Faster, more sensitive photodetector created by tricking graphene

ScienceDaily (June 5, 2012) ? Researchers at the Center for Nanophysics and Advanced Materials of the University of Maryland have developed a new type of hot electron bolometer a sensitive detector of infrared light, that can be used in a huge range of applications from detection of chemical and biochemical weapons from a distance and use in security imaging technologies such as airport body scanners, to chemical analysis in the laboratory and studying the structure of the universe through improved telescopes.

The UMD researchers, led by Research Associate Jun Yan and Professors Michael Fuhrer and Dennis Drew, developed the bolometer using bilayer graphene--two atomic-thickness sheets of carbon. Due to graphenes unique properties, the bolometer is expected to be sensitive to a very broad range of light energies, ranging from terahertz frequencies or submillimeter waves through the infrared to visible light.

The graphene hot electron bolometer is particularly promising as a fast, sensitive, and low-noise detector of submillimeter waves, which are particularly difficult to detect. Because these photons are emitted by relatively cool interstellar molecules, submillimeter astronomy studies the early stages of formation of stars and galaxies by observing these interstellar clouds of molecules. Sensitive detectors of submillimeter waves are being sought for new observatories that will determine the redshifts and masses of very distant young galaxies and enable studies of dark energy and the development of structure in the universe.

The Maryland teams findings are published in the June 3 issue of Nature Nanotechnology.

Most photon detectors are based on semiconductors. Semiconductors are materials which have a range of energies that their electrons are forbidden to occupy, called a band gap. The electrons in a semiconductor can absorb photons of light having energies greater than the band gap energy, and this property forms the basis of devices such as photovoltaic cells.

Graphene, a single atom-thick plane of graphite, is unique in that is has a bandgap of exactly zero energy; graphene can therefore absorb photons of any energy. This property makes graphene particularly attractive for absorbing very low energy photons (terahertz and infrared) which pass through most semiconductors. Graphene has another attractive property as a photon absorber: the electrons which absorb the energy are able to retain it efficiently, rather than losing energy to vibrations of the atoms of the material. This same property also leads to extremely low electrical resistance in graphene.

University of Maryland researchers exploited these two properties to devise the hot electron bolometer. It works by measuring the change in the resistance that results from the heating of the electrons as they absorb light.

Normally, graphenes resistance is almost independent of temperature, unsuitable for a bolometer. So the Maryland researchers used a special trick: when bilayer graphene is exposed to an electric field it has a small band gap, large enough that its resistance becomes strongly temperature dependent, but small enough to maintain its ability to absorb low energy infrared photons.

The researchers found that their bilayer graphene hot electron bolometer operating at a temperature of 5 Kelvin had comparable sensitivity to existing bolometers operating at similar temperatures, but was more than a thousand times faster. They extrapolated the performance of the graphene bolometer to lower temperature and found that it may beat all existing technologies.

Some challenges remain. The bilayer graphene bolometer has a higher electrical resistance than similar devices using other materials which may make it difficult to use at high frequencies. Additionally, bilayer graphene absorbs only a few percent of incident light. But the Maryland researchers are working on ways to get around these difficulties with new device designs, and are confident that a graphene has a bright future as a photodetecting material.

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The above story is reprinted from materials provided by University of Maryland.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Jun Yan, M-H. Kim, J. A. Elle, A. B. Sushkov, G. S. Jenkins, H. M. Milchberg, M. S. Fuhrer, H. D. Drew. Dual-gated bilayer graphene hot-electron bolometer. Nature Nanotechnology, 2012; DOI: 10.1038/nnano.2012.88

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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Al-Qaida No. 2 dies in US drone strike in Pakistan

FILE - This March 25, 2007, file image, made from video posted on a website frequented by Islamist militants and provided via the IntelCenter, shows al-Qaida militant Abu Yahia al-Libi. A CIA drone strike Monday, June 4, 2012, targeted al-Qaida's second in command, Abu Yahia al-Libi, in Pakistan, but it was unclear whether he was among those hit, U.S. officials said. U.S. officials say fewer than five people were hit, although Pakistani officials say more than a dozen people were killed in two days of strikes in Pakistan. (AP Photo/IntelCenter, File) THE ASSOCIATED PRESS HAS NO WAY OF INDEPENDENTLY VERIFYING THE CONTENT, LOCATION OR DATE OF THIS VIDEO

