Category Physics

Researcher holds flexible dielectric material. Pull out shows boron nitride nanosheets. Credit: Qing Wang, Penn State

It may be the solution to energy storage & power conversion in electric vehicles and other high temperature applications. “Ceramics are usually the choice for energy storage dielectrics for high temperature applications, but they are heavy, weight is a consideration and they are often also brittle,” said Prof Qing Wang, Penn State. “Polymers have a low working temperature and so you need to add a cooling system, increasing the volume so system efficiency decreases and so does reliability.”

Dielectrics are materials that do not conduct electricity, but when exposed to an electric field, store electricity...

The polarized light reflected from the leaf contains a footprint of the leaf’s biopigments. These biosignatures can be detected with a polarization filter, shown here as a pair of sunglasses. Credit: Illustration: Svetlana Berdyugina

Biopigments of plants, so-called biological photosynthetic pigments, leave behind unique traces in the light they reflect, an international team has discovered. The scientists studied these biosignatures with the help of polarization filters: If biopigments were present as a sign of life on a planet, they would leave behind a detectable polarized signature in the reflected light.

Eg Chlorophyll pigments in plant leaves, absorb blue to red light but reflect a small part of green in the visible spectrum and thus appear green...

A rock fulgurite revealed that lightning strikes alter quartz’s crystal structure on the atomic level.

Researchers once believed only meteorites could do so. At a rock outcropping in southern France, a jagged fracture runs along the granite. The surface in and around the crevice is discolored black, as if wet or covered in algae. But the real explanation for the rock’s unusual features is more dramatic: a powerful bolt of lightning.

Using extremely high-resolution microscopy, Prof Gieré et al found that not only had the lightning melted the rock’s surface, resulting in a distinctive black “glaze,” but had transferred enough pressure to deform a thin layer of quartz crystals beneath the surface, resulting in distinct atomic-level structures called shock lamellae...