scientists have invented a novel cathode that may make cheap, flexible dye-sensitized solar cells practical.
The Rice lab of materials scientist Jun Lou created the new cathode, one of the two electrodes in batteries,
a return line completes the circuit to the cathode that combines with an iodine-based electrolyte to refresh the dye.
The new cathode's charge-transfer resistance, which determines how well electrons cross from the electrode to the electrolyte,
was found to be 20 times smaller than for platinum-based cathodes, Lou said. The key appears to be the hybrid's huge surface area,
When combined with an iodide salt-based electrolyte and an anode of flexible indium tin oxide,
Based on recent work on flexible graphene-based anode materials by the Lou and Tour labs and synthesized high-performance dyes by other researchers,
because tunneling is a local effect sensitive only to the topmost layer of materials this phenomenon as observed topographically results from the tunneling of x-ray excited photoelectrons from states between the Fermi level and the work function.
and the nanowires are grown by applying electric current through electrodeposition. Nath grows the nanowires in a parallel pattern
and close and ultimately how the device moves by applying an external magnetic field. However the researchers'discovery that micro-devices can swim through some liquids with symmetrical movements does not just apply to magnetically-driven micro-robots.
When they then applied a rotating magnetic field the nickel-containing nano-screw also started to rotate causing the propeller to move forward through a liquid.
Adrian Bachtold, together with Marc Dykman (Michigan University), report on an experiment in which a carbon nanotube mechanical resonator exhibits quality factors of up to 5 million,
This allows them to determine how precise the resonator can be at measuring or sensing objects.
Scientists use mechanical resonators to study all sorts of physical phenomena. Nowadays, carbon nanotube mechanical resonators are in demand because of their extremely small size and their outstanding capability of sensing objects at the nanoscale.
Though they are very good mass and force sensors, their quality factors have been somewhat modest.
What is a Mechanical Resonator? A mechanical resonator is a system that vibrates at very precise frequencies.
Like a guitar string or a tightrope, a carbon nanotube resonator consists of a tiny, vibrating bridge-like (string) structure with typical dimensions of 1#m in length and 1nm in diameter.
If the quality factor of the resonator is high, the string will vibrate at a very precise frequency,
thus enabling these systems to become appealing mass and force sensors, and exciting quantum systems. Why is This Discovery so Important?
For many years, researchers observed that quality factors decreased with the volume of the resonator, that is the smaller the resonator the lower the quality factor,
The giant quality factors that ICFO researchers have measured have not been observed before in nanotube resonators mainly
since"nanotube resonators are enormously sensitive to surrounding electrical charges that fluctuate constantly. This stormy environment strongly affects our ability to capture the intrinsic behavior of nanotube resonators.
For this reason, we had to take a very large number of snapshots of the nanotube's mechanical behavior.
For instance, nanotube resonators might be used to detect individual nuclear spins, which would be an important step towards magnetic resonance imaging (MRI) with a spatial resolution at the atomic level.
and high electrical conductivity and are used in products from baseball bats and other sports equipment to lithium-ion batteries and touchscreen computer displays.
As the battery cycles lithium ions shuttle back and forth between cathode and anode and leave behind detectable tracks of nanoscale damage.
Crucially the high heat of vehicle environments can intensify these telltale degradation tracks and even cause complete battery failure.
an international group of scientists announced the most significant breakthrough in a decade toward developing DNA-based electrical circuits.
to date, no one has actually been able to make complex electrical circuits using molecules. The only known molecules that can be designed pre to self-assemble into complex miniature circuits,
signaling a significant breakthrough towards the development of DNA-based electrical circuits. The research, which could reignite interest in the use of DNA-based wires
(or voltage) produces a strong electric field that drives molecular rearrangements in the electrolyte next to the electrode.
The abundance and environmentally friendly nature of the element sulfur as cathode material are factors in the huge potential of lithium-sulfur batteries.
