425
At the same time , topology optimization techniques have been developed to enable the internal architecture of porous metals to be designed to achieve specified mechanical properties at will .
 engineering feature: topology optimization; machanical property: internal architecture; material: porous metals; material: be; concept or principle: mechanical properties
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: topology optimization; machanical property: internal architecture; material: porous metals; material: be; concept or principle: mechanical properties