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Properties like macro- and microstructure , mechanical properties like hardness and its course in the layers , high-cycle fatigue resistance in bending and fatigue damage mechanisms were investigated with the emphasis on fatigue crack initiation process evaluated using scanning electron microscopy .
 concept or principle: Properties; concept or principle: microstructure; concept or principle: mechanical properties; machanical property: hardness; machanical property: fatigue; manufacturing process: bending; machanical property: fatigue damage; machanical property: fatigue; concept or principle: process; process characterization: scanning electron microscopy
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 
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Answer:
 concept or principle: Properties; concept or principle: microstructure; concept or principle: mechanical properties; machanical property: hardness; machanical property: fatigue; manufacturing process: bending; machanical property: fatigue damage; machanical property: fatigue; concept or principle: process; process characterization: scanning electron microscopy