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Besides the city wall, other famous Ming-era structures in the city included the famous Ming Xiaoling Mausoleum and Porcelain Tower, although the latter was destroyed by the Taipings in the 19th century either in order to prevent a hostile faction from using it to observe and shell the city or from superstitious fear of its geomantic properties.
Who decimated the Porcelain Tower?
A: the Taipings

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Evaporation and sublimation into a vacuum is called outgassing. All materials, solid or liquid, have a small vapour pressure, and their outgassing becomes important when the vacuum pressure falls below this vapour pressure. In man-made systems, outgassing has the same effect as a leak and can limit the achievable vacuum. Outgassing products may condense on nearby colder surfaces, which can be troublesome if they obscure optical instruments or react with other materials. This is of great concern to space missions, where an obscured telescope or solar cell can ruin an expensive mission.
What is a solid touching a cold surface called?
A: unanswerable

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The terms piracy and theft are often associated with copyright infringement. The original meaning of piracy is "robbery or illegal violence at sea", but the term has been in use for centuries as a synonym for acts of copyright infringement. Theft, meanwhile, emphasizes the potential commercial harm of infringement to copyright holders. However, copyright is a type of intellectual property, an area of law distinct from that which covers robbery or theft, offenses related only to tangible property. Not all copyright infringement results in commercial loss, and the U.S. Supreme Court ruled in 1985 that infringement does not easily equate with theft.
What is the difference between robbery and piracy?
A: related only to tangible property

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Among the challenges being faced to improve the efficiency of LED-based white light sources is the development of more efficient phosphors. As of 2010, the most efficient yellow phosphor is still the YAG phosphor, with less than 10% Stoke shift loss. Losses attributable to internal optical losses due to re-absorption in the LED chip and in the LED packaging itself account typically for another 10% to 30% of efficiency loss. Currently, in the area of phosphor LED development, much effort is being spent on optimizing these devices to higher light output and higher operation temperatures. For instance, the efficiency can be raised by adapting better package design or by using a more suitable type of phosphor. Conformal coating process is frequently used to address the issue of varying phosphor thickness.
What is the percentage of stoke shift loss in non-YAG phosphor?
A:
unanswerable