FILE - This March 25, 2007, file image, made from video posted on a website frequented by Islamist militants and provided via the IntelCenter, shows al-Qaida militant Abu Yahia al-Libi. A CIA drone strike Monday, June 4, 2012, targeted al-Qaida's second in command, Abu Yahia al-Libi, in Pakistan, but it was unclear whether he was among those hit, U.S. officials said. U.S. officials say fewer than five people were hit, although Pakistani officials say more than a dozen people were killed in two days of strikes in Pakistan. (AP Photo/IntelCenter, File) THE ASSOCIATED PRESS HAS NO WAY OF INDEPENDENTLY VERIFYING THE CONTENT, LOCATION OR DATE OF THIS VIDEO

ISLAMABAD, Pakistan (AP) ? A U.S. drone strike in northwest Pakistan has killed al-Qaida's second-in-command, officials from both countries confirmed Tuesday, the most significant victory so far in the controversial bombing campaign and the biggest setback to the terror network since the death of Osama bin Laden.

Abu Yahya al-Libi was considered a media-savvy, charismatic leader with religious credentials who was helping preside over the transformation of a secretive group based in Pakistan and Afghanistan into a global movement aimed at winning converts ? and potential attackers ? from Somalia to the Philippines.

This was not the first time the U.S. had al-Libi in its sights: He was originally captured a decade ago and held by American forces at the Bagram Air Base in Afghanistan until he escaped in 2005 in an embarrassing security breach. Soon thereafter, he began appearing in videos in which he talked about the lessons he learned while watching his captors, whom he described as cowardly, lost and alienated.

White House spokesman Jay Carney called al-Libi's death a "major blow" to the group. Carney described al-Libi as an operational leader and a "general manager" of al-Qaida. He said al-Libi had a range of experience that will be hard for al-Qaida to replicate and brings the terror network closer to its ultimate demise than ever before.

"His death is part of the degradation that has been taking place to core al-Qaida during the past several years and that degradation has depleted the ranks to such an extent that there's no clear successor," Carney said.

A U.S. official familiar with the case, who confirmed that al-Libi was killed in a drone strike, said no one left in al-Qaida comes close to replacing the expertise the group has just lost. The official spoke on condition of anonymity to discuss intelligence matters.

The Libyan-born al-Libi, who was thought to be in his late 40s, was killed Monday morning in a village in northwestern Pakistan, a tribal area bordering Afghanistan that is home to many al-Qaida and Taliban members and their support networks.

A Pakistani intelligence official said late Tuesday that al-Libi was dead but declined to say how authorities knew this or whether they had seen his body. He spoke on condition of anonymity because of the classified nature of the drone program.

Al-Libi, who was considered a hero in militant circles because of his escape from the American military prison, was elevated to al-Qaida's No. 2 spot when Ayman al-Zawahri replaced bin Laden. As al-Qaida's de facto general manager, he was responsible for running the group's day-to-day operations in Pakistan's tribal areas and managed outreach to al-Qaida's regional affiliates.

Al-Libi was influential and popular within al-Qaida because of his "scholarly credentials, street cred from having escaped from Bagram, charisma and his easygoing, tribal speaking style," said Jarret Brachman, a counterterrorism expert who has studied al-Libi for the past seven years.

"People may have revered Zawahri, but they loved Abu Yahya," said Brachman.

Al-Libi was the latest in the dozen-plus senior commanders removed in the clandestine U.S. war against al-Qaida since Navy SEALs killed bin Laden in a raid on May 2, 2011 on his compound in the Pakistani military town of Abbottabad ? nearly a decade after 9/11.

Perhaps the most well-known al-Qaida figure killed in a drone strike before al-Libi was Anwar al-Awlaki, a prominent member of the Yemen al-Qaida offshoot who died last September.

Al-Libi's death will likely fuel arguments in favor of the U.S. drone campaign despite Pakistani objections. Coming in an election year, it may also boost the tough-on-terrorists image President Barack Obama has tried to cultivate.

"The killing of al-Libi demonstrates the increasing proficiency and skill ? plus good intelligence ? at work in the decade-long American war to crush al-Qaida. It makes Barack Obama the counter-terrorist in chief in leading that war," said Aaron David Miller, a former adviser to six U.S. secretaries of state and currently a senior scholar at the Wilson Center.

The use of drones has skyrocketed under the Obama administration but has dropped off recently in Pakistan, which views the program as a violation of its sovereignty. Among the Pakistani public, the drone campaign is vilified because of its perceived civilian casualties, an allegation disputed by the U.S.

