Tag Archive: science

Taiwan Engineers Defeat Limits of Flash Memory

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(Phys.org)—Taiwan-based Macronix has found a solution for a weakness in flash memory fadeout. A limitation of flash memory is simply that eventually it cannot be used; the more cells in the memory chips are erased, the less useful to store data. The write-erase cycles degrade insulation; eventually the cell fails. “Flash wears out after being programmed and erased about 10,000 times,” said the IEEE Spectrum. Engineers at Macronix have a solution that moves flash memory over to a new life. They propose a “self-healing” NAND flash memory solution that can survive over 100 million cycles. Ads by Google Roark Management – Computer Support & Repair Small Business Technology Solutions – www.RoarkInc.com News of their findings appears in the IEEE Spectrum, discussing flash memory’s limitations and the Taiwan company’s solution. Macronix is a manufacturer in the Non-Volatile Memory (NVM) market, with a NOR Flash, NAND Flash, and ROM products. Before their solution announcement, though, many engineers inside and outside of Macronix were aware of a life-giving workaround: heat. The snag is that applying heat was not found to be practical. As the Macronix team put it, the “long baking time is impractical for real time operation.” Although subjecting the cells to high heat could return memory, the process was problematic; the entire memory chip would need heating for hours at around 250 °C.
 They redesigned a flash memory chip to include onboard heaters to anneal small groups of memory cells. Applying a brief jolt of heat to a very restricted area within the chip (800 degrees C) returns the cell to a “good” state. They said that the process does not have to be run all that often. According to project member Hang‑Ting Lue, the annealing can be done infrequently and on one sector at a time while the device is inactive but still connected to the power source. It would not drain a cellphone battery, he added.
 Macronix estimates that the flash memory cells could beat the 10,000 cycle limit by lasting for as much as for 100 million cycles but a commercial product is not imminent. Instead, Macronix will present their approach—very high temperature in a very short time— this month at the IEEE International Electron Devices Meeting (IEDM) from December 10 to 12 in San Francisco. This is the forum for presenting breakthroughs in semiconductor and electronic device technology. Lue observed that in coming up with the approach, his team would not be able to lay claim to any new physics principle. “We could have done this ten years ago.” He said it took merely a leap of imagination into a different “regime.” For their upcoming IEEE presentation, they said they propose and demonstrate a novel self-healing flash, where a high temperature (>800°C), and short time annealing are generated by a built-in heater. “We discover that a BE-SONOS charge-trapping NAND Flash device can be quickly annealed within a few milliseconds,” they said. Their presentation is titled “Radically Extending the Cycling Endurance of Flash Memory (to > 100M Cycles) by Using Built-in Thermal Annealing to Self-heal the Stress-Induced Damage.” The authors are H.-T. Lue, P.-Y. Du, C.-P. Chen, W.-C. Chen, C.-C. Hsieh, Y.-H. Hsiao, Y.-H. Shih, and C.-Y. Lu.

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The Link Between Fast Food and Depression Has Been Confirmed

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According to a recent study headed by scientists from the University of Las Palmas de Gran Canaria and the University of Granada, eating commercial baked goods (fairy cakes, croissants, doughnuts, etc.) and fast food (hamburgers, hotdogs and pizza) is linked to depression.

Published in the Public Health Nutrition journal, the results reveal that consumers of fast food, compared to those who eat little or none, are 51% more likely to develop depression.

Furthermore, a dose-response relationship was observed. In other words this means that “the more fast food you consume, the greater the risk of depression,” explains Almudena Sánchez-Villegas, lead author of the study, to SINC.

The study demonstrates that those participants who eat the most fast food and commercial baked goods are more likely to be single, less active and have poor dietary habits, which include eating less fruit, nuts, fish, vegetables and olive oil. Smoking and working more than 45 hours per week are other prevalent characteristics of this group.

A long-term study

With regard to the consumption of commercial baked goods, the results are equally conclusive. “Even eating small quantities is linked to a significantly higher chance of developing depression,” as the university researcher from the Canary Islands points out.

The study sample belonged to the SUN Project (University of Navarra Diet and Lifestyle Tracking Program). It consisted of 8,964 participants that had never been diagnosed with depression or taken antidepressants. They were assessed for an average of six months, and 493 were diagnosed with depression or started to take antidepressants.

This new data supports the results of the SUN project in 2011, which were published in the PLoS One journal. The project recorded 657 new cases of depression out of the 12,059 people analysed over more than six months. A 42% increase in the risk associated with fast food was found, which is lower than that found in the current study.

Sánchez-Villegas concludes that “although more studies are necessary, the intake of this type of food should be controlled because of its implications on both health (obesity, cardiovascular diseases) and mental well-being.”

The impact of diet on mental health

Depression affects 121 million people worldwide. This figure makes it one of the main global causes of disability-adjusted life year. Further still, in countries with low and medium income it is the leading cause.

However, little is known about the role that diet plays in developing depressive disorders. Previous studies suggest that certain nutrients have a preventative role. These include group B vitamins, omega-3 fatty acids and olive oil. Furthermore, a healthy diet such as that enjoyed in the Mediterranean has been linked to a lower risk of developing depression.

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Nasa Examines ‘Tractor Beams’ for Sample Gathering

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US space agency Nasa has funded a study of “tractor beams” to gather samples for analysis in future missions.

The $100,000 (£63,000) award will be used to examine three laser-based approaches to do what has until now been the stuff of science fiction.

Several tractor-beam ideas have been published in the scientific literature but none has yet been put to use.

Nasa scientist Paul Stysley says the approach could “enhance science goals and reduce mission risk”.

“Though a mainstay in science fiction, and Star Trek in particular, laser-based trapping isn’t fanciful or beyond current technological know-how,” said Dr Stysley of Nasa’s Goddard Space Flight Center, whose group was awarded the research funding.

High-beam profile

The team has identified three possible options to capture and gather up sample material either in future orbiting spacecraft or on planetary rovers.

The approach could be put to use in space and on planetary surfaces One is an adaptation of a well-known effect called “optical tweezers” in which objects can be trapped in the focus of one or two laser beams. However, this version of the approach would require an atmosphere in which to operate.

The other two methods rely on specially shaped laser beams – instead of a beam whose intensity peaks at its centre and tails off gradually, the team is investigating two alternatives: solenoid beams and Bessel beams.

The intensity peaks within a solenoid beam are found in a spiral around the line of the beam itself, while a Bessel beam’s intensity rises and falls in peaks and troughs at higher distances from the beam’s line.

Solenoid beams have already proven their “tractor beam” abilities in laboratory tests published in the journal Optics Express, but the pulling power of Bessel beams, presented on the preprint server Arxiv in February, remains to be proved experimentally.

In all three cases, explained Dr Stysley, the effect is a small one – but it could in some instances outperform existing methods of sample gathering.

“[Current] techniques have proven to be largely successful, but they are limited by high costs and limited range and sample rate,” he said.

“An optical-trapping system, on the other hand, could grab desired molecules from the upper atmosphere on an orbiting spacecraft or trap them from the ground or lower atmosphere from a lander.

“In other words, they could continuously and remotely capture particles over a longer period of time, which would enhance science goals and reduce mission risk.”

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