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Twenty years ago, Ferenc Krausz, Theodor Hänsch, and their collaborators used a femtosecond near-infrared (NIR) laser to compel neon atoms to emit pulses of extreme ultraviolet (XUV) light that lasted a few hundred attoseconds. The landmark feat depended on the laser’s strong oscillating electric field, which tore away the atoms’ valence electrons and hurled them back half a cycle later. Now Tobias Heldt of the Max Planck Institute for Nuclear Physics in Germany and his collaborators have developed a new experimental technique that is, in a sense, a mirror image of the 2003 demonstration: they used attosecond XUV pulses to free the valence electrons and to then track their response to femtosecond NIR laser pulses [1].

When a few-cycle femtosecond NIR pulse passes through helium gas, the atoms’ dipole moments fluctuate as the electrons move away and then recollide. Those fluctuations in turn are manifest in the gas’s absorption spectrum. Heldt and his collaborators set out to measure the fluctuations and, from them, infer the electrons’ trajectories.

The attosecond XUV pulse in their experiment did double duty. It ionized the helium atoms to bring the electrons under the influence of the NIR pulse. It also interfered with the fluctuating dipole moments. As a result, the XUV pulse carried away the dipoles’ spectral imprint, which the team measured with a grating spectrometer.

This is according to a press release by the institutions published on Thursday.

“We’ve come up with an unprecedented principle. Yes, the wood transistor is slow and bulky, but it does work, and has huge development potential,” said Isak Engquist, senior associate professor at the Laboratory for Organic Electronics at Linköping University.

This isn’t the first time scientists have attempted to produce wooden transistors but previous trials resulted in versions that could regulate ion transport only. Making matters worse was the fact that when the ions ran out, the transistor stopped functioning.

Scientists demonstrate a low-power “wake-up” receiver one-tenth the size of other devices.

Kentoh/iStock.

This is according to a press release by the University of Chicago published last week.

As a ‘smart knee’ that transmits data rolls out, medical specialists and engineers predict sensors will be added to artificial hips, shoulders and spinal implants.

The team developed a cyclical process in which the device is rinsed with water, dried in relatively low heat, and printed on again.

In the electronics industry, placing several layers of components on top of each other to develop complex devices is no easy task. And with printed electronics, the task is more complicated.

“If you’re making a peanut butter and jelly sandwich, one layer on either slice of bread is easy,” Aaron Franklin, the Addy Professor of Electrical and Computer Engineering at Duke, said in a statement. “But if you put the jelly down first and then try to spread peanut butter on top of it, forget it, the jelly won’t stay put and will intermix with the peanut butter.

Continue reading “Researchers print fully recyclable electronics that replace toxic chemicals with water” »

Summary: Researchers found a way to assess consciousness without external stimulation, using a little-used approach where volunteers squeeze a force sensor with their hand when they breathe in and release it when they breathe out, resulting in more precise and sensitive measurements that may help improve treatment for insomnia and coma reversal.

Source: picower institute for learning and memory.

Studies of consciousness often run into a common conundrum of science—it’s hard to measure a system without the measurement affecting the system. Researchers assessing consciousness, for instance as volunteers receive anesthesia, typically use spoken commands to see if subjects can still respond, but that sound might keep them awake longer or wake them up sooner than normal.

To take a picture, the best digital cameras on the market open their shutter for around around one four thousandths of a second.

To snapshot atomic activity, you’d need a shutter that clicks a lot faster.

Now scientists have come up with a way of achieving a shutter speed that’s a mere trillionth of a second, or 250 million times faster than those digital cameras. That makes it capable of capturing something very important in materials science: dynamic disorder.