Convert from rotl, rotel, rottle, ratel [Arab] to liang [China]

Unit Definition (rotl, rotel, rottle, ratel [Arab])
The rotl, rotel, rottle, ratel is a traditional Arab unit of weight corresponding to the Roman libra, the French livre, and the English pound. There was considerable variation in the unit from time to time and from place to place, but usually the rotl was about 0.9-1.15 pound (450-530 grams). However, in some areas of the Near East, such as Syria and Palestine, larger rotls of 5.5 to 6 pounds (2.5-2.8 kilograms) were used. This unit has many spellings in European languages.

Unit Definition (liang [China])
The liang is a traditional Chinese weight unit. During the European colonial period the liang was equal to 1/16 catty, 1/12 pound, or about 37.8 grams; this made it the same as a tael. In modern China, the liang equals 1/10 jin or 10 qian; this is exactly 50 grams (1.7637 ounces).