9044
NMR spectroscopy confirmed the identity of the chemical composition among the patterns and showed that the crosslink density variation observed via spatially resolved T2-profiles stems from the difference of the build parameters .
 NMR, chemical composition, density, build parameters
Please list all entity words in the text that fit the category. Output format is "word1, 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:
 NMR, chemical composition, density, build parameters