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Thursday, September 30, 2010

Physicists Win MacArthur Grants

ITHACA, N.Y., & CAMBRIDGE, Mass., Sept. 28, 2010 — An optical physicist at Cornell University working to develop silicon-based devices that harness the information-processing capabilities of light and an MIT physicist whose research links the worlds of quantum mechanics and astronomy were named today as recipients of five-year, $500,000 no-strings-attached 2010 MacArthur Foundation fellowships.

Cornell University optical physicist Michal Lipson "has emerged as a leader, despite relatively modest resources, in designing optical and hybrid opto-electronic devices with silicon-based fabrication methods," the John D. and Catherine T. MacArthur Foundation said in a statement announcing her award.



Cornell University optical physicist Michal Lipson. (Courtesy the John D. & Catherine T. MacArthur Foundation)
Lipson is working to find alternatives to conventional silicon computer chips, a mature technology that uses electronic circuits and cannot match the theoretical speed and capacity of optical systems.

Lipson has demonstrated that ring modulators (circular waveguides) can effectively serve as switches for light passing through adjacent linear waveguides when the frequency of light pumped into the modulators is precisely tuned relative to the linear waveguide. Her continued refinement of both opto-electronic and purely optical circuits has decreased their size, increased their efficiency, and accelerated their switching speed. The resulting silicon-based photonic integrated circuits have the potential to improve signal transmission and processing dramatically.

"Lipson's elegant solutions to a variety of theoretical and engineering challenges in silicon photonics are paving the way for the future development of practical and powerful optical computing devices," the foundation said.

MIT physics professor and quantum astrophysicist Nergis Mavalvala's research aims to detect gravitational waves — ripples in the fabric of space and time that were predicted by Albert Einstein. Gravitational waves carry information on the motions of objects in the universe, and scientists believe that by detecting gravitational waves they will be able to observe further back into the history of the universe than ever before.

As a graduate student, Mavalvala developed a prototype laser interferometer for detecting gravitational waves. This early work led to the identification of an important stabilization principle that was later incorporated into the design for the Laser Interferometer Gravitational-Wave Observatory (LIGO), a collaboration among scores of physicists and currently the most sensitive observatory of its kind.

Mavalvala's more recent research focuses on minimizing, if not circumventing, barriers imposed by quantum physics on the precision of standard optical interferometers. One strategy she uses is to cool the macroscopic components of the device (i.e., the mirrors) into a coherent quantum state; such components, large enough to see without magnification, exhibit bizarre quantum properties previously observed only at the atomic level.


Nergis Mavalvala works in the lab at MIT. (Courtesy the John D. & Catherine T. MacArthur Foundation)

Applying strategies such as this at the scale of the LIGO instruments (i.e., kilogram-scale mirrors separated by kilometers) has the potential to boost significantly the sensitivity of the device. Through this and other technically challenging, unconventional approaches, such as squeezed coherent states and optical springs, Mavalvala is making fundamental contributions to physics at the intersection of optics, condensed matter, and quantum mechanics, the foundation said.

"Her experimental advances are enhancing our ability to detect and quantify gravitational radiation with still greater precision, data that may be critical to incorporating gravitation within a unified theory of the basic forces in the universe," the foundation said.

Since 1981, MacArthur Fellowships, also known as “genius” grants, have come without stipulations or reporting requirements – an unusual level of independence for a grant — and offer fellows unprecedented freedom and opportunity to reflect, create and explore. Nominations are accepted only from invited nominators who are chosen from many fields and challenged to identify people who demonstrate exceptional creativity and promise. The number of fellows selected each year is not fixed, and usually varies between 20 and 25. Because there is no application process for the award, the phone call that they have won often comes "out of the blue" to recipients.

The 2010 MacArthur Fellows also include high school physics teacher Amir Abo-Shaeer, director of Dos Pueblos Engineering Academy in Goleta, Calif.

Including this year's group of 23, 828 people, ranging in age from 18 to 82 at the time of their selection, have been named MacArthur Fellows since the inception of the program 30 years ago.

For more information, visit: www.macfound.orgwww.cornell.edu or www.mit.edu

Photonics.com



Thursday, September 23, 2010

Primordial Magnetic Fields Discovered Across The Universe

by Staff Writers
Los Angeles CA (SPX) Sep 23, 2010

An artist's conception of an "active galactic nucleus" courtesy of NASA. In some galaxies, the nucleus, or central core, produces more radiation than the entire rest of the galaxy. (Credit: NASA)

Scientists from the California Institute of Technology and UCLA have discovered evidence of "universal ubiquitous magnetic fields" that have permeated deep space between galaxies since the time of the Big Bang.

Caltech physicist Shin'ichiro Ando and Alexander Kusenko, a professor of physics and astronomy at UCLA, report the discovery in a paper to be published in an upcoming issue of Astrophysical Journal Letters; the research is currently available online.

Ando and Kusenko studied images of the most powerful objects in the universe - supermassive black holes that emit high-energy radiation as they devour stars in distant galaxies - obtained by NASA's Fermi Gamma-ray Space Telescope.

"We found the signs of primordial magnetic fields in deep space between galaxies," Ando said.

