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American, Chinese scientists make world's fastest man-made rotor WASHINGTON, July 20 (Xinhua) -- American and Chinese researchers have created the fastest man-made rotor in the world, spinning at more than 60 billion revolutions per minute or over 100,000 times faster than a high-speed dental drill. They described in a study published on Friday in the journal Physical Review Letters a tiny dumbbell from silica they synthesized. They levitated the dumbbell in high vacuum using a laser. The laser can work in a straight line or in a circle: when it's linear, the dumbbell vibrates, and when it's circular, the dumbbell spins. A spinning dumbbell can function as a rotor, and a vibrating dumbbell can function like an instrument for measuring tiny forces and torques, known as a torsion balance, according to the study. "This study has many applications, including material science," said Li Tongcang, an assistant professor of physics a

Perovskite-silicon solar cell combination helps researchers achieve high efficiency in photovoltaic power generation Scientists developed a tandem cell pairing two materials to convert sunlight into electricity. Their technique could help increase the amount of energy generated at a reasonable cost. © CHEOPS Photovoltaic systems, which harvest sustainable and clean energy from the sun, continue expanding faster than any other renewable energy source thanks to ever-reducing costs. In that regard, silicon-based solar cells dominate the market due to their high efficiency and stability at low processing costs. But other devices, based on the emerging perovskite technology, have also entered the spotlight. This technology appears especially promising as it may be used to boost the efficiency of silicon cells further. A team of researchers partially supported by the EU-funded CHEOPS project have combined silicon and perovskite-based cells in a ‘tandem’ formation to deliver mor