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Using well-known materials and manufacturing processes, researchers have built an effective, passive, ultrathin laser isolator that opens new research avenues in photonics.
Category: materials – Page 127
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In 2015, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) developed the first on-chip metamaterial with a refractive index of zero, meaning that the phase of light could be stretched infinitely long. The metamaterial represented a new method to manipulate light and was an important step forward for integrated photonic circuits, which use light rather than electrons to perform a wide variety of functions.
Now, SEAS researchers have pushed that technology further â developing a zero-index waveguide compatible with current silicon photonic technologies. In doing so, the team observed a physical phenomenon that is usually unobservableâa standing wave of light.
The research is published in ACS Photonics. The Harvard Office of Technology Development has filed a patent application and is exploring commercialization opportunities.
An adaptable new device can transform into all the key electric components needed for artificial-intelligence hardware, for potential use in robotics and autonomous systems, a new study finds.
Brain-inspired or âneuromorphicâ computer hardware aims to mimic the human brainâs exceptional ability to adaptively learn from experience and rapidly process information in an extraordinarily energy-efficient manner. These features of the brain are due in large part to its plastic nature âits ability to evolve its structure and function over time through activity such as neuron formation or âneurogenesis.â
âWe hypothesized if we could mimic these neurogenesis behaviors in electrical hardware, we could make machines that learn throughout their life-spans,â says study senior author Shriram Ramanathan, an electrical engineer and materials scientist at Purdue University, in West Lafayette, Ind.
A team in Korea has used sound waves to connect tiny droplets of liquid metals inside a polymer casing. The novel technique is a way to make tough, highly conductive circuits that can be flexed and stretched to five times their original size.
Making stretchable electronics for skin-based sensors and implantable medical devices requires materials that can conduct electricity like metals but deform like rubber. Conventional metals donât cut it for this use. To make elastic conductors, researchers have looked at conductive polymers and composites of metals and polymers. But these materials lose their conductivity after being stretched and released a few times.
Liquid metals, alloys that stay liquid at room temperature, are a more promising option. Gallium-based liquid metals, typically alloys of gallium and indium, have caught the most attention because of their low toxicity and high electrical and heat conductivity. They are also tough because of an oxide skin that forms on their surface, and they stick well to various substrates.
The team replicated different patterns of materials and found arrangements that would let water through more easily.
Artificial intelligence (AI) has been found to be useful in the creation of water filter materials and can quicken the process involved in making them, according to a study published today (Nov .30) in the journal ACS Central Science.
Creating a novel water purification system
From daily household faucet attachments to room-sized industrial systems, filter systems are used in a variety of items. However, it is difficult for current filtration membranes to filter water if the water is extremely dirty or has small, neutral molecules, such as boric acid, an insecticide used on crop plants.
Researchers at RMIT University have found an innovative way to rapidly remove hazardous microplastics from water using magnets.
Lead researcher Professor Nicky Eshtiaghi said existing methods could take days to remove microplastics from water, while their cheap and sustainable invention achieves better results in just one hour.
The team says they have developed adsorbents, in the form of a powder, that remove microplastics 1,000 times smaller than those currently detectable by existing wastewater treatment plants.
Further studies of the meteorite are in peril, though.
A meteorite that fell in Somalia in 2020 is home to at least two minerals that are not found on our planet. The two minerals were identified by researchers at the University of Alberta, a press release said.
Large meteorites are rare but do occur, such as the one that fell near the town of El Ali in Somalia a couple of years ago. The celestial piece of rock weighs a massive 16.
University of Alberta.
A crystalâs shape is determined by its inherent chemistry, a characteristic that ultimately determines its final form from the most basic of details. But sometimes the lack of symmetry in a crystal makes the surface energies of its facets unknowable, confounding any theoretical prediction of its shape.
Theorists at Rice University say theyâve found a way around this conundrum by assigning arbitrary latent energies to its surfaces or, in the case of two-dimensional materials, its edges.
Yes, it seems like cheating, but in the same way a magician finds a select card in a deck by narrowing the possibilities, a little algebraic sleight-of-hand goes a long way to solve the problem of predicting a crystalâs shape.
UCLA researchers and their colleagues have discovered a new physics principle governing how heat transfers through materials, and the finding contradicts the conventional wisdom that heat always moves faster as pressure increases.
Up until now, the common belief has held true in recorded observations and scientific experiments involving different materials such as gases, liquids and solids.
The researchers detailed their discovery in a study published last week by Nature. They have found that boron arsenide, which has already been viewed as a highly promising material for heat management and advanced electronics, also has a unique property. After reaching an extremely high pressure that is hundreds of times greater than the pressure found at the bottom of the ocean, boron arsenideâs thermal conductivity actually begins to decrease.
As well as admiring beautiful pictures of space, you can also listen to those pictures via sonifications. These take images and translate them into eerie sounds to illustrate the wonderful and strange phenomena of our universe. NASAâs latest sonification illustrates the rings of X-rays that have been observed echoing around a black hole in the V404 Cygni system.
The sonification was made using data from NASAâs Chandra X-ray Observatory and Neil Gehrels Swift Observatory, both of which look in the X-ray wavelength. The data from the optical wavelength come from the Pan-STARRS telescope in Hawaii. Taken together, you can see how the X-ray bursts propagate outward from a central point which is the black hole. The black hole itself remains invisible, as it absorbs all light.
However, even though black holes are themselves invisible, the material around them can glow brightly. As material like dust and gas is attracted to the black hole due to gravity, it joins into a swirling disk around the black hole called an accretion disk. This material rubs together and creates heat due to friction, and can become so hot that it glows.