3009
The decrease was caused by hydrogen embrittlement , due to the formation of large brittle particles , as demonstrated by scanning electron microscopy .
 concept or principle: hydrogen embrittlement; machanical property: brittle; material: as; process characterization: scanning electron microscopy
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: hydrogen embrittlement, brittle, as, scanning electron microscopy 
Answer:
 concept or principle: hydrogen embrittlement; machanical property: brittle; material: as; process characterization: scanning electron microscopy