An on-the-ground investigation by The Associated Press this year found that the drone strikes were killing far fewer civilians than many Pakistanis are led to believe, and that a significant majority of the dead were combatants.

Pakistan's foreign ministry spokesman Moazzam Ahmad Khan said Islamabad had not been notified about the killing of al-Libi, and declined further comment.

Even while speculation was swirling as to whether al-Libi was alive or dead, Pakistan called Deputy U.S. Ambassador Richard Hoagland to the Foreign Ministry on Tuesday to protest the drone strikes.

Members of the Pakistani government and military have supported such strikes in the past, but that cooperation has come under strain as the relationship between the two countries has deteriorated. Last November, American airstrikes killed 24 Pakistani soldiers along the border with Afghanistan.

Pakistan responded by cutting off supply lines to NATO and American forces in Afghanistan and demanding that the U.S. end the drone attacks on its territory.

But the U.S. shows no such inclination. The White House maintains a list of terrorist targets to be killed or captured, compiled by the military and the CIA and ultimately approved by the president.

A recent uptick in drone strikes in the tribal areas indicates the U.S. was tracking al-Libi or had some idea that a top al-Qaida official was in the area. U.S. drones have struck seven times in recent weeks after a relative lull earlier this year.

Pakistani and Taliban officials said al-Libi was wounded in the days leading up to Monday's drone strike, although there were conflicting accounts as to where and when.

Evan Kohlmann, a senior partner a Flashpoint Global Partners which tracks radical Muslim propaganda, said the U.S. could have tracked al-Libi the same way it tracked bin Laden, through the use of couriers used to carry messages or in the case of al-Libi, carrying the video recordings that were his calling card.

___

Dozier reported from Washington. Rasool Dawar in Peshawar, Ishtiaq Mahsud in Dera Ismail Khan, Munir Ahmed in Islamabad, Sebastian Abbot in Kabul, Afghanistan, and Steven R. Hurst in Washington contributed to this report.

Associated Press

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'Elder Scrolls Online' takes aim at 'World of Warcraft'

8 hrs.

Winda Benedetti

Will you play a magical?elf, a mysterious arrow-slinging?assassin, or an axe-swinging dude with a beard and a bad attitude? That's just one of the many?decisions you'll get?to make when "The Elder Scrolls Online" launches next year.

As the Electronic Entertainment Expo got under way in Los Angeles today,?Bethesda and ZeniMax unveiled a new trailer for the forthcoming game ? one that teases a few of the character classes players will get to select?from.

"Elder Scrolls Online" is a massively multiplayer online role-playing game (that's MMORPG for short)?set in the world made popular by the series of offline "Elder Scrolls"?role-playing games ?? "Skyrim," "Oblivion" and?"Morrowind."

Bethesda says the online game?is set about 1,000 years before the events that take place?in "Skyrim," one of last year's best games and?biggest hits.

According to the official website:

Three Alliances have emerged across the continent, each struggling for supremacy over the land. As these great powers battle one another for control of the Imperial City - and with it all of Tamriel ?? darker forces are moving to destroy the world!...

You are the hero! Create a character by choosing from the nine classic Elder Scrolls races. Then adventure through the far reaches of Tamriel against hordes of undead, uncover evil plots, and confront your destiny that will change the world.

While many "Elder Scrolls" fans (our own In-Game editor Todd Kenreck among them)?are excited to see the offline?series translated into a massively multiplayer online?game, others fear that the game already looks too much like that other well-known massively multiplayer online game ???"World of Warcraft".

Of course, the game is still early in the development process and that trailer doesn't give us much to go on. Meanwhile,?with "WoW's' popularity waning with age, it makes sense for another game to step into its big leathery boots?(especially?if you don't think "Star Wars: The Old Republic" has already done that).

For more information about "The?Elder Scrolls Online," check out the official website here.?And be sure to?check out a few screenshots from the game below.

Meanwhile,?stay tuned here to In-Game for more of?our E3 coverage.?We have?a team on the ground at?E3 in Los Angeles. ?For all the fast and furious news check out our?In-Game Facebook page?as well as our Twitter feeds:?@ToddKenreck?and@WindaBenedetti.

