GopherCentral.com Powered By PulseTV.com
Gizmorama - February 15, 2017

Good Morning,


Here's a hot news item! Scientists in Japan have developed a new material that contracts when heated. What?! It's the biggest breakthrough since Shrinky Dinks!

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin


P.S. Did you miss an issue? You can read every issue from the Gophercentral library of newsletters on our exhaustive archives page. Thousands of issues, all of your favorite publications in chronological order. You can read AND comment. Just click GopherArchives



*-- New flat lens capable of focusing a continuous bandwidth of colors --*

CAMBRIDGE, Mass. - Scientists have created a flat lens that can focus a continuous bandwidth of colors, from blue to green -- the world's first.

The lens' creators, a group of scientists from Harvard University, are the same researchers who unveiled a flat lens made up of a super thin arrangement of nanopillars. But the breakthrough lens could focus just one color at a time.

The researchers went back into the lab and found a way to correct for chromatic dispersion. Different colors of light feature different wavelengths. They are bent at a variety of angles by a flat lens, so they focus at different distances -- that's chromatic dispersion.

"Traditional lenses for microscopes and cameras -- including those in cell phones and laptops -- require multiple curved lenses to correct chromatic aberrations, which adds weight, thickness and complexity," Federico Capasso, a professor of applied physics at Harvard, said in a news release. "Our new breakthrough flat metalens has built-in chromatic aberrations corrections so that a single lens is required."

Researchers altered the shape, width, distance, and height of the nanopillars, so all types of light, blue through green, would focus at the same distance.

By giving their flat lens more control over chromatic dispersion, scientists have broadened its applications in imaging, spectroscopy and sensing.

"By harnessing chromatic aspects, we can have even more control over the light," said researcher Reza Khorasaninejad. "Here, we demonstrate achromatic flat lenses and also invent a new type of flat lens with reverse chromatic dispersion. We showed that one can break away from the constraints of conventional optics, offering new opportunities only bound by the designer's imagination."

The scientists described their optical breakthrough in the journal Nano Letters.



*-- New material that contracts when heated holds great industrial potential --*

NAGOYA, Japan - Materials scientists in Japan have discovered a new material that contracts when heated, a rarity.

The metal-ceramic composite material is composed of calcium, ruthenium and oxygen atoms. When heated, it shrinks 6.7 percent. It's a new record for negative thermal expansion, or NTE.

In many modern industries -- whether electronics, aeronautics or medical equipment -- devices and the machinery used to build them must maintain precision and predictability while enduring harsh conditions. Temperature changes can diminish these qualities, cause materials to degrade and deform as they contract and expand.

Because most materials expand upon heating, NTE materials can help industrial engineers more precisely manage cycles of contraction and expansion.

By mixing normal materials with NTE materials, engineers can create new composite materials with a thermal expansion value close to zero.

X-ray images suggest the new material is atomically altered by heat, triggering unique changes to its microstructure and resulting in a loss in volume. Scientists discovered voids surrounding the material's unique arrangement of crystal grains.

"The non-uniform changes in the atomic structure seem to deform the microstructure of the material, which means that the voids collapse and the material shrinks," Koshi Takenaka, a material scientist at Nagoya University in Japan, said in a news release. "This is a new way of achieving negative thermal expansion, and it will allow us to develop new materials to compensate for thermal expansion."

Researchers described the new material in the journal Nature Communications.

***

Missed an Issue? Visit the Gizmorama Archives

Top Viewed Issues