Scenario di nuvole incandescente visto dal Monte Paektu o Changbai Mountain in Yanbian coreano prefettura autonoma, a nord-est della Cina di provincia di Jilin
Scenery of glowing clouds seen from the Paektu Mountain or Changbai Mountain in Yanbian Korean Autonomous Prefecture, northeast China's Jilin province, 25 December 2018. The Shanghai Metro will soon be using an imaging device for passenger security checks. The device, based on passive terahertz imaging technology, can detect dangerous materials hidden under people's clothing. Passengers only need to walk through a curved walkway to be checked, and if suspicious objects are detected, the device informs security staff. The first devices are being installed at Huaihai Road M. and the Natural History Museum stations on Line 13. Bowei Thaherz Information Technology Co, the company that makes the devices, said they emit no radiation at all. Terahertz waves, with wavelengths between microwaves and infrared, are produced by the human body and can pass through thin fabrics and plastics. When objects block the waves, their shapes and positions are indicated.