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The results also show the minimum exposure time that can be used with different powder types and layer thicknesses .
 concept or principle: exposure; material: be; material: powder; process parameter: layer thicknesses
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: exposure, be, powder, layer thicknesses 
Answer:
 concept or principle: exposure; material: be; material: powder; process parameter: layer thicknesses