Science & Technology
The DNA tests were done on remains from one of the laborers' tombs surrounding the mausoleum of Qinshihuang, in northwestern Shaanxi Province.
The mausoleum was built more than 2,200 years ago.
When the tomb and its seven coffins were uncovered in February, researchers expected to find a royal mummy, given the site was metres from Tut's tomb. Dozens of Egyptian pharoahs and their relatives were laid to rest at the site.
The researchers at the University of Alberta in Edmonton filed patents earlier this month in the United States for the tool based on low-intensity pulsed ultrasound technology after testing it on a dozen dental patients in Canada.
Eric Walton, senior research scientist in Ohio State's ElectroScience Laboratory, said that with further development the technology could even be used for medical imaging. He explained why using random noise makes the radar system invisible.
"Almost all radio receivers in the world are designed to eliminate random noise so that they can clearly receive the signal they're looking for," Walton said. "Radio receivers could search for this radar signal and they wouldn't find it. It also won't interfere with TV, radio or other communication signals."
The device has a simpler design than existing state-of-the-art combustors and could be manufactured and maintained at a much lower cost, making it more affordable in everything from jet engines and power plants to home water heaters.
The tombs, covering an area of 500,000 square meters (1,000 meters long and 500 meters wide), were found after water erosion exposed part of a mountain, revealing two of the tombs.
"People just do not look at the moon anymore," said Dr. Robert Suggs, Space Environment team lead in the Natural Environments Branch of the Marshall Center's Engineering Directorate. "We tend to think of it as a known quantity. But there is knowledge still to be gained here."
Objects are visible simply because light scatters off their surfaces and into your eyes. So in theory, a cloaking device could work by steering light around an object so that you see only the light from behind it, and not the object itself. Now John Pendry, a theoretical physicist at Imperial College London, and his colleagues have worked out how this could be done with a spherical cloak that channels light around an object hidden at its centre (see Diagram).
The stuff that makes this plausible is a new generation of "metamaterials", which can be tailored to have exotic electrical and magnetic properties not found in nature. The metamaterials developed so far consist of complex arrays of metal washer-like shapes and wires. The metal shapes are smaller than the wavelength of light and so interact with it, explains Pendry. "On these scales, it is not the chemical properties of the metal that determine how it interacts with light, it's the metal's structure."
The new idea is to build a sphere of metamaterial whose components are arranged in such a way that they bend radiation around the central cavity before sending it on its way, like a ring road diverting traffic around a town.





