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Some of them such as high permeability and good stiffness are competing with each other since a larger pore size is obtained usually at the cost of a lower mechanical strength .
 material: as; machanical property: permeability; machanical property: stiffness; process parameter: pore size; machanical property: mechanical strength
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:
 material: as; machanical property: permeability; machanical property: stiffness; process parameter: pore size; machanical property: mechanical strength