"Scientists from British Antarctic Survey (BAS) have discovered previously unknown volcanoes in the ocean waters around the remote South Sandwich Islands. Using ship-borne sea-floor mapping technology during research cruises onboard the RRS James Clark Ross, the scientists found 12 volcanoes beneath the sea surface — some up to 3km high. They found 5km diameter craters left by collapsing volcanoes and 7 active volcanoes visible above the sea as a chain of islands."
More http://www.antarctica.ac.uk/press/press_releases/press_release.php?id=1541
Sunday 17 July 2011
Thursday 14 July 2011
An acoustic superlens from a few cans of cola
""Acoustic metamaterial" may sound exotic, but researchers in France have managed to assemble one from a few multipacks of cola cans. Arranged in a grid, the drinks cans act as a superlens for sound, focusing acoustic waves into much smaller regions than their metre-long wavelengths typically allow. The cans act as resonators, directing the volume of the sound to peak in a space just a few centimetres wide, and this heightened precision could improve acoustic-actuator systems."
How to make a superlens from a few cans of cola - physicsworld.com
Wednesday 13 July 2011
n.13 - due piani carichi
a) Find the magnitude and direction of the electric field everywhere and sketch the lines of the field, in the case that a sheet has positive density (+sigma) and the other an equal but negative density (-sigma).
b) find the magnitude and direction of the electric field everywhere and sketch the lines of the field, in the case that the two sheets have the same densitity with the same positive sign, + sigma.
c) Find the difference of potential V(A)-V(B), between the point A and B placed at a distance d on a line in the plane of the figure at 45° with respect to the charged planes.
Monday 11 July 2011
DNA transistor
"Passivated nanopores withstand extreme voltages.
Solid-state nanopores are a core element of next-generation single molecule tools in the field of nanobiotechnology, most prominently in the area of DNA-sequencing technology. Researchers at the IBM T. J. Watson Research Center have recently introduced a nanopore-based DNA sequencing platform, which they call a DNA transistor. Thin-film electrodes are integrated into the nanopore device for electrically interacting with translocating DNA. They have now shown that TiN electrodes inside a nanopore can be passivated and completely shielded against electrochemical deterioration even when extreme voltages are applied."
Solid-state nanopores are a core element of next-generation single molecule tools in the field of nanobiotechnology, most prominently in the area of DNA-sequencing technology. Researchers at the IBM T. J. Watson Research Center have recently introduced a nanopore-based DNA sequencing platform, which they call a DNA transistor. Thin-film electrodes are integrated into the nanopore device for electrically interacting with translocating DNA. They have now shown that TiN electrodes inside a nanopore can be passivated and completely shielded against electrochemical deterioration even when extreme voltages are applied."
electrochemical impedance spectroscopy
"Functionalized electrochemical impedance spectroscopy device targets personalized medicine.
Rapid, sensitive, accurate, miniaturized and inexpensive biosensors are highly desirable for assisting clinical medical diagnosis. Researchers based at National Chiao Tung University, Taiwan, have developed such a portable bio-sensing platform to detect intermolecular interactions using nanogold-enhanced electrochemical impedance spectroscopy (EIS)."
Rapid, sensitive, accurate, miniaturized and inexpensive biosensors are highly desirable for assisting clinical medical diagnosis. Researchers based at National Chiao Tung University, Taiwan, have developed such a portable bio-sensing platform to detect intermolecular interactions using nanogold-enhanced electrochemical impedance spectroscopy (EIS)."
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