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Category: materials – Page 191

A perfect trap for light

It doesn’t involve magic but mirrors and lenses.

Energy can be trapped in the form of electric charge and heat, but until now, it has been impossible to absorb it in the form of light using traditional methods. Now a team of researchers from the Hebrew University of Jerusalem and Vienna University of Technology (TU Wien) claims to have developed the perfect setup to trap light, according to a press release published by EurekAlert.

Although this isn’t the first time scientists have come up with a way to absorb light energy, it is probably the only “light trap” method using which light energy can be absorbed even by very thin and weak mediums.

Whether in photosynthesis or in a photovoltaic system: if you want to use light efficiently, you have to absorb it as completely as possible. However, this is difficult if the absorption is to take place in a thin layer of material that normally lets a large part of the light pass through.

Now, research teams from TU Wien and from The Hebrew University of Jerusalem have found a surprising trick that allows a beam of light to be completely absorbed even in the thinnest of layers: They built a “light trap” around the thin layer using mirrors and lenses, in which the light beam is steered in a circle and then superimposed on itself – exactly in such a way that the beam of light blocks itself and can no longer leave the system. Thus, the light has no choice but to be absorbed by the thin layer – there is no other way out. This absorption-amplification method, which has now been presented in the scientific journal Science, is the result of a fruitful collaboration between the two teams: the approach was suggested by Prof. Ori Katz from The Hebrew University of Jerusalem and conceptualized with Prof. Stefan Rotter from TU Wien; the experiment was carried out in by the lab team in Jerusalem and the theoretical calculations came from the team in Vienna.

Thin layers are transparent to light

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Huge breakthroughs, tiny changes: the next decade of artificial intelligence

Recent developments like DALLE-2 and LaMDA are impressive and seem ready for impact. Is AI ready to change the world?

Whether you love, fear, or have mixed feelings about the future of artificial intelligence, the cultural fixation on the subject over the past decade has made it feel like the technology’s meteoric impact is just around the corner. The problem is that it is always just around the corner, yet never seems to arrive. Many hype-filled years have passed us by since the releases of Ex Machina (2014) and Westworld (2016), but it feels like we are still waiting on AI’s big splash. However, a handful of recent developments—specifically, OpenAI’s unveiling of GPT-3 and DALLE-2, and Google’s LaMDA controversy—have unleashed a new wave of excitement—and terror—around the possibility that AI’s game-changing moment is finally here.

There are several reasons why it feels it has taken a long time for AI projects to bear fruit. One is that pop culture seems almost exclusively focused on the possible endgames of the technology, rather than its broader journey. This isn’t much of a surprise. When we stream the latest sci-fi movie or binge Black Mirror episodes, we want to see killer robots and computer chip brain implants. No one is buying a ticket to see a movie about the slow, incremental rollout of existing technology—not unless it mutates and starts killing within the first 30 minutes. But while AI’s more futuristic forms are naturally the most entertaining, and provide an endless source of material for screenwriters, anyone who based their expectations for AI off of Bladerunner has got to be feeling disappointed by now.

A fireproof wood achieves the highest class in burning test thanks to an invisible coating

It can also solve the carbon intensity problem in the construction industry.

Researchers at the Nanyang Technological University (NTU) in Singapore have invented an invisible coating that can be applied to wood to make it fireproof.

Modern-day buildings are built largely using concrete, steel, and glass, which are at low risk from fires. However, the production of these materials is a carbon-intensive process. Mass-engineered timber is a solution to this problem as wood harvested from sustainably managed forests has a lower carbon footprint than steel and concrete. Additionally, it allows for faster construction at lower costs, making it the ideal component for future constructions.

Researchers discover a material that can learn like the brain

EPFL researchers have discovered that Vanadium Dioxide (VO2), a compound used in electronics, is capable of “remembering” the entire history of previous external stimuli. This is the first material to be identified as possessing this property, although there could be others.

Mohammad Samizadeh Nikoo, a Ph.D. student at EPFL’s Power and Wide-band-gap Electronics Research Laboratory (POWERlab), made a chance discovery during his research on in Vanadium Dioxide (VO2). VO2 has an insulating phase when relaxed at , and undergoes a steep insulator-to-metal transition at 68 °C, where its lattice structure changes. Classically, VO2 exhibits a : “the material reverts back to the insulating state right after removing the excitation” says Samizadeh Nikoo. For his thesis, he set out to discover how long it takes for VO2 to transition from one state to another. But his research led him down a different path: after taking hundreds of measurements, he observed a effect in the material’s structure.

Big Changes In Architectures, Transistors, Materials

Who’s doing what in next-gen chips, and when they expect to do it.

Chipmakers are gearing up for fundamental changes in architectures, materials, and basic structures like transistors and interconnects. The net result will be more process steps, increased complexity for each of those steps, and rising costs across the board.

At the leading-edge, finFETs will run out of steam somewhere after the 3nm (30 angstrom) node. The three foundries still working at those nodes — TSMC, Samsung, and Intel, as well as industry research house imec — are looking to some form of gate-all-around transistors as the next transistor structure in order to gain tighter control over gate leakage.

NASA Seeks Student Ideas for Extracting, Forging Metal on the Moon

2023 annual Breakthrough, Innovative and Game-Changing (BIG) Idea Challenge asks university students to design a metal production pipeline on the Moon — from extracting metal from lunar minerals to creating structures and tools. The ability to extract metal and build needed infrastructure on the Moon advances the Artemis Program goal of a sustained human presence on the lunar surface.

Its strength and resistance to corrosion make metal key to building structures, pipes, cables and more, but the metal materials for infrastructure are heavy, making them very expensive to transport. Student teams participating in the BIG Idea Challenge, a university-level competition sponsored by NASA and managed by the National Institute of Aerospace (NIA), will develop innovative ways to extract and convert metals from minerals found on the Moon, such as ilmenite and anorthite, to enable metal manufacturing on the Moon.

The BIG Idea Challenge, now in its eighth year, invites university students to tackle some of the most critical needs facing space exploration and help create the mission capabilities that could make new discoveries possible. The challenge provides undergraduate and graduate students working with faculty advisors the opportunity to design, develop, and demonstrate their technology in a project-based program over the course of a year and a half. This NASA-funded challenge provides development awards of up to $180,000 to up to eight selected teams to build and demonstrate their concept designs and share the results of their research and testing at the culminating forum in November 2023.

Imaging an Elusive Electronic Transition in Graphene

A special microscope has visualized changes of electron current distribution that clearly indicate a transition from ohmic to viscous electron flow in graphene.

Imagine a breeze of moist air condensing into water drops and dripping down on a cold glass. Electrons can undergo a transition that resembles this gas-to-fluid condensation: the transition is controlled by temperature and produces a fluid-like state in which electrons display remarkably different dynamics than in the gas-like state. Unlike the condensation of water vapor, however, the electron transition cannot be directly imaged with a camera. One reason for this difficulty is that the pattern of this electron fluid varies at submicron scales that can’t be clearly resolved by visible light. Another reason is that electron collisions and the redistribution of electron currents do not yield a change of surface morphology that can be picked up by light reflection. This imaging challenge has so far limited our microscopic understanding of these types of electronic transitions and their use in practical devices.

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