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Blog – Page 3919

As devices get smaller and more powerful, the risk of them overheating and burning out increases substantially. Despite advancements in cooling solutions, the interface between an electronic chip and its cooling system has remained a barrier for thermal transport due to the materials’ intrinsic roughness.

Material after graphene coating. (Image: CMU)

Sheng Shen, a professor of mechanical engineering Opens in new window, has fabricated a flexible, powerful, and highly-reliable material to efficiently fill the gap (ACS Nano, “3D Graphene-Nanowire “Sandwich” Thermal Interface with Ultralow Resistance and Stiffness”).

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A new study led by DAI Qing’s team from the National Center for Nanoscience and Technology (NCNST) of the Chinese Academy of Sciences (CAS) and Javier Abajo from the Institute of Photonic Sciences (ICFO) in Spain has shown a gate-tunable nanoscale negative refraction of polaritons in the mid-infrared range through a van der Waals heterostructure of graphene and molybdenum trioxide. The atomically thick heterostructures weaken scattering losses at the interface while enabling an actively tunable transition of normal to negative refraction through electrical gating.

The work was published in Science (“Gate-tunable negative refraction of mid-infrared polaritons”).

Basic principle of the “polariton transistor”. The van der Waals heterostructure is constructed by decorating graphene on the molybdenum trioxide, and the antenna stimulates the polariton to transmit through the interface to form negative refraction. (Image: DAI Qing et al.)

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Quantum dots are semiconductor particles measuring just a few nanometres across, which are now widely studied for their intriguing electrical and optical properties.

Through new research published in EPJ B (“Third-order nonlinear susceptibility in CdS/Cdx1Zn 1-x1 S/ZnS multilayer spherical quantum dot,”), Kobra Hasanirokh at Azarbaijan Shahid Madani University in Iran, together with Luay Hashem Abbud at Al-Mustaqbal University College, Iraq, show how quantum dots containing spherical defects can significantly enhance their nonlinear optical properties.

By fine-tuning these defects, researchers could tightly control the frequency and brightness of the light emitted by quantum dots.

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An international team led by researchers from Nanyang Technological University, Singapore (NTU Singapore) has developed a universal connector to assemble stretchable devices simply and quickly, in a ‘Lego-like’ manner.

Stretchable devices including soft robots and wearable healthcare devices are assembled using several different modules with different material characteristics — some soft, some rigid, and some encapsulated.

However, the commercial pastes (glue), currently used to connect the modules often either fail to transmit mechanical and electrical signals reliably when deformed or break easily.

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A team led by Professor Andrea Morello has just demonstrated the operation of a new type of quantum bit, called ‘flip-flop’ qubit, which combines the exquisite quantum properties of single atoms, with easy controllability using electric signals, just as those used in ordinary computer chips.

“Sometimes new qubits, or new modes of operations, are discovered by lucky accident. But this one was completely by design,” says Prof. Morello. “Our group has had excellent qubits for a decade, but we wanted something that could be controlled electrically, for maximum ease of operation. So we had to invent something completely new.”

Prof. Morello’s group was the first in the world to demonstrate that using the spin of an electron as well as the nuclear spin of a single phosphorus atom in silicon could be used as ‘qubits’ – units of information that are used to make quantum computing calculations. He explains that while both qubits perform exceptionally well on their own, they require oscillating magnetic fields for their operation.

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A new all-dry polymerization technique uses reactive vapors to create thin films with enhanced properties, such as mechanical strength, kinetics and morphology. The synthesis process is gentler on the environment than traditional high-temperature or solution-based manufacturing and could lead to improved polymer coatings for microelectronics, advanced batteries and therapeutics.

“This scalable technique of initiated chemical vapor deposition polymerization allows us to make new materials, without redesigning or revamping the whole chemistry. We just simply add an ‘active’ solvent,” said Rong Yang, assistant professor in the Smith School of Chemical and Biomolecular Engineering in Cornell Engineering. “It’s a little bit like a Lego. You team up with a new connecting piece. There’s a ton you can build now that you couldn’t do before.”

This micrograph image shows an initiated chemical vapor deposition coating made by doctoral student Pengyu Chen in the lab of Rong Yang, assistant professor in the Smith School of Chemical and Biomolecular Engineering in Cornell Engineering. (Image: Cornell University)

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University of Chicago scientists have discovered a new wrinkle in our understanding of how our genes work. The team, led by Chuan He, the UChicago John T. Wilson Distinguished Service Professor of Chemistry, Biochemistry and Molecular Biology, shed light on a longstanding puzzle involved in a common way our genes are modified that is known as RNA methylation.

Published Jan. 27 in Science, the finding could have implications for for disease, as well as our picture of gene expression, development, and evolution.

For more than a decade, Chuan He’s laboratory has been focused on trying to unravel the puzzle of a phenomenon called RNA methylation, which we are increasingly understanding plays a key role in our bodies and lives—everything from cancer to PTSD to aging.

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Source of Dark Energy is black holes combined with Einstein’s gravity — experts Result potentially means nothing new has to be added to our picture of Universe It makes up most of the universe, yet hardly anything is known about the so-called Dark Energy that envelopes us. The unusual ‘something’ – one of the great mysteries of cosmology – is believed to be an unknown force that is pushing things apart more strongly than gravity and causing the universe’s expansion to accelerate.

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