Machine learning finds new metamaterial designs for energy harvesting

Electrical engineers have harnessed the power of machine learning to design dielectric (non-metal) metamaterials that absorb and emit specific frequencies of terahertz radiation. The technique drops the time needed to simulate possible configurations from more than 2,000 years to 23 hours, which should facilitate the design of sustainable types of thermal energy harvesters and lighting.

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Mosquito eye inspires artificial compound lens

Anyone who's tried to swat a pesky mosquito knows how quickly the insects can evade a hand or fly swatter. The pests' compound eyes, which provide a wide field of view, are largely responsible for these lightning-fast actions. Now, researchers have developed compound lenses inspired by the mosquito eye that could someday find applications in autonomous vehicles, robots or medical devices.

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Bottom-up synthesis of crystalline 2D polymers

Scientists have succeeded in synthesizing sheet-like 2D polymers by a bottom-up process for the first time. A novel synthetic reaction route was developed for this purpose. The 2D polymers consist of only a few single atomic layers and, due to their very special properties, are a promising material for use in future electronic components.

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Secure printing with water-based invisible ink

Researchers have developed a rewriteable paper coating that can encrypt secret information with relatively low-tech invisible ink — water. A message printed out by a water-jet printer on a manganese-complex-coated paper is invisible to the naked eye, but the message reveals itself under 254 nm UV light. The paper can be ready for another round of printing after erasing the message by heating it with a blow dryer for 15-30 seconds. The method allows reversible secure printing for at least 30 cycles.

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New synthetic polymer degradable under very mild acidic conditions

A new type of degradable synthetic polymer was prepared by Rh-catalyzed three-component polymerization of a bis(diazocarbonyl) compound, bis(1,3-diketone), and tetrahydrofuran. The resulting polymer was highly sensitive to mild acidic conditions and degraded into a combination of well-defined low molecular weight compounds. With this unique degradability, the polymer could be utilized as an environmentally friendly polymeric material.

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Nanocatalyst makes heavy work of formic acid

Researchers have reported a nanocatalyst that is able to produce hydrogen isotope compounds D2 and HD via the heterogeneous dehydrogenation of formic acid in the presence of heavy water. Amine groups on the catalyst support provided a handle for tuning the selectivity of the reaction through their basicity. It is hoped that the reported process, which is appropriate for large-scale production, can be used to improve the accessibility of deuterated materials worldwide.

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