Physicists have hypothesized for many years that a universal magnetic field should permeate deep space between galaxies, but there was no way to observe it or measure it until now.

The physicists produced a composite image of 170 giant black holes and discovered that the images were not as sharp as expected.

"Because space is filled with background radiation left over from the Big Bang, as well as emitted from galaxies, high-energy photons emitted by a distant source can interact with the background photons and convert into electron-positron pairs, which interact in their turn and convert back into a group of photons somewhat later," said Kusenko, who is also a senior scientist at the University of Tokyo's Institute for Physics and Mathematics of the Universe.

"While this process by itself does not blur the image significantly, even a small magnetic field along the way can deflect the electrons and positrons, making the image fuzzy," he said.

From such blurred images, the researchers found that the average magnetic field had a "femto-Gauss" strength, just one-quadrillionth of the Earth's magnetic field. The universal magnetic fields may have formed in the early universe shortly after the Big Bang, long before stars and galaxies formed, Ando and Kusenko said.

The research was funded by NASA, the U.S. Department of Energy and Japan's Society for the Promotion of Science.



Harimu dan harimu~


Move on.

Tu je nak taip.

Doakan ana.


[Insyirah]
-masih demam terkejut-
 09:31
23 September 2010




Thursday, September 16, 2010

Realistic Robotic Arm Within Reach

DALLAS, Sept. 15, 2010 — Lightning-fast fiber optic connections between robotic limbs and the human brain may be within reach for injured soldiers and other amputees with the establishment of a multimillion-dollar neurophotonics research center dedicated to creating realistic robotic arms that move and "feel."

The new $5.6 million Neurophotonics Research Center, funded by DARPA with industry partners as part of its Centers in Integrated Photonics Engineering Research (CIPhER) project, will develop the two-way fiber optic communication between prosthetic limbs and peripheral nerves, which will be key to operating realistic robotic arms, legs and hands that not only move like the real thing, but also "feel" sensations like pressure and heat, say Southern Methodist University (SMU) engineers, who are leading the project.

Successful completion of the fiber optic link will allow for sending signals seamlessly back and forth between the brain and artificial limbs, allowing amputees revolutionary freedom of movement and agility. Partners in the Neurophotonics Research Center also envision man-to-machine applications that extend far beyond prosthetics, leading to medical breakthroughs like brain implants for the control of tremors, neuro-modulators for chronic pain management and implants for patients with spinal cord injuries.

The researchers believe their new technologies can ultimately provide the solution to the kind of injury that left actor Christopher Reeve paralyzed after a horse riding accident.

"This technology has the potential to patch the spinal cord above and below a spinal injury," said Marc Christensen, center director and electrical engineering chair in SMU's Lyle School of Engineering. "Someday, we will get there."

The CIPhER project aims to dramatically improve the lives of the large numbers of military amputees returning from war in Iraq and Afghanistan. Currently available prosthetic devices commonly rely on cables to connect them to other parts of the body for operation – for example, requiring an amputee to clench a healthy muscle in the chest to manipulate a prosthetic hand. The movement is typically deliberate, cumbersome, and far from lifelike.

The goal of the Neurophotonics Research Center is to develop a link compatible with living tissue that will connect powerful computer technologies to the human nervous system through hundreds or even thousands of sensors embedded in a single fiber. Unlike experimental electronic nerve interfaces made of metal, fiber optic technology would not be rejected or destroyed by the body's immune system.

"Enhancing human performance with modern digital technologies is one of the great frontiers in engineering," said Christensen. "Providing this kind of port to the nervous system will enable not only realistic prosthetic limbs, but also can be applied to treat spinal cord injuries and an array of neurological disorders."

Every movement or sensation a human being is capable of has a nerve signal at its root. "The reason we feel heat is because a nerve is stimulated, telling the brain there's heat there," Christensen said.

The center formed around a challenge from the industrial partners to build a fiber optic sensor scaled for individual nerve signals. "Team members have been developing the individual pieces of the solution over the past few years, but with this new federal funding we are able to push the technology forward into an integrated system that works at the cellular level," Christensen said.

The research builds on partner universities' recent advances in light stimulation of individual nerve cells and new, extraordinarily sensitive optical sensors being developed at SMU. Volkan Otugen, SMU site director for the center and Lyle School mechanical engineering chair, has pioneered research on tiny spherical devices that sense the smallest of signals utilizing a concept known as "whispering gallery modes." A whispering gallery is an enclosed circular or elliptical area, like that found beneath an architectural dome, in which whispers can be heard clearly on the other side of the space.

The ultimate combination of advanced optical nerve stimulation and nerve-sensing technologies will create a complete, two-way interface that does not currently exist. "It will revolutionize the field of brain interfaces," Christensen said.

"Science fiction writers have long imagined the day when the understanding and intuition of the human brain could be enhanced by the lightning speed of computing technologies," said Geoffrey Orsak, dean of the SMU Lyle School of Engineering. "With this remarkable research initiative, we are truly beginning a journey into the future that will provide immeasurable benefits to humanity."

