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Despite the many advantages of using this process , there are still several drawbacks such as the need to use a large amount of a material compared to the volume of the microstructure to be built , oxygen inhibition , and difficulty in processing highly viscous photopolymers .
 concept or principle: process; material: as; material: material; concept or principle: volume; concept or principle: microstructure; material: be; material: oxygen; material: photopolymers
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: process, as, material, volume, microstructure, be, oxygen, photopolymers 
Answer:
 concept or principle: process; material: as; material: material; concept or principle: volume; concept or principle: microstructure; material: be; material: oxygen; material: photopolymers