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Microsoft's SmartGlass Opens Windows All Over the Living Room

Microsoft demoed its new Xbox SmartGlass system at the Electronic Entertainment Expo in Los Angeles on Monday. SmartGlass will connect devices running Windows 8, Windows 8 RT, Windows Phone, iOS, and Android to a user's Xbox 360 console. The Xbox SmartGlass app is available now with select games and Xbox Live content.

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Doxycycline dosage for acne treatment - Health and Fitness

The second way to get rid of acne scars is to eating a balanced diet. red They really are a unfortunate memento for an individual having suffered bad spots or maybe acne. These acids are extracted from fruits, milks, or sugars. Doctors consign different prescribe undoubted as anyone secrete inclement nodula acne that has not responded to side various treatments. So the next time, you go out and buy food make sure you do not buy these types of food. This is why back acne is so stubborn to treat. Some solutions are less expensive acne than others however may not give perfect results. Although, a number of treatment options are available, but you should give a thought to choose the proper treatment before you make the final decision. Studies Show Laser Therapy Effective At Clearing Acne treatment Dermatologist evaluates the latest laser and light sources approved for treating acne. There are certainly many contributing factors to natural skin care to clear acne red marks treatment your acne. Remember that physical beauty fades, both in the eye of the beholder with time, and in reality with age. That? s where benzoyl peroxide for creams come in. With fat transfer, the doxycycline dosage for acne treatment body reabsorbs it back into the body between half a year to a year and a half later and requires follow up injections. It is Time for the Acne Meds Products for your face. What can I do? The biological product is a low molecular weight as serves as an antioxidant and anti- inflammatory. Tomatoes possess antioxidant characteristics that prevent skin damage right from the cellular level. To hasten a zits healing time, increase blood flow to the acne doxycycline lesion. During and after menopause, skin erosion grows more uneven and so it? marks s always better to gently remove the epidermis or outer layer of skin to produce a more even appearance and clean out the pores. Beat the yolk using a fork and add 2 tsp of water 3. These include Ortho Tri- Cyclen and Estrostep. As a matter of truth, it is not uncommon for females to develop acne in their mid to late- 20? s, even if they? ve never had it prior to. It really is essentially a matter of locating the best ones. Allow the tomato juice to get absorbed well into the skin for one hour and then wash your face with cold water. A proper diet of foods consisting fruits, fresh vegetables are found to be a great preventive method against acne cysts, while foods rich in saturated fats and other dairy kind of products should not be taken when battling acne cysts. Using the remedies given here daily is an effective method of clearing acne scars. Of course, enough water on a daily basis will cleanse your internal organs and optimize it to best function the way they should. Do this a treatment few times and watch the effect on your skin. Compared to tetracycline, which may only kill bacteria, Erythromycin has each anti- inflammatory and bacteria- killing attributes. most effective acne scar treatment Health Supplements That Help Acne At some time in your life, it? s inevitable that you will face a problem you really don? t want to deal with. This is so the dosage cleanser can do its work and get deep down into the pores and rid the acne. The water in the skin surrounding doxycycline dosage for acne treatment the gland absorbs light emitted by the laser, and then acne warms up.

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Make- up can clogPores can lead to more acne. Wearing tight clothing can acne irritate the skin and, often, sometimes even worse. On the Best Acne Treatments or Cancer It? s a widely known fact that acne haunts acne treatment lemon juice the lives of teenagers and some There are many natural acne treatments, some of which will work for you and some of which won? desitin for acne t. It takes kate When you shave use your facial cleanser instead of shaving treatment lotion during flareups. It can be taken both internally and externally. Once The Aloe Vera plants are famous for their magically ability to help heal scars and wounds. As time goes by, the bacteria mutate, and

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Watch Coors Light Paint The Summer Silver

The Coors Light Silver Bullet Train is speeding towards the most refreshing summer yet, with special beer packaging, memorable local events, exclusive social media campaigns, a talent search with Ice Cube, and much more. In addition, the seasonal celebration is literally painting the summer silver with a fresh focus on local 3D art by world-renowned artists. In this time-lapse video that is sure to give you goose-bumps, watch a Coors Light Silver Bullet Pint come to life: http://www.youtube.com/watch?v=5bNlrm5j6vc

The Coors Light Silver Bullet Summer kicks off with the release of sleek, new special-edition Silver Bullet Summer packaging. Hitting shelves now, certain packs of Coors Light 12-ounce bottles and cans feature a distinctive, all-silver design with the exception of the iconic Cold-Activated blue mountains. The Silver Bullet Summer packaging will be available for about 10 weeks in all varieties of 12-ounce cans, as well as 24-loose and 6-pack 12-ounce bottles.

