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Despite broad research interest in this field , it has remained challenging to measure warpage in general as well as RS distributions in situ , which has obfuscated the mechanisms of stress formation during the printing process .
 concept or principle: research; concept or principle: warpage; material: as; material: as; concept or principle: distributions; machanical property: stress; manufacturing process: printing process
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: research, warpage, as, as, distributions, stress, printing process 
Answer:
 concept or principle: research; concept or principle: warpage; material: as; material: as; concept or principle: distributions; machanical property: stress; manufacturing process: printing process