Sunday, September 21, 2014
New light has been shed on solar power generation using devices made with polymers, thanks to a collaboration between scientists in the University of Chicago's chemistry department, the Institute for Molecular Engineering, and Argonne National Laboratory.
Researchers identified a new polymer—a type of large molecule that forms plastics and other familiar materials—which improved the efficiency of solar cells. The group also determined the method by which the polymer improved the cells' efficiency. The polymer allowed electrical charges to move more easily throughout the cell, boosting the production of electricity—a mechanism never before demonstrated in such devices.
"Polymer solar cells have great potential to provide low-cost, lightweight and flexible electronic devices to harvest solar energy," said Luyao Lu, graduate student in chemistry and lead author of a paper describing the result, published online last month in the journal Nature Photonics.
Solar cells made from polymers are a popular topic of research due to their appealing properties. But researchers are still struggling to efficiently generate electrical power with these materials.
"The field is rather immature—it's in the infancy stage," said Luping Yu, professor in chemistry, fellow in the Institute for Molecular Engineering, who led the UChicago group carrying out the research.
The active regions of such solar cells are composed of a mixture of polymers that give and receive electrons to generate electrical current when exposed to light. The new polymer developed by Yu's group, called PID2, improves the efficiency of electrical power generation by 15 percent when added to a standard polymer-fullerene mixture
read more at http://phys.org/news/2014-09-team-solar-cell-efficiency.html
Friday, September 19, 2014
Faster, smaller, greener computers, capable of processing information up to 1,000 times faster than currently available models, could be made possible by replacing silicon with materials that can switch back and forth between different electrical states.
The present size and speed limitations of computer processors and memory could be overcome by replacing silicon with 'phase-change materials' (PCMs), which are capable of reversibly switching between two structural phases with different electrical states – one crystalline and conducting and the other glassy and insulating – in billionths of a second.
Modelling and tests of PCM-based devices have shown that logic-processing operations can be performed in non-volatile memory cells using particular combinations of ultra-short voltage pulses, which is not possible with silicon-based devices.
In these new devices, logic operations and memory are co-located, rather than separated, as they are in silicon-based computers. These materials could eventually enable processing speeds between 500 and 1,000 times faster than the current average laptop computer, while using less energy. The results are published in the journal Proceedings of the National Academy of Sciences.
The processors, designed by researchers from the University of Cambridge, the Singapore A*STAR Data-Storage Institute and the Singapore University of Technology and Design, use a type of PCM based on a chalcogenide glass, which can be melted and recrystallized in as little as half a nanosecond (billionth of a second) using appropriate voltage pulses.
The calculations performed by most computers, mobile phones and tablets are carried out by silicon-based logic devices. The solid-state memory used to store the results of such calculations is also silicon-based. "However, as demand for faster computers continues to increase, we are rapidly reaching the limits of silicon's capabilities," said Professor Stephen Elliott of Cambridge's Department of Chemistry, who led the research.
The primary method of increasing the power of computers has previously been to increase the number of logic devices which they contain by progressively reducing the size of the devices, but physical limitations for current device architectures mean that this is quickly becoming nearly impossible to continue.
Currently, the smallest logic and memory devices based on silicon are about 20 nanometres in size – approximately 4000 times thinner than a human hair - and are constructed in layers. As the devices are made ever smaller in order to increase their numbers on a chip, eventually the gaps between the layers will get so small that electrons which are stored in certain regions of flash non-volatile memory devices will be able to tunnel out of the device, resulting in data loss. PCM devices can overcome this size-scaling limit since they have been shown to function down to about two nanometres.
Sunday, September 7, 2014
AMD on 9/2/2014 , in another record-setting performance of its AMD FX series processors, set a new world record for silicon processor speed according to the HWBOT.org ranking. Leveraging the powerful 'Piledriver' x86 core architecture, famed Finnish overclocker "The Stilt" pushed the envelope of silicon overclocking1 to the extreme.
"World-record frequencies are just a start. The AMD FX series of processors will enable an unrivaled enthusiast PC experience – extreme multi-display gaming and HD content creation," said Bernd Lienhard, corporate vice president and general manager, Client Business Unit, AMD. "Enthusiasts can experience seamless multitasking and unleash the real capabilities of multi-threaded applications with additional enthusiast performance-tuning features unlocked as standard."
AMD also introduced new speed- and power-optimized AMD FX Series CPUs to push the boundaries of value and efficiency in high-performance desktops. The new 125W AMD FX-8370 CPU and power-optimized 95W AMD FX-8370E and FX-8320E processors all feature 8 native CPU cores for productivity at superior price points.
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Saturday, September 6, 2014
Japan's Kei Nishikori became the first man from Asia to reach a Grand Slam final :Federer, Djokovic both lose in US Open semifinals
Serbia, during the semifinals of the 2014 U.S. Open tennis tournament,
Saturday, Sept. 6, 2014, in New York. (AP Photo/Mike Groll)
Roger Federer could not pull off another big escape at the U.S. Open,
losing 6-3, 6-4, 6-4 in the semifinals Saturday against Croatia's Marin
It was the second significant surprise of the day, coming after Novak
Djokovic was beaten 6-4, 1-6, 7-6 (4), 6-3 by Japan's Kei Nishikori, who
became the first man from Asia to reach a Grand Slam singles final.
Instead of the No. 1-seeded Djokovic against the No. 2-seeded Federer --
who have combined to win 24 major championships -- in Monday's final, it
will be No. 10 Nishikori against No. 14 Cilic, neither of whom has ever
appeared in a Grand Slam title match.
"It's just amazing, an amazing feeling beating the No. 1 player,"
Nishikori said during an on-court interview.
He had played five-set marathons in his last two matches totaling more
than 8½ hours, yet he looked far fresher than a player known as one of
the fittest on tour.
"He just played better in these conditions than I did," Djokovic said.
Under coach Michael Chang, the 1989 French Open champ, the 24-year-old
Nishikori has sharpened his mental game to pull out victories like these.
"We've been working super well," Nishikori said, referring to Chang and
co-coach Dante Bottini. "That's why I'm here."
The midday sun beat down on Arthur Ashe Stadium and a thermometer on
court showed the temperature nearing 100 degrees (37 Celsius), not
counting the humidity of close to 70 percent. Nishikori closed this one
out in 2 hours, 52 minutes.
Djokovic, who had reached the last four U.S. Open finals, outlasted
two-time major champ Andy Murray in four long, tough sets in the
quarters. But he never looked comfortable Saturday and spent much of the
match scrambling around the court as Nishikori dictated points.
"Just wasn't myself," Djokovic said.
In the third-set tiebreaker, Djokovic had four unforced errors and a
double-fault. Nishikori then broke to open the final set, and Djokovic
wasted three break points in the next game.
Nishikori converted 5 of 7 break points, while Djokovic was just 4 for 13.
"Other than that second set, my game today was not even close to what I
wanted it to be," Djokovic said. "A lot of unforced errors, a lot of
Chang, the New Jersey-born son of Taiwanese immigrants, knows a thing or
two about groundbreaking victories. At age 17, he became the youngest
man to win a Grand Slam title when he upset Ivan Lendl and Stefan Edberg
(now Federer's coach) at Roland Garros.
A severely infected right big toe forced Nishikori to miss tuneup events
before the U.S. Open, and he feared that his lack of conditioning would
make for a short stay at Flushing Meadows. Instead, he keeps sticking
around -- on the court and in the tournament.
"I guess I love to play long matches," he said with a grin.
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