The Worlds Most Refreshing Beer can also be enjoyed in the innovative Coors Light Silver Bullet Aluminum Pint (see it in three-dimensional art form here: http://www.youtube.com/watch?v=5bNlrm5j6vc), which launched nationally earlier this year. Its the perfect package for anyone looking for an alternative to glass but wants the benefits of a bottle, whether theyre headed to the beach, concerts in the park or just hanging out with friends at a backyard barbecue. The Silver Bullet Pints wide mouth and re-sealable cap provides cold beer on the go and a full 16-ounces of refreshment as cold as the Rockies.

As the temperature heats up, The Coors Light Silver Bullet Summer campaign will showcase amazing three-dimensional art displays in cities across the country. At these exhibits, passersby will be able to interact with an oversized Silver Bullet Pint literally splashing down in the form of large 3D artwork. This optical illusion comes to life when people take pictures and video posing with the pint. Coors Light is encouraging spectators to capture and share their personal experiences with these visual art works whether it be texts to friends, posts on Facebook, #silverbullet3D on Twitter, and on Coors Light Facebook page. Watch the time-lapse video of this explosive art here: http://www.youtube.com/watch?v=5bNlrm5j6vc

The art displays will feature the work of two talented artists, Melanie Stimmell Van Latum and Julie KirkPurcell. Melanie is a graduate of Art Center College of Design in Pasadena, CA and spent eight years working on the iconic Comedy Central series South Park where she oversaw the transition from infamous paper cutouts to flawless digital animations.

Julie Kirk-Purcell is among the most admired and respected chalk artists of her time. Beginning her street painting career almost 20 years ago, she has traveled the world honing her craft and sharing her elaborate original designs with well-known clients such as The Walt Disney Company & Studios, Universal Studios, The Howard Hughes Corporation, BankMuscat, Bloomburg LLP, Chrysler Corporation, Lexus Corporation and the Long Beach Aquarium of the Pacific.

The Coors Light Facebook page and YouTube channel will also feature exclusive content, including a new augmented reality app, Coors Light Cold FX, which allows people to insert the Silver Bullet Pint into photos and videos captured on smart phones.

This will be our boldest, coldest summer yet, said Kedric George, Coors Light director of innovation and activation. Everything were doing this summer is about reinforcing the message that when you want cold refreshment, you just have to find the blue mountains.

For more information on the Coors Light Silver Bullet Summer, please visit CoorsLight.com or www.facebook.com/CoorsLight. Dont forget to watch the freshest video of the summer here: http://www.youtube.com/watch?v=5bNlrm5j6vc

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Car Insurance Online Guide | Auto Insurance

Online shopping has many advantages but are there any benefits to purchasing car insurance online? Many folks who shop for online car insurance quotes have realized that the convenience of receiving insurance information on their computer can save time and money. Here are some of the benefits of online car insurance quotes:

Cheap Car Insurance:

To receive multiple real-time online car insurance quotes allows you to save money instantly. If you were to shop around for quotes on the phone, you would typically spend a lot of time talking to agents. Agents usually will not let you off the phone or out of their office until you have caved in and purchased insurance from them. By choosing to purchase your car insurance online, you are taking advantage of being in control to decide which insurance quotes are the best fit for you. There is no pressure to purchase right away and you can always come back to the quotes you have received and make a decision.

Immediate Results:

Purchasing insurance online allows you to receive instant comparisons between quotes. Many insurance companies are able to give you instant quotes online. There are also many websites that provide fast insurance quote services that allow users to compare online insurance quotes from multiple companies. Receiving instant results saves a lot of time and saves you the hassle of calling multiple agents and companies for pricing information.

Being Educated:

Being able to receive instant and cheap insurance quotes is important, but shopping online for your insurance also gives you another advantage; a way to educate yourself. You will be able to find out a lot of information about insurance policies and coverage levels. You can also look up insurance company rating information to find out about customer service and financial strength.

Disadvantages:

Even though there are many benefits to buying insurance online, there is an important factor that is missing; a live agent. Sometimes purchasing insurance in person or over the phone can be a more personalized experience, especially if an agent knows you and what your needs are. Even though many online insurance companies have contact information, they will generally not take the time to explore your personal finances to offer you a tailored policy that can fit your budget and needs. A real live agent can be an invaluable asset while purchasing car insurance.

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