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The grain structure mechanism was studied using finite element analysis in order to reveal the growth mechanism of grains under rapid solidification condition .
 concept or principle: grain structure; concept or principle: finite element analysis; concept or principle: mechanism; concept or principle: grains; manufacturing process: rapid solidification
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 concept or principle: grain structure; concept or principle: finite element analysis; concept or principle: mechanism; concept or principle: grains; manufacturing process: rapid solidification