The center brings together researchers from SMU, Vanderbilt University, Case Western Reserve University, the University of Texas at Dallas and the University of North Texas. The Neurophotonics Research Center's industrial partners include Lockheed Martin (Aculight), Plexon, Texas Instruments, National Instruments and MRRA.

Together, this group of university and industry researchers will develop and demonstrate new increasingly sophisticated two-way communication connections to the nervous system.

For more information, visit: www.smuresearch.com

Source: Photonics.com



Wednesday, September 15, 2010

Engineers Make Artificial Skin Out Of Nanowires

by Staff Writers
This is an artist's illustration of an artificial e-skin with nanowire active matrix circuitry covering a hand. A fragile egg is held, illustrating the functionality of the e-skin device for prosthetic and robotic applications. Credit: Ali Javey and Kuniharu Takei
Berkeley CA (SPX) Sep 13, 2010 - Engineers at the University of California, Berkeley, have developed a pressure-sensitive electronic material from semiconductor nanowires that could one day give new meaning to the term "thin-skinned."

"The idea is to have a material that functions like the human skin, which means incorporating the ability to feel and touch objects," said Ali Javey, associate professor of electrical engineering and computer sciences and head of the UC Berkeley research team developing the artificial skin.

The artificial skin, dubbed "e-skin" by the UC Berkeley researchers, is described in a Sept. 12 paper in the advanced online publication of the journal Nature Materials. It is the first such material made out of inorganic single crystalline semiconductors.

A touch-sensitive artificial skin would help overcome a key challenge in robotics: adapting the amount of force needed to hold and manipulate a wide range of objects.

"Humans generally know how to hold a fragile egg without breaking it," said Javey, who is also a member of the Berkeley Sensor and Actuator Center and a faculty scientist at the Lawrence Berkeley National Laboratory Materials Sciences Division.

"If we ever wanted a robot that could unload the dishes, for instance, we'd want to make sure it doesn't break the wine glasses in the process. But we'd also want the robot to be able to grip a stock pot without dropping it."

A longer term goal would be to use the e-skin to restore the sense of touch to patients with prosthetic limbs, which would require significant advances in the integration of electronic sensors with the human nervous system.

Previous attempts to develop an artificial skin relied upon organic materials because they are flexible and easier to process.

"The problem is that organic materials are poor semiconductors, which means electronic devices made out of them would often require high voltages to operate the circuitry," said Javey.

"Inorganic materials, such as crystalline silicon, on the other hand, have excellent electrical properties and can operate on low power. They are also more chemically stable.

But historically, they have been inflexible and easy to crack. In this regard, works by various groups, including ours, have recently shown that miniaturized strips or wires of inorganics can be made highly flexible - ideal for high performance, mechanically bendable electronics and sensors."

The UC Berkeley engineers utilized an innovative fabrication technique that works somewhat like a lint roller in reverse. Instead of picking up fibers, nanowire "hairs" are deposited.

The researchers started by growing the germanium/silicon nanowires on a cylindrical drum, which was then rolled onto a sticky substrate. The substrate used was a polyimide film, but the researchers said the technique can work with a variety of materials, including other plastics, paper or glass.

As the drum rolled, the nanowires were deposited, or "printed," onto the substrate in an orderly fashion, forming the basis from which thin, flexible sheets of electronic materials could be built.

In another complementary approach utilized by the researchers, the nanowires were first grown on a flat source substrate, and then transferred to the polyimide film by a direction-rubbing process.

For the e-skin, the engineers printed the nanowires onto an 18-by-19 pixel square matrix measuring 7 centimeters on each side. Each pixel contained a transistor made up of hundreds of semiconductor nanowires.

Nanowire transistors were then integrated with a pressure sensitive rubber on top to provide the sensing functionality.

The matrix required less than 5 volts of power to operate and maintained its robustness after being subjected to more than 2,000 bending cycles.

The researchers demonstrated the ability of the e-skin to detect pressure from 0 to 15 kilopascals, a range comparable to the force used for such daily activities as typing on a keyboard or holding an object. In a nod to their home institution, the researchers successfully mapped out the letter C in Cal.

"This is the first truly macroscale integration of ordered nanowire materials for a functional system - in this case, an electronic skin," said study lead author Kuniharu Takei, post-doctoral fellow in electrical engineering and computer sciences.

"It's a technique that can be potentially scaled up. The limit now to the size of the e-skin we developed is the size of the processing tools we are using."

Other UC Berkeley co-authors of the paper are Ron Fearing, professor of electrical engineering and computer sciences; Toshitake Takahashi, graduate student in electrical engineering and computer sciences; Johnny C. Ho, graduate student in materials science and engineering; Hyunhyub Ko and Paul Leu, post-doctoral researchers in electrical engineering and computer sciences; and Andrew G. Gillies, graduate student in mechanical engineering.

Source: Nanotech



Thursday, September 9, 2010

Eid Mubarak!


Taqaballahu minna wa minkum!
~May ALLAH accept the good deeds from me and you~

By the way, baru kenal seorang sahabat di Facebook, dan sangat-sangat suka profile picture dia.



Salam aidilfitri untuk semua, maaf zahir dan batin~



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