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From 2016 , with the progress in AM technology and wider understanding of the fact that complex designs can be realized in real AM products , biomimetic approaches began to be the subject of research in more than 150 papers per year .
 manufacturing process: AM technology; engineering feature: designs; material: be; manufacturing process: AM; concept or principle: biomimetic; material: be; concept or principle: research
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:
 manufacturing process: AM technology; engineering feature: designs; material: be; manufacturing process: AM; concept or principle: biomimetic; material: be; concept or principle: research