The key points are caloric value of coal, the fusing characteristics of coal ash and the temperature at furnace center.

其要点是煤的热值，煤灰的熔融特性以及炉膛的中心温度。

youdao

Chang Mai straddles one of Asia's great crossroads - a southern spur of the Silk Road - fusing commerce and culture between points farther north and west in modern-day China, Laos and Myanmar.

BBC: Shopping in Chiang Mai