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Laser power , scan speed , layer thickness and sloping angle of a surface were systematically varied to understand their effects on surface roughness .
 process parameter: Laser power; process parameter: scan speed; process parameter: layer thickness; concept or principle: surface; machanical property: surface roughness
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: Laser power, scan speed, layer thickness, surface, surface roughness 
Answer:
 process parameter: Laser power; process parameter: scan speed; process parameter: layer thickness; concept or principle: surface; machanical property: surface roughness