490
In addition , we analyzed and discussed the surface integrity of the channels in terms of the microstructure , surface hardness , and residual stress .
 engineering feature: surface integrity; concept or principle: microstructure; concept or principle: surface; machanical property: hardness; machanical property: residual stress
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:
 engineering feature: surface integrity; concept or principle: microstructure; concept or principle: surface; machanical property: hardness; machanical property: residual stress