"Due to excellent electrical conductivity, mechanical strength and chemical stability, nanocarbon materials have played an essential role in the area of advanced energy storage,
However, most contributions concerning carbon/sulfur composite cathodes possess a relatively low areal loading of sulfur of less than 2. 0 mg cm-2,
which prevented the full demonstration of the outstanding performance of C/S composite cathodes.""The areal capacity of commercially used lithium-ion batteries is about 4 mah cm-2,
and therefore, the areal loading of sulfur in the cathode of lithium-sulfur batteries needs to be improved greatly,
"The areal capacity can be increased further to 15.1 mah cm-2 by stacking three CNT-S paper electrodes, with an areal sulfur loading of 17.3 mg cm-2 as the cathode in a Li
and possesses exciting properties such as high mechanical stability and remarkable electrical conductivity. It has been touted as the next generation material that can conceivably revolutionize existing technology
Materials scientist Regina Ragan and electrical engineer Filippo Capolino have created a nano-optical sensor that can detect trace levels of infection in a small sample of breath.
or cathode and scratched the surface with sandpaper to form a light panel capable of producing a large stable and homogenous emission current with low energy consumption.
The new devices have luminescence systems that function more like cathode ray tubes with carbon nanotubes acting as cathodes
and a phosphor screen in a vacuum cavity acting as the anode. Under a strong electric field the cathode emits tight high-speed beams of electrons through its sharp nanotube tips a phenomenon called field emission.
The electrons then fly through the vacuum in the cavity and hit the phosphor screen into glowing.
We have found that a cathode with highly crystalline single-walled carbon nanotubes and an anode with the improved phosphor screen in our diode structure obtained no flicker field emission current and good brightness homogeneity Shimoi said.
Field emission electron sources catch scientists'attention due to its ability to provide intense electron beams that are about a thousand times denser than conventional thermionic cathode (like filaments in an incandescent light bulb.
That means field emission sources require much less power to operate and produce a much more directional and easily controllable stream of electrons.
The resistance of cathode electrode with highly crystalline single-walled carbon nanotube is very low. Thus the new flat-panel device has compared smaller energy loss with other current lighting devices
which can be used to make energy-efficient cathodes that with low power consumption. Many researchers have attempted to construct light sources with carbon nanotubes as field emitter Shimoi said.
of which shows this super accuracy adds Associate professor Andrea Morello from UNSW's School of Electrical engineering and Telecommunications.
This kind of coupling is a direct consequence of the glass fibre geometry and the laws of electrodynamics.
#New nanomaterial introduced into electrical machines Lappeenranta University of Technology in Finland has constructed the world's first prototype electrical motor using carbon nanotube yarn in the motor windings.
The presently most electrically conductive carbon nanotube yarn replaces usual copper wires in the windings. The motor prototype is built by the LUT Electrical engineering group as a start towards lightweight efficient electric drives.
The test motor output power is 40 W it rotates at 15000 rpm and has almost a 70%efficiency.
In the near future carbon nanotube fibers have potential to significantly enhance the performance and energy efficiency of electrical machines.
Researchers are constantly searching for opportunities to upgrade the performance of electrical machines; to this end one of the objectives is to find higher-conductivity wires for the windings.
The best carbon nanotubes (CNTS) have demonstrated conductivities far beyond those of the best metals. Thus future windings made of CNTS may have a double conductivity compared with the present-day copper windings.
In order to make CNTS easy to manipulate they are spun to form multifiber yarn. If we keep the electrical machine design parameters unchanged and only replace copper with future carbon nanotube wires it is possible to reduce the Joule losses in the windings to half of the present-day machine losses.
Carbon nanotube wires are significantly lighter than copper and also environmentally friendlier. Therefore replacing copper with nanotube wires should significantly reduce the CO2 EMISSIONS related to the manufacturing
and operating of electrical machines. Furthermore the machine dimensions and masses could be reduced. The motors could also be operated in significantly higher temperatures than the present ones says Professor Juha Pyrh nen who has led the design of the prototype at LUT.
No definite upper limit for the conductivity Traditionally the windings in electrical machines are made of copper which has the second best conductivity of metals at room temperature.
Despite the high conductivity of copper a large proportion of the electrical machine losses occur in the copper windings.
According to Pyrhnen the electrical machines are so ubiquitous in everyday life that we often forget about their presence.
In a single-family house alone there can be tens of electrical machines in various household appliances such as refrigerators washing machines hair dryers and ventilators.
All these use copper in the windings. Consequently finding a more efficient material to replace the copper conductors would lead to major changes in the industry tells Professor Pyrh nen.
There is a significant improvement potential in the electrical machines but we are now facing the limits of material physics set by traditional winding materials.
Superconductivity appears not to develop to such a level that it could in general be applied to electrical machines.
We expect that in the future the conductivity of carbon nanotube yarns could be even three times the practical conductivity of copper in electrical machines.
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