Ilia Malinin of the United States is the only figure skater to land a quadruple axel in competition. We break down why it’s so hard.

For at least a decade, the quadruple axel jump was figure skating’s white whale. “It’s been this unreachable thing, like the four-minute mile” once was, says Matthew Lind, a technical specialist for U ...

Distributed Integrated Energy Microgrid, as a key infrastructure for the low-carbon transition of regional energy systems, faces critical challenges in achieving optimal operation—primarily due to ...